Category Archives: General Entomology
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.
The fall semester has started, but instead of mourning the end of summer break, I’m quite excited to be teaching again. I am the TA for general entomology this fall, with my advisor as the instructor. It’s offered every other year, so I’ve had to wait patiently (and TA intro biology labs) for my chance to dive in again.
So far it seems like we’ve got a really motivated, enthusiastic class. Some of them already have experience working in the entomology collection, or with volunteering/working in our lab – they’re going to keep me on my toes, for sure.
For one weekend we embarked upon our traditional field trip, along with the Yale entomology class, to the Yale Forestry Camp at Great Mountain Forest in Norfolk CT. The purpose is to jump-start their insect collections, which make up the majority of their grade for the course. But it’s also a great time to learn collecting techniques, bond with classmates, meet other students/researchers, and just have fun outside. We had about 35 people at the camp, which was a large number of people to wrangle and feed, but we survived! We used just about every sort of insect trap device there is.
I thought I’d share some highlights from the trip.
Working in the laboratory.
We’ve had a few mini field trips locally since then, always a lot of fun, always a lot of cool insects.
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.
Last weekend we took the general entomology class to the Yale Camp at the Great Mountain Forest in Norfolk, CT. We joined up with the general entomology class from Yale. Dave likes to plan this trip every time he teaches the course. Not only do the students catch a lot of insects, but it allows for good class bonding time, since we encourage a lot of interaction during the lab portion of the course.
Even though there was a severe storm Saturday afternoon, we were able to make the most of our time there. Lots of blacklighting Friday night, a late night caterpillar walk, sorting and pinning specimens, quizzing the students to help them study, lounging by the fireplace, insect charades, and staying up late gossiping. Some people left Saturday night, some left early Sunday, and some of us went for a beautiful morning hike. I caught about a dozen Acronicta caterpillars on red and white oak – really important for my research. So I was quite pleased.
Here are a few pictures from the weekend… check out our class flickr page for more.
Dave giving a lecture on caterpillars.
At one of the many blacklighting set-ups we had going. Lots of insects, and lots of red efts that came to eat them!
Two of my little Acronicta caterpillars. Aren’t they adorable?
The biggest caterpillar you will ever see in the northeast – Hyalophora cecropia. He spun his cocoon the next day.
Classes started this week – how did that happen so fast??
I am the TA for general entomology. Somehow ended up with four students from field entomology (you mean I didn’t scare them off?), which means they already know my tricks, which means I’ve got to come up with some new material (lectures, quizzes, jokes) this semester. And I have to find a way to reel myself in and listen to the professor (my advisor) and do things his way. That will probably be the most challenging part!
So far it seems like we have a really great group of motivated students – I’m excited to spend more time with them and help them with their collections. We won’t be doing as much collecting during class time as field entomology, but we will take some fun trips.
I have a flickr page for the class that I started here, if you’d like to see the sorts of things we catch around CT.
This is the craziest thing we saw on our walk today- an ambush bug eating a bee. But what are all the flies doing? Any idea on ID or what the swarming is about?