Bug o’the Week – Gray Hairstreak Butterfly

Howdy, BugFans,

 

There are a number of wildflowers that the BugLady stores in her mental “Texas Wildflowers” file because even though they occur elsewhere, she first saw/photographed them in Texas.  So, when she photographed this Gray Hairstreak in New Jersey, she put it in her “Butterflies of the East” file, but it doesn’t really belong there.  Gray Hairstreaks are, in fact, the most widely distributed American hairstreak, and they spill over into Canada, Central America, and the northern edge of South America.

 

That being said, there are plenty of places, especially in the northern half of that huge geography, where they are present but not common, or are present some years and not others.  They’ve been seen in more than half of Wisconsin counties but are rated as “uncommon” at the excellent Wisconsin Butterflies website https://wisconsinbutterflies.org/butterfly).

 

Why “hairstreak?”  These small butterflies in the family Lycaenidae and the subfamily Theclinae have one or two slim (hair-like) tails on the lower “corner” of each hindwing.  Some species also have Technicolor, false eyespots near the base of each tail.

What’s the point?  Many Lepidopterans have spots on the upper surface of their wings, spots that look like big, owl eyes that startle predators as the butterfly/moth flies away.  A hairstreak’s trickery happens when it’s perched, with wings folded.  Its eyespots and antenna-like tails are designed to fool predators into thinking that the butterfly’s head is where its tail is.  Hairstreaks even add a behavioral component – a nectaring hairstreak often moves its hindwings up and down, simulating the movement of twitchy antennae.  A butterfly that loses a chunk of its hindwing can survive (https://bugguide.net/node/view/52241), but a butterfly that loses its head – not so much.

 

Researcher Dr. Andrei Sourakov at the University of Florida suggested that while birds (and maybe lizards) are fooled by this display, it also provides a good defense against jumping spiders – sharp-eyed ambush hunters that ply the flower tops.  Jumping spiders, which usually grab the front end of a butterfly and inject venom into the thorax, attack the hairstreak’s false head and find no torso beneath to inject.

 

Gray Hairstreaks (Strymon melinus) (melinos means “ashen”) are not fussy about where they live – they’re happy in open spaces, parks, road edges, grasslands, gardens, and weedy, disturbed areas, often quite dry; they’re not fussy about food, either (BugFan Tom just passed along the wonderful term “catholic victulators”).  This flexibility in diet and habitat explains their wide distribution.  Adults nectar on a variety of plants with short, tubular flowers, like composites; and the caterpillar food list includes almost 200 species in about 20 plant families, especially peas, clover, cotton, hops, and mallows.  They are what the Butterflies of Massachusetts website (https://www.butterfliesofmassachusetts.net/) calls “Switchers” – butterflies that broadened their palettes when the European settlers brought Old World crops to the New World.  Young larvae feed in/on flower buds and developing fruits; older larvae may feed on leaves, and they have sometimes been a problem for bean and cotton growers (in cotton country, the caterpillars are called “cotton square borers”).

 

These lovely butterflies are small, with wingspreads of around 1 ¼”.  Males and females are similar, but females’ forewings are wider and rounder.  Their upper wings are gray-blue https://bugguide.net/node/view/1091008/bgimage), and they perch with their wings spread more often than other hairstreaks do.  Here’s a glamour shot https://bugguide.net/node/view/948914/bgimage, and a Gray Hairstreak gallery https://www.marylandbiodiversity.com/viewSpecies.php?species=529.

 

Males are territorial and feisty, spending their afternoons perching on vegetation, checking out any intruders, and watching for willing females. The Animal Diversity website says that “Mating pairs are normally spotted at night, and females oviposit during the midafternoon.”  Females lay eggs singly (rather than in clusters) on the flowers, flower buds, young fruits and nearby leaves of a host plant.  The caterpillars are greenish at the start, but older individuals range in color from gray to pink https://bugguide.net/node/view/225961/bgimagehttps://bugguide.net/node/view/1320020/bgimage.  Here’s a nice life cycle series: https://bugguide.net/node/view/1134476.

 

Quick Science-y detour: Gray Hairstreak larvae are myrmecophiles (ant-lovers) – often tended by ants https://bugguide.net/node/view/59955 – an arrangement that is not uncommon in the Lycaenidae.  Ants harvest a sweet liquid from the caterpillar’s dorsal nectary organ (“honey gland”) and in exchange may protect them from predators (one source says that when searching for the well-camouflaged Gray Hairstreak caterpillars, it’s easier to look for the attendant ants instead).  The honey gland is located on the caterpillar’s seventh abdominal segment, and there’s a “tentacle organ” on the eighth segment that emits a chemical that gets the ants all riled up and defensive because it’s similar to an ant alarm pheromone. Larvae of many Lycaenid species also communicate with ants via ant-like sounds (clicks and hums) or by sending vibrations through the substrate; tropical biologist Philip DeVries calls them “singing caterpillars.”  An alternate explanation for this communication and honey sharing is that it deters the ants from preying on the caterpillars.

 

The Gray Hairstreak pupa also makes noise.

 

There are two broods in Wisconsin, starting late April/early May, and four, spanning most of the year, in the south.  Say Douglas and Douglas in Butterflies of the Great Lakes Region (2005), “Individuals from the spring brood are on the average smaller and darker than those from the summer brood.”  Those darker, smaller individuals may absorb heat better during the cool, early months of their flight.  The final generation of the year overwinters in a sheltered spot in the chrysalis stage.

 

But not in Wisconsin (at least historically), because it is unlikely that a Gray Hairstreak chrysalis could survive the polar vortex.  About Iowa, tropical enough to produce three broods each year, Schlicht, Downey, and Nekols (Butterflies of Iowa, 2007) tell us “Given the dearth of collections before mid-June, it seems likely that this species simply cannot overwinter in Iowa”.  So, where does that first generation come from?  Some sources say definitively that the Gray Hairstreak is not migratory.  Period.  Others say that the early individuals we see in the northern part of their range have flown in from the south to establish small colonies, except in the years when they don’t.  Douglas and Douglas again – It is likely that this species is highly vagile – capable of migration throughout its range.”

 

Butterflies of Massachusetts analysis shows that Gray Hairstreaks are appearing earlier in spring today than they were 150 years ago and concludes that climate change will probably not be a problem for it.

 

Meanwhile, we need a much better name for this exquisite butterfly.  “Gray hairstreak,” while literally descriptive, just doesn’t do it justice.

 

 

Kate Redmond, The BugLady

 

Bug o’the Week – Dark Fishing Spider

Salutations, BugFans,

 

The DARK FISHING SPIDER is one BugLady’s favorite spiders (even though it isn’t even a crab spider).  First of all, it’s beautiful.  Second, it’s big, one of the biggest in North America – the leg-span of a large female can approach four inches!  Third, it’s a challenge to sneak up on and photograph.  The Hail Mary shot of the spider that’s snugged up under a wooden railing, in which the BugLady could see the front of her camera but not the back – a selfie of sorts – shows its typical attitude when company calls.

It’s in the Nursery web spider family Pisauridae, and we have visited the family in the form of the elegant Six-spotted fishing spider (https://uwm.edu/field-station/6-spotted-fishing-spider/) and in the form of the nursery web spider Pisaurina mira (https://uwm.edu/field-station/nursery-web-spider/).  Dolomedes is Greek for “wily” or “crafty,” and tenebrosus is from the Latin for “dark/gloomy/absence of light.”

