Last year the BugLady had so many midsummer stories to tell that she wrote one episode about dragonflies, and a second about “other” (because as seasoned BugFans know (well) her camera gravitates to dragons and damsels). She’s got a heap of pictures to share again this year, but she’ll mix and match the groups in a two-part summer feature.
ROSE CHAFER BEETLE – The BugLady saw a single Rose Chafer last year and wrote about it https://uwm.edu/field-station/rose-chafer-beetle/. This year, she found bunches of them – orgies of them (she’s not sure what the collective noun for Rose Chafers is, but she’s pretty sure it’s “orgy”). And she was enthralled by the leggy designs they made on the undersides of milkweed leaves.
American CopperBronze Copper
COPPER BUTTERFLY – A highlight of the BugLady’s recent explorations of Kohler-Andrae State Park was finding two species of Copper butterflies – American Copper and Bronze Copper (she rarely finds Coppers). The Coppers are in the Gossamer-wing butterfly family Lycaenidae, along with the Harvesters, Hairstreaks, Elfins, and Blues. Their caterpillars feed on plants in the rose and buckwheat families (dock, sorrel, and knotweed).
VIOLET/VARIABLE DANCER – The BugLady was talking to a friend recently about the colors that dragonflies and damselflies come in. Black, black and yellow, green, blue – even red. But purple?
FLY ON PITCHER PLANT – This is just the way it’s supposed to work. Insects with a “sweet tooth” get lured to the lip of the pitcher plant and partake of the (slightly narcotic) nectar there. Judgment impaired, they mosey around a little, maybe venturing onto the zone of down-pointing teeth below the lip, and then onto the slick, waxy zone below that. It’s all downhill from there.
GOLDENROD CRAB SPIDER on yarrow (not all Goldenrod crab spiders have red racing stripes). Incoming insects have trouble seeing her, too. Out of all the species of crab spiders in the world (about 3,000), only a very few have the ability to change colors, and that ability is limited to the female of the species. Her color palette includes white, yellow, and pale green. She sees the background color with her eyes, and because a wardrobe change takes her between three days and three weeks she tends to stay on her chosen flower. Her base color is white, and switching involves either creating yellow pigment or reabsorbing and then sequestering or excreting it.
Why? Good question. Scientists have tested spiders on matching and non-matching flowers (which they often sit on), and they saw no boost in hunting success when the spiders matched their background (she likes prey that’s bigger than she is, like bumblebees, because she has eggs to make. She loses weight on a diet of small flies). When spiders themselves are the prey, they are not picked off more often on non-matching flowers. Maybe the color change gives her some sort of advantage when she forms her egg case, or maybe it’s a vestigial solution to a long-ago problem.
ORANGE-LEGGED DRONE FLY – This Syrphid/Flower/Hover fly is so serious about its bumble bee disguise that it makes a loud buzz when it’s flying
SEDGE SPRITE TUSSLE – the BugLady was in a bog not long ago when she saw two damselflies tussling on some leaves. At first, she thought there was some predation going on, but that didn’t make sense because they were both Sedge Sprites. He had grabbed her and was wrestling with her, and she was having none of it. He suddenly flipped her around and clasped the back of her head with the tip of his abdomen (SOP for mating dragonflies and damselflies). Rather than reaching forward and taking his sperm packet, she ultimately gave a couple of good shakes and dislodged him. One small drama.
PHANTOM CRANE FLY – Flies come in all sizes and shapes, but this magical creature in white spats is the BugLady’s favorite. It lives in dappled, brushy wetland edges where it flickers through the vegetation like a tiny wraith.
FORKTAIL AND POWDERED DANCER – Eastern Forktails are voracious hunters that go after other damselflies, even those close to their size. The mature female forktail (in blue) found a teneral (young) Powdered Dancer (in tan) that was probably not a strong flyer yet.
We’ll bring the sweep nets, bug boxes, and Insect ID books, if you bring your curiosity and enthusiasm for learning about the 6-legged creatures crawling and buzzzzzing around us!
Family Nature Club is a free offering to our community designed for kids, teens, and their families. We facilitate outdoor, environmental-education based experiences for families to enjoy together.
Meet at Joan M. Pick Nature Preserve in West Bend (address below).
All ages are welcome!
Pre-registration is required by October 10 at 11:59 pm.
This program is free to attend, but donations are greatly appreciated!
In late spring, BugFan Sara sent some “Who-is-this-and-what-is-it-doing??” pictures – small “bumble bees” were excavating the outer surface of a clay bread oven in her back yard (the BugLady gave Sara bonus points for having a clay bread oven in her back yard). While she was mulling her answer, the BugLady found a reference to an Anthophora bee that is sometimes referred to as the Chimney or Turret bee. That looked promising, and her hunch was confirmed by BugFan PJ. Thanks, folks.
