Tag Archives: The Wonderful World of Insects

Borers, Odd Insects, Wood-attacking Insects

Bobbleheads of the Insect World

During the winter months, I often get reports of intimidating-looking, but harmless and quirky wasp-like creatures known as “wood wasps” (Family Xiphydriidae).  What makes them quirky?—They’re basically the bobbleheads of the insect world, which always reminds me of going to baseball games as a kid.

Having “wasp” in the name can evoke a certain amount of anxiety, and you can already guess that wood wasps are related to the yellowjackets and paperwasps of late summer.  However, the wood wasps belong to an early branch within ant/bee/wasp group (the Order Hymenoptera) and lack the anatomical structures and ability to sting.

Side view of a “wood wasp” showing the scrawny “neck” and “bobblehead” appearance. Photo Credit: PJ Liesch, UW Insect Diagnostic Lab

Wood wasps have a distinct appearance, so once you’ve trained your eye, they’ll be hard to miss the next time around.  These insects tend to be about an inch long with slender, dark-colored bodies and orange legs.  There are often some pale stripes or patches on or just behind the head and in some cases the tips of the antennae can be pale as well.  The most diagnostic feature gives wood wasps their bobblehead status in my book—the bulbous head of these insects is attached by a scrawny “neck” when viewed from the side.  You can even imagine it bobbing back and forth, if only a tiny spring were attached.

You might ask yourself, how are these insect bobbleheads active in winter when most other insects are scarce?  The answer boils down to firewood.  The pale, grub-like larvae of wood wasps live in the wood of dead or dying trees.  When these trees are chopped into firewood, we end up hand-carrying the insects into our cozy winter abode.  If the wood isn’t used in the fireplace right away, the larvae take advantage of the spring-like conditions and transform into active adults indoors.  To those unfamiliar with wood wasps, you can scratch your head for days trying to find the source, but once you recognize them and their origins, moving the firewood to a colder location is the simple fix.

Beetles, Big Bugs

Buckets of Beetles

Many naturalists will relate to this post: as nature enthusiasts, everyday tasks sometimes end up taking much longer than expected due to fascinating biological distractions just beneath our feet.

As I was mowing the front lawn over Memorial Day weekend, I stumbled upon a prehistoric-looking stag beetle, which is always a neat creature to come upon.  As an entomologist, my first instinct was to pick it up to make a closer examination.  Typically, I run into stag beetles a few times each year and it’s usually the large, “reddish brown stag beetle”: Lucanus capreolus (see image below).  The beetle I found was a bit smaller, darker, and lacked the bicolored legs of L. capreolus, but was still a good-sized insect at over an inch long.  After a beverage break and some Internet browsing, I figured I must have been looking at the closely related Lucanus placidus.  Interesting, I thought, and placed the stag beetle back on a portion of the lawn that had already been mowed, lest it face the wrath of a metallic tornado.

At roughyl 2 inches long, the "reddish brown stag beetle" (Lucanus capreolus) is amongst our largest beetles in Wisconsin. Photo Credit: PJ Liesch, UW-Entomology
At roughly two inches long, the “reddish brown stag beetle” (Lucanus capreolus) is amongst our largest beetles in Wisconsin. Photo Credit: PJ Liesch, UW-Entomology

Another pass or two with the mower and I spotted a few more stag beetles.  I was no longer simply stumbling upon these beetles—something else must be going on.  Once again, I stopped mowing to take a closer peek in the taller grass, only to find even more beetles.  Within the span of five minutes, I had found nearly forty stag beetles in the lawn near a low spot where a tree must have previously stood.  As with the first specimen, I gently relocated these beetles and rushed to finish mowing in the dwindling light.

Around 10:30 PM, I wandered back outside with a flashlight to see what the beetle situation looked like.  I had no idea what I was about to stumble upon—hundreds of battling stag beetles!  Male stag beetles use their large mandibles to compete for females, which made my front lawn seem like a combination of the Bachelorette mixed with Gladiator.  It was astonishing to see the sheer numbers of stag beetles present in a single spot at a given time.  In an attempt to count them, I starting placing them into an empty flower pot.  The forty I had spotted earlier seemed like a drop in the bucket—quite literally!  The bucket was nearly full to the brim with 250 beetles, and I eventually stopped counting.  I’d estimate that I spotted nearly 400 stag beetles in a single night.

