Winter Insects and a Spring Foreshadowing

With the extreme cold snap and the slow march of winter, most people think that insects and other small animals would be too chilly to make an appearance. Their diminutive size might lead one to think that they would freeze solid out in the environment. For the most part that is true: insects tend to either hibernate or migrate during this time of year to avoid extreme cold. But what about those that enjoy the cold? Many groups only come out this time of year and have special adaptations (such as natural antifreeze - apparently common in Arctic species) to survive the low temperatures. Here are a few cold-loving groups that come to mind:

• winter crane flies (Trichoceridae) - a family of mosquito-like flies related to their warm weather cousins, the true crane flies (Tipulidae); you may have seen them at your porch light
• winter stoneflies (Taeniopterygidae) - develop in well-oxygenated streams especially in the mountains; they emerge in the fall, winter and early spring
• snow crane flies (Tipulidae: Chionea sp.) - these small, wingless, spider-like flies only come out in cold weather, usually being observed on snow
• snow scorpionflies (Boreidae) - these tiny, hopping insects are only found in the Northern Hemisphere, most commonly in mountainous areas with snow; their larvae feed on mosses
• snow fleas (Hypogastrura) - often seen in masses on snow, these tiny springtails (not true fleas) enjoy the cold weather
• some dung beetles (Scarabaeidae) - in my studies on the seasonality of dung beetles in NC, I found that a few species were only present in the cooler months of the year (below)

Aphodius distinctus is one of the dung beetles that is present in the fall and winter, but not during other times of the year (from Bertone 2004).

More types of insects than you think are active in the frigid times of the year*. Most go unnoticed (maybe because we are inside more) and pass their days doing what they do and not bothering us.

Others are a sign of what's to come. Despite their autumnal name, the fall cankerworm moths (Alsophila pometaria) have been out and about for a few months. In fact, just two weeks ago I was alerted to a plethora of females mistaking some campus building pillars for trees. The wingless females were clinging to the cement and some had started to lay their eggs. No doubt others had already done so since they appeared in the late fall.

Female fall cankerworms are strange moths that lack wings (though not unique among Lepidoptera).

The tiny, barrel-shaped eggs of the fall cankerworm laid in a nice batch.

I was also surprised by the abundance of male fall cankerworms at lights and elsewhere this year - something I have not particularly noticed in the past. Males, unlike the wingless females, have large, drab wings and look...rather moth-like and fairly mundane.

Male fall cankerworms are fully-winged and can be found at lights during the cooler months.

So what does this mean? I am assuming the abundance of adults is a direct result of the previous spring's many, many larvae that plagued local trees and bushes, raining down from above on silken strands. But does that mean that we will have as many (or, even more) this coming spring? I am not sure, but we will know in a few months when these little guys come out:

Fall cankerworm caterpillars are all too familiar "inchworms" in recent years.

Oh, and don't forget about spring cankerworms! The silver lining? At least it will be warm outside.

*there is even a whole group of insects, the ice crawlers (Grylloblattodea) that only exist in the cold mountains of the Northern Hemisphere, though in the US only in the Western part of the country; they cannot live much above freezing and will die sitting in a person's hand!

Uninvited Holiday Guests

Insects, like all animals, must survive the winter (in one way or another) to reproduce the next year. There are two main strategies to do so: migrate or "hibernate". Of course there are famous insect migrations including monarch butterflies (Danaus plexippus) and several species of dragonflies (Odonata). However it is much more common for insects (and other arthropods) to hunker down for the winter in a nice secluded place. Insects overwinter in different life stages - either as eggs, larvae/nymphs, pupae (if they are holometabolous), or adults. The stage that overwinters usually depends on the type of insect, but sometimes can be determined by environmental or geographical factors.

