Sick praying mantises
In the following, some symptoms are listed with their causes, treatment recommendations or preventive measures. These are only personal experiences and there is no guarantee for the correctness of the information.
- Black eyes:
Only rarely are black spots on the eyes a cause for concern. Mostly it is a mechanical destruction of individual ommatidia (single eyes of the facet eye), which can be caused by multiple bumping against walls or simply by age reasons. However, when the entire eye turns black, the animal should be isolated from the others. The latter appearance is likely to be an bacterial or fungizidal infection. If the eyes are dark only at night and bright during the day, this is a natural adaptation to low light conditions.
- Missing limbs: Moulting or cannibalism can lead to shortened or missing limbs and antenncae, which often has no serious consequences. Shortened limbs may even regenerate completely in with following moultings. Occasionally, even additional moulting is done for healing purposes.
- Deformations: Before and during a moult, the humidity should be slightly elevated, otherwise the animal may get stuck in the skin and it may cause deformations (torn limbs). In order to avoid falling down during the moulting process, the animal must be able to hold on well (to gauze or branches) and be left completely alone until it has cleared out of the old skin and hardened. If an animal is so badly deformed that it can no longer walk or eat, freezing is, according to current scientific knowledge, the best form of salvation.
- Crooked wings:
Not straight wings are a common phenomenon, especially in large praying mantises. The last time a praying mantis skins (adult moult), it must position itself vertically, head-up, in order to inflate and harden the wings by gravity. If there is no possibility for the animal to hang vertically, crooked wings can be the result. Normally wing deformation does not cause any health problems, but mating problems can occur if the female has crooked wings.
- Food denial: One to two days before and after a moulting or the building of oothecae mantises can refuse the food. In this case, everything is fine. In case of persistent refusal of food and thinning abdomen, one should check the keeping parameters (temperature and humidity) and adjust if necessary. A common beginner’s mistake is a constantly high humidity. In case of doubt prefer too dry than too moist!
- Dark spots:
Brown spots on body or wings can be caused by feces (from feeder insects or the praying mantis itself). These can usually be washed off with water. Older animals can have also permanent dark spots of the wings, which is normal. If, however, legs or arms become completely brown and then black, it is probably a fungal infection. Then the animal needs to be isolated from others and kept warm and dry.
If an animal spits out a brown-black and foul-smelling liquid from the mouth, it is a sign of illness. In this case, other feeder insects should be offered (preferably easily digestible food such as flying insects) and the temperature raised to restart the digestive tract. Frequently too high humidity can also be the cause.
- Eggbound: In rare cases, a female hesitates out oviposition for so long that her abdomen thickens and eventually bursts. This is usually the case with unmated females who are waiting for a male. An increase in air humidity and temperature can, in exceptional cases, move a female building an ootheca.
- Parasites: Especially imported oothecae or animals can have parasites. There are several varieties of parasitism among praying mantises, but they are little known. However, experience has shown that plants and / or soil from temperate zones are not hazardous.
- Other: In most cases you can not do much against bacterial and fungal diseases and they often go undetected. Often too high humidity is the cause of unclear symptoms.
If you suspect illness (lethargy, vomiting, refusal of food) I generally recommend isolating the animal from others, raise temperature (~ 28 ° C) and lower humidity (~ 30% relative air humidity).