Perhaps the holy grail of the mantis world for most breeders and enthusiasts, Idolomantis diabolica is known for it's size, colours and threat display. This mantis has baffled some of the most experienced keepers and breeders, but now, after some years, the secret formula to their surviving and thriving has been discovered some what. This set of info should give you the start to their care. Once you know the tips and tricks to this species, they can be relatively easy and very rewarding. This mantis, despite it's size, is very very skittish and gets scared easily. Many people lose them to stress by holding, wrong food type and so on. This mantis should be handled rarely, if at all, and their threat display should not be intentionally brought about for photo opportunities, as this stresses the mantids out greatly.
Idolomantis diabolica belongs to the family Empusidae and is one of the largest species of mantids to mimic flowers, if not one of the largest species of mantids full stop. Adult females grow to 11-13 cm in length, males grow to 10 cm. They are native to Tanzania and have been documented in several other East African countries. This mantis is not for beginners due to it being one of, if not the most picky species we have commonly in our trade. It is only for experienced breeders who can keep this species in our trade, as this species is struggling in the wild, and we need to reduce the amount of ootheca collected from the wild as much as possible. It is advised that unless you have an interest in breeding the species, or have very good experience with other species in the family Empusidae, you should not attempt to raise this species. Gongylus gongylodes and Blepharopsis mendica are both good starter species in this family.
This species, as an absolute must, requires a basking lamp/heat bulb. It can be 60-100W depending on size of enclosure, space, etc. This mantis requires the highest temps also, in the range of 35-45C (95 - 113F) during the day, and down to 20-30 (68 - 86F) at night. They love to hang upside down under the bulbs and this is where you will find them for most of their lives. Another very important requirement is the design of the enclosure. The family Empusidae does not have the same feet structure other mantids have that allows them to walk on glass and acrylic, this includes Idolomantis. They need a complete mesh cage either self made, or simply ordered online. Below are two examples you can use perfectly for Idolomantis.
The cage on the left is perfect for up to 8-10 L1 nymphs, and the cage on the left can house 2 adults, but can hold many nymphs if you have the patience to feed each one. Bulbs must be placed above the enclosure to allow the specimens to 'bask', despite them being insects, not reptiles. Many people lose their specimens due to the lack of light. Ventilation is also key, and the large mesh cages should do this for themselves.
Humidity is a very hot topic among breeders for this species, but I personally, being on my 4th continuous generation with my colony of 30+ individuals, seem to have cracked it. This species is very susceptible to season changes and this must be replicated for them to be willing to breed and achieve the colours everyone to desperately want. From 1st instar to 7th instar, they must be kept bone dry. Their skin when moulting more cracks, rather than sliding off with moisture, and the low humidity removes the ability for the skin to stick to them, opposite to other species, so it is my recommendation to keep it between 10-30%. I never spray mine at this point in their lives, but depending on your location, you may need to spray every week or so. When the turn into subadult (L8), they then must be kept at very high humidity (70-90%), in order to replicate the southern Africa rainy season. This allows the shedding to adult to be successful, as this is where many people lose their mantids. This may require spraying up to 4 times a day, depending on your location.
It is also recommended to not use a substrate. If a young Idolomantis nymph falls, a loose substrate will not allow them to right themselves. Simple paper towel lining the bottom of the enclosure is perfect, as their feet can just grip the paper and they can easily flip themselves.
Idolomantis diabolica is one of the few species that can be kept communally. They can be kept with either other Idolomantis, or with Gongylus gongylodes, which some have had remarkable success with, others have had rather gruesome failure with, so do this at your own risk, but it can be very rewarding having your own colony set up.
Being part of the Empusidae family and mimicing flowers, this species prefers flying prey, and when I say prefer, I mean you will find it very difficult to get them to eat anything else unless they are starving. L1-L2 nymphs can eat fruit flies, and L2 onwards can easily take down green and blue bottles. Other prey items loved by them are craneflies, moths, hawk moths, butterflies, bees, and stinkbugs. Idolomantis are very good at disarming bees and wasps, and the odd bee is a great treat. This species will need a constant supply of flies, and should be fed every day. However, due to their stressful nature, feeding one fly at a time (unless in a communal setup) is advsied as overcrowding causes stress, which in turn causes health issues. Make sure the food items are varied also.
However, they can be 'trained' to take roaches. Red runners (Blatta lateralis) can be used as they have the speed to get their attention. However, results will greatly improve with the use of tongs. Using tongs also allows you to feed adult Idolomantis with large Dubia roaches. The health of the roaches is vital for this species and need to be fed honey, fruit, veg and be drinking regularly to give the mantids what they require. Crickets are an obvious no no. If crickets or similar insects are fed to this species, they will have trouble producing ootheca, and it turns the material they produce to make ootheca into a sloppy mess. It is not worth the risk.
This species is one of the hardest species to breed in the hobby. If the replication of seasonal humidity is done, this is usually what will set the mantids off for breeding. Adults become mature enough for mating 2 to 4 week after shedding to adult. Due to their skittish nature, they need plenty of space, so the male can run away if he is stressed or scared. Males can be identified by their abdominal segments, or easily by their feather-like long antenna. Females have short thin antenna. The species will naturally breed over a long time, so keeping the pair in a very large enclosure for 2 weeks should be sufficient. They usually mate at night.
Ootheca must be kept at the same high heat and humditity as the adults, and you usually leave it in the place it was produced, unless it has been formed directly under the heat bulb, which you should move to not overheat the eggs. Ventilation is also very key as mould will kill the eggs very easily.