|second instar larvae in September.|
|Pre-pupal S. cessus larva below and two still growing S. aloeus larva on top (December 2013)|
|Larva in the pupal chamber, photographed through the wall of the container|
So I got clay, first from my mother-in-law's backyard, and when that didn't work, from Madera Canyon. Finally the larvae settled down and buried themselves deeply. Three of them stayed close to the transparent walls of the container so I could watch their progress. Except there was none. All winter long, and through March and most of April, the big larvae were just sitting in their pupal chambers, if that's what they were. Occasionally they turned over. They seemed to loose volume and became more opaque than before, but for months nothing else happened. I began to wonder if they might need a cold stimulus. Then, in April, I could see one pupae, but it soon darkened and died. Brett checked the ones he was keeping in Nebraska at this time, and they were dead as well. Still, one larva was holding out and one was hidden from sight.
|S. cessus pupa lying on its back|
On the 19th of May, the visible larva had changed. It was either dead or? I decided to dig it up. When I broke through the hard crust of the pupal chamber, I found a healthy, gold brown pupa and the empty last larval skin. This one will go to Brett to complete his collection of developmental stages.
Insects are soft and vulnerable at this stage, so I carefully placed the beetle back on the clay. I assume he would need a rough surface to find traction for the now rather functional front legs to pull away from the rest of the pupal exuvium.
|teneral beetel with pupal skin, exuvium|
For several hours the hardening and darkening process of the exoskeleton progressed. This what it looked like at 11 pm.
I the morning a perfectly hardened and dark beetle was trying to bury himself in the clay again.
I kept the containers with eggs and larvae in our basement in the water heater room, where it's dark and the temperature never changes dramatically. I do not know where the beetles get their input about the seasons. I am raising 3 species now, and they all seem to have their own, species specific rhythms. Strategus aloeus beetles, of the three-horned species, laid their eggs much later than their smaller relatives S. cessus. Then the larvae grew faster, buried into the depth of their containers and pupated. There was no great winter pause. Right now, in May, they are all resting as pupae.
|Dynastes granti larva, much larger than the S. cessus larvae, with a darker head capsule and darker setae|
I assume that in nature the freshly hatched S. cessus stay buried in their pupal chambers until the first strong monsoon rain wakes them up. I have seen mass emergencies during those early storms twice in Madera Canyon. The beetles mate then and their flight period does not last very long.