Thus, as the days begin to cool and darkness descends earlier in the evening this holiday season, you may be getting more than your in-laws invading your home. Most do so by finding a nice brightly-colored home as a landmark during warm days where they aggregate on the siding, in eaves, or along windows. The most common nuisance insects overwinter as adults that may become active within homes during warm days of the season - a common occurrence here in NC which has a mild, fluctuating winter. Mass movements of these insects into living areas can be difficult to deal with and are a real annoyance. The following are some of the more common insects to enter houses.

- True bugs (Hemiptera) - the worst offenders -

Kudzu bugs aggregating in the crack of a tree; could easily be a window or the gaps in the siding of a house.

Bugs are among the most common insects found aggregating on and entering homes in the cooler months. Their numbers and the pungent smell they produce (they're not called stink bugs for nothing!) can be bothersome to people that want to enjoy the comforts of their indoors. Although bugs are generally harmless, kudzu bugs (Plataspidae: Megacopta cribraria) are sometimes known to cause irritations on skin, brought about by the secretions they produce. Brown marmorated stink bugs (Pentatomidae: Halyomorpha halys), another recent introduction into the US, also find it nice and cozy in houses. Along with these invasive bugs, many other types, including leaf-footed bugs (Coreidae: Leptoglossus) and boxelder bugs (Rhopalidae: Boisea trivittata), enjoy breaking and entering for a nice place to hibernate.

Kudzu bugs: one is alright, but hundreds are bad news!

Brown marmorated stink bugs find your home when it's cold outside.

Leaf-footed bugs may be seen around the home.

- Flies (Diptera) - can we use your attic? -

Figure from Oldroyd's magnificent book, The Natural History of Flies (1964). 

Several groups of flies will spend the winter in attics, barns and other man-made structures, safe and cozy away from the elements. The most common are called cluster flies (Calliphoirdae: Pollenia sp.), named for the fact that they often "cluster" in groups of hundreds in the attics of homes. Normally they are out parasitizing earthworms, but in the fall and winter when things slow down they get the urge to swarm homes. Face flies (Muscidae: Musca autumnalis) will also do this, usually around areas with livestock, their primary food (larvae live in dung and adults feed on facial secretions). On warm days these flies may come out of hiding to stretch their wings, much to the dismay of homeowners.

Cluster flies are drab (for blow flies) and have golden hairs on their thorax.

- Ladybugs (Coccinellidae) are pretty - but get them out of my house! -

"Ladybugs are great, right? They eat all the pests and are nice to look at." Tell that to someone whose living room is overrun by these red and black beasts. Most ladybugs do a fine job of staying outside and being good neighbors. However, one species in particular (though there are a few others) - the multicolored Asian ladybug or harlequin ladybug (Coccinellidae: Harmonia axyridis) - loves to come into homes. This highly variable species was first introduced into the US in 1916 for the control of pests and has been readily available for farmers and homeowners to purchase. In the 1980s it finally became established, and is now the dominant ladybug in much of its range. Thus there have been some concerns about this species. First, it may be pushing out native ladybugs with its voraciousness, which is not good for our biodiversity. Second, it can be structural nuisance pests. Along these lines, when they do enter homes in large numbers they can sometimes bite people and, like many ladybugs, reflexively bleed a noxious substance that may cause skin irritation and allergic reactions. For both of these reasons, the cartoon-like insects can be less funny than they are nightmare inducing.

Multicolored Asian ladybugs, though sometimes beneficial, are often a nuisance.

- So what can you do about it? -

The best way to deal with these insects is to first make sure that they cannot enter your home. Search for cracks and holes in the siding or under eaves. Any crack or hole small enough for the average insect to enter should be repaired or covered. While pesticide sprays on the South sides of the home may kill or deter some insects, they are not long-lasting, nor are they particularly effective. Once in the home, it is best to vacuum the insects up and collect them into hot soapy water or freeze to kill them. Spraying indoors usually does more harm than good, so cultural practices mentioned above work best.

About that pumpkin....

So Halloween has come and gone, but it's still Fall (Thanksgiving's on the way!) and everything is already red, yellow and orange. Why not keep that pumpkin spirit going?

