Anyone noticing one of these small brown objects on a leaf could easily dismiss it as bird droppings. Only a close look will reveal their secret–these cases house hungry beetle larvae, who can munch on the leaf in the security of their protection and disguise. For my own part I only discovered these insects when I took a closer look at some of the contents of my sweep net. They seem to be relatively common in Texas in the late spring as I turned them up frequently at a number of field sites.
These insects are a type of leaf beetle (family Chrysomelidae), belonging to the sub-family Cryptocephalinae (literally “hidden head”), the case-bearing leaf beetles, or casebearers. (For those not up to date with Latin naming conventions, the “-dae” suffix is used to indicated families, and the “-nae” suffix is used for subfamilies.) The ‘case’ is a gift provided by the mothers–they wrap the eggs in layers of fecal matter, which the larvae later add to.