You don’t have to go far to find adventure! In fact, exploring the natural areas around you is one of the easiest ways to stay healthy, to connect as a family, and to discover incredible new things!
Don’t forget, Riveredge has ten miles of trails that are open every single day from dawn to dusk and are absolutely free to access for members, or a small trail fee for non-members. The opportunities for exploration are endless:
- Hunt for some of the hidden treasures around Riveredge’s ten miles of trails, like the Riveredge Ruins, Labyrinth, the Larsen Climbing Rocks, the Tipi, and more! Check out our trail map for the location of some of these gems.
- Go on a treasure hunt to find our hidden geocaches. Stop by the front desk to find out how you can rent a GPS that has the coordinates of the geocaches around the sanctuary!
- Check out one of our brand new “Take It With You”adventure bags, themed backpacks that can be taken out to the Riveredge sanctuary with you, chock full of tools and ideas for you to explore Riveredge at your own pace. These packs will be coming in the next few weeks!
- Download some apps that will help enhance your visit, like Leafsnap, iBird, and iNaturalist. Check out our new blog post on how Riveredge is working to incorporate technology and the outdoors in a balanced way, and stay tuned for a new set of programs and blogs designed to share how technology can be incorporated into your own family’s nature experiences.
Don’t forget the easiest opportunity for exploration: pick a trail, start walking, and see what amazing natural wonders show themselves to you! Adventure awaits, and it’s calling your name!
It’s a beautiful irony, right? A nature center promotes getting outside, a.k.a. being “unplugged”,” yet also supports digging into your pocket for that smartphone to enhance your experience. While we are certainly a pro-hands on, mud-under-the-fingernails kind of nature center, we also recognize that there is a great opportunity to enlist technology to further learning, make connections, and spark curiosity among today’s digital learners (ah-hem, let’s face it, if you live in the twenty-first century, you are one, too).
So, how do we balance technology and nature as a force for good to inspire the next generation of environmental stewards? Our short answer: Meet ‘em where they’re at.
In today’s world, this means, both, (1) acknowledging how the digital revolution is changing learning and (2) exploring how technology can be used as a tool to strengthen our connection with the natural world.
There is lots happening in the research and education community to explore the first question, but less is known about the role of technology and nature.
(Pictured: Students in the Homeschool Ed-ventures program study plant succession through direct observation while working together to share their understanding using a ComicBook app).
Curiosity as the App
For nearly fifty years, Riveredge has subscribed to an inquiry-based method of learning in which investigation starts with asking good questions. Students from K-Gray explore queries like, how can you tell the health of a river, how is a forest like a prairie or pond, or even how do our actions impact the land. While these are just a small sample of what is studied at Riveredge and in our schools each and every day, no matter the scale, we believe that the most powerful tool for investigation is our mind, and the power of asking good questions is what we as parents, educators, and mentors are tasked with teaching our kids. In other words, we believe that curiosity is the driver of learning and technology (both digital and nondigital) is a tool that can be used to capture, explore, and create new ways to deepen our connection with nature.
Try it out!
So, whether you look to nature as a digital detox or you are looking for new ways to appease your curiosities through technology, we hope you’ll join us in this conversation. Keep an eye out for some of these events starting this summer and into 2018.
- There’s an App for That program series: A spin on traditional nature programs that includes all the fun hands-on experience but leaves you with some resources you can take home as your own “pocket naturalist.”
- Take it with you Packs: Explore Riveredge through a new set of eyes by renting one of our (free) packs that each feature some our favorite themes, scientific tools, and downloadable field friendly apps.
- Parents be on the lookout for a nature tech blog series that features ideas for incorporating technology outside that you and your family can try out in your own backyards and nearby parks this summer.
- We also have some technology and nature-themed special events in the works to highlight how technology and robotics are helping us better manage land and conservation.
Do you have thoughts or ideas about nature and technology? We’d love to hear from you! Please contact Carly Hintz, Educational Technology & Evaluation Specialist at Riveredge. Reach her at email@example.com or 262-375-2715.
Someone asked the BugLady recently if she ever runs into a bug who she doesn’t know. Short answer – all the time, but mostly her guesses are in the right ballpark (order – for sure; family – often). In the case of the Pygmy Backswimmer, she had to switch ballparks a bit (thanks, BugFan Gretchen).
Anyway, the BugLady was out scooping and photographing pond critters recently, and she found this lovely little bug (emphasis on “little”). Because it was moving around with its dorsal side up (in the shallow end of the plastic spoon she uses for photography, at least) and because it lacked a prominent, hairy, oar-like third set of legs, she didn’t take it for a backswimmer (philosophical question – if you spend all your time swimming around with your ventral side up, does it become your dorsal side?). Here’s a picture of a correctly-oriented pygmy backswimmer http://bugguide.net/node/view/113408/bgpage.
First – the pedigree. Pygmy backswimmers are true bugs (order Hemiptera) and are in the suborder Nepomorpha, the aquatic bugs, along with water boatmen, giant water bugs, backswimmers, water scorpions, and more. It’s not in the family Noctonectidae with the more familiar backswimmers (an infant backswimmer that she photographed that day is also pictured here); it’s in the family Pleidae, a family with maybe 40 species worldwide, five of those in North America. A number of different characteristics for separating the various species of Pleidae have been considered, adopted, and then rejected (microscopic structures on minute’ bugs), and bugguide.net notes that “the family is in need of revision.”
They occur globally except for the Poles and some distant oceanic islands, and almost all dally in clear, still, weedy waters. One North American species has extended its range to Guam, traveling tucked away in aquarium plants. Look for them, often in small groups, among the leaves of submerged vegetation. Though they may inhabit ephemeral ponds and can dry out for a while when the pond does, they generally live in permanent waters.
Today’s bug is Neoplea striola, the most common Pleid in eastern North America. It is tiny, hovering around 2mm (less than 1/8th of an inch), oval, with a strongly domed back, big red eyes (all the better to see you with, etc.), and very short antennae that it keeps tucked close to its head. It locomotes with its second and third sets of legs and grabs its prey with the first set.
