I notice that, in the classified ads, there is a "black form" of a D.hercules beetle being offered. Although I cannot comment on this particular specimen I know, from having a number of specimens of D. hercules collected over the last thirty years, that a standard brown coloured D. hercules male will turn jet black purely from grease from the body seeping into the wing cases, and the resultant appearance appears permanent, unless of course the specimen is degreased using petrol or another non- polar solvent. I know other collectors who have found the same thing.
This is not to say that the specimen being offered is not a genuine black form, however, it seems that it is rather more likely to be a greasy "normal-coloured" male.
Last Edit: Jul 3, 2018 22:22:39 GMT -8 by johnnyboy
Patrick, thanks for posting a photo your black Dynastes.
Here is a photo of the Dynastes male of mine. It was wild caught in Ecuador 1993. It started out as with brown elytra but, after I pinned it, grease seeped out of the body, slowly stained the area around the pin until it had covered all the wing cases and turned them jet black. If I soaked it in petrol it would degrease it and make it brown again, however as I have 10 different D. hercules males I'm happy to have a black example.
Post by johnnyboy on Sept 24, 2012 23:10:02 GMT -8
If it is a greasy specimen, rather than a black form, then it would depend on how long it has been "greased up" whether it would reveal its true colour by a simple quick solvent soak or a long bath in acetone or petrol.
In any event, I am happy with my black specimen even though it is caused by grease, (as in many respects this should be considered "natural" as it has not been tampered with or treated with any chemical agents, even if the black colouration is not structural) and I'm sure other collectors would feel the same.
Anyone with any experience of collecting, dealing or breeding Hercules beetles would realise that this is the result of bodyfat rather than structural coloration. However, the advert is quite straight forward and purely descriptive apart from the term "rare" which implies that the specimen is a form which it most likely isn't of course.
The grease has not totally saturated the elytra so it is dark coloured, as claimed, rather than black. The more northerly Dynastes species, such as D. maya, D. hyllus and D. tityus, especially if bred, seem to grease up very readily.
Last Edit: Oct 11, 2012 23:53:56 GMT -8 by johnnyboy
Elmers glue is PVA based. While PVA is not dissolved by pure acetone, acetone has a strong affinity for water and will readily absorb it from the surrounding air. This means that it would be likely that, if you use acetone as a degreaser, it will contain water and will dissolve the Elmers glue that you have used.
If the acetone is pure, because of its strong affinity with water, it has a drying effect which may make the beetle really brittle.
Therefore I would use gasoline, which is a very effective degreaser, rather than acetone to degrease the specimen.
Post by exoticimports on Jul 25, 2018 9:31:10 GMT -8
OK, I have a hercules that was set two months ago and slowly turned black. It is now soaking in lighter fluid. I sprayed it while upside down, hoping some of the fluid would leak under the elytra, then let it settle into the fluid. So far some grease or goo appearing in the fluid. Will report back over time.
Day 2: most of the lighter fluid evaporated. Wiped "goo" off the outside of the elytra, must have accumulated from being in contact with the metal pan. Specimen is still 95% black, though I can see some streaks of green. Specimen set near window to dry out.
I soaked the whole beetle for a couple of days. Elmer's would more than likely dissolve. I've used Acetone for years now on moths more than any thing. Like to blow dry them a little to get the hairs fluffy again on the moths. Never can even tell it was done except for the perfect specimen. And no the beetle came out the same as it went in except no more black.
A really good degreaser is toluene. I've used it on moths. It smells nice and is relatively non-toxic. Best used in a polythene (polyethylene) container with lid. I use a balsawood board, with a small metal plate screwed to it to pin the specimen to, this is held in place in the plastic container by placing a powerful magnet on the base of the container.
Post by boghaunter1 on Aug 4, 2018 12:53:51 GMT -8
As leptraps said use white gasoline, aka... Coleman's (or any other brand) camping fuel... commonly used everywhere in camping stoves & readily available in gallon containers (cheaper than acetone or lighter fluid) in any hardware store. Acetone is good, but does leaves specimens extremely brittle;it's fumes are dangerous/harmful to inhale in closed areas and its extreme flammability make it very dangerous (even static electricity can ignite it). I use acetone on dragonflies only, and I use it outdoors.
Post by exoticimports on Aug 6, 2018 2:37:35 GMT -8
Here is where I am so far after five days of experimentation.
Soaked the hercules specimen in acetone. Again and again. I did not notice any brittleness. However, the acetone did destroy repair glue.
The elytra did return to a beautiful green. One problem- and a repeated problem- the pin hole continues to leak body fluid up through the elytra, so a black spot appears, and then grows. So it's gone back into the acetone repeatedly.
I will probably use a syringe to inject acetone and see if I can somehow flush the body cavity.