Family Apidae is a big umbrella in the bee world that includes Bumble, Cuckoo, Carpenter, Digger, and Honey bees – 1,000 species of them in North America and 5,000 species elsewhere. The star of today’s show is in the tribe Anthophorini, the Digger bees (68 species in our area and 766 worldwide). What they all have in common is a bumble-bee-ish appearance and the habit of most species of making nest tunnels in the soil.
In 1929, entomologist Phil Rau published a paper about Chimney bees in the journal Psyche. The BugLady is interspersing her information with excerpts from Rau’s paper, written back in the days when scientific writing allowed a more lyrical tone.
“They are neither timid nor aggressive, but they certainly are self-reliant…how conspicuous they are as they noisily swing their ponderous bodies to and fro on the wing, arrive home and scramble into their burrows or come tumbling out headlong and dash off into the sunny fields, with all the exuberance of boys just out of school. They have none of the shy, stealthy ways of maneuvering, whereby some of the smaller and daintier varieties of bees and wasps hold their own in a competitive world.”
Chimney bees are generalist foragers that pollinate a wide array of wildflowers, and they’re also important pollinators of agricultural crops like cranberries, asparagus, tomatoes, blackberries, raspberries, and persimmons. Their docility (if you handle one roughly, it’s more likely to bite than sting), home-body ways, and gregarious nesting make them interesting to researchers looking for potential large-scale pollinators. Their long tongues https://bugguide.net/node/view/925446/bgimage allow them to reach the nectar in clover flowers.
Rau recalled watching female Chimney bees licking rust on old fence wire. A colleague speculated that while carnivorous insects glean minerals from the blood of their prey, the nectar-feeding Chimney bees may get minerals from rust.
Chimney bees are on the wing from late spring through late summer. Males emerge almost a week before females, and they attract females by deploying pheromones that are carried in their moustaches! Mating occurs on flowers (she mates once, but he may mate several times). After they mate, the female looks for a spot to excavate a tunnel, often in a clay bank above a stream, usually in the same nest area she emerged from.
Some solitary bees and wasps won’t tolerate the nearby nests of their sisters, but chimney bees prefer company. As Rau wrote, “Since they work in colonies, or more correctly remain to build on the site where they were born, the result is a very conspicuous village, sometimes a very crowded and busy town of these masonry turrets … At a busy season when many of these huge bees are bustling about with very audible hum and zip, the entire village with its many wonderful towers and industrious citizens form a spectacle which is in itself quite capable of overawing any but the most unemotional individual.”
She employs a pretty unique construction method – she brings water or mud to her site and uses it to soften the clay so she can dig. Each mouthful of dampened clay that she removes goes into building a chimney. Rau describes it: “With a portion of the water they would wet the hard, yellow clay, remove a mouthful of it, back out and apply it to the last ring in the chimney. The bees would carry the mud under the thorax with the front pair of legs, while the two hind pairs furnished locomotion; as the bee backed out of the nest to the opening, the ball of mud was passed to the hind legs, and she now held her footing with the front legs while with hind legs she slapped the mud onto the last layer and with many active thumps with the tip of the abdomen, punched and beat it into shape. ‘Punched’ is really the right word correctly to describe the gesture.”
Chimneys may be very short or up to 3” long, and they are oriented randomly. No one knows exactly why she makes the chimney (other than that it’s a convenient way to dispose of the diggings) – researchers have guessed that it protects the tunnel from rain and blowing debris, that it helps with thermoregulation of the nest, that there is social significance for the community, and/or that (as Rau suspected) it helps her find her tunnel among all the others https://bugguide.net/node/view/1592323/bgimage.
Two factors may limit the building of chimneys – drought and a lack of clay in the nesting area. Rau wrote that “A. abrupta made nests either with or without turrets, and the turret-making activities were directly correlated with water conditions. They required water in abundance, and when it was plentiful, so too were the turrets; in droughty years they struggled on with few and small or no turrets, and their nesting activities were much reduced.”
She creates up to seven cells along the length of the tunnel (which is about 4” long), and here’s the magic part. The walls of the tunnel and of each of the egg cells are lined with a waxy substance she makes in a gland called a Dufour’s gland. The liquid made by the gland starts out clear, but it dries to a solid, waxy sheet that keeps moisture out of the tunnel and the cells. She carries pollen and nectar into the cell and mixes them with liquid from the Dufour’s gland, injects an egg into the mix (which one researcher describes as a “soupy mass”) and seals the cell with clay. The tunnel is covered with a clay plug when all the egg cells are provisioned. A large, communal nest may contain 5,000 cells.
Because the females don’t cap their tunnels when they are out looking for water, nectar and pollen, other females may try to take them over. Writes Rau “Not infrequently an animated fight was to be seen between two females, one evidently trying to usurp the burrow that had been made by another, and often dead bees were found at the foot of the bank.”
