My question is literally stated already in the title, but I will state it again.
What is the best way to remove Carabidae genitalia?
Is there any specific method or way or preservation/dissection that should be used rather than another?
Thanks everyone, I thank you all for any assistance given.
Cheers,
Connor Graham
As you likely know it is more difficult the smaller the specimen. When I do in rare cases pull genitalia what I take a size 0 or smaller pin, use some pliers and bend the end into a small hook. That will help you catch hold of the aedeagus and pull it out, but it is very delicate work because you have to be careful not to pull it out entirely. This would be a good question to put on Bugguide.net since itās so specific.
@harsiparker might have more experience since I donāt work with beetles anymore.
It is probably just morbid curiosity, but I have to ask why one would remove Carabidae genitalia? And why shouldnāt one pull the aedeagus out entirely? BTW: I had never seen the word āaedeagusā before. Now that Iāve looked it up, Iām trying to figure out how to work it into a conversation.
What a hilariously literal topic.
I tend to push rather than pull. Open the elytra enough to see the top of the end of the abdomen. Use a fairly blunt pin such as a normal dress-makerās pin to break through the tergites maybe 2 tergites before the tip, and push the whole genitalia out the end. No good on dried specimens. It needs to be either fresh or better if pickled for several weeks in 70% alcohol. NOT neat alcohol, as that makes the specimen very brittle. If you want to end up with a nice neat specimen, you might have difficulty getting the elytra back into position. You probably needed to open them anyway to see if it was long or short-winged.
And as for why you would want to remove a ground beetleās genitalia: how else do you pass the time during lockdown?
If the beetle isnāt too big i do this beneath a water surface, so that the specimen canāt slip away and get lost. Besides, you can see more details of the tissue if the specimen is submerged, as the tissue will expand under water, but form a ādropā or āballā when exposed to air.
I use a hooked needle, for small specimen i make a very small hook by hitting a hard surface with the point of the needle. I hold the specimen with a flexible forceps while removing the genitalia.
I really like to do a how-to video of advanced beetle mounting (really small specimen, removing the genitalia), but i canāt attach a camera to my stereo microscope to film the process.
I use one of these containers to submerge the specimen (dont know how this is called in english): https://duckduckgo.com/?t=lm&q=BlockschƤlchen&iax=images&ia=images
oh, and i use acetic acid to soften dried specimen. Alcohol makes them stiff.
This kind of work is frustrating when you start, but it will become easier with practice.
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i think it would be difficult to get rid of the glycerin sticking to the specimen after the procedure. Glycerin will catch water from the air as it is hygroscopic. For that reason it is part of the liquid in my pitfall traps (it makes sure that the trap does not dry out even in hot weather). Glycerin itself will evaporate not or VERY slowly. The specimen from these pitfall traps often have an āoilyā appearance after mounting and drying. I think its because of the glycerin. I would thus not recommend glycerin to soften specimen.
I think they are called a solid watch glass.
Hire a very inebriated mohel.
If I remember, ammonia works pretty well for that.
Short answer is most species of beetle canāt be IDād to species without examining the male genitalia, which have to be pulled out. If you remove them entirely you have to mount them separately, to keep them with the specimen so itās just annoying. I HATE doing this.
If you can manage to get a phone camera rigged up they work pretty well. Just and idea. A video like that would be incredibly helpful!
I looked that up too and I thought it was intresting. I knew insects had privates but I never knew they got dissected
I canāt help with Carabids specifically, but I used to dissect flea beetles many years ago as part of a research project. We used alcohol in a petri dish, a dissecting scope, and a pair of fine (tipped) forceps. Each beetle was poked where the elytra started, and basically I pulled the abdominal exoskeleton off. Males had large bright red/orange testes and were discarded. For females we picked out the ovaries and eggs, then measured the size of the eggs. I think that was done with a compound scope, but itās been a long time ago. BTW, the reason for this was that female flea beetles seemed to stop developing eggs (except for those which were about to lay) when they were captured. The guys in charge wanted to understand why so we could rear them in the lab. Agricultural Research, on Canola.
Aedeagus overall are usually simple to mount or store. If I need it to be kept wet, I keep it in a small vial of alcohol which is labeled with a series of numbers and letters and those numbers and letters match up with those on a small label that is below the normal labels with the pinned specimen. These vials are super tiny and I made a rack for them and I store them on that.
For example, if the genitalia is from Anisodactylus sp., the tiny label, and the label on the vial would say something similar to IAAGSV1. This is actually from one of my A. binotatus specimens. It stands for Isopropyl Alcohol, Anisodactylus, Genitalia Storage Vial 1. The one means that it is the first genitalia preservation of that style that I have done for that specific species.
I have found that sometimes when dead male beetles are found on the sidewalk or side of the road on hot days, I can still remove their aedeagus if they are sun-dried, or just dried over time. I can usually just take ahold of the aedeagus with tweezers, and then I can slide it out without any issues. But only with the dry ones, the freshly killed/dead ones normally ned minor dissection.
Agreed.