Nymphs


When raising nymphs, one should always keep in mind that these are usually more sensitive and fragile concerning disturbance than adults and require a more humid atmosphere for successful moulting. The nymphs of more robust species (e.g. Haaniella, Heteropteryx, Dares, Eurycantha or Lamponius) as well as numerous other less pretentious species can be kept together in one cage with the adults. For more problematic species (e.g. Phyllium, Eurycnema or Cranidium) larvae or ones which have very small and fragile hatchlings (e.g. Lopaphus spp. or Pseudodiacantha macklottii) it is more wise to keep the small nymphs separate from the much larger adults to prevent them from being disturbed during the ecdysis. For very large species, e.g. from the genera Eurycnema, Phobaeticus or Pharnacia, it has proven very prolific to keep the subadult (= last instar) nymphs each in one cage for its own. This clearly decreases the danger of difficulties during the final ecdysis. At best, gauze-cages or glass-terrfragile Cranidium gibbosum Larveariums with a minimum height of 50 cm are used with the foodplant being placed exceptionally in the upper third of the cage. There should not be any branches or similar in the lower two thirds of the cage! This compels the insects stay close to the top of the cage and enables them to have enough space for doing their skin-shed successfully.

The number of insects depends on the size of the cage. If too many specimens are kept together in one cage this causes stress Phyllium Larveand a high competition which usually results in a high mortally of the nymphs. Mostly the insects disturb each other during the moulds which causes the loss of legs or a “plunge” of the moulting insects which inevitably results in the death of the concerning specimen. Directly after the successful ecdysis the phasmids usually hang on their old skin to await the new chitin to harden and finally eat it. The consumption of the old skin appears to play an important roll for the hardening of the new chitin. Thus the insects are very vulnerable directly after the skin-shed, when the new chitin still is weak and soft. Especially the final ecdysis has shown to be problematic in many of the large and winged species or the living-leaves (Phyllium). This may be mainly due to the wings reach their final development with the final ecdysis and if the atmosphere is too dry these are often crippled. In some species this problem may cause high losses of nymphs.

When the young nymphs are sprayed one should take care that the water is vaporized very fine due to very fragile nymphs may stick to the water droplets and drown. This is a particular problem with the flat and thin bodies of the newly hatched nymphs of living-leaves (Phyllium). But as the nymphs require a more humid atmosphere than adults to enable successful moulting, the humidity should be checked regularly. For species which prefer a more dry and better ventilated atmosphere but require plenty of humidity for the ecdysis it has proven useful to cover the cage with foliage during the night and / or to put a container of damp sand or vermiculite on the cage floor. This ensures plenty of humidity at night when most of the moulting takes place. The foliage or container with damp soil should then be removed from the cage in the morning. This method has proven prolific with species like e.g. Eurycnema, Monandroptera or Phyllium. In some species only the cage floor should be sprayed as drinking the water droplets would cause diarrhoea and the death of the insects.

In certain species (e.g. Phyllium) the males reach maturity much faster than females, which is due to having a smaller number of skin sheds. In addition many male insects are very short-lived and may already die after only 6-10 weeks. Followingly in this cases, females would reach maturity when all the males from the same generations have already died! To prevent this problem there is the possibility to keep the male nymphs separate from the females and at much lower temperatures (at least 5 °C below the temperatures used for females). This allows to extend the duration of the males development and to have adult males and females at the same time. Another possibility would be to start a culture (if possible) with small nymphs and eggs or at least with nymphs of various stages.
Often, the newly hatched nymphs of certain species seem to have problems in starting to feed, which may cause extreme losses. This is mainly due to the leaves of the offered foodplants, particularly a problem with rhododendron, being too thick for the small nymphs to eat them or if the margins of the leaves are dehydrated caused by frosts. This can be solved by cutting off the (dehydrated) margins of the leaves, increasing the number of nymphs in the cage or introducing larger nymphs. Alternatively, if one has only a very small number of nymphs of the problematic species, nymphs of other less bulgy species can be introduced as well.
For handling small nymphs it has proven best to use a pair of spring-steel-tweezers with a rounded tip or alternatively a soft brush. The spring-steel-tweezers allows to grip even the smallest and most fragile nymphs without causing them any harm.