Neoplea striola keeps body and soul together by preying on tinier aquatic stuff like mini-crustaceans and aquatic invertebrates; they’ve been known to take tiny fish and tadpoles, and they’re not above cannibalism. They eat lots of mosquito larvae, but apparently they leave other mosquito predators alone. They’ll also pick off, from below, springtails and other little stuff on the surface film. They use their eyes to hunt, along with vibrations, and possibly chemical signals. In a study published in Rotifera IX: Proceedings of the IXth International Rotifer Symposium (2000), researchers reported that although pygmy backswimmers are not opposed to eating rotifers, predator size was less important than the predator’s food-getting style and apparati, and that “The construction of Neoplea’s forelegs provides mechanical advantages in capturing relatively large prey, but is not well-suited for capturing and subduing small, mobile prey.” Here’s one feeding on a hydra https://www.nature.ca/rideau/b/_sidebars/pop06_b5-e.html.
Like other carnivorous Hemipterans, they insert their beak into their prey, pump in some meat tenderizer, and then slurp out the softened innards. Despite their size, they are eaten by predatory aquatic insects, ducks, and a few amphibians. Noctonectidae can deliver a memorable jab to the human anatomy, but Pleid beaks are just too small.
Some sources say that they swim well (they can swim with their dorsal side up, but they usually don’t), while others say that their swimming is barely adequate and they use claws on their hind tarsi to crawl among the leaves of aquatic plants. Flight? Not so much. Populations include both micropterous (short-winged) and macropterous individuals, the first, essentially flightless, and the second able to disperse to nearby bodies of water.
Aquatic organisms have developed an array of methods for obtaining oxygen. Some absorb it from the water; others must surface for it. Pygmy backswimmers are in the “diving bell” school – they poke up through the surface film, grab some air, stash it on their body, and then use it under water (this air reservoir is referred to as a physical gill). To this end, the ventral surface of the abdomen is covered by small, water repellant (hydrophobous) hairs, and air is captured and stored in this pelt. This load of air is what makes Pleids see the world belly-side-up http://bugguide.net/node/view/49767 – their bellies are more buoyant than their backs. The air-carrying mechanism is so efficient that their average dive time is 39 minutes, and they can adjust the size of their air load depending on what they’re doing and how warm the water is.
Pleids take good care of this very important interface. A European counterpart, Plea minutissima, crawls out of the water to groom it! It cleans microbes from its undersides using an antiseptic secretion produced by glands in the thorax – glands that in some terrestrial insects are scent/defensive glands. It’s called “secretion grooming,” and the bug leaves the water to do it because the stuff is somewhat water soluble, so it gets more bang for its buck on land. It leans to one side, making a tripod of the three “downhill” legs, and cleans itself with the other three. If it fails to do this, microbes will grow in the pubescence and oxygen capacity will plummet.
Pygmy backswimmers lay their eggs in the stems of water plants using a spurred structure at the end of the abdomen to pierce the stalk. They spend three weeks in the egg and another six to eight weeks becoming adults. When chilling water signals the end of fall, they overwinter as adults in a state of diapause (suspended animation) and can even survive a top-to-bottom freeze of their wetland, using stored oxygen.
Like the Notonectid backswimmers, pygmy backswimmers communicate by stridulation (rubbing two body parts together), and they can hear via a sensory organ on the front of their face. They may signal others in their group by stridulation.
It’s May. Go outside.
Kate Redmond, The BugLady
Bug of the Week archives:
Another celebration of insects that are not good enough nor bad enough nor beautiful enough nor bizarre enough to have fan clubs, or common names, or even much of a biography.
The BugLady thinks that this lovely little micromoth looks a bit skunk-ish. It’s LANDRYIA IMPOSITELLA (no common name, and no explanation of its interesting species name). It’s in the Flower moth/Teardrop moth family Scythrididae, a family with only 43 species in North America. Not a lot is known about the biographies of these small, dark, moths. Their caterpillars, described in one old text as having tufts of hair growing from small warts, tend to be miners or skeletonizers of leaves of plants in the aster, goosefoot, stonecrop, and grass families. Adults are diurnal (day-flying).
Heart-leaved aster is the host of Landryia impositella’s caterpillar. It creates mines/tunnels in the leaves, one caterpillar per leaf, overwinters as a caterpillar and pupates in the next spring. Adults often nectar on yarrow flowers. The BugLady photographed this moth in mid-July.
Landryia impositella has the dubious honor of having the lowest internet profile of any insect the BugLady can recall researching – four pages of hits, some of them faux, and most others annotated checklists.
As seasoned BugFans know, the BugLady is inordinately fond of crab spiders, a.k.a Flower spiders, family Thomisidae, and she thinks these MECAPHESA CRAB SPIDERS are beauts. Crab spiders’ hunting style is described as “sedentary” – rather than build a trap web, they sit still, front pairs of legs poised, and wait for their unwary prey. They are so-named because of their shape and stance and sideways movements.
Spiders in some of the crab spider genera are chunkier-looking, but the more commonly seen flower-top crab spiders, like the goldenrod crab spider, are a bit more svelte (and, of course, male crab spiders have a smaller abdomen and are “leggier” than females). Because there is a lot of variation within species, it can be hard to tell the difference between the various genera unless you look them right in the eyes (for a great visual, see http://bugguide.net/node/view/4999). Mecaphesas tend to look a bit translucent, and they have reddish bands on their legs, and some books say that spiders in the genus Mecaphesa are spinier (thanks, as always, to BugFan Mike for the ID). Some of the spiders listed Misumenops in older books are now in Mecaphesa. There are about 18 species in the genus in North America.
Mecaphesa likes to hang out in fields and grassland edges on flowers and on the tips of branches that are in bud. They are preyed upon by some species of mud dauber wasps, who stun them and stuff them into molded mud brood cells to be food for their young.
