Nita described how true bugs such as box elder bugs and stink bugs differ from beetles. True bugs have beakish mouthparts that they use to suck liquids from plants or prey and undergo a gradual metamorphosis—the immatures, called nymphs, look similar to the adults. Beetles have chewing mouthparts and undergo a complete metamorphosis—their immatures are grubs that don’t look anything like the adults.
Larry told us about the endangered Valley elderberry longhorn beetle that feeds only on elderberry shrubs. The beetle grubs live under the bark for one or two years before emerging as mostly black females or mostly red males.
Along the river bank, we found clumps of sandbar willows with sawfly stem galls. At the water’s edge, we found fewer insects than we did the previous year, possibly due to a lot of off-leash dog activity. However, we we happy to see cabbage butterflies, lady beetles, and box elder bugs.
Larry told a story about successful ash whitefly biological control. The ash whitefly came into California in the 1980s and quickly became a significant pest of fruit trees because it had left its natural enemies behind in the Middle East and Mediterranean. Larry was sent to Italy by the CA Dept of Food and Agriculture to find those natural enemies. One of the parasites he found was tested and released in California and soon got the ash whitefly population under control. The tiny parasite continues to do its job.
Nita told us about a new local pest, the brown marmorated stink bug, that feed on just about everything. In late fall, adult bugs fly into people’s houses where they stay until spring. On the East Coast, they’ve become pests of apple, pear, and peach orchards. A tiny parasitic wasp, Trissolcus japonicus, lays its eggs in the eggs of the stink bugs. As a wasp larva develops, it eats the inside of the egg and the stink bug never hatches.
The insects by the river match the ever-changing plant cycles, so chances are we’ll always see something new. In August, the FORB adventure will feature dragonflies, and we should see a cross section of insect life very different from that of mid-May.