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Yes, keeping flies in 98% (absolute alcohol) is usually only necessary if they are being used for DNA analysis. This grade of alcohol will dehydrate specimens more and will also be more difficult to curate because the spirit evapourates too fast. Diluting it to 70% slows down evapouration and dehydration, but for soft-bodied flies it is always preferable to take them through a rehydration/extraction process to prevent the specimen from shrivelling up when the alcohol evapourates. But for tachinids I haven't found this necessary.

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yes. I know. I will send some for DNA analysis.

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Very informative thread. A few more newbie questions.

- How do you hold the flies when pinning not to break bristles etc? They are generally quite fragile, I believe.

- How do you arrange the legs and wings in the right position? I think lepidopterists use (rice) paper to pin down the wings when drying.

- How do you know what pin size to use? Are there a rule of thumb for this?

- If killed in alcohol. Can the flies be pinned directly or do they need to be dried first? ... or maybe you never pin flies that have been in liquid?

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"How do you hold the flies when pinning not to break bristles etc? They are generally quite fragile, I believe."


I put the fly on the table and simply I push the pin manually against the table (of course, I use a protection to avoid damage for table). Then I use another pin to help putting the fly in the middle of the pin.
Of course, I do this with 100% concentration and holds the fly very gently. There are specific FORCEPS SOFT that can help you to handle soft and very fragile specimens.


"How do you arrange the legs and wings in the right position? I think lepidopterists use (rice) paper to pin down the wings when drying."

Gently with a forceps soft, for example. Or with a normal pin!

"If killed in alcohol. Can the flies be pinned directly or do they need to be dried first? ... or maybe you never pin flies that have been in liquid?"

YES. You can pin the flies even AFTER they have been in ethanol.

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I guess the fly must not be too dry to be able to adjust the wings. I thought the wings (and legs) might revert back to original position when trying to move them. There must be a reason the butterfly collectors use pin and paper to set them in the wanted position.

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right, crex. It is important to pin the fly very early because they turn very brittle with the time. Not just for wings, but bristles as well.

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The way people arrange a specimen when it is pinned is largely dependent on the way the insect is identified. Lepidopterists mainly use wing pattern so it's important to arrange the wings so all 4 are visible. With Diptera it isn't so important to pin them like that and in fact I prefer specimen side-pinned with wings at 45-degrees so that areas under the wings (the legs and pleurae) are also clearly visible.



Flies are quite soft and floppy until they have dried so any pinning and arranging must happen while they are soft and pliable. In a relaxed state they can be handled easily with pointed forceps. Once pinned the specimen is always held using the pin.

How do you arrange the legs and wings in the right position? I think lepidopterists use (rice) paper to pin down the wings when drying.

I side-pin into a sheet of foam and if anything needs holding (not wings - usually genitalia or legs) I use more small pins, crossed to hold the parts firmly.



In general you should use the largest diameter pin you can without damaging the specimen (within reason). It is a thing you learn with experience and by seeing other specimen collections though. My advice is to go to a museum and ask to see their collections.



Flies out of alcohol tend to be fairly floppy but stiffer than if freshly caught. The worst thing with alcohol is that the genitalia are usually locked fairly tightly and when the alcohol evapourates some soft-bodied flies can dehydrate and crumple. I am lucky because tachinids don't usually have this problem so they would just need to lay on some paper for a few minutes to drain away most of the alcohol and then thay can be pinned.

Chris R.

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Would be nice to see some of your flies being pinned and drying. Mine look like they're being give a session of acupuncture.

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Is there a preference for fixating the specimens (poison, freezing...)? Has anyone noticed any up or down sides of any method?

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I like Tony T's collection
Johl daniel

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I find the boxes from www.ento-meier.de superior. They are quite expensive though. www.kabourek.cz has good stuff too.

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Hello Dipterists,

Just a quick post to say how useful I have found this thread. So far I've just examined flies that have died and fallen to the floor of my conservatory. However they are fragile and hard to manipulate to check features against the keys. So I'm thinking that maybe I should join the mainstream and start pinning fresh specimens. On the basis of this thread and Chris Rapers excellent article at http://chrisraper...rating.htm I have placed an order for pins, plastazote and forceps with Watkins and Doncaster, along with a drilled pinning block to standardise the positioning on the pins, although I have only the haziest idea of how to use this. Thanks to Diptera.info for providing such a valuable resource!

Martin

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Welcome to the forum Martin - I'm glad you enjoyed my article. I am planning more in the future that should cover other aspects of entomology and expand on some of the stuff I started in my blog.

Feel free to message or email me if you want to ask anything. There are some very good dipterists in your part of the world so I'm sure you'd be welcome to go out in the field with some people this year.

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@Chris

I have began to pint flies laterally, but all the way, my main problems are in how to shape legs unfolded downwards and wings at 45º. I do some "acupunture" with small pins to fix the legs in the best way and wait some minutes.

I usually take them out of Barber liquid (a relaxing liquid, it might work as well as ethyl acethate).

I am working with flies collected in liquid traps (a solution to attract the olive fly) so I got hundreds of Muscidae, Sarcophagidae and Calliphoridae and, I has short experience, I found the legs folded in the body and is quite difficult to see the meron. Is there an easy may to manage with them?

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@Rafael

I tend not to worry too much about making the wings and legs perfect but if you do want to make sue that the meral bristles are visible then I think you are doing the correct thing - use micropins to hold them in the correct position. The advantage of lateral pinning is that this kind of manipulation (and more importantly the male genitalia) is possible because you pin it against a large piece of foam. When you get more experience you won't need to look for meral bristles - you will just know which family the flies fall into.

I know of Barber's fluid but I tend to use normal water - just make some tissue paper wet and lay the flies onto it for 24-36 hours. Ethyl-acetate has the opposite effect - it dries specimens and makes them harder and more brittle. That's why you tend to only use ethyl-acetate on greasy specimens that are already pinned

The most important thing to work on with sarcophagids is to expose the male genitalia - you can ignore the females if you have lots of good males. When sarcophagids are not soft they will be very hard to manipulate, so try to pin them as fresh as possible or very well relaxed otherwise you will rip-off the genitalia, trying to fold them open