Category Archives: Invertebrates
It’s finally fall here in New England, and the insects are on their way out – either dying, or bundling up for the winter. However there are always a few that cling to life through the first few cold nights, unwilling to admit that summer is over (I know that feeling quite well).
Here are a few caterpillars I found while walking in a nearby park at dusk.
First is Schizura unicornis, the Unicorn Prominent, of the family Notodontidae. In this photo you can see the “horn” from which the name is derived. It looks as if the caterpillar is molting, with the old head capsule just barely clinging to the head.
This species overwinters as a larva, fashioning a protective cocoon in leaf litter. They wait until spring to actually pupate, which is unusual amongst caterpillars (typically pupation occurs in the fall, and the winter is spent as a pupa). I imagine these caterpillars will be above ground feeding until their host plants succumb to the cold.
These caterpillars appear to be Hyphantria cunea, the Fall Webworm, of the family Erebidae. There were several fuzzy clumps of them on various plants, surrounded by loose webbing. These guys will continue to live gregariously in their messy webbed homes until they are ready to pupate in preparation for the winter. I’ll keep on the lookout for others, there are still plenty of hardy, determined caterpillars out there.
That was the question a student had this morning.
The caterpillar was wiggling a bit, but didn’t look so good. Upon closer inspection, it appeared it had burst open, and something was actually… inside of it.
Without further ado, here is what happened next:
I have yet to identify the parasitoid, it appears to be a fly maggot of some sort. I will be back with an update if we put a name on it.
Yes, it had eaten all of the caterpillar’s insides.
No, the caterpillar is no longer alive.
[UPDATE] The maggot is in the family Tachinidae.
Dermestid beetles (family Dermestidae) can either be a useful ally or a nuisance, depending on your point of view. There are several hundred species worldwide, and many have found ways to either enrich or aggravate our lives.
If you are interested in taxidermy or specimen preparation, these industrious beetles are one of the best ways to de-flesh and clean skeletons. Entire colonies are kept by hobbyists, universities and museum collections and put to use, both adults and larvae feasting on an array of carcasses. They especially enjoy hair, skin, and feathers.
Due to their knack for feeding on dead or decaying materials, they are essential outdoor decomposers. Some species prefer plants, some prefer animals, and some get rather esoteric in their choices (like specializing on praying mantis egg cases). Our knowledge of these ecosystem services also allows us to use them in forensic investigations.
But most people don’t think of these applications. They are more concerned with the “larder beetles” in their pantry, pouring out along with the cheerios into their cereal bowl. Or “carpet beetles” munching on wool coats, or silk scarves, and other natural fibers in their closet. Any open window is an invitation for a visit.
And if you’re an entomologist, the phrase “dermestid beetle” should strike fear into your heart. All the qualities that make these beetles desirable for cleaning vertebrate skeletons makes them especially destructive if let loose in an insect specimen collection. These beetles don’t just like the taste of skin and fur, they have quite a fondness for insect chitin and dried innards.
Every entomologist I know has horror stories of dermestid beetles infesting their collection. The main specimen collections here at UConn are chemical-free, meaning they have strict quarantine procedures in order to thwart these beetles and other pests. Specimen boxes must be frozen twice, if they’re allowed inside at all.
I was cleaning out a storage room for the entomology teaching lab, and came across a set of student specimen boxes. That had been overlooked since 1994. Needless to say, dermestid beetles had a feast. The boxes were absolutely filled with insect bits and old dermestid skins. Just about all of the specimens are ruined, and will be thrown away.
So, what should you do? In your home, make sure all food containers are tightly sealed and secured (anything that comes in a bag, I transfer to a jar). Store winter sweaters and other important clothes in sealed containers or plastic bags. Ensure all household screens are tightly fitting with no gaps.
For an insect collection, you can choose to use chemicals like mothballs, but they wear off after a while (I have personally observed collections with chemicals tacked into one corner… still filled with dermestid damage. See the first image above.) Your best bet is to keep the collection sealed in a tight wooden box or glass topped drawer. Cardboard boxes, such as we give students, should be temporary. When in doubt, if a collection will not be regularly used, keep the box(es) in a sealed plastic bag of some sort. Also keep workroom/lab windows closed, or ensure screens are tightly fitting. My advisor likes to say “dermestids smell insect specimens the way you smell Starbucks!” Which may or may not be true. Probably true.
If you hear the phrase “monkey slug”, your first thought is probably not of a caterpillar. But that is indeed the common name for Phobetron pithecium, a caterpillar/moth in the family Limacodidae.
Limacodidae are collectively known as the slug caterpillars due to their reduced legs and slimy looking underbelly. They even crawl by means of a liquified silk trail that they glide effortlessly across. So that is where the “slug” part of the name comes from. But “monkey”? No one is quite sure. The adults are called hag moths, which doesn’t sound very flattering, though they are adorable little moths.
I have never seen one of these caterpillars in the wild, however a friend of mine (Sam Jaffe of The Caterpillar Lab) was kind enough to part with a few of his fuzzy little charges. I have no use for them in my research, but they have been fun pets.
A few more facts:
They can cause allergic reactions in some people (I have not tested myself yet, but just look at those hairs and spines!). However they have glided across my hands with no reaction, so it would probably require rubbing the hairs into your skin.
They do have a head, but it is usually hidden.
They feed on a variety of trees and shrubs, mine are feeding on oak.
