Right across the road from those mud-covered eggs in Kentucky, there were some tiny poop-covered eggs waiting to be discovered. I might have just passed them off as droppings if I hadn’t seen the associated larvae that had hatched from some of them. They were the eggs of Neochlamisus platani, the sycamore leaf beetle. This species is one of the case-bearing leaf beetles (Chrysomelidae: Cryptocephalinae), whose larvae begin life carrying around the shell of excrement that covers the eggs they hatch from, adding their own excrement as they grow. This particular species feeds on sycamore (Platanus occidentalis), and its larval case is distinctive because it is covered with the trichomes (hairs) from the underside of its host tree’s leaves.
In For Love of Insects (and in this paper), Thomas Eisner writes about a green lacewing larva (Chrysopidae: Ceraeochrysa lineaticornis) in Arizona that similarly covers itself with sycamore trichomes. He suggests that the trichomes are a plant defense–impeding movement and feeding of herbivorous insects, as well as slowing evaporative water loss from the leaves–that the larva is appropriating for its own defense, as well as for camouflage. Clearly, the leaf beetle larvae are doing the same thing. There is at least one other kind of larva that protects itself with sycamore trichomes, but I’ll save that for Part 2.