Category Archives: Uncommon Insects

Aquatic Insects, IDL Highlights, Odd Insects, Phenology, Uncommon Insects

Insects on the Snow

Despite the season, there’s a surprising number of insects and related arthropods that can be found on the snow during the winter months here in the Midwest.  Such creatures have fascinating life histories and special adaptations (such as natural “antifreeze”or cryoprotectants) that allow them to not only survive, but remain active at low temperatures.  Even these adaptations have limitations and winter insects generally aren’t active if temperatures are below ~20˚F (-7˚C).  Most activity occurs on mild winter days when temps close to or just above freezing.

If you’re curious to learn more about the stories behind these winter creatures and others, I’d encourage you to check out Bernd Heinrich’s Winter World: The Ingenuity of Animal Survival. Read on to learn about some of our commonest “winter” insects in Wisconsin and nearby states:

Snow Fleas: If you follow this blog, you might recall the example of snow fleas from two winters ago.  These dark-colored springtails (Collembola) can sometimes be abundant enough to give large swaths of snow a sooty appearance.  Snow fleas can be common on mild winter days and if I’m out cross-country skiing in the Northwoods, I’m often more surprised if I don’t spot any.

Up-Close View of a Snow Flea. Photo Credit: Daniel Tompkins via Wikipedia

Snow Flies: One of the weirdest examples of a “winter” insect would be “snow flies” from the genus Chionea.  Despite their spider-like appearance, snow flies are actually a type of wingless Limoniid crane fly.  Being wingless and generally slow moving might sound like an easy target for predators, but by being active at cold temperatures these insects can actually avoid the many predators that feed upon related flies during the warmer months.  Interestingly, their physiology is so specialized, that these unusual insects can be active between about 20˚F (-7˚C) and 32˚F (0˚C), but if it’s a warm winter day with melting snow it can actually be too hot for them!  If you’d like a more detailed look at these insects, check out J.R. Schock’s article in The Kansas School Naturalist.

Snow fly (Chionea sp.) on the snow in northern Wisconsin. Photo credit: PJ Liesch, UW Insect Diagnostic Lab

Winter Crane Flies: I occasionally get reports of “swarming mosquitoes” on winter days, and perhaps you’ve bumped into a cloud of tiny delicate flies out in the snowy woods or on a mild fall or spring day.  What you’ve likely encountered are winter crane flies (Family Trichoceridae).  These delicate flies are related to mosquitoes but have no interest in blood.  The adults are simply trying to mate and the larvae are scavengers.  

A winter crane fly (Family trichoceridae) that landed on the snow. These can be spotted flying on mild fall, winter, and early spring days. Photo credit: PJ Liesch, UW Insect Diagnostic Lab

Snow Scorpionflies: In my mind, one of the more elusive winter insects is the snow scorpionfly.  Despite having “scorpion” in the name, these aren’t scorpions (or true flies for that matter).  Rather, they belong to a small order of insects (Mecoptera), which includes some bizarre examples, such as the common scorpionflies, hangingflies, and earwigflies.  Like the snow flies, the snow scorpionflies are also flightless and simply wander about on the snow when conditions are right.  In the Midwest, we only have two species from this group Boreus brumalis and Boreus nivoriundus, and both species are associated with mosses.

A snow scorpionfly. Elusive, but fascinating creatures. Photo credit: PJ Liesch, UW Insect Diagnostic Lab.

Aquatic insects: If you’re near open streams or rivers during the winter months, certain aquatic insects can sometimes emerge and be found on the snow.  Caddisflies and stoneflies are two of the commonest examples.  I recall ice climbing one winter’s night at Governor Dodge State Park west of Madison and reaching the top of a frozen waterfall only to spot dozens of adult “aquatic” insects active on the snow.  The conditions must have been just right that evening, as I also saw hundreds of tiny Cynipid wasps (from oak galls) on the snow as I descended the access trail from the climb.