ROVE BEETLES (family Staphylinidae) are one of those “wait – that’s a beetle??” groups. Why? Because most beetles have a hard elytra/wing covers over the whole, or almost the whole abdomen. Elytra are actually the front pair of wings, highly modified to protect the soft flying wings underneath. The elytra of many (but not all) species of rove beetles are very short, and the flying wings that they protect must be unfolded when needed and then carefully refolded (like a road map) when not needed, a task that the beetle may use its abdomen and legs to accomplish. The exposed abdomen is somewhat susceptible to drying, so rove beetles favor humid environs, mainly on the ground, under leaves, rocks, and logs. Without full-sized elytra, the remarkably-flexible rove beetle can squeak into some pretty small spaces (without full-sized elytra, they are often mistaken for earwigs). There’s a nice overview of the family in the University of Florida’s excellent “Featured Creatures” series at http://entnemdept.ufl.edu/creatures/misc/beetles/rove_beetles.htm. Rove beetles have graced these pages in the form of the Hairy and the Shore rove beetles.
The rove beetle du jour is in the genus Platydracus and the BugLady thinks it’s either P. zonatus or P. mysticus (she’s leaning toward the latter), beetles of woods and grasslands and the windrows of beaches. Both species feed on other insects as larvae and as adults, and they may be effective biological controls of some “problem” insects. According to one source, Platydracus mysticus may be suffering a population decline since the mid-twentieth century, possibly due to habitat change and competition with non-native rove beetles.
Spring is here – go outside – look at bugs.
Today’s episode celebrates the Carolina Saddlebags, the third saddlebags species to grace these pages; but first, a brief commercial message.
- Birders (and non-birders) are urged to tune in to the Great Wisconsin Birdathon (wibirdathon.org), which will be heating up any minute now. Teams take pledges from donors and then head out for a day of birding in May in order to raise money for bird conservation initiatives in Wisconsin. The number of teams has exploded this year, and the BugLady gets a kick out of some of the team names.
- Fans of the Great Lakes should check out the Walk to Sustain our Great Lakes, in which Julia and Alyssa will, starting in August, take a little stroll from the Milwaukee harbor to Lake Superior. A number of classroom teachers have already signed on to follow their progress/interact with them when school resumes in fall. See http://www.wsogl.com/.
- While you’re at it, read all about the 2017 SEWISC Garlic Mustard Pullathon at https://sewisc.org/.
We now return to our regular programming.
First of all, a little about the saddlebags genus Tramea. It’s in the skimmer family Libellulidae, a genus with seven species known from North America, four of which have been recorded in Wisconsin. They’re named for the dark patches at the base of the hind wings, conspicuous when they fly overhead (they‘re tireless flyers and can circle overhead for far longer than you and your camera feel like waiting). Striped Saddlebags http://wiatri.net/inventory/odonata/SpeciesAccounts/SpeciesDetail.cfm?TaxaID=175, the latest addition to Wisconsin’s saddlebags list, are in a subgroup called the “narrowsaddle” saddlebags, because the saddle is only about as wide as the dragonfly’s abdomen. Our other three species (Red, Black, and Carolina) are “broadsaddle” saddlebags.
They are often called “dancing gliders” because of their unusual reproductive behavior. A male patrols a territory, and when a female nears, he accosts her, using his legs to grab her and manipulate her so that he can get his claspers onto the back of her head. Saddlebags mate for about 10 minutes, perched on vegetation (she can store sperm and need only mate once), and then they fly out over the water in tandem at about knee height or lower (our knees), looking for an area with lots of emergent vegetation. When she is ready to oviposit, he releases her (http://bugguide.net/node/view/654958/bgimage, demonstrated here by Black Saddlebags) but continues to guard her from above (hover guarding). She drops to the water’s surface, tapping it gently to loosen some eggs, and then dances back up to rejoin the male, and then they do it again. Paulson, in Dragonflies and Damselflies of the East, says (about Black Saddlebags) that the dance is observed from underwater, and that bass and other predatory fish have been known to follow a preoccupied couple (needless to say, saddlebags prefer fish-free ponds). Unattached males may follow, too, and take advantage of the brief uncoupling to steal the lady. She may oviposit solo, but if she does, she moves ten times faster than she does when a male is guarding her.
These are largish dragonflies, around two inches long, with broad hindwings, a slim abdomen, and a round head. And they are fast, reaching speeds of 17 mph. They may rest high in a tree or near the ground, invisible either way (the BugLady is always inadvertently kicking them up out of the grass). In hot weather, they may droop their abdomens as they perch, a reverse “obelisk” position that has the similar result of averting overheating by minimizing the amount of sun that strikes the abdomen http://bugguide.net/node/view/96096/bgimage, and they do the same thing in flight. Not surprisingly, the majority of internet hits for saddlebags are photo sites.
The books say that the genus Tramea is considered one of the most highly evolved genera of dragonflies. The BugLady saw that statement a number of times, without elaboration, in connection with the saddlebags and also with the rainpool gliders (genus Pantala). In the case of the gliders, it seemed to be associated with physiological and behavioral adaptations that allow them to fly for huge distances, feeding in the air (they even have the ability to store fat and use it for energy on long flights), and that allow their naiads to develop quickly in very temporary bodies of water. Of course, gliders are also famous for ovipositing on car windows in parking lots, thinking they are over water, so they lose a bit of credibility there.
We’re near the northern edge of saddlebags’ ranges here in Wisconsin (check species ranges at the Wisconsin Odonata Survey http://wiatri.net/inventory/odonata/SpeciesAccounts/), and have fun with the maps at the really cool national dragonfly range-finder at http://www.odonatacentral.org/index.php/MapAction.windowed (type the genus of your dragonfly into the “Taxa” box (in this case, Tramea) and select your species from the drop-down list).