Happy pumpkins are just glowing! (Photo by Matt Bertone)

Unfortunately, chances are by now your pumpkin is looking more like this:

This pumpkin used to be happy. (Photo by Sara Prado)

If you're lucky you can get it to the trash or compost without the bottom falling out (I wasn't that lucky). Even if you didn't carve a scary face in it, it will likely be in decline seeing as it is a fruit off the vine and it is slowly being broken down by bacteria and fungi. If there is a wound on the pumpkin from rough transport, it opens the pumpkin to these microorganisms. This is prime food for many insects that love to eat the nutritious soup.

Most of these insects are flies. Flies love rotting vegetable matter. Vinegar or fruit flies (Drosophilidae) are particularly fond of rotting fruit. Some walk all over their giant bounty, waving their patterned wings around while seeming to dance. They do this to attract mates and establish that they have found a nice source of food for their precious little maggots.

This vinegar fly (Drosophilidae: Chymomyza amoena) may have a dance party on your over-ripe pumpkin.

Other common flies include dark winged fungus gnats (Sciaridae) whose larvae love to eat the molds and other fungus growing happily on the pumpkin flesh. The small black flies swarm around the pumpkin and settle after a disturbance.

A mating pair of dark-winged fungus gnats (Sciaridae) - a scene you may see on your rotting pumpkin.

Many other fly species may be found among the decaying Jack-O-Lantern as well. However, flies aren't the only visitors to such a great source of food. Beetles, earwigs, isopods (sowbugs & rolly-pollys), slugs/snails, and other organisms like this type of substrate to feed on as well.

Picnic beetles (Glischrochilus) and other Nitidulidae love rotting vegetation. This is from last year's pumpkin.

Isopods may nestle themselves inside or under the pumpkin to feed.

"I am looking for a nice moldy pumpkin pie" says the snail. Slowly, he might find yours....

Of course, if you are responsible and discard your pumpkin while it is still fairly fresh, you won't have to deal with these insect and other small animals. But then again you may not see some of these cute little critters setting up shop and recycling your autumnal fruit festivity. Oh well, they can find the compost bin too I guess...

The New Bug Guy

Hello everyone! My name is Matt Bertone and I am the new entomologist for the Plant Disease & Insect Clinic. I will be taking over for the now-retired Dave Stephan, a great entomologist with years of encyclopedic knowledge who will not be easily replaced. I do hope to follow in his footsteps, however, and to learn as much as I can about the insects and other animals that affect the daily lives of North Carolinians. But first, let me tell you a little bit about myself.

I was born up North (don’t hold it against me) and lived most of my formative years in Pennsylvania. From a young age I was obsessed with the natural world (see below photo). It started with the usuals like dinosaurs and such, but quickly turned into a passion for insects, spiders and other creepy-crawlers¹. They were so strange and diverse that there was always something amazing to learn.

Only the nerdiest kids know how to draw
a microscope in kindergarten.

After high school I entered college at Salisbury University on the Eastern Shore of Maryland. I had a great time there and took as many zoology courses as I could. There I met many great scientists and was introduced to research studies and continuing to graduate school. I was not aware of the universities that had entomology programs and applied to NCSU on a whim after seeing one of my colleague’s certificates from the department. After applying I was very happy to be accepted and had no idea how wonderful the area, school and people were going to be.

In 2001 I started my master’s work on dung beetles (Scarabaeidae & Geotrupidae) inhabiting cattle pastures in the Piedmont (Salisbury, NC) and coastal plains (Goldsboro, NC) under the advisement of Dr. Wes Watson. The project was great. I was introduced to a charismatic group of insects, researching their seasonality, abundance and diversity, and performing experiments to show how they help fertilize different soils. I was also happy to participate in extension work, since teaching in any format is another passion of mine.

A rolling dung beetle (Melanocanthon bispinatus)
from North Carolina.

