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Post by rayrard on Aug 18, 2014 9:36:56 GMT -8
Hey everyone,
I had brought a jar of moth specimens killed in ethyl acetate home and they were killed laying in a "normal" moth position (wings laying flat out). I took them out of the ethyl acetate and put them in a tupperware into the freezer for the night. Now today when I took the specimens out of the freezer and they thawed out, the specimens folded up into a wings-down "V" with the forewing muscles locked up very rigidly. The wings are so locked up in the downwards position that even using forceps the wings do not want to fold up, and even worse the wings start folding at the shoulder in some specimens when I try and flex them up for pinning.
Now why do they thaw like this and how do I avoid this. If I pinned them last night without freezing they would have remained in relaxed, flat positions, but if I left them until today they would have dried out. Is it something about killing in acetate and then freezing that causes the muscles to contract to full downbeat position? It makes it much more frustrating to pin.
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Deleted
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Post by Deleted on Aug 18, 2014 10:13:05 GMT -8
I dont use a killing agent. Freezing does it. I have had some specimens fold up and some have not. I know one thing for sure catocala are hard enough for me to spread without them folding up.
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Post by rayrard on Aug 18, 2014 10:21:16 GMT -8
If I'm in the field, I need to use a killing agent or else the specimens will beat each other up
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Deleted
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Post by Deleted on Aug 18, 2014 14:49:09 GMT -8
I don't ever catch enough have to worry about that. I can hold all the specimen jars I need with both hands.
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Post by nomihoudai on Aug 19, 2014 0:03:46 GMT -8
I keep my specimen in the killing jar until I go home. Then I transfer all the Geometridae and flat winged moths into envelopes. At that moment their muscles are still soft and easy to move. Then I freeze everything if necessary. I hope this helps with your problem.
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Post by Adam Cotton on Aug 19, 2014 7:02:28 GMT -8
If you can get it I think a KCN killing jar does not have the same effect as ethyl acetate.
What you have experienced is a form of rigor mortis. If you put these specimens into a relaxing box for 24 hours after removing them from the freezer they should lose their stiffness.
Adam.
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Post by exoticimports on Aug 19, 2014 7:06:20 GMT -8
I don't use any killing agent when in the field. I simply put the bug into a glassine envelope and stuff it into the box. Just don't put so many in that it squishes the abdomen. I've carried specimens for hours that way with zero damage.
If you are collecting at a light and get big moths (or beetles) just us a syringe and shoot them with a little alcohol.
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Post by admin on Aug 19, 2014 12:19:10 GMT -8
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evra
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Post by evra on Aug 19, 2014 14:07:53 GMT -8
It sounds to me that they might be at least somewhat dried out. If they really got soaked with ethyl acetate in the killing jar, they get stiff no matter what you do. I would start by field pinning them and then putting them in a relaxer for 3-4 hours. You should be able to squeeze the thorax with forceps to be able to move the wings.
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Deleted
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Post by Deleted on Aug 19, 2014 14:32:23 GMT -8
I think I'm going to give Adam's suggestion a try when the time comes. Some Catocala seem to "dry" out even when put fresh in the freezer. The common denominator may be if the specimen had recently eaten anything before it was captured. A "empty" moth may just dry out faster.
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Post by admin on Aug 21, 2014 10:12:59 GMT -8
I think I'm going to give Adam's suggestion a try when the time comes. Some Catocala seem to "dry" out even when put fresh in the freezer. The common denominator may be if the specimen had recently eaten anything before it was captured. A "empty" moth may just dry out faster. It is so easy to rub the scales off the thorax of Catocala. For these I am very careful. I try to use a jar instead of a net whenever possible. I hit them hard with ethyl acetate in a kill jar with a Plaster of Paris bottom, so that they are stunned quickly without flapping around and damaging themselves and without touching any liquid killing agent. Then I remove them from the jar as soon as possible with tongs and carefully fold them up in a glassine envelope. I put the envelope in a ZipLoc plastic bag so that the specimen does not dry out and put that bag on ice in a cooler. It is actually better if the specimen is still alive. Then when I get home it goes into the freezer - still in a sealed plastic bag. I can spread them later with no problems. |
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Deleted
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Post by Deleted on Aug 21, 2014 12:59:13 GMT -8
Clark,
Have u ever had the wings fold up? I have some of mine do it and some dont. I have noticed the ones with folded wings are more brittle even stored in the same container with the ones that stay flat.
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Post by admin on Aug 21, 2014 18:31:51 GMT -8
Clark, Have u ever had the wings fold up? I have some of mine do it and some dont. I have noticed the ones with folded wings are more brittle even stored in the same container with the ones that stay flat. I fold the wings up after capture and then freeze them fresh in glassine envelopes. I've never had their wings fold up on the spreading board, if that's what you mean. If you freeze them when they are just stunned and not dead then that is the best. They are very supple when thawed. But you need to prevent freezer burn so they should be in ZipLoc bags. |
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