Carolina Saddlebags (Tramea carolina) have been recorded in about 15 counties in Wisconsin, scatter-gunned throughout the state. These are primarily eastern/southeastern dragonflies that range from Nova Scotia to Texas, and they’re listed as a rare migrant here in God’s Country, but sightings seem to have been on an uptick in recent years (more dragonfly watchers? climate change?). Carolinas prefer shallow ponds, swamps, and lakes, and very slow streams as long as there is plenty of emergent vegetation and the water is not muddy, and they are a bit more tolerant of the presence of fish than their confreres.
They are one of two red broadsaddle saddlebags on the Wisconsin scene, but neither of the red species is as widely distributed in the state as the Black Saddlebags. How can you tell them apart? Short answer – sometimes you can’t (so maybe there are more Carolinas out here than we think).
Another name for the Carolina Saddlebags is the Violet-masked Glider. Typically, the Red Saddlebags has a lighter, redder-colored face, and the Carolina’s is described as “metallic violet” (males’ faces and abdomens are more intensely-colored than females’). Another big difference lies at the other end of the dragonfly; a Red Saddlebags has a few black marks across the top of the eighth and ninth abdominal segments, but in the Carolina, the black is much more extensive and wraps around the sides of the abdomen. And then there’s the shape of the saddle itself. Some saddlebags are remarkably cooperative and will sit still for photographs, but they often hold their wings in a way that hides the tell-tale perimeters of those red saddles. For a great comparison, see http://dragonfliesnva.com/My%20Documents/KevinPDF/pdf/identify/species/CarolinaSaddlebags-FINAL.pdf. And just for fun, some younger individuals can be almost as dark as Black Saddlebags http://bugguide.net/node/view/789608/bgimage.
The naiads (aquatic young) are green, with five, short “tails” at the end of their abdomen http://bugguide.net/node/view/224444/bgimage. They excel at mosquito control – in one test, consuming 38 in two days. When their final transformation into an adult occurs on land, they leave behind an empty shell (exuvia) as witness https://waltersanford.wordpress.com/tag/carolina-saddlebags-dragonfly/. Adults continue to feed on mosquitos, catching and consuming their prey on the wing. They feed all day, until dusk, and they may be found in smallish feeding swarms in company with others of their species.
Yes, they migrate to the North Country in small numbers in early summer. The BugLady has photographed juvenile/teneral Carolinas in Southeastern Wisconsin, so they breed here, too. They are not among the five species censused in a Citizen Science project run by the Xerces Society/Migratory Dragonfly Partnership (http://xerces.org/dragonfly-migration/migration-monitoring/) (don’t forget Dragonfly Woman at https://thedragonflywoman.com/dsp/report/). Carolina Saddlebags are less migratory than the phenomenal Black Saddlebags, but they do make up a small percent of the southward migration along the Atlantic, where they help to fuel the fall raptor migration.
Kate Redmond, The BugLady
Bug of the Week archives:
Guest location: the Twin Cities
Guest moth photographer: BugFan-in-Law Steve
At the very beginning of April, the BugLady received an email with pictures from her sister, BugFan Molly (who also mails interesting little packages containing six-legged critters). Seems that Molly spied something moving when she was out in her yard, looked closer, and then snagged her camera-wielding husband to record it. In her own words, “about 11:00 this a.m. I found this moth. It was crawling through the leaf litter in the garden. You could see only tiny buds of wings, barely visible on its back. In the time it took me to run into the house to get Steve & camera, the wings had exploded out…and kept on going… o my!”
If you’re having trouble finding it in the first shots, that’s the point of emerging as a leaf-colored moth on a leaf-covered substrate – good spotting, Molly!
It’s a Green-spotted fruitworm moth a.k.a Speckled green fruitworm moth and Speckled Green Quaker (Orthosia hibisci), a totally non-green moth that was obviously named after its caterpillar (unless it’s a Subdued Quaker Moth, Orthosia revicta, but the BugLady doesn’t think so).
Brief Aside – in recent years, the BugLady has not used abbreviations for insect names as frequently as she did in the early years, because she started checking what other meanings her abbreviations might have, lest she offend. She likes using the abbreviations, because some insect names are long and are repeated multiple times during an episode, and the BugLady, let’s face it, is a three-fingered typist. Corporate, military, geo-political, and academic acronyms are usually harmless, but, oh my, those people at the Urban Dictionary need to wash their brains out with soap! Ick!! Anyway, this one gets the Good Housekeeping Seal of Approval.
The SGFM/GSFM/SGQ is in the Owlet moth family Noctuidae, and in the subfamily Noctuinae, some of whose caterpillars, often called cutworms and armyworms, target agricultural crops. Noctuidae is a big family with more than 2,500 species in North America and about 12,000 worldwide, one of those “pardon our dust” groups whose taxonomy is constantly under review. The SGFM (not Surface Green Function Matching) is found from coast to coast in North America, but, since it likes woods and water, is found more sparsely in the desert and Great Plains.
There are a bunch of shots of unidentified caterpillars in the BugLady’s “X-files,” and by chance, a few of them look like they might be the GSFM (not Synthesis Gas From Manure). Caterpillar colors vary http://mothphotographersgroup.msstate.edu/species.php?hodges=10495. The caterpillars are catholic eaters – you can’t be picky if you burst upon the scene this early in the year. Their menu includes trees and shrubs in the rose, willow, maple, birch, honeysuckle, ash, heath (blueberry), and buckthorn families. The caterpillar pictured here was feeding on glossy buckthorn – BugFan Jim says that eventually, insects will discover that this aggressive, invasive shrub is a vast, unused food resource and will help to keep it in check.
The caterpillars, common in woodlands early in the season, make a welcome bit of protein for returning songbirds. Caterpillars start feeding on the leaves, then move to the flowers, and then to the fruits. The GSFM (not the Government Statistics Finance Manual) is on USDA Wanted Posters, because its nibbling on young fruit causes aborted fruits or deep, scarring/malformations https://entomology.ca.uky.edu/ef214, https://content.ces.ncsu.edu/green-fruitworm, and because when they are present in large numbers, they cause some defoliation (though they’re such early feeders that trees have time to put out new leaves). Their numbers vary from year to year and location to location; in big years, they’ll eat anything, and when populations are low they’re not considered much of a pest.