 

They inhabit half of the continent, from the Dakotas to Texas to the Atlantic, and up into southeastern Canada.  Within that range they are often found near water, but they also stray far from it, commonly living on trees in woodlands and sometimes gaining access to basements (they may bite if handled – you might, too – but they aren’t aggressive).  They are mostly nocturnal hunters, sitting quietly on a vertical surface by day.

 

Females, with a body length of up to an inch, are about twice the size of males.  Their bodies range from pale https://bugguide.net/node/view/1367817/bgimage to dark, and from brown https://bugguide.net/node/view/1317001/bgimage to gray https://bugguide.net/node/view/1310830/bgimage (plus the odd, orange juvenile https://bugguide.net/node/view/805420/bgimage), and they have both black and light-colored markings.  Their legs are banded, and their eight eyes are arranged in two curved rows (the BugLady has never met a Dark fishing spider that was quite this cooperative: https://bugguide.net/node/view/1496981/bgimage).

 

With a name like “fishing spider,” it’s not surprising that their list of prey includes tadpoles, small fish, and aquatic insects.  These they find via vibrations produced when the prey traverses the surface film.  The spiders can skate, row, or run across the water (their legs are waxy); they can also dive below the surface to catch their supper, and an alarmed fishing spider may hide below the surface, too, for up to half an hour, breathing air that’s caught in its hairs.  Woodland dwelling fishing spiders feed on invertebrates (even slugs).  Larry Weber, in Spiders of the North Woods, says that they can tackle cricket-sized prey, and the BugLady found a picture of one with a small spring peeper.  They are ambush hunters; they don’t spin a trap webs, and they eat several times their own weight each day.

 

“Nursery web” refers to the female’s habit of preparing a shelter for her egg sac, which can hold 1,000-plus eggs (https://bugguide.net/node/view/24768/bgimage).  She has carried it around since she formed it, and she will conceal it when it’s about time for the eggs to hatch (https://bugguide.net/node/view/1111062/bgimage) so that the spiderlings will have shelter after they emerge.  The similar-looking wolf spiders also carry an egg sac, but they carry theirs at the rear, attached to their spinnerets; nursery web spiders carry their egg case up front, in their jaws (https://bugguide.net/node/view/277075/bgimage), and so cannot feed for the duration.  Egg sacs hatch in mid-summer; partially-grown spiderlings overwinter under loose bark, in rock piles, tree holes, etc. and mature late in the following spring.

 

We have spoken before about a spider Mom’s little habit of boosting the odds of her reproductive success (more young, fitter young) by grabbing a protein meal, in the person of spider Dad, immediately after mating.  And sometimes in the person of an auditioning male, if she doesn’t like the cut of his jib, or has a headache, or gets annoyed, or decides that he would serve her better as a meal than as a mate.  It’s called sexual cannibalism.

 

Researchers discovered that female Dark fishing spiders are so inclined, but his becoming a snack isn’t because he doesn’t absent himself quickly enough, after the fact.  For him, mating is physiologically lethal – he dies spontaneously.  He doesn’t go to waste, though, and his contribution ensures the continuation of his genes.  A female may re-mate, but a male will pay more attention to virgin females (he can tell by the scent of the silk she lays down).  All in all, an interesting take on monogamy.

 

Of course, there’s a video of pair mating, complete with unnecessarily intrusive music, here: https://www.youtube.com/watch?v=PUtWvbi2kTI.  Spoiler alert – tenderhearted BugFans should avert their eyes at 2:40.

 

This behavior/inevitability is not shared by other nursery web spiders or even by other members of the same genus.

 

Late last spring, the BugLady shared the boardwalk at Riveredge’s Ephemeral pond with a half-grown STRIPED FISHING/NURSERY WEB SPIDER (Dolomedes scriptus) (“scriptus” for “written,” a reference to the markings on the back of its abdomen https://bugguide.net/node/view/869686/bgimage).

Like the Dark fishing spider, the Striped fishing spider is found over much of eastern North America, but it is more wedded to wetlands than is its very similar, slightly larger, more common relative.  It’s often seen sitting on floating vegetation, its front legs on the surface film, monitoring for ripples, but here’s one with a damselfly https://bugguide.net/node/view/252108/bgimage, and there are reports of them preying on crayfish!  Say researchers Scott, Dillard, Foltz and Loughman, “The spider had ingested the majority of the crayfish’s abdomen at the time of discovery, and had used silk to anchor the crayfish to the undersurface of the rock where feeding was taking place.”

 

Kate Redmond, The BugLady 

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Supporting Environmental Education through A Community Thrives at Riveredge

Urban Education at Riveredge Nature Center

Children today are spending less time outdoors, despite studies that support benefits to time spent in nature. Milwaukee Public Schools (MPS) students score significantly lower (20.8%) in science than the statewide average (49.7%). Further, urban areas are increasingly losing green space. As a result, access to and comfortability with natural resources may inhibit Milwaukee area students from learning about science in natural environments. Through urban education programs at Riveredge, such as River Connection and the LUMIN partnership, Riveredge provides thousands of students the chance to learn hands-on in nature. You can support students learning about waterways at Riveredge by donating to A Community Thrives. Read below to learn by these programs are so important with quotes from students about their experiences.

LUMIN Partnership

Beginning in 2011, Riveredge partnered with Lutheran Urban Mission Initiative (LUMIN) schools to provide access to field-based environmental education for urban youth enrolled in LUMIN schools. Students travel to Riveredge for on-site programming paired with lessons in their classrooms. Regular collaboration with teachers, administrators, and curriculum specialists informs Riveredge to adapt programming to best meet the needs of the students while providing relevant experiences to support grade level curriculum.

“I learned about the river and how to help nature.”

Following the 2017-18 school year, Riveredge evaluation staff found that LUMIN students that participated in the program are more likely to explore new places and things in nature (27% increase). The LUMIN partnership brings an average of 1,000 pre-school through 8th grade students to Riveredge every year.

The River Connection Program

The River Connection program was established in 1998 to provide socioeconomically disadvantaged children access to environmental educational experiences that would likely be unavailable to them otherwise. The River Connection Program is a collaborative undertaking of two well-respected environmental education organizations within the Greater Milwaukee area: Riveredge Nature Center and The Urban Ecology Center. This collaboration optimizes the opportunity for students to compare and contrast the rural Milwaukee River location of Riveredge Nature Center and the urban Milwaukee River location of the Urban Ecology Center.

The entire experience, including the bus ride is an educational opportunity when taking part in The River Connection Program. Students make observations about the changes they see in the land over the course of the trip to Riveredge. Then, after testing the water here and comparing the results with water tested in Milwaukee, they’re able to hypothesize what uses of the land makes a difference in what is found in the water.

“It was scary but fun.”

It’s natural to fear that which we have little experience. For many children, nature can be an intimidating if they have little or no familiarity with the natural world. The LUMIN partnership brings several classes from Milwaukee to the Milwaukee River and Riveredge’s natural sanctuary to participate in the River Connection program.

“We got out into the country.”