Caddisfly on the snow near a Northwoods stream. Photo credit: PJ Liesch, UW Insect Diagnostic Lab

Spiders: Hexapods aren’t the only arthropods getting in on the winter fun.  Species from at least a half-dozen families of spiders can occasionally be spotted on the snow on mild winter days.  They might be pretty lethargic, but it’s still interesting to see creatures like that out-and-about on the snow.  The video clip below shows a spider I spotted on the snow in Northern Wisconsin on New Year’s Eve a few years ago when the air temperature was right around 30˚F (-1˚C).

 

  

Bugs, IDL Highlights, Odd Insects, Uncommon Insects

Jeep ‘Adventure’ Leads to an Unexpected Insect Discovery in Wisconsin

On average, I see 2 – 3 new, non-native insect species show up in Wisconsin every year through my work at the UW Insect Diagnostic Lab (3 so far in 2021!). I’ve mentioned this in previous blog posts, but humans make excellent accomplices in moving species from one spot to another on the globe. This last spring, I saw one of the most interesting cases of my career which highlights this point exactly.

Like any good globetrotting adventure, this story involved a rugged, adventurous mode of travel—a Jeep. This particular Jeep had been imported in late 2020 and after a period of time in the eastern US, it eventually wound up in a small town in central Wisconsin. Unbeknownst to the owner of the vehicle, this Jeep also contained unexpected insect stowaways.

These insects managed to survive for months sheltered within the Jeep and would become active when the vehicle was in use—unexpectedly wandering out of nooks and crannies, much to the displeasure of the driver. Obviously, this isn’t something a new car owner wants to see, so a pest control professional was consulted about the insects and they got in touch with me at the UW Insect Diagnostic Lab to figure out what the specimens were. In the initial conversation, the mystery insects had been described as “stink bugs” and I figured that overwintering nuisance insects like the brown marmorated stink bug might have been involved. The photos, however, hinted at something far more puzzling.

The initial photo I received of the mystery insect on a car window.  Limited resolution, but definitely not a stink bug or anything else that I recognized. This certainly was a “we’re not in Kansas anymore” type moment.

By this point, I had been running the UW Insect Diagnostic Lab for six years and hadn’t seen anything quite like the insect in the photo. I requested a sample to get to the bottom of this mystery under the microscope.  I handle so many cases at the diagnostic lab (~2,500 annually), that I can generally identify most specimens to family (or perhaps even genus or species-level) with a quick peek. In this case I was utterly perplexed, meaning I had to run it through a general family-level taxonomic key for the true bugs (Order Hemiptera). In Borror and DeLong’s Introduction to the Study of Insects the specimens keyed out to the Family Heterograstridae.

From the Hemiptera family key from Borror and DeLong’s Introduction to the Study of Insects. The asterisk symbol (*) is always a surprise.

An asterisk is always a surprise when you encounter it in a taxonomic key. It generally means one of two things: you either took a “wrong turn” in the decision-making process (and misidentified the specimen) or it’s something rare or highly unusual. Something seemed amiss, so I consulted a few other keys to further confirm the Family Heterogastridae. In North America there’s only a single genus (Heterogaster) from this family and three species known from the west coast of the US. The specimens in my possession looked markedly different. Because the Family Heterogastridae is mostly a footnote in the western hemisphere, it’s hard to find information on this group of insects.

This is why geographic clues can be so important in diagnostics and why I request this information with every sample at the UW Insect Diagnostic Lab. Knowing where a specimen was collected and/or originated helps tremendously in learning more about it. Through follow-up conversations, I learned that the Jeep was manufactured in and imported from Melfi, Italy—meaning there was a good chance I was looking in the completely wrong hemisphere for the information needed to identify it.

This led to many evenings of armchair sleuthing. During this process, I’d like to imagine myself as Jason Bourne tracking down members of an international conspiracy while a suspenseful soundtrack blared in the background, but in reality I was mostly just locating pdfs of scientific papers and using Google Translate. Such work could have taken months or even years a few decades ago, but was now possible in the matter of a week or two.