The “arms” can come off, the hairs are in fact embedded in a scaffold of some sort of slime that covers the body. This is a feature common to many limacodids.
Here are some photos I took of these guys today.
I was lucky enough to be invited to be a guest speaker for a National Moth Week event held by the Friends of Taconic State Park in Copake Falls, NY. I grew up in upstate NY, but had never been to that region before. I spent most of the afternoon chatting with my wonderful hosts, eating yummy food, and then I gave my talk and spent the night looking for moths – I’ll hopefully get a chance to go back and explore the park during the day.
My talk was about how every week is moth week in my life, as well as how amateurs can help with our scientific endeavors. I couldn’t do my dissertation work without an army of collaborators around the country and around the world. I’m hoping I inspired a few more people to check their porch lights (or gas station lights). When it comes to basic natural history observations, science is accessible to everyone. And we need all the help we can get!
After the talk a few people stuck around to check out the moths. There were several blacklights, a mercury vapor light, and some bait painted on trees (and soaked into ropes).
One of the first visitors to the blacklight, a Hermit sphinx, Linteneria eremitus.One of the sheets, early in the night.Gathering around the sheet. Poke nature!The new president of the society, Brian Boom, was my gracious and enthusiastic host – and he was well liked by the Pandorus sphinx (Eumorpha pandorus). As usual, I had to pose with a moth on my nose. Darapsa myron. And a few of the other goodies we saw: Top row: Tolype velleda, Acrolophus sp., Herpetogramma pertexalis, Darapsa myron
Middle row: Linteneria eremitus, Haploa confusa, Prolimacodes badia, Lymantria dispar
Bottom row: Haploa clymene, Pantographa limata, Crambus sp., Idia aemula
What a great way to celebrate National Moth Week!
Moth Week continued for me in Keene NH, the home of The Caterpillar Lab, run by the caterpillar photographer/whisperer Sam Jaffe. Sam is a wonderful naturalist, who ambitiously has undertaken this caterpillar outreach project. Sam and his minions currently have a physical lab where they keep their livestock (hundreds of caterpillars!), which is periodically open to the public. They do caterpillar shows at farmer’s markets and museums, you can see their schedule on their facebook page.
Here is just one of their charges… a gigantic Citheronia regalis caterpillar. Also known as the hickory horned devil… for obvious reasons.
We help each other out by trading eggs and caterpillars, and that is always a good excuse for a visit. His intern Liz allowed us to blacklight at her place, and so the bug nuts gathered round. This pic of the sheet was pretty early in the night, it was really hopping by midnight!
It is the time of year for Catocala, the underwing moths. This big one is Catocala unijuga, the Once-Married Underwing (I sure wonder how it got that name?)We also got a few female dobsonflies (Corydalus cornutus), they look like they are straight out of a horror movie. And much more vicious than the males, who have larger, but ineffectual, mandibles.
Waiting at the sheet… We also got a few spiders… this fishing spider ate quite a few of our moths!We decided to take a break from circling the sheet for some gas station light hopping. Sam has a few favorite spots. Despite my enthusiasm, I fell asleep on the car ride (though I’m told I was muttering some weird things in my attempt to stay awake and make conversation). Luckily I rallied and arrived well rested and ready to catch some more moths. There was a big Antherea polyphemus waiting for us, as well as a wall covered in wonderful moths. Including this sphingid, the Hydrangea sphinx, Darapsa versicolor. We were very disappointed that it was a male. Still a nice find though! At the next stop we hit another jackpot – plenty of Acronicta moths for me, and a few other pretties.
I love the patterns on this one, I was excited to finally see one! The lettered habrosyne, Habrosyne scripta, in the family Drepanidae.
We ended up back at the sheet, where I snagged a few more moths. All of these vials contained a female Acronicta, pretty amazing for one night! I’m never disappointed collecting in NH. I did learn something interesting, we have noticed a pattern – the female Acronicta moths tend to come out earlier. Once we get to about midnight, it’s almost all males at the sheet.
Eventually we packed up, sorted moths, and got some sleep. Not a bad way to celebrate national moth week.
When moths emerge from their pupal shell, their wings start out small and shriveled. Over time the wings expand and harden so the moth is able to fly.
Unfortunately, sometimes things go wrong, and the wings aren’t able to expand. We see this periodically here in the lab, and we’re not sure why. Yesterday this little fuzz ball, Proserpinus lucidus, emerged. Perhaps due to the fact that it was not actually due to emerge until spring, its wings never expanded.
For reference, here is a fully formed adult (from Moth Photographer’s Group)
If you have raised moths and/or butterflies before – have you had this experience before, and do you have a sense of why it may have happened? One of my hypotheses is that a moth may spend too much time in the pupal shell once fully formed, and the wings could become hardened before actually emerging. Or in the case of our moth, being kept in a cool room for overwintering, it may have simply been too cold.
The other day we had a surprise visitor in the lab.
We had a Hyalophora gloveria cocoon sitting around in the lab, with the pupa presumed to be dead (the cocoon had a bird peck-hole, so we thought it was eaten or badly damaged). But the moth pulled through, and emerged as a perfectly formed adult! Here she is posing with a few members of the lab. Having a live fluffy moth in the lab was quite a treat for us this time of year.
She hung around for a few days and laid a few eggs before she was destined to become a specimen. We could not release her because 1) this species is from Arizona so we are outside her native range, and 2) it is below freezing here in CT anyway. I am not sure what the destiny of the eggs will be.