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Post by prillbug2 on Mar 19, 2011 13:42:30 GMT -8
For beetles, I use ethyl alcohol in a 35mm or larger vial, except when there is long pubescence on the body which could mat up when it's wet. They are dead in less than 10 minutes. I remove them that day so that fats don't leach into the vial. For Lepidoptera, I use ethyl acetate, and have never had problems with killing them. My killing jars are stuffed with a bottom layer of paper towels, with the ethyl acetate poured on them to make a blotter. Then I place a second layer of sheet cotton over that. Result, a weapon of mass destruction. I never have trouble with specimens stiffening, unless I've left them in the jar more than 24 hours, and actually, it takes only five to ten minutes to kill the insect, before they are transferred to an envelope or placed in a dump container with a wet piece of cotton. Micro-moths are killed with Amonium carbonate, lab grade. I only pinch a lep, if there are more than one specimen in the jar. Keeps them from rubbing each other silly. I've never had any problems with spreading anything after taking them out of the jar. It only happens if the insect is left in the jar more than 12 hours, and rigormortis sets in. But it can be relaxed after 24 hours in a relaxing chamber. Oh, by the way, I spread my Papilio androgeus after 24 hours in the relaxing box and that is pretty much how long all of my leps take, because I never take them out of the envelope and use the envelope as a secondary relaxing media, since I use a wetter method than everyone else. I've covered this before in the old forum. Jeff Prill
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Post by bluemoth on Mar 21, 2011 14:57:50 GMT -8
Just letting you know I injected only small tiny amount of Potassium salt in to a small silk moth (Io) at rear part of thorax. It immediately did not move but stayed a bit ridged for about a half hour then slowly relaxed. I have not attempted to spread it but my friend who uses this tekneak has not had any problems. Sense only a very tiny bit need be injected to be effective it did not discolor the scales of my moth. You need a lot more ammonia to kill a similar sized moth. Now if you do not want to pinch your large butterfly or put a big catocala moth into a killing jar ware it will thrash about this is a perfect way to put an insect to sleep. It would work wonderfully on a trip ware there may not be a freezer.
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Post by starlightcriminal on Mar 29, 2011 11:09:37 GMT -8
KCl (Potassium Chloride) is a very effective killing agent. It interrupts the Na+/K+ pump in cells which must be a very specific equilibrium to function. Water intoxication results in death due to the ion concentration in the blood being thinned, thus disrupting the equilibrium. The opposite, over saturation with KCl, also causes an imbalance. Water intoxication can lead to death as can too much Na+ or K+. A lethal injection, for example, is exactly this- the component in the so called "triple cocktail" that stops the heart is an injection of KCl. Hence it is a very effective killing agent, instantaneous more or less, for anything biologic. Shoot for a 3.3M (molar) stock of KCl, that is the saturation limit of this salt. Three tbsp. in 50mL is approximately correct although the molecular weight of potassium chloride varies depending on the source and intended application. It's really not important to be spot on however since the point is simply to undermine the ionic pump of the heart.
It will not destroy the specimens color and will be far more easily spread than something "fixed" with a non-native chemical. There is already K+ present in insects, you would just be adding a little more.
You are correct, this is an effective method of euthanisia and safe for specimens. It has the disadvantage of having to be directly injected though, where cyanide, ethyl acetate, etc. are volatile and can be used in a jar. For me, jar suffocation takes longer and runs a higher risk of damage than a quick injection.
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Post by saturniidave on Mar 29, 2011 15:13:44 GMT -8
Not too good if you miss and jab your finger though? Dave
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Post by starlightcriminal on Mar 29, 2011 16:18:13 GMT -8
Only if you happen to go right into an important pathway that leads directly to the heart. In a moth, a few microliters is a high percentage of their body weight. In people, it's virtually unnoticeable. What size syringe are you using? Now if you main-lined the stuff, say "bye bye." But I suspect any other moth killing agent administered this way would have precisely the same affect (save maybe ethanol at a low enough volume). So an accidental finger prick is ok- a little bit uncomfortable, like salt water in a wound, but ok. Would I recommend carelessly euthanizing moths that are sitting on your femoral artery, no.
Also good to mention it doesn't explode or go bad over time, just gets more concentrated or forms crystals. Overall, probably the safest of the chemistry mentioned here. It is the only we naturally have at high levels in our bodies.
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Post by Chris Grinter on Mar 29, 2011 16:18:57 GMT -8
When you consider you're injecting a massive (relatively) dose of liquid into the body water is the only thing that won't work right away (but still does eventually). I use windex, ammonia or ethanol to inject when I'm in the field, it's instant.
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Post by saturniidave on Mar 29, 2011 16:37:55 GMT -8
Unless I am very far from home all my material is bought home alive and put in the freezer after a second inspection, the first being when it is caught. I use a 'coolbag' or other type of cooler with 'freezer packs' inside, when kept cold and in absolute darkness I find almost all moths settle down very quickly and remain so until I put them in the freezer. I do of course put them individually into small plastic pots first. There are a couple of species that won't settle whatever you do so an ethyl acetate killing jar is also taken, if they are not killed fairly quickly they are stupefied enough to calm down in the coolbag. I find this method pretty good as it lets you have a good look at the moths before you kill them so avoiding any unnecessary killing of damaged or unwanted moths. These are released in the garden or in a nearby habitat similar to the one they were collected in. On distant trips I purely use ethyl acetate, keeping the killing jar well topped up. Dave
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Post by papilio28570 on Mar 29, 2011 20:11:03 GMT -8
Ammonia injection here. Instant death from less than a drop and no rigor mortis. Small leps get pinched, placed in envelope and then placed in EA jar when I get back to camp or the truck.
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Post by starlightcriminal on Apr 4, 2011 11:17:19 GMT -8
It seems we have some confusion regarding "stiffness" and rigor. Rigor is a chemical reaction, "stiffness" can be either from actual rigor (crosslinking of myosin/actin resulting from Ca+ ions diffusing after death) and the stiffness that occurs from dessication. If you are worried about real rigor, it doesn't really matter which chemical you chose since both actin and myosin will denature over time regardless of what you short of extreme, permanent freezing. Dessication can be a whole other issue- not all molecules that once were "wet" will become "wet" again and often if they do it is with considerable loss of integrity.
I prefer freezer method myself but have used EA, KCl, a few ethers and various alcohols in a pinch. It's always worth experimenting a bit with something that isn't terribly valuable. I still prefer freezing. Killed and stored in one fell swoop.
Ammonia, like KCl, would be a native product so it too should be quite safe for specimens over the long term.
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