Gonometa nysa is an impressive lappet moth from Africa that has a few interesting features. The males have highly iridescent, metallic blue abdomens and the greenish/grayish larvae are among the biggest caterpillars I have seen in my life. They are also well camouflaged and seem to have a ‘mossy’ look and are well camouflaged on algae or moss covered tree trunks. Like most other Gonometa and Lasiocampidae species found in Africa the larvae are armed with spines. These spines make handling the larvae a very painful experience; the spines are designed to break off and stick in your skin like splinters. Not only are they among the biggest, but they are also among the most unpleasant to handle larvae I have experienced; these very sharp spines almost feel like tiny shards of glass. Their cocoons are also covered with these spines. Among other places, it was reported in Cameroon, Congo, Equatorial Guinea, Gabon, Ghana, Guinea, Kenya, Nigeria, Sierra Leone, Uganda. It is also a very large Lasiocampidae – among the biggest. The females can have a wingspan of around 12 centimetres in size, although males are significantly smaller. Not much is known about the ecology of this moth in the wild at all, although they seem to be very polyphagous and are easy to breed for that reason.
- Difficulty rating: Average – The rearing is very easy with almost no mortality. But larvae test your patience by growing very slowly [3 to 5 months] and are painful to handle. Also males emerge before the females, this makes it challenging to have a male and female at the same time.
- Rearing difficulty: 5/10 (From egg to pupa)
- Pairing difficulty: 5/10 (Archieving copulations)
- Host plants: Prunus, Robinia, Eucalyptus, Quercus, Rubus, Fagus, Salix and many more
- Natural range: Africa – Cameroon, Congo, Equatorial Guinea, Gabon, Ghana, Guinea, Kenya, Nigeria, Sierra Leone, Uganda.
- Polyphagous: Yes
- Generations: Multivoltine (continuously brooded)
- Family: Lasiocampidae (eggar moths)
- Pupation: Cocoon (silk encasing)
- Prefered climate: Warm and humid (but not too wet) – Tropical Africa
- Special notes: The larvae are among the biggest I have ever seen in my life including the big Saturniidae species. Handle with caution, they have very nasty, sharp spines.
- Wingspan: 70 – 120mm (a huge Lasiocampidae)
- Binomial name: Gonometa nysa (Druce, 1887)
Gonometa nysa is one of the larger Lasiocampidae from Africa; but not too much known about the faunistics of this species. The good news is that Gonometa nysa is easy to rear. The bad news is they test your patience to the limit. Rearing the larvae should take about 3 to 5 months depending on the food you offer them and the temperature. The larvae are among the largest I have seen; spanning from 10cm to 16cm(yes!) in length. Their development is extremely slow, but luckily they seem very polyphagous. I myself have raised them on a mix of Quercus, Salix, Robinia, Eucalyptus and Prunus, all of which they are happy to feed upon.
One feature of Gonometa one should be aware of is the fact they hurt. Yes indeed, it may be the species with the most unpleasant larvae I have reared ever. Though they are not even venomous, the bodies of the larvae are armed with razor sharp spikes that will embed themselves into your skin like splinters. Even worse, when touched the larvae they may assume a “threat pose” and try to strike you by ramming you with their heads and thorax. Many times I had to peel the spines out of my arms and hands. At first I was impressed, but as it kept happening it became annoying to deal with!
In fact, one of my friends in the Netherlands made the mistake of rubbing his eyes with his hands after touching a larva. Yes, one of the spikes made it into his cornea and had to be removed by a doctor, rendering him blind for a week. So please beware if you are rearing Gonometa (I think any member of this genus may have these spines!).
The eggs of Gonometa nysa are creamy white, perfectly round and the micropyle is visible as a black dot. The eggs hatch in about two weeks time and freshly hatched larvae have black and white stripes and a lot of hair.
The young caterpillars seem to be semi-social and are often found together in small clusters bundled around the stem of their respective host plants. They are very polyphagous and will feed on many types of deciduous trees. Prunus, Robinia, Eucalyptus, Quercus, Rubus, Fagus, Salix are among the accepted host plants.
After a few weeks, the larvae will be much larger. From the second instar and beyond they seem to turn grey, and appear to have spines on their backs. From this point the larvae will become solitary and require a little bit more space and ventilation too, although they seem to cope well with being reared in a high density. .
As they get larger, the larvae will develop an agressive temperament. If touched, the larvae can assume a threat pose and raise themselves in a ‘cobra-like’ fashion and assume what is also called a ‘sphinx-like’ position – the family Sphingidae is named because of the larvae that often rest like this – and raise their thorax from the surface. In this position, if touched, they will slam their head or thorax into anything that touches them. This is an effective defense mechanism because the larvae are covered with sharp and painful spines. So beware that if they are handled, the larvae may purposely slam their bodies into your fingers which can hurt because of the spines .
As they grow bigger and bigger, the caterpillars will reach impressive sizes. They seemed to span between 10 and 16 centimetres; I assume size difference is because larvae that will become female moths are larger than the males.
It is important to keep the big larvae well ventilated. If reared in plastic boxes with no fresh air they may suffer from infections. They are best reared in plastic containers with the lid removed, cages, or sleeves. In regards to food plant they seem very open minded and can be raised on a mix of different kinds of plants. Many kinds of Rosaceae and Fabaceae are eaten. They do not mind being raised in a high density however and seem reasonably tolerant of eachother, despite being solitary at this point.
After spinning up, they spin cocoons made of very though, dry, papery silk and as a finishing touch, they arm them with their very own spines before pupating. This makes touching the cocoons just as risky to touch as the larvae! The good news is that the moths emerge quite rapidly from their cocoons; expect to see the moths between 1 to 2 months. This makes up for their very long development time as larvae.
Pairings of this species seem to be very short and do not last for a long time, for that reason they may be hard to observe, and there is a high chance you will miss it if you are not paying attention. Interestingly they were also easy to handpair, on the condition that the females are not stressed out or disturbed (handle them very gently). Problematic is the fact they are considerably larger than the males and take much more time to develop in their pupae; this makes it harder to have a male and female out at the same time in order to archieve a pairing, for males hatch earlier from the cocoons than the females.
The females of Gonometa nysa are quite large and remind me of a medium sized Citheronia (Saturniidae). The females are very fat and have heavy abdomens – they don’t like to fly much for that reason unless disturbed. Instead they prefer to sit still in a good spot, where they will spend days waiting for a male to arrive. Females have a very clumsy but powerful flight; their wings make a lot of noise when they fly, buzzing almost like a heavy beetle in flight. Females have the habit of dumping their eggs if stressed out.
The males of Gonometa nysa are small and have a much more active lifestyle. Every night they will become active and fly around a lot looking for females. Their appearance is almost like that of a hawkmoth (Sphingidae) with rather short hindwings that are covered by the forewings. Interestingly, they have a metallic blue abdomen. This feature is hardly visible in the resting position, but if startled, the moths will lift their wings to reveal their abdomen and will sometimes even make twitchy movements in order to show it off. This potentially scares away predators that are confused by the shiny blue flashing abdomen. They seem to lose their tarsal claws rather fast if places in certain types of cages made of netting. This may make it more difficult for them to reachh the females. Below I would like to provide some pictures.
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