Adults, in the early days of spring, visit birch and maple sap drips for nourishment, and then switch to nectar from maple and willow flowers. They are considered pollinators.
SGQs (not the Scottish Guitar Quartet) overwinter as pupae in minimalist cocoons in the soil http://bugguide.net/node/view/894463/bgimage , ready to go when the ground warms. Females lay eggs (100 to 300 of them) in trees as the leaves emerge; their caterpillars are on the job by the end of April and have disappeared by the end of June, tucked away under the soil until the following year. There’s only one generation per year.
Although Molly’s moth emerged in the daylight, they are nocturnal. The BugLady needs to start turning her porch light on.
Kate Redmond, The BugLady
Bug of the Week archives:
The BugLady has been hanging out at the ephemeral pond again; what follows is a revision of a BOTW from 2012 (different pictures, somewhat different cast of characters). By now, many of these critters have whole BOTWs of their own at http://uwm.edu/field-station/category/bug-of-the-week/.
She celebrated Easter at the Church of the Ephemeral Pond this year – a choir of peepers, wood frogs, and leopard frogs gave witness that there were, indeed, Easter eggs, but the BugLady didn’t see any. In past years, Belted Kingfishers have gathered at the pond to enjoy the frog spectacle, too, but they’re a bit late this year, or maybe the pond is early.
Ephemeral ponds are (most years) just that – ephemeral (they’re also called vernal or spring ponds, but because some hold water in fall instead of spring, “ephemeral” is a more inclusive term). These are the here-today-gone-tomorrowponds, the gather-ye-rosebuds-while-ye-may wetlands. The wonder of ephemeral pools is that they are populated by animals that take this annual disappearing act in stride – animals that are prepared to dry up with the pond or to get out of Dodge (timing is everything), and therein lie many tales.
An astonishing array of animals use ephemeral ponds as a place to drink, hunt, and breed, but an ephemeral pond is a challenging place to call home. The still, shallow water warms quickly (which encourages speedy metamorphoses) but contains little oxygen. As the water evaporates, its inhabitants squeeze into increasingly smaller spaces; water quality declines as waste products, including carbon dioxide, increase; and food gets harder to find. The handwriting is on the wall. The annual drought makes these ponds unsuitable for fish, which wreak havoc if they find their way in from nearby waterways in flood time. Do animals live there because they’ve developed adaptations that let them survive drought, or do they live there because the pond’s cycles give them something they need – a dry period?
Not every puddle that disappears seasonally is an ephemeral pond; the presence of certain indicator species verifies its status. Wood frogs, blue-spotted salamanders and fairy shrimp are considered obligate species (direct indicators) in Wisconsin, and finding empty caddis fly cases or encysted fairy shrimp eggs in the leaf litter of a dry depression in fall also identifies an ephemeral pond. A massive Citizen Science project to identify and census ephemeral ponds in southeastern Wisconsin is written up here: http://greentier.wisconsin.gov/topic/Wetlands/documents/reportEphemeralPondsMappingAccuracyAssessment.pdf.
Who lives there?
DRAGONFLIES – The BugLady photographed ovipositing (migrant) common green darners across a crowded pond on Easter, but they’re not the only dragonfly species that will use it, and damselflies do, too. Some young Odonates hatch and develop quickly, “goosed” by the warming water temperatures, and they emerge as adults before their pond disappears. Other dragonfly and damselfly species lay eggs in summer or fall, and their eggs go through a period of diapause (suspended animation), restarting when the pond fills again.
MOSQUITO larvae feed by filtering tiny stuff (bacteria, protozoa, algae) out of the water, and they are food for a host of carnivorous aquatic insects and for larval salamanders. The very-active larvae are called “wigglers;” the also-active pupae are called “tumblers.” The BugLady read that some species of mosquitoes lay eggs on damp mud near the pond’s edge – these enter diapause and can be dormant for years until the water rises again.
WATER TIGERS (a BugLady favorite) are the larvae of Predaceous diving beetles (family Dytiscidae), and their name is richly deserved. They grab their prey (lots of mosquito wigglers, fairy shrimp, and the odd tadpole) and inject meat-tenderizing enzymes through their sickle-shaped mandibles. Although they are aquatic as both larvae and adults, the winged adults can escape to a wetter spot when the ephemeral pond dries, but they may also overwinter in the mud and litter of the dry pool. This one shared the plastic spoon with a daphnia.
GIANT WATER BUG NAIAD- The BugLady loves these bugs (the front end is very sharp – handle with care), and not just because the male is caregiver for the eggs that his lady glues onto his back. Its strategy for drought is to find permanent waters until the ephemeral pond opens up for business next spring. In the low oxygen of the ephemeral pond, he rocks his body back and forth, sloshing water on the eggs and keeping them wet and oxygenated.
WATER MITES are a diverse bunch both in appearance and habit. Many nymphs (and some adults) are predators or parasites of aquatic insects, and they are commonly seen on dragonflies and damselflies. They move by scrambling through the water, and they can survive in low oxygen concentrations.
CADDISFLIES creep around the vegetation of the pond wearing shelters made of bits of plants that they fasten together using homemade silk. Some species are herbivores that, while feeding, break down large pieces of plant material into smaller ones that smaller critters can eat. Others are carnivores – the BugLady read of one species that feeds on larval salamander embryos from un-hatched egg masses. Their eggs overwinter.
PLANERIA, flatworms, are not related to leeches, which they somewhat resemble. Most scrounge bacteria, algae, and dead stuff from the pond floor, ingesting it through a ventral siphon. They get through the winter as eggs, and the adults of some species can encyst themselves. These dazzling green planeria are ephemeral pond specialists that carry around a bunch of photosynthesizing algae in their tissues. The planaria get oxygen and some sugars from the deal; the algae gets shelter and carbon dioxide.