Results from the 2017-18 pre/post survey found that 94% of students said they learned something new about nature, 82% of students said they would like to do the day’s activities again, and 90% of students said they want to do more to help nature. These findings indicate students’ desire to learn about, explore in, and care for the environment. In fact, 75% of students had never visited Riveredge before the River Connection program, and 85% responded either “yes” or “maybe” when asked if they’d come back to Riveredge again. The River Connection program provides impactful environmental education experiences for an average of 700 5th grade students each year.

“I loved the field trip so much!”

By expanding the science curriculum, the River Connection program and LUMIN partnership is fostering greater awareness in both students and teachers of the roles they play in nature. Exposure to both nature centers provides a broad portrait of Wisconsin’s natural landscape, illuminating the rural (Riveredge) and the urban (UEC). This diversity in exposure is critical, in both enhancing the learning experience through comparison and opening new doors to nature that students may not have considered before.

“I learned about the river and how to take care of it.”

This is just a small handful of stories collected from the thousands of students who have been impacted by urban education at Riveredge.

Riveredge subsidizes these programs to offset the costs for schools, but we cannot do it alone. With your help, thousands of kids can continue to get their hands dirty, learn about nature, and discover the interconnectedness of life. Together, we can foster the next generation of nature stewards to care for the bountiful natural resources of southeast Wisconsin.

Click Here to Support Environmental Education Today!

Bug o’the Week – Dung Beetle

Salutations, BugFans,

 

Sometimes, the secret of getting a good picture is “Right time, right place, right toys.”  The BugLady has been longing to do an episode on dung beetles – they’re amazing insects, and they live right here in Wisconsin, but clearly, she has not been in the right place at the right time, kicking over the right clods (first dictionary definition).  Thanks to BugFan Freda for pictures of an international dung beetle, which will stand in for Wisconsin species.

“Dung beetle” refers to beetles whose lives are intertwined with dung, but the term is not exclusively a taxonomic one.  True, most of its practitioners belong to the beetle family Scarabaeidae and the subfamily Scarabaeinae, but the name is also applied loosely to any beetle that makes its living in dung.  In Wisconsin, that includes a member of the Clown beetle family Histeridae and a member of the Water scavenger beetle family Hydrophilidae, who swims in dung, but whose relatives swim in water.

 

Researching the dung beetle is like researching a rock star.  There are True Facts, YouTube videos, Facebook, kids’ pages, and even a graphic novel or two!

 

Because they have Super Powers.

Like many scarabs, dung beetles are drab, stocky, and well-armored, some with a horn or an exaggerated “brow” that’s used in fighting, and with legs adapted for gripping, digging, and pushing.  They use their antennae to catch the scent of excrement.

 

Though they don’t especially like cold weather, dung beetles live in a variety of different habitats (deserts, grasslands, agricultural lands, and woodlands) on all continents but Antarctica.

 

Why are dung beetles dung beetles?  Because, as adults and as larvae, they eat and live, in and around animal droppings.  They prefer the droppings of herbivores and omnivores, which tend to be somewhat under-digested.  Adults eat the liquid portion, not the roughage, and the larvae feed on the solids.  Some species eat carnivore poop, fungi or decomposing fruits.  They don’t drink.

 

They meet and mate around dung.  Dung beetles are divided into three groups, depending on style – dwellers, tunnelers, and rollers.  Dwellers keep it simple – adults don’t excavate the soil or manipulate the dung, they just lay their eggs on top of a manure pile.  The larvae hatch and feed within the maturing manure pile, but the adults move to one that is fresher and wetter.

Tunnelers dig into the soil below a dung pat and make tunnels and egg chambers.  The male hauls bits of dung into the tunnels, and the female arranges them (it stays fresher underground) and lays eggs.  Both parents may stay in the manure with the larvae, and the male uses his headgear to defend his female, food and family from rival males with prolonged, underground pushing contests.  Tunnelers dodge some of the parasites and predators that find “dwellers.”

 

It’s the Rollers that most intrigue us.  An adult male locates a pile of good stuff (not too dry), breaks off some pieces, and compacts them, forming a ball.  This he offers to a female, and if she’s willing, they roll it away to a likely spot, watching as they go for rival beetles that may try to steal it (early naturalists thought that the other beetles were just helping the happy couple).

 

When they find a soft substrate, they bury the brood ball by hollowing out the space below it so it sinks into the ground.  After mating, the male leaves to sow his wild oats elsewhere, and the female makes a few more brood balls and lays a single egg in each, sealing them by smearing them with a paste of saliva, feces, and dung.  In some species, she stays to tend the grubs, which are described as “six legs and a mouth.”  She only lays a handful of eggs in her lifetime, and she works to ensure their survival!

 

Dung balls are also made and buried as food caches.

 

Dung beetles provide a variety of important ecological services (one of which is that without them we’d be knee-deep in, well,……).  They aerate the soil, recycle nutrients, improve water circulation, and disperse seeds, all of which encourages plant growth and improves conditions for grazing animals.  Fewer cow pats means less habitat for dung-loving, cow-biting flies (one cow pat can generate 3,000 flies).  And they break down and prepare the dung for species that will use it after they do.

DUNG BEETLE FUN FACTS

  • Instead of searching for their supper, some smaller species ride around on their suppliers and wait for a deposit to be made.

 

  • On the Great Plains, a wonderful owl called a Burrowing Owl (kind of the meerkat of owl species http://www.birdweb.org/birdweb/bigger_image.aspx?id=3889&type=p) collects the droppings of large grazers and places then around the entrance to its underground home.  Beetles find the dung and do their thing, and the owls have a steady supply of protein morsels.

 

  • A dung beetle may fly 30 miles to find dung, can roll a ball that weighs up to 10 times its weight, and can bury dung that is 250 times heavier than it is in a single night.

 

  • Dung beetles use celestial signals to chart a course from Point A to Point B.  Diurnal species roll their dung balls in a straight line, navigating by the sun (going around obstacles and then correcting).  Nocturnal species use polarized moonlight, and one species even uses the Milky Way to orient.

 

  • In various parts of Asia, dung beetles are used medicinally or are eaten.  In ancient Egyptian beliefs, the forming, transporting, and burying of a dung ball was a metaphor for the daily renewal of the sun.

 

Do dung beetles light your fire?  Find out more about them in this BBC Earth video by the venerable David Attenborough: https://www.youtube.com/watch?v=Zskz-iZcVyY,

 

And in this TED talk: https://www.mensaforkids.org/teach/ted-connections/dance-of-the-dung-beetle/,

 

and in this bulletin about dung beetles in Wisconsin: https://fyi.extension.wisc.edu/wbic/files/2016/08/Dung-Beetle-Ext-fact-sheet-final.pdf,

 

and in this article about the amazing dung beetle-nematode connection (it’s not gross – promise): https://www.theatlantic.com/science/archive/2018/10/dung-beetles-sexually-transmitted-worms/571804/.

 

Kate Redmond, The BugLady 

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Asian Multicolored Ladybug Redux

Greetings, BugFans,

 

The BugLady heard a funny sound while she was reading the other night, the kind of small thunkthunkthunk that made her wonder if there might be a small leak in the roof.  After a little reconnoitering (and, mercifully, dry fingers) she traced the sound to a ladybug that was bouncing off of the inside of the lampshade by her chair.  First (live) Multicolored Asian ladybug of the year.

