The Society for the study of flies (Diptera)

andrewsi25 · 2019-02-19 13:07:19

I have never had much problem at all with specimens greasing, but recently I am finding that some Muscids and a lot of Heleomyzids are greasing up really badly after pinning. Are there factors which can lead to more greasing or is it just a run of bad luck? I am not knowingly doing anything different in the way I deal with the specimens. Heleomyzids are the main ones affected...especially Suillia spp.

Thanks for any advice. I am okay, incidentally, with dealing with it, but just keen to know whether there are ways to reduce it in the first place.

Thanks

Ian

Andrew Cunningham · 2019-02-20 01:20:43

andrewsi25 wrote:
I have never had much problem at all with specimens greasing, but recently I am finding that some Muscids and a lot of Heleomyzids are greasing up really badly after pinning. Are there factors which can lead to more greasing or is it just a run of bad luck? I am not knowingly doing anything different in the way I deal with the specimens. Heleomyzids are the main ones affected...especially Suillia spp.

Thanks for any advice. I am okay, incidentally, with dealing with it, but just keen to know whether there are ways to reduce it in the first place.

Thanks

Ian

Hello Ian,

I find that some families grease up more than others and heleomyzids are one of them. If I have a greasy specimen I wish to retain then I put it in a small pot of fresh ethyl acetate overnight and it clears them very well.

Regards,
Andrew.

andrewsi25 · 2019-02-20 12:34:38

Thanks, Andrew

I do the same. It was more whether there are ways of dealing with the flies to minimise greasing. I just wondered whether something like leaving flies in the fridge for a while before freezing might help. Might it be that specimens taken in winter grease more than those taken in the summer perhaps? Do frozen specimens grease more when thawed out than those killed with ethyl acetate. That sort of thing.

I have not had such a bad run of greasing with Heleomyzids before...it is affecting quite a lot at the moment.

Cheers

Ian

conopid · 2019-02-20 22:39:58

Yes, I too find that Heleomyzids grease up readily. How do you deal with the greasing Ian? I have tried submerging specimens in acetone, but mostly it does not work.

Last edited by conopid (2019-02-20 22:40:13)

Andrew Cunningham · 2019-02-20 23:30:15

conopid wrote:
Yes, I too find that Heleomyzids grease up readily. How do you deal with the greasing Ian? I have tried submerging specimens in acetone, but mostly it does not work.

Nigel. I leave them in ethyl acetate at least overnight. This needs to be fresh ethyl mind, used stuff will have the grease from previous specimens. If they come out still a bit greasy, then I do it again with fresh material until the grease is all gone since the specimens do not have an infinite supply of grease obviously.

Regards,
Andrew.

andrewsi25 · 2019-02-21 00:25:52

Hi Nigel

I do the same as Andrew, and an overnight soaking works well removing the grease, but the specimens do lose some of their natural colour...dusting is affected, I think. I do wonder whether there is some reason why the greasing is more prevalent in specimens taken in the winter.

Ian

The Society for the study of flies (Diptera)

#1 2019-02-19 13:07:19

Greased specimens

#2 2019-02-20 01:20:43

Re: Greased specimens

andrewsi25 wrote:

#3 2019-02-20 12:34:38

Re: Greased specimens

#4 2019-02-20 22:39:58

Re: Greased specimens

#5 2019-02-20 23:30:15

Re: Greased specimens

conopid wrote:

#6 2019-02-21 00:25:52

Re: Greased specimens

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