FAIRY SHRIMP – In the early days of the pond, females produce soft-shelled “summer” eggs (some fertile, some infertile but parthenogenic that hatch into more females). If you zoom in on the female, you can see eggs. The summer eggs hatch quickly. As the pond winds down, they form “winter eggs” that have a thick shell that protects them from desiccation and that can withstand years of drought (up to 15 years), and that must be dried and re-hydrated in order to hatch. Maybe 3/8 of an inch long, the male has claspers on his “face” and the female’s face is hammerhead shark-shaped.
These tiny guys, which are either SEED SHRIMP OR CLAM SHRIMP (the BugLady isn’t sure which) do look like seeds and clams, but they are Crustaceans, (very) distantly related to crayfish. Most are well under ¼” in length, which means they are targeted by many of the pool’s predators. The eggs of both are drought-resistant.
DAPHNIA are another BugLady favorite, partly because she can’t believe that she can actually photograph them. These tiny Crustaceans eat minute bits of algae, bacteria, and debris, and everybody eats them. Their jerky progress through the water gives them an alternate name – water flea. They overwinter as drought-resistant eggs. Daphnia eggs hatch within the female’s brood chamber and are released when she molts, and the BugLady is wondering if this shot captures a few young daphnia within the brood chamber.
PHANTOM MIDGE LARVA – a predaceous (sometimes omnivorous) larva that floats through the water column like a tiny dirigible, its paired air sacs fore and aft revealing its presence. Its stillness and transparency afford it camouflage; it grabs its prey with specially adapted antennae. It’s on the menu of larval salamanders and other predators.
WATER SOWBUG – Yes, related to the guys that peer up at you when you pick up a flowerpot in the summer. They don’t swim, exactly, but they paddle-walk slowly along on the pond bottom, feeding on detritus that they find along the way. Their young hatch from eggs within the female’s pouch, and they don’t have any special adaptations to survive the drought.
SCUD – these amphipods scoot around the pool (or the BugLady’s plastic spoon) on their sides, demonstrating their alternate name “sideswimmer.” In a fish-free habitat, they can be plentiful. Like water sowbugs, they are omnivore-detritivores, chewing on organic detritus while they hold onto it with their front legs. When the water dries up, they bury themselves in the mud.
The BugLady recommends the nifty booklet A Guide to the Animals of Vernal Ponds by Kenney and Burne, Massachusetts Division of Fisheries and Wildlife. And check out Massachusetts’ Vernal Pool Association at http://vernalpool.org/vernal_1.htm, where they describe ephemeral ponds as “wicked big puddles.” Pictures of animals can be found at http://vernalpool.org/sci_x.htm.
If ephemeral ponds light your fire, check this (which the BugLady thinks looks interesting but cannot vouch for): http://herpcenter.ipfw.edu/outreach/vernalponds/vernalpondguide.pdf.
Go outside – visit an ephemeral pond. The Game’s afoot!
Kate Redmond, The BugLady
Bug of the Week archives:
Most insects begin their lives inside an egg that’s been deposited near/onto/into the correct food source, in the correct habitat for the eventual young. The BugLady often photographs these eggs, but she didn’t know much about them. Here are some Selected Short Subjects about insect eggs (and the BugLady apologizes in advance, she couldn’t help herself).
- Insect eggs come in all sizes and shapes and colors (and some change colors between the time they are deposited and the time they hatch). For some eggsquisite pictures, see http://www.atlasobscura.com/articles/the-blobby-dazzling-world-of-insect-eggs (ignore the text, which has a major eggsample of a “publish-in-haste-and-repent-at-leisure” boo-boo). Some eggs are laid alone, some in clusters, and some en masse, enclosed in a webby or gelatinous protective case. In some species, females detect pheromones left by recent, egg-laying females that tell them “This space is taken.”
- Insect eggs are pretty small. How small are they? The Book of Insect Records tells us that, at 0.027mm by 0.02mm, the tiniest insect egg belongs to a tachinid fly (an egg parasite that oviposits within the egg of another insect): http://entnemdept.ifas.ufl.edu/walker/ufbir/chapters/chapter_07.shtml. The website comes from the University of Florida, which publishes lots of good insect information on-line http://entnemdept.ifas.ufl.edu/walker/ufbir/chapters/index_order.shtml. Here’s another egg parasite at work – https://blogs.scientificamerican.com/compound-eye/use-this-simple-photographic-trick-to-make-tiny-insect-eggs-look-enormous/. And yes, there are egg parasites that victimize other egg parasites – an entomological matryoshka doll. For a long time it was believed that insects with complete metamorphosis (egg-larva-pupa-adult) laid smaller eggs and had smaller young because they were more “unfinished” when they hatched than did insects with incomplete metamorphosis (egg-nymph-adult), but that’s not eggactly true.
- Like an onion, an insect egg is layered, the layers manufactured within the female’s reproductive system via a process called oogenesis. In general, the outer layer/egg shell/chorion is made of lipo-proteins, sometimes covered with a waxy coat. The chorion may be sticky initially, so it will adhere to the surface it’s placed on. There are several layers between the chorion and the inner layer, which is called the cell wall or vitelline membrane and which wraps the nucleus and yolk. The surface of the shell has one or more tiny openings called micropyles, usually located on the top of the egg, and it may be minutely textured.
- The egg that is manufactured within the female contains at its core an unfertilized female gamete/germ cell. Fertilization happens when sperm find their way through one of the micropyles/micropylar canals after the egg shell is formed around the nucleus. After fertilization, division of cells in the nucleus will result in an insect embryo that eats the yolk particles.
- Seems like a lot of fuss – what’s the advantage of this system? Only that developing a weatherproof egg allowed insect ancestors to emerge from life in the sea about 400 million years ago, that’s all (although aquatic insects still lay their eggs in water – more about that in a sec). An inner membrane called the serosa restricts water flow through the egg shell; holding inside the moisture that Mom put there so her little bug wouldn’t desiccate, and keeping eggscess water outside. This has allowed insects to eggspand into almost all environments. Silverfish and a few groups of flies don’t have a serosa, but they lay their eggs in moist habitats, and their embryos develop really fast.