Please enjoy this rerun of an episode from a few years ago – some new words and new pictures.

 

We didn’t do it,” say the websites of Departments of Natural Resources in a number of states, trying to make it very clear that they are NOT releasing Asian ladybugs in order to feed Wild Turkeys.  In fact, a Kentucky site declares emphatically that the state of Kentucky has never released them, but points a finger at neighbors to their South who have.  (In Wisconsin, the rumor is that the DNR stocks rattlesnakes to control turkeys – also false, on so many levels).

 

Multicolored Asian ladybugs (Harmonia axyridis) need no introduction – they’ve been around for a century (but especially for the last 30 years), and we know them by many names – Southern, Japanese, Harlequin, Halloween, and Pumpkin beetles, plus Aziatisch lieveheersbeestje (Holland), Asiatischer Marienkafer (Germany), and in Britain, jokingly, the Many-named ladybug.  Plus a few words that wouldn’t get past the censors.  The BugLady is intrigued by the genus name, Harmonia (which the beetle shares with a plant) but could find no explanation for it.  There are three Harmonia beetle species on our continent; all are introduced and well-established, and the Multicolored Asian ladybug is the most widely distributed.

The name “ladybug” is, of course, a bit misleading, since these are beetles (Coleoptera), not True bugs (Hemiptera), so “ladybird beetle” is more accurate.  There are close to 500 North American species in the ladybird beetle family (Coccinellidae) (from the Latin “coccinus” (scarlet) which comes from the Greek “kokkos” (berry)), and many of their lifestyles are similar.  See https://uwm.edu/field-station/ladybugs-three/ to find out more about the natural history of ladybugs.

 

There’s some discussion about when and how the Asian ladybug was finally established in North America.  It was brought to California in 1916 to control aphids but died off, was reintroduced there in 1964 and 1965, and it was released in a dozen Southern and Atlantic Seaboard states plus Nova Scotia between 1978 and 1982.  Each time, it did its job for a season or two, but then failed to thrive.  A number of sources cite a release in Louisiana in 1988 as the one that “took,” and the beetle subsequently traveled to almost all corners of the continent under its own steam (apparently, it doesn’t like the far, northern Rockies).  The alternate theory is that the successful colonizers arrived without fanfare in the Ports of New Orleans and Seattle and seeded themselves.  Whatever the truth, the Asian ladybug became common in the Midwest about 20 years ago, in the Northeast 25 years ago, and in the Northwest 30 years ago, and its numbers have grown considerably beyond “abundant.”  The Audubon Society Field Guide to North American Insects and Spiders, published in 1980, does not mention it at all!

On its home turf in the Far East, the Asian Ladybug feeds in forest and orchard trees, eating aphids (50 to 60 per day, say some sources, and up to 5,000 in a lifetime), and a few other small, soft insects, plus insect eggs, and it was deployed against soybean aphids in Japan (both the adults and the larvae are carnivores).  Those same soybean aphids, immigrants from Japan, made their first North American appearance – in Wisconsin, in fact – in 2000.  In the US, the beetle is used to control aphids in orchards (it’s very important to the pecan harvest), on roses and other ornamentals, and on agricultural crops including soybeans, alfalfa, corn, and tobacco, lessening the need for insecticides.  It also has a fondness for native lady beetles, and in fall, the Asian ladybug may be omnivorous.

 

The predators that kept their numbers in check in Asia were left far, far behind, and other than a few parasitic wasps, almost nothing goes after Asian ladybugs here.  Their red/red-and-black colors tell birds and other potential predators to think twice.  What are they advertising?  Along with some other beetles like lightning and soldier beetles, ladybugs ooze hemolymph (the insect equivalent of blood) that contains a bad-smelling, bad tasting chemical from their leg joints in order to discourage predators (it’s called reflex bleeding).  The chemical occurs in higher concentrations in the hemolymph of Asian beetles than it does in native beetles, and the Asian ladybug also manufactures a designer chemical called harmonine, which is antimicrobial.

At 5 mm to 8 mm long (9/32”), the Asian ladybug is a bit larger than its native cousins.  There are at least 16 different color phases (see http://bugguide.net/node/view/397), from red to orange to utterly plain to densely-spotted (one source said that a beetle with lots of spots is more likely to be a female).  They have reddish-brown legs, and most individuals have a black “letter” on the prothorax (the first of the three segments of the thorax) – either an “M” or a “W,” depending whether the beetle is coming or going.  The larva is likened to a tiny, spiny alligator.  In good weather with plentiful food it takes about a month to grow from egg to adult, and there are several generations per summer.  They overwinter as unmated adults – in Asia, they seek out crevices in tall, sunny, light-colored rock faces.

So – granted that this exotic beetle does a really good job of controlling equally exotic aphids on important crops, is there another side of the coin?  Let’s unpack a few sentences from the preceding narrative.

 

It has a fondness for native ladybugs.”  A dramatic decline in populations of native ladybugs has followed the arrival of Asian ladybugs, simply because it’s such a super competitor.  It has no compunctions about cannibalism; it eats a lot of aphids, robbing native beetles of food; diseases that afflict native ladybugs bounce off the Asian ladybug; and it even carries a microbe that kills the competition.  In Minnesota, the populations of three native ladybugs have plummeted.  Citizen Science, anyone? http://www.lostladybug.org/participate.php.

In fall, the ladybug may be omnivorous.”  And it especially likes to feed on sugary, ripening grapes, usually taking advantage of an opening in the fruit made by a bird or wasp.  The beetles get caught up in the harvest and pressed with the grapes, and whole batches of wine and grape juice have been tossed – even recalled from stores – due to the subsequent “ladybug bouquet.”

 

They overwinter as unmated adults.”  A few sites call it a “Home Invasion.”  On warm, sunny days right after the first crisp days of fall, they look for those ancestral crevices in those ancestral light-colored cliffs and find –-the sunny sides of light-colored buildings that are insufficiently sealed, allowing entry.  They just want to be warm and dormant all winter, and then they want to leave in spring.  They don’t breed or chew on the houseplants or carpets or the dog or the dog food or the floor joists – in fact, they (allegedly) don’t feed at all.  The BugLady’s not so sure about the no-eating part because she finds them in the compost bucket and around the sticky rim of the honey jar, but maybe hers just haven’t settled down to the ascetic life yet.

 

Sometimes there are astronomical numbers of the things.  They swarm.  It literally “rains beetles.”  They gather by the thousands in attics and walls.  Ladybugs use a chemical attractant called an aggregation pheromone to summon a crowd, and that pheromone persists, guiding future generations to the spot.  Their hemolymph stains surfaces and their odor persists – one source describes it as the sour smell of rotting leaves (this will get us ready for the Brown marmorated stinkbug, though).

 

Other than the odd nip, they don’t injure humans (Cowboy up, BugFans – their “jaws” are tiny and your skin is tough), though some people are allergic to them.  One sufferer, then the head of the Entomology department at a Kentucky university, reported runny eyes and clogged sinuses after contacting the hemolymph; other people experience asthma or contact dermatitis.

