On a field trip a few weeks ago through the woods at Henning CA, one of our members found this tiny insect. It took a little while to track it down, but I believe it is either Cuerna septentrionalis, a black and red leafhopper or Cuerna costalis.
This is a member of the Cicadellidae family of leafhoppers, a group which is colorfully diverse although structurally similar. There are over 3,000 known species in the US, ranging from 2 to 20 mm in length. Ours was 7 mm, around a quarter of an inch.
They can be found in nearly any habitat that has vascular plants. Both the adults and larvae feed on stems and leaves. In doing so, they extract nutrient poor xylem with a thin mix of organic substances and minerals. They also may transmit plant diseases, in some cases producing significant economic damage.
Females lay their eggs in living plant tissue and the larvae that hatch will grow through 5 molts. After egg laying and molting, the eggs and subsequent instars are coated with a light dusting of water-repellent waxy material (brochosomes), a liquid secreted from their anus. This is thought to repel not only water but their excreta which is sticky and could hinder their movement. It is also thought to carry pheromones, giving a whole new meaning to the "after" in aftershave. Not a very appealing trait to us, but it works for them.
This is one of a series of finds on a Master Naturalist training field trip. More pictures from the field trip are at Finds from the Field.