- Too much of a good thing? Turns out that the qualities that allow the egg shell to protect the developing bug from drying out and from getting squished and (with varying success) from predation are not quite so good for oxygen eggschange. The answer – more “pyles” or pores. Though some air can be absorbed through the shell itself, the main ingress area(s) is/are other pore(s) called aeropyles. (older references say that the micropyle also allows oxygen to enter; others differentiate and use the term “aeropyle” for pores involved in gas exchange). The number and arrangement of these pores depends on the species.
- Insect eggs face big swings in air temperature, and although embryos have higher metabolisms at higher temperatures (needing more oxygen), the rate of diffusion of oxygen through the chorion doesn’t necessarily keep up. This can result in low oxygen concentrations (hypoxia) within the egg (one source said that the hatching of common green darner eggs is triggered by hypoxia). In the recent BOTW about millipedes, the BugLady mentioned that arthropods were bigger 400 million years ago, when temperatures were cooler and atmospheric oxygen concentrations were higher. Information about the interseggtion of temperature, metabolism, and oxygen diffusion through the chorion suggests that arthropod eggs may also have been super-sized.
- How about aquatic insects that still lay their eggs under water? Blogger Dragonfly Woman, an eggspert on giant water bugs in the family Belostomatidae, tells us that “Many aquatic insect eggs don’t have aeropyles at all and depend on oxygen flowing directly through the shell.” She continues “[Abedus herberti eggs] have a structure called a plastron network. Plastron networks are meshworks made up of many tiny projections of the chorion. This meshwork is thought to trap air against eggs when they are underwater so that they don’t drown. Many terrestrial eggs have these plastron networks and this structure may allow them to survive accidental submersion for some time. Water bugs also usually have plastron networks that may be responsible for their survival while they are underwater. Lots of other aquatic insects that lay their eggs in water don’t have these structures at all.” Read her full eggsplaination at https://thedragonflywoman.com/2011/02/07/the-anatomy-of-insect-eggs/. Amazing pictures.
- How long does it take for an egg to hatch? Anywhere from a few days to months. Many months, in the case of insects that overwinter in the egg stage.
- Eggs, it seems, don’t move, so they’re sitting ducks for predators. Like their parents, many eggs are chemically protected against egg grazers and egg parasites. The operative chemicals may be manufactured by Mom, or she may sequester them from plants that she eats (or both) before incorporating them into the shell. Though direct paternal care of eggs is rare in insects, males of some species gift the female with toxic chemicals during courtship, and these are built into the egg. Her eggs may have a toxic shell, be decorated with toxic hairs, be disguised with camouflage colors or brilliant with aposematic colors, or be unpalatable because of a layer of eggscrement. In the “Very Cool” department, a female (herbivorous) stinkbug dots the outside surface of each of egg with feces that contain bacteria needed by her offspring to digest plant materials. The newly-hatched bugs hang around the egg mass for a while, ingesting the bacteria.
- Honeybees are the only insects that incubate their eggs and young (by using body heat to keep the temperature in the nursery between 92 and 97 degrees) (they flap their wings like crazy). Other insects are at the mercy of the temperature of air or water around them. Warmer surroundings = faster hatching.
- What do the plants think of all this? Most than you’d eggspect. The BugLady recalls the days when living things were divided firmly into two Kingdoms, Plant and Animal (eggcept for some pesky flagellated, unicellular, chlorophyll-bearing organisms lurking uneasily in between). Plants were defined as organisms that didn’t move and didn’t have a sensory system and that produced their own food. More and more studies show that plants not only receive signals, but they also communicate with other plants chemically (great Ray Bradbury short story about a man who designs a machine that lets him hear plants). Research shows that plants recognize, react to, and communicate with plants downwind about grazing by caterpillars like gypsy moths, and that tomato plants are aware of oviposition by a moth and mobilize defensive proteins in their leaves before the caterpillars even hatch.
Write researchers Kim Jimwon et al, “Thus far, plants appear to recognize at least three events as indicators of future herbivory. First, some plants increase resistance against insects when a neighboring plant suffers insect herbivory. In this case, plants appear to “eavesdrop” on volatile organic compounds released by the neighboring plant under herbivory and elicit their defenses. Moreover, the volatile-receiving plants showed priming of defenses, meaning the receiver plants activated faster or stronger defenses upon the anticipated herbivory. Second, insect footsteps can induce defensive responses in plants…. Third, oviposition, one of the most common events preceding insect larval herbivory, can induce a variety of direct and indirect defenses of plants.”http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0037420. For more about plant “senses”, see https://www.pri.org/stories/2014-01-09/new-research-plant-intelligence-may-forever-change-how-you-think-about-plants. And, of course, in the eggscalating chemical battle, a few insects can secrete chemicals that moderate the plant’s anti-herbivore tactics. The BugLady’s head may eggsplode.
After last week’s episode on Common green darners, BugFan Linda, whose eggstraordinary videos of pond life were featured in a January BOTW, responded that she had posted this video just a few days before https://www.youtube.com/watch?v=SgsEMAKUeX8. AWESOME, Linda, thanks!
Kate Redmond, The BugLady
Bug of the Week archives:
A common green darner was reported near La Crosse (WI) on March 24 of this year, and a few others have been seen since then (and even though the winter of 2016-17 has been “Winter Lite,” the BugLady is ready for spring and dragonflies). The BugLady wrote very brief biographies of the green darner in 2010, in BOTWs about spring dragonflies and about dragonfly swarms, but there’s much more to the common green darner story.
They are in the darner family Aeshnidae, a group of large, powerful dragonflies (“darner” because their long, darning needle-like abdomen has led to folk tales about their sewing people’s lips or ears shut).