 

Ladybugs are for sale in garden stores and websites (there are elaborate instructions about preparing the garden so that the ladybugs don’t fly away home).  Although some sites don’t say which species they’re supplying, most sell the native Convergent ladybug (Hippodamia convergens) which are captured in the wild in their winter aggregations.

 

DNA studies tell us that Asian ladybugs in America were introduced from Asia, but Asian ladybugs in Africa, South America, and Europe came from eastern North America!  The United Kingdom’s Ladybird Survey laments that “Despite the American experience, the animal was also released into Italy and elsewhere in Europe.”  It’s been spotted in England, and the word is out to monitor native UK species.  Humans are, indeed, slow learners.

 

And, yeah – we did do it.

 

The BugLady

Bug o’the Week – Spotless Antlion – a Tale in Three Parts

Howdy, BugFans,

 

PART ONE – THE BACKGROUND:

As we all know, there’s a huge difference between looking and seeing.  The BugLady has a wooden pier across the top of the dune that protects her from Lake Michigan.  One day, at the end of June, she looked down and had an “Oh, Duh!!!” moment when it finally registered that the little pits in the sand at the top of the dune were the handiwork of a fascinating insect called a doodlebug or antlion.

Eight years ago, she wrote about antlions in the person of the Spotted-winged antlion (mistakenly using the term “nymph” interchangeably with “larva” to describe the immature antlion – please disregard).  Anyway, read the amazing story about how they dig pits and capture supper at https://uwm.edu/field-station/spotted-winged-antlion/, and watch a great video of same at https://www.youtube.com/watch?v=tcGjPItaKEg.

Some antlion highlights:

 

Antlions/doodlebugs are named for their immature stage, and there is no separate name for the adults, which don’t eat ants.  They are in the family Myrmeleontidae, which is in the Order Neuroptera (the “nerve-winged” insects), an order that has some unique members like

lacewings https://bugguide.net/node/view/114661/bgpage,

and mantisflies https://bugguide.net/node/view/1273550/bgpage,

and owlflies https://bugguide.net/node/view/1230894/bgimage, and more, but which no longer includes the dobsonflies (hellgrammites), alderflies, and fishflies (now in order Megaloptera).

 

The “doodle” in “doodlebug” refers to the squiggly trail that is left by a pit-digging larva as it walks around (backwards) looking for a place to excavate.  Doodlebugs are usually found in places that are somewhat sheltered and are soft underfoot, like fine-grained soil, sawdust, tree holes, and, yes, dunes.

Adults look like damselflies, only more fragile; they are weak, crepuscular/nocturnal flyers that come in drab colors and have conspicuous antennae (here are some good pictures https://bugguide.net/node/view/115388)https://bugguide.net/node/view/552173/bgimage).  Their larvae are the stuff of horror films – hairy, short-legged, and pear-shaped, with impressive, toothed mandibles that are not wasted on vegetables https://bugguide.net/node/view/264599/bgimage, and https://bugguide.net/node/view/611552/bgimage.

Adults are short-lived (maybe a month), but the larvae are not.  Eggs are laid in a soft substrate, and when they hatch (in about a month) the larvae start to feed.  Depending on food supply, they will spend between one and three years as larvae, molting three times before they pupate in a silk cocoon.  They’ve been at it for 150 million years.

 

Doodlebug larvae feed on small invertebrates, but not all species dig pits – some ambush their prey above-ground (and those species walk frontwards, not backwards).  In his Guide to Observing Insect Lives, Donald Stokes suggests that we drop an ant into a pit and watch the action.  Several BugFans have confessed to the BugLady that they did this and then felt such remorse about the almost-inevitable Death from Below that they helped the ant to escape.  A doodlebug injects toxic chemicals into its prey with its hollow “fangs,” pre-digesting the tissues and allowing the antlion to imbibe its prey’s liquefied innards. Adults eat pollen, nectar, and/or very small, soft insects; not much is really known about their feeding habits, but they sport impressive bristles on their legs.

Some birds have figured out that there’s something edible at the bottom of an antlion pit, and the BugLady read an account of a wasp that parasitizes doodlebugs by allowing herself to be grabbed, using her heavily armored hind legs to hold open those lethal jaws while she inserts an egg in the doodlebug’s neck, and then escaping, leaving her eventual larva to feed on doodlebug.  And there’s also a bee fly whose larvae parasitize antlion larvae and pupae.

 

PART TWO – THE DELIBERATION:

After the lightbulb finally went on, the BugLady established a Doodlebug Sanctuary and spent some time trying to photograph the pit-makers.  She saw the adult in mid-August, about six weeks after she recognized the pits, and by mid-September, the larvae had stopped refreshing their pits after rainstorms (which could be their normal phenology, but we had lots of rain about then.  We’ll see).

There are only about a half-dozen antlion species in Wisconsin, so coming up with an ID should be easy, right?  One problem she encountered is that one antlion species looks pretty much like the next to the BugLady.  Another is that species’ scientific names keep appearing and then totally disappearing from the literature.

 

She narrowed it down to two possibilities – Myrmeleon immaculatus, widely distributed in Wisconsin and in the US, and the much less common Cryptoleon signatum/Brachynemurus signatus.  Most (but not all) sources say that antlions in the genus Brachynemurus chase their prey rather than making pits, and Myrmeleon immaculatus is listed in a WDNR bulletin as the only pit-builder in the state.  Both are listed for Sheboygan County in a 1972 survey (https://scholar.valpo.edu/cgi/viewcontent.cgi?article=1173&context=tgle), which contains a lovely account of light-trapping Brachynemurus signatus in the sand dunes of the county.  Brachynemurus signatushas an abdomen that is much longer than its wings, but the adult that the BugLady photographed was only minutes old, and so may not have been done expanding or have developed its “finished colors.”

 

PART THREE – SO, IT MUST BE MYRMELEON IMMACULATUS:

The BugLady found a common name for Myrmeleon immaculatus in a reference from 1897 – the Spotless antlion.  Its diet consists mainly of ants, but it will consider anything that it can overpower in its pit, like spiders, flies, mites, small beetles, and caterpillars.  It will also consider cannibalism, especially when pits are densely spaced, and adults that emerge and walk across the sand looking for something vertical to climb must negotiate a minefield of occupied antlion pits on their journey.

 

Doodlebugs decide where to dig based on microclimate (soil texture and temperature are big factors), not on a survey of potential prey availability, and they if they guess wrong, they have to move to a more populated neighborhood.  Larvae that make small pits capture small prey (and ignore large prey that wanders in), and doodlebugs that make larger pits accept a greater diversity of prey sizes.  Hungry larvae dig smaller pits.

 

Eggs are laid in sheltered spots and are camouflaged by sand and debris that stick to them because of the tacky substance Mom coats them with.  The pupal case also seems to be disguised as a sand heap https://bugguide.net/node/view/556979/bgimage.

 

On his bugeric blogspot, Eric Eaton says that you can become a doodle bug whisperer! “Folklore states that if you lean over a doodle bug pit and repeat the phrase ‘doodle bug, doodle bug, come into view’, it will spit sand and move. There is some truth in the legend. Doodle bugs respond to vibrations and the human voice can cause just the right amount of vibration to spring an antlion to action.”