Thanks to Interlibrary Loan and other online resources, I tracked down manuscripts from a half-dozen European and Middle Eastern countries in multiple languages and spent hours pouring over posts on Italian and French insect forums looking for clues. I finally found my answer in a scanned pdf version of Jean Péricart’s Hémiptères Lygaeidae euro-méditerranéens, vol. 1., which identified the specimens as Platyplax inermis—a species associated with Salvia spp. plants in the Mediterranean region.

Map showing reports of Platyplax inermis from its native range. Map credit: iNaturalist.

Having finally identified the stowaway insects and their origin, my work was mostly done at that point. The species happened to be on the USDA-APHIS regulated plant pest list (technically, the entire family Heterogastridae is listed), so I reached out to colleagues at the USDA-APHIS office in Madison to hand off the case. Specimens were sent off to an APHIS field office in Chicago and then off to the Smithsonian for further confirmation, a few specimens are also being deposited in the Wisconsin Insect Research Collection.

While most cases at the UW Insect Diagnostic Lab aren’t anywhere near this exciting, even insect diagnosticians get to live vicariously every once in a while.

 

Big Bugs, Bugs, In the News, Tree Insects, Uncommon Insects

Brood X Cicadas in the Midwest?

Will we see Brood X cicadas in Wisconsin or the upper Midwest this year? Read on to find out: Cicadas—they’re all over the news and soon to be out by the billions. All this buzz is about periodical cicadas, a group of species from the genus Magicicada which emerge once every 17 years (or every 13 years in some cases). Periodical cicadas are only found in the eastern United States and vary by location and the timing of their activity. To help categorize these insects, entomologists refer to each cohort of cicadas as a “brood” and have numbered them with Roman numerals. This year’s cicadas are referred to as Brood X (i.e., Brood ten) and last emerged in 2004.

Two periodical cicadas on a rock
Brood XIII periodical cicadas in Lake Forest, IL in June of 2007. Photo Credit: Janet and Phil via Flickr (CC).

Periodical cicadas are amongst the longest lived insects and their long life span and massive emergences are believed to be a survival strategy—by overwhelming predators with sheer numbers, they simply can’t all be eaten. But the wait for their appearance is a long one.  Periodical cicadas spend 17 years below ground as juveniles (nymphs) feeding on the sap from tree roots, before making their way above ground. Their emergence is associated with soil temperatures, and when the soil has warmed to 64˚F, they emerge. This corresponds to parts of April, May, or June depending on the location on the map. Once they make their way above ground, the cicadas molt and transform into adults.  Shortly thereafter, a raucous mating free-for-all commences. After mating, the females cut small slits into twigs of trees to deposit their eggs. The eggs hatch and the juveniles head to the soil for their lengthy development. Periodical cicadas don’t live long as adults (a matter of weeks), so it’s a long build up to a noisy grand finale.

Ground covered by periodical cicadas
Ground covered by periodical cicadas. When these insects emerge, it can be by the billions! Photo credit: James St. John, via Wikipedia (CC).

With all the attention in the news, many Wisconsinites and other Midwesterners are wondering if they’ll be able to see or hear Brood X cicadas in their area this year. For Wisconsin, Minnesota, Iowa, and most of Michigan and Illinois the answer is no—although they aren’t terribly far away either. Brood X cicadas can be found in over a dozen eastern states, but primarily emerge in three main pockets:

  1. Indiana, Ohio and nearby slivers of eastern Illinois and southern Michigan
  2. Southern Pennsylvania and parts of nearby Delaware, Maryland, Virginia, New Jersey, and New York
  3. Eastern Tennessee and nearby parts of North Carolina and Georgia
Periodical Cicada Brood Map from US Forest Service
Map of active periodical cicada broods of the United States. Map credit: USDA Forest Service. Click map for full size version and additional information.