A handful of battling stage beetles. Photo credit: PJ Liesch, UW Entomology.
A handful of battling stage beetles. Photo credit: PJ Liesch, UW Entomology.

I did eventually confirm that the species of stag beetle in the lawn was Lucanus placidus.  According to the scientific literature, aggregations have been noticed in lawns on occasion.  In Kriska and Young’s “Annotated Checklist of Wisconsin Scarabaeoidea” (2002) an aggregation of 15 males and females was once noted beneath a black oak tree in the state.   I’m not entirely sure what kind of tree used to occupy the low spot in my front lawn, but the stag beetles obviously loved it (note: stag beetle larvae live in decaying wood).  As an interesting side note, the same low spot was also home to the “Dead Man’s Fingers” fungus (Xylaria polymorpha), another biological curiosity in its own right.

It’s amazing what you can find in your own back yard or front lawn if you take the time to look!

Pollinators

Be Thankful for Insects

As we’re sitting down for the Thanksgiving feast, there’s one thing we should all be thankful for, whether we realize it or not: insects.  It turns out that insects are involved one way or another with many of the foods we’ll be stuffing ourselves with.  Without those very insects, the dinner table would have a drastically different appearance.

Squash Bees (Peponapis pruinosa) inside of a cucurbit flower. These bees are partially responsible for your pumpkin pie. Photo Credit: USDA ARS
Squash Bees (Peponapis pruinosa) inside of a cucurbit flower. These bees are partially responsible for your pumpkin pie and squash dishes. Photo Credit: USDA ARS

Think about the ubiquitous pre-dinner veggie platter at the family get-together.  If you already have seeds of carrots, celery, broccoli, and cauliflower, you can technically grow a batch of these crops just fine.  But with many vegetables, insect pollinators help produce that next batch of seeds.  Then there’s the cheese and cracker appetizer plate.  Being made from wheat (a wind pollinated plant), crackers technically don’t require insects to be produced.  You might also think that cheese (being a dairy product) is also unaffected by insects.  However, insects play a role in the production of alfalfa, which is a common food source for cows.  Without alfalfa, cheese, butter, and other dairy products would be harder to produce, and could be tough to find at the grocery store.  Oh, and without insects as pollinators, we wouldn’t have the almonds on the outside that smoked cheese log anymore.

Some of the items from the main course don’t rely on insects to make it to the table: turkey and potatoes.  Technically, wild turkeys can feed on insects as part of their diet, although they can feed on many other things as well.  If you’ve recently seen The Martian, you’ll remember astronaut Mark Whatney growing potatoes sans insects to survive, so those mashed potatoes would still make it to the table.  Bread and dinner rolls (from wind-pollinated wheat) would still be around.  We could also have certain vegetables that can self-pollinate without insects, such as lima beans (who doesn’t love a great big helping of lima beans…).  However, some big players on the dinner table rely on insects for pollination, including the many types of squash.  One of the most crucial Thanksgiving dishes, the cranberry sauce, wouldn’t be around as cranberries rely on bees for pollination.  It’d be a sad Thanksgiving if there were no cranberry sauce.

As we finish dinner and get ready to watch football, it’ll be about time for dessert and coffee to perk up. Unfortunately, that’s where some bad news comes in.  Without insect pollinators, we wouldn’t have pumpkins to make the traditional pumpkin pie, or some of the spices, like nutmeg, to flavor it.  The whipped cream to go on top?  Well that’s one of those dairy products that could be hard to come by in a world without alfalfa.  Maybe you don’t care for pumpkin pie and prefer apple, cherry or blueberry pie instead?  Those fruits all rely on insect pollinators as well.  Maybe we’ll forget about dessert and go right for that coffee so we don’t fall asleep on the couch.  Just keep in mind that insects are also responsible for the pollination of coffee plants.

When it comes to Thanksgiving tomorrow, be thankful for family, friends, good health, and also the insects that helped put a lot of that great food on the table.