Most of our Wisconsin darners are in the famously-confusing mosaic darner genus Aeshna. Common green darners (Anax junia) (“Lord of June”) are one of two species of Anax darners found in the state. Common green darners are, well, very common, not just here but across the country. And Central America. And Hawai’i. And Canada. And there are populations in Tahiti and the West Indies. And strong winds have blown individuals to Great Britain, China, and Russia. The other Anax, the stunning Comet darner (Anax longipes) is a rare visitor and even rarer breeder in Wisconsin.
Green darners have a 3” long body and a 3 ½” wingspan; their striking “wrap-around” compound eyes may be made up of as many as 50,000 simple eyes, apiece. They practice sexual dimorphism – both males and females have a green thorax, but males have a predominantly blue abdomen with a purple stripe, and females have a rust-colored abdomen with a darker stripe. Tenerals (newly-emerged adults) may take a week or more to solidify their adult color patterns and have female-ish coloration in the interim, and a chilly darner is a darker-colored darner. Both males and females have prominent cerci (claspers) at the abdomen’s tip. Common green darners have a characteristic bull’s-eye spot on their “forehead” that comet darners lack. They can move each wing independently, which lets them hover, and even fly backwards. They perch vertically, frequently in low vegetation, so they usually spot the BugLady before she spots them.
The long, slim, immature green darners (naiads) are found in still or very slowly-moving, shallow waters, preferably without sunfish and bass (nice set of naiad pictures here http://bugguide.net/node/view/238726/bgimage). Adults frequent the air above those habitats but may be seen far from water.
Two populations of common green darners – one migratory, the other resident – form tag teams in the air over Wisconsin. Migrants from the south arrive early, often in late April, as their prey (small, aerial insects) start to appear. They are the offspring, or the offspring’s offspring, of the darners that flew south in the fall (no, they apparently do not return to their natal ponds). “Shivering” their wing muscles to heat up the thorax allows them to be active in cool weather, and they also bask in the sun. This is so effective that temperatures as high as 110 degrees have been measured inside the thorax (which challenges the whole definition of cold-bloodedness). The picture of the female with the battered wings was taken in early July, suggesting that she was a migratory female who was reaching the end of her trail.
The migrants mate and die by the end of June, leaving their eggs in the water, just as the naiads of the resident population emerge as adults. These residents live a month or two as adults, depositing their eggs in late summer as the migrant adults emerge. Resident naiads overwinter under the ice in a state of suspended animation called diapause and take 10 or 11 months to mature (possibly more, in the chilly waters “Up North”), while the migrant naiads need less than half that time.
Mating commences when a male clasps a female at the back of her head in mid-air (one source said that she can reject his advances), then they retire to a perch to mate. Females oviposit in the open, in woody and herbaceous plant material below the water’s surface.
The books say that these are the only darners that oviposit in tandem. The books also say that a couple flying in tandem may be strafed by rival males. The attendant male doesn’t have many options; he may flap his wings at the intruder, shake his abdomen, land in vegetation, and even bite his challenger. According to Paulson, in Dragonflies and Damselflies of the East, females may curl their abdomen under and close their wings when under attack. The BugLady photographed (badly) an unattached male as he dive-bombed a second male whose abdomen was deeply submerged (presumably with an ovipositing female at the other end of it).
The BugLady once found a female stuck in an especially dense and sticky, dragonfly-eating patch of blanket algae. Did the female attempt to perch on the algae as she oviposited and get her wings stuck, only to be abandoned by her mate? Or, alternatively, did she get thirsty and then get stuck? Dragonflies “drink” by immersing their abdomen – water enters through the exoskeleton (the BugLady was able to fish her out with a stick).
The naiads are active predators that will eat anything they can grab using their foldable “lower lip” (labium) – zooplankton, other aquatic insects (including dragonfly naiads), tadpoles, larval salamanders, and fish fry are all fair game. In his wonderful write-up of the common green darner, Kurt Mead (Dragonflies of the North Woods) muses that “If dragonfly larvae were eight to sixteen inches long, as they probably were 300 million years ago, we would dare not swim in fresh water for fear of being attacked” (read the whole account at http://www.mndragonfly.org/html/behavior.html). Despite their spiny exteriors and their ability to shoot forward by expelling a spurt of water forcefully from their abdomen, they are eaten by frogs, fish, and by other aquatic insects. There’s even an “aquatic” parasitic wasp that lays its eggs in those of the green darner. Aprostocetus polynemae, apparently walks down a twig or leaf stem into the water to find dragonfly eggs.
Adults catch insects in the air and may eat them in mid-flight or on a perch. They can also pick prey from a leaf or from the ground, and they’ve been known to stake out bee hives, to the distress of the bee-keeper. At least one ambitious common green darner killed a hummingbird, and this fact is mentioned every darner write-up, though the BugLady suspects it’s pretty uncommon. Adults are preyed on by robber flies, birds, spiders, and by other dragonflies; the people who monitor the fall raptor migration tell us that the southward movement of American Kestrels synchs with that of the darners, and that kestrel migration is fueled by darners.
So, green darners migrate. Like birds, they respond to a suitable weather front – cold fronts for the southern flight and warm fronts for the far less conspicuous northern trip. The journey south may take several weeks of stop-and-start flying (averaging 7 miles a day but capable of far more, depending on the wind), and they may be accompanied by black saddlebags and variegated meadowhawk dragonflies. They migrate dramatically, sometimes in huge swarms that may take hours or days to pass a fixed point. Bluffs on the west edge of Lake Michigan are great places to catch the show at eye level. Dragonfly swarms are a late summer phenomenon, so tuck this address away for reporting swarms and contributing to Dragonfly Woman’s database: https://thedragonflywoman.com/dsp/report/.
The common green is the State Insect of Washington – so much more exciting than Wisconsin’s honeybee (and you thought the state insect was the mosquito!).
As always, don’t eat them – they carry parasites.
Kate Redmond, The BugLady
Bug of the Week archives:
This is (drum roll) episode #450 by the BugLady’s count. From its humble beginnings in the summer of 2007.