While we won’t see Brood X cicadas here in Wisconsin, we will see other periodical cicadas in the not so distant future. Wisconsin is home to Brood XIII cicadas, which last emerged in 2007, meaning that the next big emergence in the Badger State is only a few years off in 2024. In the meantime, we’ll still see and hear plenty of our typical “dog day” cicadas during the warm days of summer.  To learn more about Brood XIII cicadas in Wisconsin, check out this post from last year.

Beetles, Big Bugs, Butterflies, IDL Highlights, In the News, Invasive Species, Ornamental Pest, Outdoor Insect Invaders, Uncommon Insects, Wasps and Bees

Hindsight: 2020 Trends at the Wisconsin Insect Diagnostic Lab

When the COVID situation reared its head back in March of 2020, I wasn’t sure how it would impact activities at the UW Insect Diagnostic Lab.  While there was a shift to handling diagnostics mostly remotely, in the end, 2020’s caseload of 2,533 ID requests was just shy of 2019’s all-time record of 2,542 cases.  

With Governor Evers’ Stay-at-Home Order last spring, our attentions were occupied by the unraveling pandemic and caseload at the UW Insect Diagnostic Lab was lighter than usual around that time.  However, as Wisconsinites shifted to working from home, it meant spending more time in yards and many Wisconsinites pulled out their green thumbs and established COVID “Victory Gardens”.  As a result, the diagnostic lab saw a record number of cases in July of 2020, with close to 600 ID requests that month alone. 

Monthly caseload at the UW Insect Diagnostic Lab in 2020. Credit: PJ Liesch, UW-Entomology.

Outreach activities of the lab saw a dramatic shift as well.  With in-person presentations and workshops off the table, virtual events afforded new opportunities—like a Japanese beetle seminar in July which drew nearly 900 participants. Regular events, like my appearances on WPR’s The Larry Meiller Show also continued through 2020, although I fielded calls from my home’s “reading nook” rather than the WPR studio.  

One of the biggest insect stories of 2020 was the Asian giant hornet.  Last May we learned that Asian giant hornets had survived the winter in the Pacific Northwest.  This of course led to a distinct increase of so-called “sightings” of that insect in Wisconsin, although every  “sighting” ended up being common insects from our area.  Last year, I saw dozens of ID requests for insects which ended up being look-alikes such as cicada killer wasps, pigeon horntails, and great golden digger wasps.  To date, the nearest sighting of the Asian giant hornet is well over 1,000 miles from us here in Wisconsin and poses no immediate threat to the upper Midwest.  Further reading: 6 Things to Know about the Asian Giant Hornet.

Some invasive pests had big years as well.  The viburnum leaf beetle, lily leaf beetle, purple carrot seed moth, and brown marmorated stink bug all increased their footholds in the state. Japanese beetle numbers varied a lot depending on where you were located in Wisconsin.  Some areas saw little pressure during droughty periods, while other parts of Wisconsin saw high Japanese beetle activity.  Gypsy moths had been quiet in Wisconsin for several years, but increased their numbers last year.  I saw a distinct increase of gypsy moth cases in 2020, and I’ll be keeping a close eye on that species in 2021.   

Come fall, we saw some stretches of unseasonably pleasant temperatures in October, November, and December.  During those periods, multicolored Asian lady beetles—which had been lurking in the background for several years—returned to the spotlight.  The multicolored Asian lady beetle activity around Wisconsin was some of the highest of the last decade.  Not to be left out of the fun, minute pirate bugs were abundant in some parts of the state and made warm, sunny fall days a little less pleasant due to their biting habits.  Speaking of biting insects, black flies were abundant in 2020 and made outdoor activities more challenging in June and July.  Mosquito activity varied around the state, although we did see a few cases of the Eastern Equine Encephalitis in 2020.

While we won’t see a big emergence of 17-year periodical cicadas in Wisconsin until 2024, small numbers of out-of-sync “stragglers” did emerge in southeastern Wisconsin last summer. 

A female Dryinid wasp. The forelegs are highly modified into scythe-like claws used to grasp other insects. Photo credit: Ty Londo.