Frequently, however, the fights appeared quite alarming without proving fatal. One pollen-laden mother was seen backing out of her hole with the front leg of an intruder in her mandibles. The visitor showed no fight, but resisted with all her might; at the foot of the hole, every little gain that the rightful owner made was offset by the intruder pulling her back. At last the intruder lost her hold, and as they went tumbling to the ground they engaged in a pugnacious embrace.
After laying in the “soup” for five days, the egg hatches, and the larva feeds on the provisions and the cell lining. They overwinter as pre-pupae, finish their metamorphosis in spring, and emerge from the tunnel.
And if all that weren’t enough, male Chimney bees climb up grass stems in the evening, grip them with their jaws, and sleep suspended by their mandibles https://bugguide.net/node/view/1801603/bgimage.
The BugLady has been hitting all her favorite wetlands and taking pictures and editing pictures, and it’s July 4th, and she hasn’t quite gotten a crisp, new BOTW ready. Since she has been a slug, writing-wise, she decided to rerun an episode from 2019 about slugs. And besides, she is really tickled by the Scottish poem about slugs.
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.”
The BugLady is getting ready for the annual firefly show (for BugFan Tom in the Deep South, the show’s almost over). She has been seeing day-flying fireflies in the air in the wetlands she visits – for more about day-flying fireflies and about firefly natural history, see https://uwm.edu/field-station/lightning-beetle-again/ (after 5 years, not all of the links work).
Most important question first – are they fireflies or lightning bugs? This is, of course, a question of great scholarly debate, and it was one of the questions on the wonderful, interactive Harvard American dialect survey of a decade ago. Turns out that the “firefly” of the West, Western Upper Great Lakes, and New England is the “lightning bug” of the South and much of the Midwest https://www.rochesterfirst.com/weather/weather-blog/lets-settle-this-are-they-fireflies-or-lightning-bugs/.
Purists, of course, know that these are neither bugs nor flies, and that the term “lightning beetle” is more appropriate. They’re in the family Lampyridae.
Identifying fireflies isn’t quite as much fun as watching them. Not everything with a colorful, shield-shaped thorax is a lightning beetle – there are some species in the closely-related Soldier beetle family (Cantharidae) that do a pretty impressive job of mimicking fireflies https://bugguide.net/node/view/478194/bgpage, https://bugguide.net/node/view/285149, https://bugguide.net/node/view/1068384/bgpage, and every time the BugLady looks through her firefly pictures, she finds a ringer. She recommends Fireflies, Glow-worms and Lightning Bugs by Lynn Frierson Faust. The BugLady tried to ID these to genus – fingers crossed.
Go outside. Look for fireflies (and if you catch them, release them in a timely fashion).
How long have people been enthralled by insects? Probably since they started slapping them and scratching the bites and discovering that they occupied the same caves. For fellow History Geeks, a timeline of entomology – (be sure to click on the picture by van Kessel) https://en.wikipedia.org/wiki/Timeline_of_entomology_%E2%80%93_prior_to_1800.
This week, June 19th to 25th is National Pollinator Week. Bumble bees are the main pollinators of red clover (an important livestock food) because the nectar prize is deep in the floral tubes, and some species of long-tongued bumble bees have tongues long enough to reach it. Here’s a guide to native pollinators: https://www.pollinator.org/pollinator.org/assets/generalFiles/3002022284_Bee-Identification-Guide.pdf.
The BugLady usually closes for the month of June so that she can hit the trails, find newly-minted insects (preferably ones that she hasn’t written about yet), and start building up a stash of pictures for future episodes – by spring, her picture files are dominated by unidentified insects. Also, having hit 700 episodes at the end of March, the BugLady feels the need for a victory lap/vacation. Never fear – there will be something buggy in your mailbox every Tuesday in June.
We’ve spent the last five weeks celebrating American Wetlands Month, but really, every day is Wetlands Day, so here’s an encore episode from 2011 that was in the queue when we ran out of Tuesdays in May. New words; new pictures.
SCUDS
Sit down and put your feet up, it’s a long story.
OK, the BugLady could (and will) regale you with all sorts of arcane facts about scuds (aka amphipods or sideswimmers), but the main “take-home” here is that scuds are a hoot! And they’re pretty cute, too. What impresses people about scuds is their locomotion – they zip around in your collecting basin, pausing under the shelter of vegetation, and then they’re off again. In The New Field Book of Freshwater Life, Elsie B. Klots says that they walk and crawl, “skittering’ on their sides by flexing and extending their entire body, and frequently rolling up on their sides or back.” Anne Haven Morgan, in her Field Book of Ponds and Streams, adds that “Amphipods are accomplished water acrobats and can climb, jump, swim or glide with equal ease.”