 

Kate Redmond, The BugLady

Bug o’the Week – Gray Field Slug

Salutations, BugFans,

 

The BugLady found this impressive (1 ½” to 2”) slug climbing around on her cottage in early October.  It has been almost 11 years since we last considered slugs (time flies!).  For a quick Slugs 101 review, see https://uwm.edu/field-station/slug/.  Recent BugFans please note that slugs, while not insects, are fair game because BOTW uses the kindergarten definition of “bug,” not the entomological one.  Thanks (as always) to the very versatile BugFan Mike for help with the ID.

One reason that slugs seem so foreign to us is that they lack familiar landmarks like legs, wings, and body segments.  So, what are you looking at when you’re looking at a slug?  They lead with two pairs of retractable, regenerate-able, sensory tentacles.  The top (dorsal) pair, which is used for sight and smell, has eyespots at the tips (slugs can see light and dark and blurry shapes but can’t focus on images), and the lower pair is used for smell, taste and touch and to move food to the mouth.  These four appendages can be aimed in different directions simultaneously, but the lower pair is often pointed downwards in order to pick up cues from the slug’s substrate.  The mouth, complete with rasping “teeth,” is on the underside of the head.

 

A saddle-shaped cover behind the tentacles, called the mantle, protects the slug’s innards; there’s an all-purpose opening on (almost always) the right side of the mantle called the pneumostome (one author calls it a “blowhole”), which has reproductive, excretory, and respiratory functions.  Beyond the mantle is the tail.  The muscular lower surface of a slug is the “foot;” its rhythmic undulation allows the slug to move, and it produces the infamous mucous/slime that keeps its body moist and “greases” its passage.

About that slime.  It’s a multipurpose substance that is both sticky and slippery, that aids in locomotion (some species use it as a bungee cord), that absorbs water, that protects slugs from bacteria and fungi, that leaves a trail for the amorous (and the carnivorous) to follow, and that discourages predators.  The BugLady found a tantalizing note about Hermann Lons, a German poet and malacologist (mollusc specialist) who discovered that slug slime tastes awful “in a particularly remarkable self-inflicted experiment” (about which she could find no further details).  Slug slime is also the strong yet flexible inspiration for researchers trying to develop a next-generation surgical adhesive.

 

Evaporation and slime production constantly rob slugs of their water reserves.  They can tolerate microclimates with a range of humidities as long as they can replenish liquid by eating and by absorbing water through their skin.  In hot, dry summer weather or when food is scarce, they will aestivate under debris or dirt, and they can fast for several months.

 

To place slugs within their proper taxonomic sphere, they are in the very diverse Phylum Mollusca (octopi and squid, scallops and oysters, snails and slugs), in the Class Gastropoda (“belly-foot” – snails and slugs), and in a land slug family named Agriolimacidae.

The GRAY FIELD/GARDEN SLUG (Derocerus reticulatum, aka Agriolimax reticulatum), one of about a dozen slug species in Wisconsin, is a European slug that’s described throughout both its historic and its more-recently-embraced ranges as a “synanthrope” – a species of plant or animal that lives in habitats modified by humans and that benefits from human association.  “Syn” means “with” and “anthropos” means “man,” and the term is applied equally to species we like (Golden retrievers) and species we don’t (Norway rats).  Across the Pond, it’s found in Western Europe and Africa; but it has hitchhiked (oh, so easily) pretty much around the world.  In North America, it’s found across southern Canada and the northern tier of states, plus a smattering of Central, Mid-Atlantic and Pacific Coast States.  It likes gardens, agricultural fields, roadsides, parks, and greenhouses.

 

Slugs are hermaphrodites, which means that they have both male and female reproductive organs – an individual can be the fertilizer or the fertilizee’ (and they can self-fertilize), and all can lay eggs.  In our area, Gray field slugs reproduce in late summer and early fall – Mom-Dad meets Dad-Mom in an elaborate dance that involves slime, a chase, and the waving of the sacrobelum.  Eggs (as many as 700 in all) are laid in small bunches under stones and leaves and in crevices as fall rains soften the soil.  They generally overwinter as eggs, hatch in spring, mature by late summer, and die not long after laying eggs.

 

Gray field slugs, notoriously, feed on the leaves and fruits of a wide range of agricultural and horticultural plantings and tree saplings, damaging leaves by rasping random holes in them.  They are also scavengers that eat dead, soft-bodied invertebrates like worms and other slugs.

 

One of the questions that the BugLady always asks when she’s researching is “What does it eat?” and the next question is “What eats it?”  Members of the ground beetle family Carabidae are important predators of Gray field slugs both here and abroad.  This beauty, a (coincidentally) European ground beetle that is now established here and is a fellow synanthrope, is a slug connoisseur https://bugguide.net/node/view/632699/bgimage (business end https://bugguide.net/node/view/1566065/bgimage).  The Gray field slug, however, can detect the odor of its ground beetle stalkers with those sensory tentacles, and chemicals mimicking ground beetle scents may have a future in crop protection.

 

When a ground beetle or other predator grabs a Gray field slug, the slug waves its tail back and forth and throws out lots of unpleasant, milky-colored slime (normally, its slime is clear).  The final trick in its playbook is to break off the tip of its tail and leave it in the mouth of its attacker as it scoots away.

 

Gray field slugs operate within a home range where they revisit food plants and home sites.  The BugLady’s slug notwithstanding, they tend to be nocturnal, and Wikipedia tells us that they can travel as far as 40 feet in one night.

 

Fun Slug Fact: when a slug ambulates across a copper surface, the copper reacts with chemicals in its slime and gives the slug a little shock.

 

Another Fun Slug Fact: the defensive slime produced by the Australian Red triangle slug is so sticky that it can glue a pursuing frog to a branch.  For days.

 

Final Fun Slug Fact: if you get slug slime on your person, it will be easier to remove if you let it dry and then rub it with a cloth than if you wash it with soap and water.

 

The BugLady looked around for a nice, uplifting literary quote about slugs.  She couldn’t find any.  They’re all allude to slugs’ perceived negative attributes, like this “We have descended into the garden and caught three hundred slugs.  How I love the mixture of the beautiful and the squalid in gardening.  It makes it so lifelike” (Evelyn Underhill); and this, “Bob Dylan impresses me about as much as …well, I was gonna say a slug but I like slugs” (Don Van Vleit); and this, “It seems to me the worst of all the plagues is the slug, the snail without a shell. He is beyond description repulsive, a mass of sooty, shapeless slime, and he devours everything” (Cecelia Thaxter).  Oblivious to the fact that slugs are, yes, perfect (and that possibly they find us repugnant).

 

Slugs in poetry?  The BugLady found this wonderful poem by George T. Watt; it’s dense, but lean into it and read it a few times http://www.scottishpoetrylibrary.org.uk/poem/slugs/ (Note – Ein Heldenleben – “A Hero’s Life,” is a work by Strauss).

 

About slugs, Watt goes on to say that “Slugs haes trevelled awa on its ain journey, ye maun tak it whaur it’ll gang.”

 

Words to live by.

 

Kate Redmond, The BugLady

 

Bug o’the Week – Bugs without Bios XIII

Salutations, BugFans,

 

Another celebration of (regrettably) anonymous bugs.  There are in the neighborhood of 100,000 insect species in North America, but not everyone has a biographer (note to self – it takes a lot longer to research the unsung species than the notorious ones).