No two years are the same at the UW Insect Diagnostic Lab and that includes some of the “X-Files” type cases as well.  Some of my favorite cases from 2020 include identifying phorid flies from dead radioactive cats (it’s a long story…), a grim-reaper-esque dryinid wasp, several massive black-witch moths from Central America, and a case involving a black widow spider found in a head of broccoli from the grocery store.  Never a dull moment at the UW Insect Diagnostic Lab!

—PJ Liesch
Director, UW Insect Diagnostic Lab

IDL Highlights, Odd Insects, Tree Insects, Uncommon Insects

Some Insects Don’t Understand Social Distancing

In the grand scheme of things, most insects (and spiders) are loners.  Perhaps they set a good example for us in 2020 with their social distancing.

Of course, insects have to find a mate to reproduce at some point in their lives*, but out of the 1 million+ described insect species, being truly “social” isn’t the norm.  There certainly are some well-known examples of insects that are eusocial—i.e., they live together as a colony.  Examples include ants, certain types of wasps (such as yellowjackets and paper wasps), some bees, termites, and a few other interesting examples.  However, there are many insects that are much more solitary in their habits.  If you think of our bees in the Great Lakes region, we have roughly 500 species.  Other than honey bees, bumble bees and a few others, the vast majority of these species are solitary creatures with each female doing her own thing.

Two herds of Cerastipsocus venosus barklice. Photo submitted to UW Insect Diagnostic Lab.

Interestingly, there’s a quirky insect that can be commonly encountered this time of the year and it missed the memo on social distancing.  I’m referring to an interesting species of barklouse (Order Psocodea): Cerastipsocus venosus.  Barklice are relatives of true lice (e.g., head lice and pubic lice) but they’re really quite harmless to humans and tend to be scavengers.  Barklice make up an obscure group of insects and many entomology students simply identify them to “order” level as this group can be challenging to narrow down further to family, genus, or species.

Group of Cerastipsocus venosus juveniles. Note the striped abdomens which make them easy to identify. Photo submitted to UW Insect Diagnostic Lab.iny

If you haven’t encountered Cerastipsocus venosus (aka “tree cattle”) before, it might catch you off guard to find a group (formally known as a “herd”) of these small insects hanging out together on the bark of a tree or a rock in your yard.  The tiny juveniles are particularly striking with yellow stripes on their abdomens.  The adults are larger (up to 1/4″ long) and possess black wings.

A Cerastipsocus venosus adult. Note the black wings, which are only found in the adults. Photo submitted to UW Insect Diagnostic Lab.

Rest assured, these barklice pose no threat to trees or other plants in our yard and these native insects simply nibble on lichens, and pieces of dead tree bark.  Every year I get many reports of these insects in mid- and late- summer at the UW Insect Diagnostic Lab and there’s no need to spray or do anything about these if you spot them in your yard.  These barklice don’t seem to stay in the same place for very long, so perhaps their herds just move along looking for greener pastures.

*Some insects are able to reproduce asexually, and don’t technically have to find a mate…

Flies, Odd Insects, Pine Insects, Uncommon Insects

The Stories that Insects Tell

Imagine taking an American history class where many of the important events were reduced to mere footnotes or skimmed over entirely.  Anyone taking the class would be shocked at this notion—I mean, the Civil War was a big deal after all!  When you look at a different field of study—biology—such a trend has surprisingly occurred, with insects getting the short end of the stick.  Insects are the most diverse and abundant animals on the planet and make up roughly 70% of the 1,000,000+ described animal species.  Yet, many introductory biology textbooks skim over insects (and invertebrates in general) in favor of more charismatic megafauna—a trend that has only gotten worse over time.  Insects may be small, but they serve crucial roles in the world around us from pollinating plants to serving as the base of food webs.  Appropriately, E.O. Wilson referred to insects as “the little things that run the world” in his famous call for their conservation.  It’s difficult to conserve these little creatures that run the world when so few people really get to know them.  