Their pedigree: Scuds aren’t insect “bugs”, but they are located under the giant umbrella of the phylum Arthropoda, along with insects, crayfish, scorpions, spiders, sowbugs, centipedes, fairy shrimp, and more. Arthropods (“jointed legs”) are a mighty bunch that includes more than three-quarters of all animal species! Within the arthropods, scuds are in the subphylum Crustacea, class Malacostraca, and the order Amphipoda. That’s a bunch of big names for a small critter, and it doesn’t stop there – common names for this often indistinguishable bunch include freshwater shrimp, scud, sideswimmer, and gammarid (Amphipoda includes a large family, Gammaridae). The taxonomy of these critters is, of course, under review.
Most Amphipods are Marine, but there are about 150 species of freshwater scuds in North America. They are secretive bottom-dwellers, gracing cool, well-oxygenated springs and pools that have some calcium in the water for their shells (one source linked the size of scuds to the availability of oxygen in the water). They prefer waters that are “fish-lite,” and they may grace these waters in huge numbers, up to 10,000 per square meter. Look for scuds in tangled vegetation or under decaying leaves. Through these thickets, they crawl and pull themselves along, using clawed legs and bodily contortions.
Some species of amphipods are highly specialized, living in hot springs, caves, marine estuaries, or in deep, underground springs, and others are able to survive the drying of ephemeral ponds by burrowing into the mud. The presence of some kinds of amphipods testifies to a waterway’s purity, but many species of scuds are tolerant of varying degrees of pollution. They can’t live in poorly-oxygenated waters, and some species have fairly limited temperature “windows.”
The BugLady read of behemoth scuds that grow as large as an inch, but most are barely half of that. Like a flea, a scud’s body is ultra-streamlined – arched and laterally flattened (if you look at them head-on, they’re pretty slim). The front end (cephalothorax) consists of the head and the first segment of the thorax and is home to eyes, antennae, and mouth. That’s followed by seven segments of thorax, with each segment bearing a pair of long climbing/walking legs (the first two pairs end in claws that are used in feeding and mating). Gills are located at the base of the thoracic legs. The last six segments are the abdomen, with six pairs of shorter appendages/legs that aid in locomotion and also push oxygenated water toward the gills (Amphipoda means “both kinds of foot”). Scuds come in a variety of mostly neutral to pastel colors (influenced by their diet) and are often translucent. Telling one genus from another may require a microscope.
So, how does a scud make sense of the world? Scuds are light-averse, preferring starlight to sunlight. Their two pairs of antennae are sensitive to both touch and smell. While many amphipods see through well-developed, functioning, compound eyes, species restricted to caves and underground springs may be eyeless or have only vestigial eyes (but well-developed tactile hairs). Normally-eyed species may evolve into blindness when restricted to permanently dark environs.
And where do little scuds come from? Males and females swim piggy-back for days, preparatory to The Act. If she needs to molt during that period, they separate briefly and then get back together after she has shed. Like water sowbugs, female scuds have a structure called a marsupium on the underside of their thorax. He passes sperm to her, and it mixes with the eggs (1 to 50 of them) in her marsupium. She will carry the eggs around for one to three weeks until they hatch, and then she’ll carry the little tykes for an additional week. If the dissolved oxygen in the water decreases, she may “ventilate” her marsupium by moving her first three pairs of abdominal legs to create a current. The next time she molts, her fully-developed (but microscopic) young are released.
The young scuds shed their exoskeleton eight or nine times on their way to adulthood (the exoskeleton splits across the back between two thoracic segments; the front half of the body is pulled out of the old exoskeleton first, and then the rear half), and adults continue to shed throughout their lives (which, if they’re lucky, may span more than two years).
The BugLady encountered a bit of amphipod ambiguity about whether a female breeds more than once. Pennak, in his venerable Fresh-Water Invertebrates of the United States, states that most species of amphipods breed only once. Other sources say that females can have several broods (up to 10) between April and October, but they must dance the dance each time. According to Morgan, a female that produces 22 eggs every 11 days potentially has 24,221 offspring in a year (but egg mortality is high).
What do they eat? Scuds are listed as detritivores, which means that they eat detritus – fragments of decaying organic stuff (including their own, shed skins) – from the water around them. This “recycling” – breaking down organic materials into ever-smaller pieces for re-use by ever-smaller critters – is an important ecosystem service. They also graze on the thin layer of algae, fungi and bacteria that covers submerged leaves, and although only a few species are predators, scuds may nibble on dying or freshly-dead aquatic critters. They use those first two pairs of clawed feet to hold a morsel while they chew on it. Scuds tend to live in waters too constricted and shallow for fish, but fish can be a major predator. In the Western lakes where scuds were introduced as trout food, they make up almost a half of the trout’s diet.
If you Google “freshwater amphipods,” most of your hits will be photos and scientific articles, but if you Google “freshwater scuds,” you’ll find fishing sites and opportunities to buy scud-like lures. Several of the fishermen’s sites point out that scuds are related to shrimp and propose that although they are small, scuds might taste good in garlic sauce (what wouldn’t??). The presence of the usual compliment of parasites in scuds suggests culinary caution.