In 2004 I began my PhD work under Dr. Brian Wiegmann on the evolution of true flies (Diptera), one of the most underappreciated – yet extremely diverse – groups of animals. I used genetics to see how different groups of the more “primitive” flies, like mosquitoes and midges, were related to one another. It was eye opening to learn the things flies do and I could (and may well in the future) go on and on about them. Needless to say, I found another group to love².

The elephant mosquito (Toxorhynchites), a large and distinctively blue fly, 

is one of the few beneficial mosquitoes. Larvae eat other mosquito larvae and adults do not bite. This male was sucking goldenrod nectar in Garner, North Carolina.

Following my degrees I have worked on various projects including a computer-readable glossary for the anatomy of wasps, bees and ants (Hymenoptera) and a citizen science project on the arthropods (insects, spiders and relatives) that are found in Triangle homes (a project through NCSU and the NC Museum of Natural Sciences).

Now I’m here in the clinic! I am very excited to help people find out what little leggy things are on their plants, eating their crops, and inside their homes. Please feel free to send photos or specimens to the clinic. I will do my best to get an ID, so that a specialist can recommend the proper action. All said, I hope to serve science and the citizens of North Carolina well in this position!

Other facts about me:

• I am a huge (literally and figuratively) insect geek, competing in many insect quiz bowls (Linnaean Games) during my time at NCSU
• I am an avid insect macrophotographer (my Flickr) and graphic designer
• I enjoy music, movies, games and cooking
• Last but certainly not least, I have an amazing wife and daughter, and a baby on the way (as well as two dogs)

¹ I also love reptiles, amphibians, fish, and many other groups of organisms (even plants!)
² I highly suggest anyone interested in flies read Harold Oldroyd’s captivating tales in The Natural History of Flies – it is very easy to read except for some scientific names (which you can just pretend are like the variously named creatures from Tolkien or Dr. Seuss!)

Entomologist David Stephan to Retire

(Special thanks to Dr. Jack Bacheler, whose words formed the nucleus of this blog.) 

David Stephan, circa August 1973

After almost 40 years, David Stephan will step down from his position as the Entomology Specialist for the Plant Disease and Insect Clinic. Dave has been responsible for the identification of all insects, spiders, mites, and many other kinds of pests submitted to the Clinic by the public, extension agents, consultants, pest management companies, and researchers. Dave developed a reputation for being able to identify anything dead or alive that walks, digs, flies or swims. He was often called upon to identify the cause of arthropod plant damage even in the absence of physical remains of a pest.

Also a competent herpetologist, Dave additionally carried out a number of special identification and research projects with NCSU faculty, other scientists and students; worked closely with personnel from the NCSU Insect Museum; and was extensively involved with homeowner and agent training in the identification of insects and other arthropods. He was a regular presenter on satellite (later internet) training sessions broadcast several times a year to Cooperative Extension Agents and Master Gardener Volunteers.

David Stephan, April 2011

Dave's knowledge is not only broad, but deep. Beyond being able to identify many "critters", as he calls them, he also knows their life cycles and natural history. He has spent thousands of hours on the phone explaining insects and what they can and cannot do. We celebrate with Dave that he'll now have more time to spend in his beloved outdoors and doing the sorts of entomological taxonomy he enjoys, without the pressures of the clinic.

Beyond his formidable technical skills, Dave's diversity of interests and talents will be missed in the PDIC. Without Dave's black belt in the art of bad puns, the clinic will be a safer but duller place. He is a connoisseur of weather, of new words, of motion pictures, and of science fiction, particularly the Star Trek and Babylon 5 series. In spare moments we've chatted about everything from Broadway show tunes to the refractive index of diamonds. His is a mind that makes connections.

Last week, colleagues old and new joined to thank Dave for his many contributions to the Plant Disease and Insect Clinic, the Entomology Department, the North Carolina State University Extension Service and to the citizens of North Carolina. Since a replacement entomologist has not yet been hired, there will be a period of time during which insect identification services will not be available at the clinic. Please see the announcement on our home page for details.

Dave, don't forget: live long and prosper.