Family: Chrysomelidae
Subfamily: Cryptocephalinae
Length: 3.2-4.9 mm
These remarkable beetles have two primary defenses. One is that they resemble caterpillar droppings, so that predators often overlook them. In fact, specialists in this tribe of beetle are so attuned to look for caterpillar droppings, some museums are rumored to possess pinned caterpillar droppings in their holdings, collected by mistake by an overzealous entomologist. The other major defense is their somewhat spherical form, such that when they pull in their legs and play dead, they quickly roll off a leaf and blend into the leaf litter below.
Warty Leaf Beetles make up the tribe Chlamisini. Beyond that, identification can get tricky, and even experts disagree markedly over how many species there are in this group. Some specialists emphasize small morphological differences, and posit many species, while others say the food plant is the key determinant, and that number of species is not so large.
Right: Lateral view of Neochlamisus sp.
There are five genera in the tribe in North America, but two are found only in the southwest (Pseudochlamys and Diplacaspis).
Chlamisus is a mostly western genus too, but one species appears in the East, Chlamisus foveolatus. One trait of C. foveolatus is that its legs, antennae, clypeus, and frons are yellowish to orange.
The remaining two genera in the East are Neochlamisus and Exema. The Exema species are smaller, measuring about 2.0-3.5 mm from front to back, while Neochlamisus measure 3.2-4.9 mm. Most Exema beetles are found on members of the Aster family, while Neochlamisus beetles are usually found on trees and shrubs and the canes of Blackberry and Raspberry.
Right: Experts who emphasize food plants would call this beetle Neochlamisus alni, since it was photographed on Alder. Other specialists state that there a number of similar species that also feed on Alder.
Insects of West Virginia