HERAEUS PLEBEJUS (no common name): This pretty, little Dirt-Colored Seed Bug was a “life bug” for the BugLady – she knew it was in the “true bug” bunch, Hemiptera (which narrowed it down to 10,200 possibilities in North America) but she eventually stumbled across its identity and looked it up.  When the BugLady’s initial searches for species information draw a blank, she will back up to the insect’s genus and then to its family.  In this case, she struck out at pretty much every level – even the venerable An Introduction to the Study of Insects (Borrer and DeLong) in her home library had no info about Dirt-colored seed bugs.

 

So – it’s in the Dirt-colored Seed Bug family Rhyparochromidae (“rhyparos” means “dirt” and “chromus” means “colored”).  Rhyparochromidae used to be Rhyparochrominae, the largest and most diverse subfamily in the Seed bug family Lygaeidae (the family of the familiar milkweed bug).  Rhyparochrominae was elevated to family status about 30 years ago, and there’s been a lot of taxonomic fiddling ever since.  Most Rhyparochromids feed on seeds that they find on the ground, but some climb up plants for their supper, and there are a few blood-suckers in the crowd.  Some associate with ants, and a bunch of family members (but not today’s star), are able to stridulate (make noise by rubbing one body part against another).  Most have swollen-looking front legs armed with stiff spines that help them get a grip on seeds https://bugguide.net/node/view/742080/bgimage.  Some Rhyparochromids are economically important (in a negative way).

 

Heraeus plebejus is the most widespread of the four Heraeus species in North America; bugguide.net says that it occurs in “e. NA to AZ (QC-FL to IA-TX-AZ), Mex. / W. Indies,” and that it’s often found on sumac leaves.  Many of the seed bugs are pretty picky about what kind of seeds they eat, but the BugLady couldn’t find out anything about this species’ diet.  Insects foraging for seed on the ground probably aren’t choosy.  And that’s it.

ZENODOSUS SANGUINEUS (no common name) is a member of the Checkered beetle family Cleridae, which we have met before https://uwm.edu/field-station/checkered-beetle/.  The Clerids are a group of small, hairy, often-colorful, mostly predaceous beetles, many of whose larvae operate under the cover of tree bark, where they prey on the larvae of a variety of bark and cone-boring insects.  Adults feed on adult beetles that they find on flowers and other vegetation (though there are some outlier pollen feeders and scavengers).  Some species may prove to be effective biological controls of bark beetles.  American Beetles, Volume II tells us that “The higher classification of the Cleridae has undergone considerable categorical oscillations.”

Formerly known as Thanoclerus sanguineus, this little beetle is found from North Dakota to Arizona to North Carolina to Maritime Canada, under bark, in woody tunnels, and in galls and decaying fungi.  It is active but shy, and hides quickly when alarmed.  Adults overwinter under bark.  Other than that, this beetle’s internet presence is mostly on park and natural area biodiversity lists.  Glamour shot: https://bugguide.net/node/view/168452/bgimage.

EUPATORIUM/IRONWEED BORER MOTH (Carmenta bassiformis): Two groups of moths are called Clear-winged moths.  There are a few moths in the Sphinx moth family, including the wonderful Snowberry and Bumblebee clearwings that hover at bergamot and thistle flowers in summer (and lead the BugLady on a merry chase).  The other is the Clear-winged moth family Sesiidae, which we have visited before in the form of the squash borer moth https://uwm.edu/field-station/cornworms-and-hornworms-and-squash-borers/.  Their wings are “clear” due to an absence of scales https://bugguide.net/node/view/432923/bgimage. Many of these odd, little Sesiid moths are more waspy than mothy in appearance; they are bee and wasp mimics, a few even sporting yellow scales where bees would have pollen collecting equipment.  Some are agricultural pests and some are quite spectacular, with fancy anal tufts (in one species, the tuft is said to resemble the long, trailing, third set of legs of a wasp in flight) https://bugguide.net/node/view/484442/bgpagehttps://bugguide.net/node/view/367514/bgpagehttps://bugguide.net/node/view/1010752/bgimagehttps://bugguide.net/node/view/1542393/bgimage.

 

 

There were actually lots of hits when the BugLady Googled Eupatorium Borer Moth, but the sum total of their information was “larvae feed in the roots of Ironweed, and probably also Eupatorium (Joe-Pye-weed).”  Eupatorium moths are found in grasslands and edges east of the Great Plains.  Females advertise by emitting “Come hither” pheromones; they subsequently lay single eggs at the base of Joe-Pye or Ironweed plants, and the larvae bore into the roots and feed.  They overwinter as larvae and tunnel up into the stalks before pupating in spring.  Adults are nectar feeders, and neither stage is considered a pest. For nicer picture than the BugLady’s: https://bugguide.net/node/view/669993/bgimage.

 

Kate Redmond, The BugLady

Bug o’the Week – Azure Bluet

Howdy, BugFans,

 

Even in a group of damselflies that are called bluets, the Azure Bluet is an amazing color!

Bluets are damselflies in the Narrow-winged/Pond Damselfly family Coenagrionidae, which also includes the dancers, forktails and sprites. Most of Wisconsin’s 20 species of bluets are in the genus Enallagma (the American bluets), and except for two species that apparently didn’t get the memo (Orange and Vesper Bluets), males of most species have various amounts of blue and black on their thorax and abdomen (the front end of a Rainbow Bluet is so exciting that you don’t even notice the rear end).  For the sake of identification, bluets are divided visually into three groups.  If the abdomen is mainly blue, they’re in the “blue-type bluet” group; if it’s mostly black, they’re “black-type bluets; and if it’s about fifty-fifty, they’re “intermediate-type bluets.”  Bluets can be tricky to identify, and hand lens examination may be required.

 

Females are another story altogether; they’re greenish or tan far more often than blue, and when they are blue, they are less so than males.

 

 

Azure Bluets (Enallagma aspersum) are small (about 1 ¼”), black-type bluets.  In most bluet species the 8th and 9th segments, at the end of the abdomen, are blue, but the Azure Bluet also has blue on part of the 7thsegment.  Female Azure Bluets don’t have tan or green forms, and they are almost as blue as males, but instead of a solid blue tip, their abdomen has a pair of “spats” on both segments 8 and 9.  Males have large “eyespots” (postocular blue spots) on the back of their heads, and females’ eyespots are smaller.

Bugguide.net tells us that the Azure Bluet has a wide range – “Most of the Eastern United States, also a disjunct population in Montana. In Canada, reported from Ontario, Quebec, New Brunswick, and Nova Scotia.”  Within that range it’s found in a variety of (preferably fish-free) shallow lakes, ponds, swamps, bogs, and wetland edges with a lot of vegetation, but it’s pretty adaptable and will colonize gravel pits and man-made ponds.  Paulson, in Dragonflies and Damselflies of the East, says that it is “a good disperser, and often is one of the first Odonate species to colonize new aquatic habitat.”  It’s not widely distributed in Wisconsin; Bob DuBois, in the excellent Damselflies of the North Woods calls it “local in our region, but may be abundant once found.”  It’s a “Most Wanted” species in Wisconsin.