With their sheer diversity and abundance,  knowing the insects also helps us better understand the world, and everyday life, around us.  Getting to know the many different insects is a bit like learning a foreign language.  Travel to an exotic country where you don’t speak the local tongue and you’d have a hard time understanding the everyday happenings around you.  As you picked up words and phrases of that foreign language, things will become easier to understand.  Along these lines, if you can recognize the insects around you, it helps interpret the stories they tell.  Truly knowing your insects is like possessing an all-powerful decoder ring to the untold stories that surround us.  

Let’s look to flies to illustrate this point.  To many folks, a small fly found in their home is assumed to be a fruit fly, and a large fly, a house fly.  But there are dozens of different flies that commonly show up indoors—each with their own story to tell.  Fungus gnats hint at overwatered houseplants, moth flies indicate build-up in a bathtub drain, and metallic blow flies can alert you to a mouse trap in need of checking.  Outdoors, other species of flies can provide clues that gauge water quality, indicate the presence of specific plants, or solve crimes—but only if one knows how to interpret their clues.  If a picture is worth a thousand words, I’d argue that a properly identified insect is worth even more.  

The unusual fly species, Asteia baeta. At only 2mm long, these flies can readily be mistaken for fruit flies to the naked eye. Photo Credit: PJ Liesch, UW Insect Diagnostic Lab

This holiday season, my own love of insects led to a scientific discovery that would have gone unrecognized in most households.  A day after setting up our “real” Christmas tree, I noticed several tiny flies at the windows of our home.  My curiosity was piqued and like any good detective, some sleuthing was needed.  I recall an undergraduate professor telling the class, “a biologist without a notebook is off duty” to which I’d add, “an entomologist without vials is off duty”.  So now I was off, vials in hand, on an insect hunt in my own house.  Once the specimens were examined under the microscope, I recognized the flies as a rare species (Asteia baeta) from the poorly-known family Asteiidae.  There isn’t much written about these flies, but they’re known to be associated with fungi, vegetation, and tree sap, which told me that the new Christmas tree was the source.  These flies have only been spotted in Wisconsin a few times and no preserved specimens exist for that family in the Wisconsin Insect Research Collection (I’ll be donating some soon).  Looks like our Christmas tree came with it’s own entomological story to tell this year—I’m glad I knew how to listen.

The source of the unusual flies—apparently our cat wanted to try and hunt for them as well. Photo Credit: PJ Liesch

Big Bugs, IDL Highlights, Uncommon Insects

Mantid Mania

If you spotted one of the unusually large green or brownish insects working on its kung fu moves in late summer, you would have undoubtedly spotted a praying mantis.  These insects are an unusual sight in Wisconsin as we really don’t have native mantids in our area.  The closest native mantid, the Carolina mantis (Stagmomantis carolina), occurs in the southeastern US and does makes its way as far north as Iowa, Illinois, and Indiana.  A stray may show up in Wisconsin on occasion, but this seems to be an exception, rather than the norm.

A female Chinese Mantis (Tenodera sinensis) blends in on vegetation in late summer. Photo credit: Jill Schneider.

When mantids are found in the upper Midwest, the culprits are typically two introduced species: the European mantis (Mantis religiosa) and the Chinese mantis (Tenodera sinensis).  Both of these species have been in the country since the late 1800’s and have become well established in North America.  Of these, the Chinese mantis stands out with its sheer size as it can approach 5 inches in length with its outstretched legs.  The Chinese mantis is our largest and commonest species, based on observations.

Overall, mantids are much more common in southern states. The scarcity of these insects in the upper Midwest has a lot to do with their life cycle.  For the species in our region, females lay egg pouches (oothecae) in late summer or early fall in exposed locations—twigs, gardening stakes, and similar spots.  If there’s a harsh winter, these exposed egg masses face the brunt of the cold and mortality is high.  As a result, the vast majority of Wisconsin’s mantid sightings are restricted to southern and eastern counties where temperatures are slightly warmer during the winter months.  In 2017, there was a distinct increase in mantid sightings, likely due to the two consecutive mild winters in our area.  Assuming an egg case makes it through the winter, hundreds of juvenile mantids emerge in spring and surviving individuals reach maturity by late summer.