About the humble scud, the Pond Informer website says, “Apart from being nutrient recyclers, they collectively serve as a high-quality type of food for secondary consumers. They aren’t just consumed by fish; they are also a favorable prey type for larger crustaceans, wetland birds, amphibians, semi-aquatic reptiles, and riparian mammals. Gammarids are often considered ‘keystone’ species wherever they occur because their presence helps shape and establish working patterns for the existing ecosystem.”
When she posted this episode in 2011, the BugLady said that it wasn’t known how scuds got from one pond to another. She received an email from BugFan Don, who wrote, “Back in the good old days when I still went duck hunting, we would get ducks like bluebills and ring necks that had lots of scuds on their feet and leg feathers. They would still be alive when we got the ducks home. To suggest that these diving ducks carry scuds from pond to lake is not unreasonable.
Duck hunters called them shrimp. I’ve heard stories about seeing retrieving dogs covered with the things. These tend to be stories of the past, though. No one seems to see scuds in such abundance any more.
The minnow sellers in western Minnesota have introduced fathead minnows into a lot of the big shallow lakes that were used by the divers [diving ducks] that fed on the scuds. Bluebills leave Minnesota in worse shape than when they entered. It takes a really severe winter to kill the fatheads so they tend to persist and they decimate the scud populations. The divers responded by moving their migration and resting sites further west, into South Dakota. The minnow merchants prospered, in spite of laws that prohibit moving live fish from pond to pond.”
John Muir was right – everything IS connected!
Fun Fact about Scuds – according to J. Reese Voshell, Jr. in A Guide to Common Freshwater Invertebrates of North America, “scud” comes from a Norwegian word, skudda, which means “to push.” The word was Anglicized as scud “and came to mean to move or run swiftly.”
Another Fun Fact about Scuds – an American scud that somehow made its way to Europe is out-competing the native scuds and is considered invasive.
Rounding out American Wetlands Month, the BugLady would like to give a shout-out to our hard-working, home-grown Wisconsin Wetlands Association. The WWA reminds us that 75% of Wisconsin wetlands are on private lands, and that effective wetland protection involves educating both landowners and policy-makers. To learn about wetlands in Wisconsin, check the Wisconsin Wetlands Association website https://www.wisconsinwetlands.org/ (and they wouldn’t turn down a donation, either).
WATER STRIDER REVISITED (2012)
Anyone who has watched Water striders in action has been wowed by the four-point shadow that marks their path over shallow waters. Photographers chase them, often futilely – a literal flick of the wrist sends the wily Water strider out of focus at speeds of one meter per second. The BugLady first wrote about Water striders in February of 2008 and decided to take a second look. What she discovered changed the episode’s rating from “G” to “PG.”
Water striders are in the True Bug Order Hemiptera, and in the family Gerridae. There’s also a family of half-pint Water striders called the Riffle bugs/Broad-shouldered Water striders, (Veliidae), and in some cases, it takes a microscopic internal examination to distinguish one family from the other. Sources disagree about how many species we are graced with – estimates range from 45 to 85 species of Gerrids in North America and from 750 to 1,400 worldwide. Most are found on quiet or slow-moving fresh waters, but about 10 percent live on salt water.
They have lots of common/regional names – water spiders (they’re insects, but if you count more than six legs, take a nose-count, too; it might be two Water striders in tandem – more about that later), pond skaters, water scooters, magic bugs, water skeeters, and in some parts of the South, “Jesus Bugs” (because they walk on water). Many species are long and thin; some have wings and others are wingless, and some species have both winged and wingless forms, depending on where they live. Most measure half an inch or less, but there’s an eight-inch Vietnamese water strider that’s billed as the largest invertebrate working the water’s surface.
Each pair of legs has a different task. The short, hooked, front pair catches food; the second pair rows the Water strider from one place to another; and the third pair, the longest, may do a bit of rowing, but it usually steers.
How do they DO that? The top layer of water molecules (the surface film) is “stickier” than those below because of its contact with the open air. Water striders skate on the water’s surface film on tiny, non-wet-able hairs at the bottoms of their tarsi (the final leg segments – their feet). According to J. Reese Voshell, Jr. in A Guide to Common Freshwater Invertebrates of North America, retractable claws are located above the bottoms of their feet, so the claws do not puncture the surface film as they skate. Long, thin legs allow them to distribute their weight over a larger surface.
Their legs and bodies, too, are covered by hydrofuge hairpiles (water-repellant hairs), at a density of several thousand hairs per square millimeter! Raindrops and splashes of water roll off without weighing the Water strider down, and if by chance they are submerged, air trapped in the hairs helps them bob to the surface and gives them something to breathe during the trip. Water striders can hop up off of the water’s surface, and many species can fly. When they are working the surface film, they breathe like terrestrial insects, through openings in the sides of the body.
