A parasitoid is an organism that spends part of its life living inside or attached to another ‘host’ organism. Often, in general entomology classes the scenes from the “Alien” movies are used as imagery to describe the parasitoid-host relationship (i.e., the xenomorph).

I realized that I have several posts on woodwasps (see here too), but never really talked about their biology. Woodwasps have fairly long ovipositors that could potentially fool people into thinking they have long ’stingers’, but in all reality they don’t sting at all. Woodwasps are attracted to dead or dieing trees and use those long ovipositors to lay eggs into the wood of the tree. When they lay eggs in the trees, they also inject fungus and mucus. As the larvae develop they feed on the fungus deposited by the female. Woodwasps have several different natural enemies, a couple of them being parasitoids. Ibalia is one such parasitoid. Ibalia is attracted to the fungus and eggs of the woodwasp and the female deposits an egg of her own inside an egg or first instar larva of the woodwasp. The Ibalia larva develops within and eats the woodwasp larva from inside out, eventually killing it.

Upon opening up the body cavity of a woodwasp larva I was preparing to dissect, I was greeted by something unexpected…a little Ibalia larva.

A striking resemblance to the xenomorph, eh?

Anyone want to ID those birds for me?

(Ok, so someone is just now learning how to play with photoshop, trust me, I am not that crazy)

Warm and Fuzzy Holiday Wishes To You All!

I drive by this lovely little pond every morning on my way to work. Today I was able to snap a shot of the early morning fog before hitting up the office. There’s no better way to start your morning than on cool, quiet shores.

So, the more I get used to the ins-and-outs of this website, the more I poke around other websites to see what others do, and the more I notice different trends.

One of the things I find quite peculiar is that several sites have a side bar called an “Amazon Wish List” or something to that extend. From what I can ascertain, people make up a list of things they’d like and generous folks can purchase it for them, donate money to their paypal account, or what have you.

Now, I can’t say that I am presumptuous/bold enough to do something like that (yet), but it did give me an idea.

When I was first starting out my insect collection I used to have my family and friends send me dead specimens from their respective parts of the world. Odd as I am, I really enjoyed getting random bugs in the mail from all over. And it was always really fun to hear the collecting stories my friends and family had.

Hence, I got the idea to start an insect wish list. At this point I don’t think I need to be so specific as to narrow it down to certain species, but if you would like to nab me a bug and mail it to me for my personal collection, I would be much obliged. I could even start featuring photos of the specimens y’all send in and you could see what kinds of things people are finding around their homes, gardens, and sides of the world.

So, here are some collecting guidelines:
1. My friends and family have put the insect specimens in all sorts of containers ranging from envelopes, ziplock baggies, tupperware containers, and film canisters. I have found that envelopes and ziplocks put inside tupperware actually work the best for keeping the body parts safe from crushing. Or, just putting the envelopes/ziplocks in the cd/small box-shaped cardboard from the post office works well. If you are well-equipped and so inclined, you can also pin the specimen(s) before you mail it.

2. Once you have collected your insect (dead or alive), put it in the freezer for at least a day or two to make sure it stays dead and you kill any thing that may be trying to hitch a ride. I know it sounds a bit strange putting insects in your freezer, but if it makes you feel any better, lots of entomologists do it One of the perks of putting the insect in the freezer, aside from killing it, ensures that when you thaw the body out and go to pin the insect, the internal organs/hemolymph help stick the insect to the pin by acting like a glue.

3. Be sure to include a note that details who it was collected by and the location (i.e., city, state). Also include what it is (if you know) and if there are any local common names for it.

4. When you are ready to mail it to me, click on the ‘ask an entomologist’ tab and send me a little message saying that you would like to mail me an insect specimen and I will respond with a mailing address.

5. Only accept this invitation if you don’t mind paying for postage, unless you have a lot of really cool stuff, than we could arrange something.

Or maybe he just had a hankering for the wrapper…

Luis:

What goes on inside a pupa?

There are three different types of insect metamorphosis (ametabolous, hemimetabolous, and holometabolous). Insects that are holometabolouss have a complete metamorphosis and go through a pupal stage.

The pupal stage is often referred to as the inactive phase in the insect life cycle because the insect isn’t moving or eating, however, physiologically speaking there is much internal activity taking place. Most internal reconstruction occurs in this stage.

I’ll just stick to the holometabolous insects for simplicity sake. Once the larva molts to the pupa, histolysis (the breakdown of tissues) and phagocytosis (the ingestion of bacteria and foreign bodies) takes place.

During this time (when the larva molts to a pupa) the developing wings, which have been developing internally in the larva, become everted and visible. Reconstruction begins to take place after histolysis, and the adult appendages begin to develop from epidermal thickenings called imaginal buds/discs. The details of the imaginal disc development vary between insects.

The muscular system goes through a lot of modification and the different muscles’ fate can either:

1. Pass through the pupal to adult molt unchanged,

2. Be destroyed and not replaced,

3. Destroyed and replaced,

4. Existing muscles reconstructed,

5. New muscles formed that weren’t previously there (formed by free myoblasts)

The alimentary canal (which is the esophagos, forgut, midgut, and hindgut) is remodeled differently depending on whether the insect eats a different diet as an adult compared to when it was a larva. Generally the forgut and hindgut are formed from imaginal rings, the midgut is reformed by regenerative cells in the epithelium.

The trachea (breathing tubes) shows almost no change, with the exception of new branches. The circulatory system also shows little change during the larva-to-pupa-to-adult molt. The central nervous system becomes more concentrated, the nerve cells and glial cells increase in number.

The control of metamorphosis (i.e., all of this stuff I have been talking about concerning the larva to pupa molt and the molt to adult) is controlled by hormones, including juvenile hormone, and ecdysone.

To escape from the pupal cuticle, hemimeabolous insects swallow air to increase volume and split the cuticle along a line of weakness. The adult pulls itself out, often with the help of gravity, and begins to expand its wings by pumping them. For holometabolous insects, escape from the pupal cocoon is a bit trickier. Different insects have developed different ways to escape, some have mandibles to chews through the pupal case, some have spines on their abdomen that help break through the case as they moved back and forth, and some produce softening secretions that actually break down the case.

Much cooler though are of course the cyclorrhapha flies. They have a structure called a ‘ptilinum’, which is a membranous sac (or basicaly a balloon) that is everted by pumping blood. The balloon presses against the puparium wall and splits the line of weakness.

Picture courtesy of http://entomology.unl.edu

Whew! So, all of that is going on during the ‘inactive‘ stage of the insect.
If you’d like to read a more detailed description, “The insects: Structure and Function” by Reggie Chapman, is the book I used as a reference for this post.

Remember my previous post on winter moths?

Well here is an update.

One of the women in the lab I work at brought in 3 females that had been outside her home. If you remember from that other post, the females don’t fly and don’t have developed wings. Lucky for you an me, I happened to have my camera at work that day.

Note the size difference between the female and the dime.

And in the picture below you can see the long scales on the non-functional wings.

You can imagine what they chock that abdomen full of…eggs.

Quite a striking difference between the males and females, don’t ya think?