Chinese mantis (Tenodera sinensis) cleaning a leg. Note the enlarged (“Popeye-like”) raptorial forelegs lined with spines to subdue prey. Photo Credit: Jill Schneider.

Not only are mantids fascinating creatures to watch, but they’re impressive predators as well.  A number of adaptations place mantids amongst the top predators of the insect world.  First off, large eyes give them excellent stereoptic vision—if you’ve ever watched a mantis, they’ve watched you as well.  Camouflage also benefits many mantids, with color patterns that allow them to stealthily hide on plants, waiting to ambush unsuspecting prey with ninja-like agility.  The tropical orchid mantis (Hymenopus coronatus), even takes camouflage to an extreme with bright pink coloration to blend in on flowers.   The grisliest adaptation would be the enlarged “raptorial” forelegs armed with spines, which allow mantids to rapidly seize and impale prey and hold them in a final, lethal embrace as they begin to eat.  Mantids typically eat a variety of flies, moths, bees, butterflies, and other insects, but large mantids have even been known to prey upon birds on occasion [Note: it’s pretty gruesome and involves eating brains!].  Mantids aren’t picky eaters, so cannibalism can even be a significant challenge to those trying to raise them.

While uncommon in our area, reports of mantids may continue to increase in the future with climbing temperatures and milder winters—something to keep an eye out for!

 

Medical Entomology, Uncommon Insects

A Mysterious Tingling Sensation: Bird Mites

If I had to pick the most misunderstood creature I regularly encounter at the UW Insect Diagnostic Lab, it’d be bird mites.  Perhaps you’ve never even heard of bird mites before—tiny arachnids that suck the blood of the birds nesting in your back yard.  Under the right conditions, those same mites can wander indoors and be a temporary nuisance to humans.

If you haven’t heard of bird mites before, your first inclination may be to do a quick Google search to learn more.  Unfortunately, the Internet is rife with misinformation about these creatures.  In the age of fake news, here’s another gentle reminder to assess the credibility of online sources.  I’ve encountered “official sounding” websites full of misleading, downright wrong, and in some cases, dangerous management recommendations about bird mites.  I’ve also had to console clients on multiple occasions because they’ve read about bird mites online—only to believe that the mites will be infesting themselves, their homes, and vehicles indefinitely.

Although small (<1 mm long), bird mites can be seen with the naked eye, and their nearly constant movement helps give them away.  Perhaps the best description of their appearance is walking flakes of pepper.  Under magnification, bird mites have a somewhat tick-like appearance with their eight legs and long, prominent mouthparts.  The mites are often whitish in color with some black on the body but can turn darker after feeding.   Each year, I typically bump into 10-20 bird mite cases during the spring and summer months.  The mites can actually be quite common but simply aren’t encountered unless you have a bird nest very close at hand: under a back deck, on a patio light fixture, in a gutter or a damaged soffit area or in a shrub just outside a bedroom window.

Bird mite. Photo Credit: Whitney Cranshaw, Bugwood.org

True to their name, bird mites are parasites that feed on the blood of birds.  These mites are often most noticeable when young birds have just left the nest and the mites wander desperately looking for a blood meal.  Without their avian host, bird mites have a short time to live, but they can make their way indoors where they can crawl on and inadvertently try biting humans and pets.  Although the mites can be an itchy tingly nuisance, bird mites cannot survive on humans or in homes for any significant length of time.  The literature suggests that off of their avian hosts, the common bird mites may be able to survive a matter of weeks under the most ideal of conditions.  In most cases, the conditions off the birds are so hostile (too dry) that survival is limited to a few days at best—especially in a modern home with air conditioning.

