Silkmoths and more: Stoermeriana species Malawi

I had social caterpillars before, but never one like this Stoermeriana species from the Malawian Dzalanyama Forest. They group together in all caterpillar stages, even in the final instar when most other species tend to spread out further. The larvae cluster in what can only be described as a huge caterpillar ball consisting out of more then a hundred individuals. Even the cocoons are spun together in a large group of one cocoon next and on top of the other. It's not a tent caterpillar though. The caterpillars do not make a web. Well I suppose I could have expected this. The small bright yellow eggs - which by the way are very uncharacteristically looking for a Lappet - were deposited closely together in multiple long rows and so forming a large mat of eggs. The first instars are very small and not capable of chewing the thick Pinus sylvestris needles. I suppose when you can find a pine species with longer and thinner needles (like for example a radiata or patula), you could start them immediately on these plants. If not, you'll have to work around this and start with either Picea abies or a Carex species. That's right. They do not only eat conifers, but also species out of the sedge family. I guess Cyperus might be one of the natural hosts. Given the fact that they form large groups extra caution is needed concerning hygiene. Diseases can spread rapidly, so make sure everything stays dry and very clean. If you do that, they are not difficult at all. An average room temperature is good enough. First instars are best kept in small plastic containers (because of their size), final instars best in a netted cage (to give a good air circulation which helps preventing diseases). Caterpillars take around three months to develop. The pupal stage is short (around two weeks). The first males are already emerging. You can expect to see the imagines in one of my next posts.