With a few minor twists and turns, the life history of an Azure Bluet mirrors that of any bluet.  Males hang out along the shore chasing rival males away from good egg-laying spots and waiting for females, which don’t approach the water until they are reproductively ready.  After mating https://bugguide.net/node/view/1259233/bgimage, they fly in tandem, looking for a suitable spot for her to oviposit.  The period between mating and ovipositing can be dicey – rival males are ready to pirate the lady – so the male retains his grip on the back of her head (contact guarding).

 

After mating, a typical female bluet perches on a favorable stem at the surface and backs down the plant stem, inserting eggs into it as she goes (see the accompanying photo of a pair of Marsh Bluets); if she submerges, the male releases her.  Female Azure Bluets take the bull by the horns, find a good piece of vegetation, and march down it headfirst to oviposit near the base of the plant.  She may descend more than a foot below the surface and stay under for 15 or 20 minutes (she turns gray while she’s down there, according to Paulson).  It is theorized that this will allow her eggs to survive the drop in water level caused by a summer drought.  The male waits for her above-decks and reclaims her, but she’s no longer interested.

Like other damselflies, the immatures (naiads) are aquatic.  Here’s a picture of a just-emerged Azure Bluet: https://bugguide.net/node/view/385530/bgimage.  They are carnivores as adults and naiads.

 

An Azure Bluet’s amazing color is all the more amazing because no blue pigment exists in bugs (or vertebrates, either).  Before the advent of eyes (about 600,000,000 years ago) color didn’t matter.  The world was far from black and white – animals get some of their pigments in the foods they eat, so there probably was color in that dark world – but its appearance was unappreciated.  It was only AE (After Eyes) that color mattered.  Which gave rise to one of the BugLady’s favorite quotes: “The eye of the trilobite tells us that the sun shone on the old beach where he lived; for there is nothing in Nature without a purpose, and when so complicated an organ was made to receive the light, there must have been light to enter it.”  (Louis Agassiz, Professor of Zoology, Harvard, 1870). 

For better or worse, color makes its wearer conspicuous, which can be desirable (courtship displays or warning coloration) or undesirable (red sea slug on green kelp – oops!).  Lots of colors come from dietary pigments – flamingoes are pink because of a carotenoids that they get from the tiny crustaceans they eat.  Blue is tough to glean from dietary pigments.  It’s a structural color, formed when light reflects off of tiny structures within the layers of the cuticle, an arrangement that bounces blue light back at the beholder.  The intensity of the blue can vary depending on the amount of light and the angle of the viewer.

To find out more about this arrangement, see http://www.npr.org/sections/health-shots/2014/11/12/347736896/how-animals-hacked-the-rainbow-and-got-stumped-on-blue.  For a deeper, more technical dive, try this one http://what-when-how.com/insects/coloration-insects/.

 

Up until the third week of January, we were having “Winter Lite” here in God’s Country.  Since then we’ve had snow, more snow, a visit from the Polar Vortex, ice, and even more snow.  We haven’t had a long winter, but at the risk of sounding like wimps, we’re ready to start that slow climb toward spring (the BugLady heard a Cardinal singing the other day).  In that spirit, she offers this quote from Canadian broadcaster, reporter, and writer Peter Gzowski: “We need spring. We need it desperately, and, usually, we need it before God is willing to give it to us.”

 

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

 

Bug o’the Week – Speed-dating the Spiders – Variegated Spider

Greetings, BugFans,

 

The BugLady found this striking spider at Riveredge Nature Center one early summer day.  What it lacks in size (it’s less than ½”), it surely makes up for in beauty (thanks for the ID, BugFan Mike).

 

There’s not a lot of information out there about the Variegated spider (Sergiolus capulatus).  Only one source gave it a common name, but most of the other species in its family don’t have common names, either.  It is found across the eastern US from the Atlantic to the Great Plains, usually on the ground, under leaf litter, and in grasslands, open areas, and in sunny spots in deciduous woods.  It favors dry habitats over moist ones.

 

Except for a few genera, its family members tend to be drab, and all of them sport conspicuous twin spinnerets at the end of their abdomen.  Scientists speculate that the Variegated spider’s color pattern mimics that of some species of velvet ants that can be found in the same neighborhoods (a velvet ant picture is included here).  Velvet ants (family Mutillidae) are actually flightless, female wasps whose stingers pack quite a wallop.  Nobody messes with velvet ants.

Like crab spiders and jumping spiders, Variegated spiders do not spin an elaborate trap web; they stalk their prey on foot (more about that in a sec).  Most sources call them nocturnal, but a few disagreed, calling them diurnal (daytime) hunters.  In any case, they spend their “down” time, and cooler days and nights, in a snug, silk-lined retreat.

 

The BugLady started finding good stuff (most of the good stuff is silk-related) when she researched the family rather than the species.  Variegated spiders are in the Ground spider family Gnaphosidae, aka the Flat-bellied or Stealthy ground spiders (one source said that Gnaphosidae is Greek for “living in the dark”).  There are about 2,000 species in the family; just over 300 of those are found in North America, where there are more species in the west than in the east.

 

To back review, spiders are capable of making different kinds of silk for use in different situations, like egg cases and trap webs and balloons and shelters and safety nets and more https://uwm.edu/field-station/the-wonders-of-webs-i-spider-silk/.  Not all spiders have or need all the options, and producing silk is “expensive,” energy-wise.

 

Ground/Gnaphosid spiders often go after prey that is as large as or larger than they are, like ants, and their fellow spiders (araneophagy).  It’s dangerous – a predator can get hurt in a wrestling match, and some prey may be venomous – but ground spiders have developed an impressive strategy for subduing struggling prey.  It’s called a “swathing attack.”

 

A hunting Gnaphosid spider approaches its prey and typically tries to make some tactile contact with it.  That touch allows it to gauge whether or not it will be able to subdue its food without a fight (by wrapping it in a “leg basket”).  If it does need to deploy silk, it targets the prey’s legs and mouth with thick, sticky globs of silk.  In an article in the Journal of Experimental Biology, researchers Wolff, Řezáč, Krejčí, and Gorb called it “hunting with sticky tape” (http://jeb.biologists.org/content/220/12/2250).

 

They point out that food-getting drives many adaptations.  Some animals avoid “risky prey,” but Gnaphosids have developed a modified spinning apparatus that produces an especially gluey silk that that is both stretchy and strong.  It allows them to immobilize prey very effectively, but at a cost.  When foraging spiders like Jumping spiders or Crab spiders launch themselves at their prey, they first attach a bit of web to their substrate; if their lunge takes them over the edge of a leaf, they’ve got an anchor/dragline.  Dragline silk also functions in navigation, communication, trap-web construction, and egg sac suspension.  Gnaphosid spiders aren’t able to make dragline silk, but it doesn’t seem to have bothered them much – Gnaphosidae is the 7th-largest spider family, and its members are especially dominant in dry, open areas.

 

Ground spiders use a different kind of thread to make a sac for their eggs, and females stand guard until the eggs hatch, like the closely-related Clubionid spiders.  They also weave silk into mesh-like shelters that they stay in when they’re not hunting.

 

Here are a couple of neat spider sites: https://www.emporia.edu/ksn/v55-december2007/ and https://fieldguides.fieldmuseum.org/sites/default/files/rapid-color-guides-pdfs/390_1.pdf.

 

Kate Redmond, The BugLady