As with many pest control situations, eliminating the source of the problem often brings about rapid results and bird mites aren’t any different.  If you’ve found bird mites, removal of the bird nest once the birds have left the nest is the single most important step.  Like flipping a switch, mite activity typically drops off rapidly within a day or two of the nest being removed.  Indoors, dry conditions pose the biggest threat to bird mites, so running your AC and/or dehumidifier may help hasten their demise.  Vacuuming, using sticky tape, or wiping up mites with a damp soapy cloth can all help eliminate any additional stragglers that made it indoors.  Pest control professionals typically also apply to residual product to nearby areas to help control any residual mites.

If you think you may be dealing with bird mites, contact the local University Extension service in your state/country for advice.

Ants, Odd Insects, Uncommon Insects, Wasps and Bees

The Case of the Hitchhiking Bog Wasps

While most of the cases at the Insect Diagnostic Lab involve fairly common insects, I do also see my fair share of unusual cases each year. One of my favorites from 2015 involved a miniature “bog wasp” from the family Eucharitidae: Pseudochalcura gibbosa. Due to their small size, these tiny (~2 mm long) wasps would simply go unnoticed in most cases––that and the fact that you’d most likely have to be wandering around in a bog to find them. So how exactly did these tiny, easily-overlooked “bog wasps” end up being submitted to the Insect Diagnostic Lab?  Simple: a homeowner found several in a second story bedroom of their house. This simply didn’t make much sense, so I knew there must have been a deeper story at play. Whenever I get an unusual case like this in the diagnostic lab, I often have to track down additional pieces of the puzzle before things make sense.

Bog Wasp-Pseudochalcura gibbosa
The tiny, hump-backed wasp: Pseudochalcura gibbosa. Photo Credit: PJ Liesch, UW-Entomology.

In this case, this particular home was located near Rhinelander, Wisconsin, where there’s certainly an abundance of bogs. As part of their life cycle, the females of Pseudochalcura gibbosa lay eggs on Bog Labrador Tea (Ledum groenlandicum), a common shrubby plant in northern bogs. The eggs spend the winter on the plants and hatch the following spring. However, these wasps aren’t plant feeders, and their presence on Labrador Tea is temporary. What they’re really after are immature carpenter ants (Camponotus sp.) to feed on. After the eggs of Pseudochalcura gibbosa hatch, it’s thought that the wasp larvae hitch a ride on foraging carpenter ant workers back to their nest. Once they’ve dropped off their six-legged taxis in the ant nest, the tiny larvae of Pseudochalcura gibbosa behave much like a wood tick on a dog: they hang off of and feed on carpenter ant larvae and pupae. In some cases, dozens of small wasp larvae may be present on a single carpenter ant larva. Eventually the tiny wasps complete their development and leave the carpenter ant nest to head back to the bog.

Having identified the wasps as Pseudochalcura gibbosa, I was suspicious that a carpenter ant nest was also present in the home and simply hadn’t been found yet. After some detective work, the homeowner eventually confirmed the presence of carpenter ants in the house. With that final piece of the puzzle I had my explanation for how the wasps had hitchhiked from a nearby bog to an upper story bedroom: it’s was all the ants!

Outdoor Worms, Uncommon Insects, Wasps and Bees

Tobacco Hornworm et al.

It’s not unusual for gardeners to find large caterpillars of the Tobacco Hornworm munching on their tomato or pepper plants.  Hornworm caterpillars get their name from the horn-like structure at the back end of the insect and while many species of hornworm caterpillars are known from Wisconsin, the tobacco hornworm is one of the largest and can reach lengths of over 3″.  If all goes well, the caterpillars eventually transform into large, grayish sphinx moths with a series of yellowish dots on the sides of the abdomen.

However, tiny parasitic wasps will sometimes kill a caterpillar before it can turn into an adult moth.  Female Cotesia wasps inject eggs into a tobacco hornworm caterpillar and the developing wasp larvae live as internal parasites.  At a certain point, the wasp larvae have matured and move to the outside of the caterpillar to spin silken cocoons and transform into adult wasps.  Biological control in action!

Hornworm
Tobacco hornworm caterpillar with dozen of cocoons from parasitic wasps. Photo courtesy of Deb Zaring.