The folks at MIT have, of course, dissected Water strider propulsion. The feet of Water striders create tiny dimples on the water where they sit. When they locomote, their feet push down and back, forming a small indentation off of which they rebound, moving forward as if bouncing on a trampoline (for every action, there is an equal and opposite reaction – life is physics) (while they were at it, the MIT researchers built a Robostrider using an aluminum soft-drink can. Of course.).
What are they doing on the surface film, anyway? A lot of eating. They have, like other true bugs, piercing-sucking mouthparts. Their prey are small terrestrial invertebrates that fall, or mistakenly fly, down onto the surface film and get stuck in it, sending out tiny ripples that mark their throes. Water striders monitor the surface film with their front legs and skate toward the disturbance. They also feed on tiny animals that float up from below, like emerging gnats and midges and mosquitoes. Pierce, slurp, discard, repeat.
Birds prey on Water striders, and so do some other aquatic Hemipterans, but because of a nasty secretion from their scent glands, only the hungriest fish will eat them. If Water strider populations get dense, they may solve the problem with cannibalism. They are sometimes infested by the red nymphs of Water mites.
Water striders practice Simple/Incomplete metamorphosis – they hatch (from eggs laid on plants and stones under the water or near its edge) looking like mini-adults. They shed and grow over a period of about six weeks before reaching maturity, adding a few all-important adult appendages, living in the same habitat as the adults, and eating the same food. The adults of the summer’s final brood overwinter at the bottom of the pond, in plant stems, or out of the water, sheltered along the shoreline in winter.
Males and females defend their own territories during breeding season but abandon territories and congregate cooperatively at other times of the year, even sharing a “kill.”
The BugLady discovered, upon revisiting the Water striders, that they have pretty gritty sex lives. Here’s the “G-rated” version. Water striders, especially males, do a lot of signaling in the form of ripples as they move about; they have ripple signals to communicate “repel” (when they want to be alone), “threat,” and courtship. A male in courting mode may send out a repel signal to a passing Water strider, and if the signal is not returned, he sends out a courtship signal. If she is receptive (female Water striders are the deciders), he may stick with her during the whole breeding period.
And here’s the PG version: According to articles in Discover magazine in 2010 and 2012, reluctant brides of some common Water strider species may be blackmailed by males who skate up and grab hold. If she resists his charms (by deploying a genital shield), he starts tapping rapidly on the water surface. Researchers think this might have started off as a simple demonstration of his fitness, but the behavior evolved into something more sinister. Another predator of animals caught in the surface film is the Backswimmer, who hunts from below, and ripples created by the male Water strider are known to attract Backswimmers to the scene. Scientists postulate that the female, especially if she has encountered Backswimmers before, is aware of the danger (she is, after all, the one whose belly is closest to the Backswimmer – the male is shielded by her body), and she yields to the male in short order, whereupon he stops tapping. They noted that males are aware of the Backswimmer’s presence and actually tap faster when Backswimmers are around.
After the mating process, the male may stay on her back for up to two days, which hampers her hunting prowess.
Evolution is at work again in the strategy developed by a small genus of Water striders. When the male is a nymph, his antennae are only somewhat thickened, but in his final molt, the antennae develop dramatic hooks and spines that match the shape of the female’s head and eyes and allow him to grasp her more firmly (even so, seven out of eight females manage to elude him).
If wetlands are the transitional spongy/submerged/semi-submerged/sometimes-submerged areas between high ground and deep water, what might some wetlands look like? Swamps are wet woodlands, while marshes are wet areas with standing water whose vegetation is mostly non-woody. Peatlands like bogs, which have no sources of water other than precipitation and run-off, so water stalls there and becomes acidic; and fens, which are fed by springs and are often alkaline. And then there are sedge or wet meadows, scrub/shrub thickets, and more (for more info, see https://dnr.wisconsin.gov/topic/Wetlands/types.html) and https://www.wisconsinwetlands.org/learn/about-wetlands/wetland-types/.
Water scorpions have simple/incomplete metamorphosis, looking when they hatch pretty much like they will as adults, adding a few parts (the wings and the “naughty-bits”) as they molt (five times) and mature. As is typical with insects that practice simple metamorphosis, both the adult and the immature water scorpions live in the same habitats – muddy-bottomed ponds and very slow streams with submerged vegetation – and both dine from the same menu. What’s sauce for the goose is sauce for the gander.
They hang out, usually head-down https://bugguide.net/node/view/1682158/bgimage, on aquatic vegetation and in the detritus just off-shore, gripping with their second and third pairs of feet, legs bent. Their passage through the water is sloth-like, and swimming, also using their second and third pairs of legs, is not their forte. In fact, in A Guide to Common Freshwater Invertebrates of North America, author J. Reese Voshell, Jr. says that water scorpions are so sedentary that not only do algae and micro-invertebrates form colonies on them, but other aquatic insects may deposit eggs on them! This immobility is part of their “stealth” hunting tactic.
