after being brought out of the 'fridge. Once taken out of the 'fridge [ for a couple of days or so], they cannot be put back, as development will have begun and will continue, so they will hatch anyway. The larvae will take Hawthorn [Crataegus], Oak [Qercus] and Sweet Chestnut [Castanea], but best of all is Walnut [Juglens]. They can be reared in plastic boxes provided they are not crowded, but generally they do better in a cage or sleeved outside. The fully grown larva is especially attractive, being covered in long bluish - white hairs, and takes up to two months to reach this stage, depending on temperature. The cocoon, which is spun on the foodplant, is a beautifully engineered, netted affair, through which the striking pupa can be clearly seen. This enables a pupa to be sexed without butchering the cocoon. Although it looks fragile, it is quite strong and would probably double quite well as a pan scrubber. There is only one generation a year and the adults normally emerge in Oct/Nov. Wingspan is around five inches and they are extremely active, the males having one of the fastest 'tear my own wings off' syndromes of any species. They therefore need a largish cage and cool conditions. Both sexes can be stored in a 'fridge for two weeks or more while waiting for a partner. The only pairing problems which I have experienced occurred when temperature was too high [male self destruction preferred to female lure]. A medium sized flight cage [mine are about 18ins. square by 24ins. High], indoors in an unheated room seems to work well. They remain coupled until the following evening, so pairings are easy to confirm.Separate the virgin and pregnant females because when one begins to lay, it seems to trigger the others, and as infertile ova doesn't always collapse for quite some time, a lot of duff ova will need to be kept for a considerable period. The females lay a largish number of ova stuck together in clumps. Not difficult and certainly one of the most rewarding species to rear, D.simla ova are readily available this Winter. A simla [sorry!] species is D.japonica which is slightly smaller and whose adults emerge Aug./Sept. And by the way, if you use Oak as the foodplant, it is mandatory while cleaning out the larvae, to hum 'Dick-tie a plowka ribbon round the old Oak tree' [those of you who are old enough to remember it, that is !] - NEIL WEST 5.1.99The Care of Platymerus biguttata (the two-spotted Assassin Bug)
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The shiny dark brown eggs with white lids are of a similar size and shape to those of many phasmid species. They hatch into nymphs with a black head and thorax, and a bright red abdomen. After a few moults, the red darkens through burgundy to a deep purple, and the legs are divided into sections of black and bright yellow. Adults remain with the yellow parts to the legs, but are otherwise uniformly black, apart from a white spot on each of the elytra, hence the Latin name biguttata, meaning two- spotted. The adult bugs are around 1 and a half inches (roughly 4cm.) in length, and need to be examined fairly closely (gloves are recommended) to distinguish the sexes. The male abdomen is thinner and more pointed at the end, and the segments are more distinct. Looking from the underside, the female abdomen is wider and flatter, and comes to a straight edge at the end. There are rumours that this species is parthenogenetic, but I have seen mating activity, and do not separate the sexes. The most distinctive part of the Assassin Bug's appearance is its rather wicked looking proboscis, which it uses to impale its prey, to inject venom, to suck out the body fluids, and to drink droplets of water from the sides of the tank.
The Living Environment:
I have found Assassins to be the easiest insects to house. A very thin layer of dry sand will suffice as a substrate. I just use enough to cover the bottom of the tank. Provide a number of pieces of cork bark for shelter and the set-up is complete, although it is necessary to provide a light weekly spraying of water to the sides of the tank. The only disadvantage of this species is the gradual build-up of mealworm skins on the floor of the tank. When it becomes difficult to see that there was ever sand in the tank, discard the substrate, having checked for eggs and surviving livefood. As the bugs seem happy to stay on the cork bark, it is best to simply remove all of the shelters into a lidded container until the substrate has been replaced.
In captivity, by far the easiest and most readily taken form of food is the humble mealworm, Tenebrio molitor. As an occasional treat, cockroaches prove very popular, as do caterpillars (mainly Yellow Underwings which have become very unpopular in my garden!!). Naturally, the young can only take smaller specimens, but they are also happy with buffalo worms, which are considerably smaller than mealworms. For some reason, I have never seen one of my specimens showing the slightest interest in crickets. Assassins drink water sprayed on the sides of the tank..
The eggs are laid loosely on the substrate. It is a matter of personal preference, but I believe that it is beneficial to remove them (when the tank is cleaned) and place them in a small clear container with damp peat. Apart from the opportunity to observe the nymphs as they hatch, this method allows the young to be kept separately, meaning that there is a reduced risk of cannibalism and selected smaller grubs can be placed in the "nursery" tank only, where they are needed. A Final Warning: Platymerus is a fierce predator, with two main weapons at its disposal: a sharp proboscis full of venom, and the facility to spray venom through the end of its abdomen. Even if you are wearing gloves, please do not allow the insect's hind quarters to get anywhere near your eyes. It hurts! This is not a dangerous insect, but it pays to take precautions so that you can fully enjoy the easiest species I have ever kept in culture. - [David Brierley.]
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