They’re equipped to fly https://bugguide.net/node/view/126649/bgimage, and fly they do, but not often, and almost always at night (say most – but not all – sources), and they must emerge and spread and dry their wings before take-off. They are known to bask in the sun.
Despite their resemblance to the terrestrial, vegetarian walking sticks https://bugguide.net/node/view/1874213/bgpage, water scorpion are carnivorous, ambushing aquatic invertebrates like daphnia, seed shrimp (ostracods), backswimmers, water boatmen (a favorite), and even tiny fish fry and tadpoles. They spot their prey with protruding compound eyes https://bugguide.net/node/view/1679712/bgimage, “lunge” at it by straightening their legs suddenly (without letting go), nab it with mantis-like front legs, stab it with a short beak (which is capable of piercing human skin, so handle with care), and inject it with tranquilizers and tenderizers.
Two long filaments on their south end are not stingers, but they explain the “scorpion” part of the name. These lock together to form a breathing tube, the tip of which the bugs position just at the air-water interface. Oxygen seeps down the tube and is stored as a bubble under the fore wings, against the abdomen. They can use that bubble of air when they want to go deeper than their “snorkels” will reach (the structure of the filaments doesn’t allow water to enter), and in well-oxygenated water, oxygen suspended in the water can diffuse into the bubble, giving the insect extra breathing time.
According to a website called the Pond Informer, “The mating process for water scorpions typically occurs in the months of April and May. To attract a female mate, a male will perform stridulation. He will create a chirping sound that is produced when he rubs his legs against his body, similar to crickets rubbing their wings together. Once he has attracted a mate, the male water scorpion will lay diagonally across and on top of a female, and he will grab onto her thorax using his front legs. Shortly after mating has occurred, the female will deposit her eggs – she usually does this around dusk.”
Her eggs, which are laid at or above the water’s surface in plant stems, rotting wood, or in damp spots like algae and moss near the water’s edge, have respiratory filaments that protrude from the eggs and allow them to take in oxygen https://bugguide.net/node/view/1861200/bgimage, and some sources say that the eggs can also glean oxygen from the plant stems they are inserted into. She can lay about 30 eggs in one evening. Newly-hatched nymphs make a dash for the water’s surface (there’s no room for breathing tubes in the egg https://bugguide.net/node/view/570259/bgimage).
Water scorpions overwinter as adults, under the ice, equipped with a chemical defense against freezing.
Fun Fact about Water scorpions – an alarmed individual may squeak, and then it may play dead, and it may squeak if it’s scooped out of the water.
Another Fun Fact about Water scorpions – they can sense the depth of the water they’re in by the water pressure.
We’re celebrating American Wetlands Month with up close and personal views into the lives of some of its citizens, as seen in some slightly refurbished, vintage BOTWs.
Wisconsin has about five million acres of wetlands these days, down from an estimated 10 million acres 150 years ago. Early explorers referred to this territory as the Great Swamp, but today, only about 15% of the state is covered by wetlands. Wetlands were considered waste areas that needed to be turned into something “more productive,” and they were drained and filled and altered, and many were used for dumps.
DAPHNIA(2012)
Back into the water we go and into the realm of another NETI – not the pot, the “Not-Exactly-True-Insects.” Daphnia are at the lower limit of what the BugLady can accomplish with her 50mm macro lens (though she does have a recognizable shot of a Cyclops……), and Daphnia, aka water fleas, are yet another example of great stories coming in small packages.
How small? Pretty much at the edge of what the naked eye can easily detect/identify. One source describes them as the size of the “equals” sign on the keyboard. They’re listed as less than 5mm.
The short version – daphnia are oval-ish, shape-shifting, widely-distributed, exhaustively-studied (right down to the pH of their teeny-tiny digestive tracts), unbelievably fecund, highly variable, planktonic, freshwater crustaceans. That sentence bears a little “unpacking.”
Who are they, scientifically speaking? Daphnia are in the Phylum Arthropoda, subphylum Crustacea (like the water sow bug of recent BOTW fame), class Branchiopoda (with fairy shrimp and a few others), order Cladocera, and the family Daphniidae. For our purposes one of the more common daphnia, Daphnia pulex, will serve as Everydaphnia. According to Ann Haven Morgan, in her lovely Field Book of Ponds and Streams, “In 1669 the Dutch naturalist Jan Swammerdam described the common water flea as Pulex aquaticus arborescens – ‘the water flea with the branching arms’ – and ‘water flea’ it has remained ever since.” It was officially described and welcomed into the Linnaean system in 1785.
You can see what? A translucent carapace/shell of its own creation wraps around the daphnia’s thorax and abdomen. The carapace looks like a tiny bivalve/clam-type shell, but it is actually a single, “folded” piece that doesn’t quite meet on the ventral (belly) side, forming two “valves” but with no hinge. Neither the segments nor the first pair of antennae can be seen easily, and the legs are found in the gap between the edges.
Based on an exhaustive study of daphnia anatomy, the BugLady figures that the dark ovals that can be seen on the dorsal side in some of her Daphnia pictures are young in the brood chamber. The front blob on the adult’s head is the eye, and the second blob in the head seems to be part of the intestinal tract. Unlike (almost all) insects, which do not molt after achieving maturity, daphnia molt about 25 times in their lives, and when they are in reproductive mode, they release a brood each time they molt.
How do they navigate their world? Daphnia are found in all sorts of aquatic habitats, including ephemeral ponds but not including fast-moving or polluted waters. Its large, compound eye rotates constantly, sensing changes in light intensity – daphnia don’t like light much, and many species move up and down in the water column from a pond’s surface to its floor several times during a 24 hour period. The mouth, the small, first antennae, and the setae (hairs) on the ventral edge of the shell pick up “smells.” These hairs on the ventral edge of the shell and the sensory hairs on the antennae are their touch “organs.” They breathe through their body surface. “Rowing” movements of the larger pair of antennae also provide the jerking locomotion that earned them the water flea moniker.
Most individuals live only a short time, but some may live about a year, eating organic detritus, bacteria, algae, and some micro-zooplankton and dodging their many predators. A current set up by their legs delivers food into the mouth.
Sex – or not: As soon as the water starts to warm, offspring are produced solo, by Mom (a talent called parthenogenesis). She’s pretty good at it, too, popping out as many as 40 at a time, all female. According to Morgan, “one Daphnia pulex produces a brood of eggs every two or three days [other sources said 10 days] and with its descendants it is said to produce 13,000,000,000 in 60 days.” It only takes the young a few molts to achieve reproductive adulthood, and when they do, they already have eggs in their brood chamber. Daphnia eggs hatch in the brood chamber, and the young stay there for a few days; they are released when Mom molts, at which time she reloads the brood chamber.
While she is cranking out more and more offspring, the water temperature is changing (warming in summer or cooling in fall), the water is getting more crowded, food is declining, and the concentration of waste products is rising. These stressors cause her to produce some male offspring (up to 50%), and orgies ensue. The eggs produced by these sexual unions (which introduce some genetic variation) are called winter eggs. Extra layers are added to the walls of the brood chamber for the winter eggs. The whole “egg container” is called an ephippium, and the egg-filled ephippium is released as a unit that can survive winter cold and drought. If the drought is temporary and the pool refills in fall, the eggs in the ephippium hatch (most of them are female) and the cycle is repeated.
Who cares?? Well, fish care – a lot. Daphnia are bread and rice to many young fish, comprising up to 90% of their early diet! Carnivorous bladderwort plants care, too; Morgan says that one bladder can hold up to three daphnia. Aquatic insects also appreciate them, and wading birds. Aquarists (not Aquarius’s) care – daphnia provide food for aquarium animals.
Scientists care. The translucency of their carapace allows scientists to watch a daphnia’s innards at work. Daphnia are almost universally available, are easy to rear in the lab/school, and look cute under (and can survive under) the cover slip of a slide. You can subject them to alcohol, nicotine, prescription drugs, etc. and watch their reactions, study immunity, disease, cellular function, and more.
Scientists are so enthralled with daphnia that they have worked out the genomic sequence (which wades deeper into scientific waters than the BugLady is comfortable going). Suffice it to say that humans have 20,000 to 25,000 genes and daphnia have 31,907, more than one-third of which are unique to daphnia, and many of which are duplicates! One of the legacies of the late, great entomologist Dr. Tom Eisner is the mantra that knowing the natural history of an organism can help us hypothesize what is/isn’t/should be happening internally. Daphnia are short-lived critters that survive in constantly-changing conditions, and scientists think that the environment may help determine which of the duplicate genes will be expressed.
The rest of us care, too. In his Freshwater Invertebrates of the United States, Pennak says that “the water fleas have been favorite objects of observation by both amateur and professional biologists ever since the invention of the microscope.” The BugLady was charmed to discover that there are daphnia tee-shirts.
And we can barely see them!
Life is Physics. The various creatures of the surface film have developed different ways to navigate the meniscus—Water treaders actually “run” at the meniscus slope and then use their front legs to pull themselves “uphill.” The BugLady recommends this beautifully-photographed article about bugs and https://thales.mit.edu/bush/index.php/2005/04/14/wetting-climbers/ (you don’t have to do the math–the folks at MIT already did it for you).
Bugs in culture: “I was stunned by the perfection of the insects.”—Pablo Neruda
