Polyphylla decemlineata

The ten-lined june beetle (Polyphylla decemlineata) is one of the most attractive pests in the Western US. It emerges towards the end of June / early July here in Fresno at which time it begins showing up at porch lights.

It's the unseen larvae (feeding as grubs on roots) that cause the damage, and they are known to feed on a variety of plants. In a suburban neighborhood (were I live) it isn't really possible to know who's yard they are coming from and so controlling them can be a challenge. If you have unhealthy grass (or grassy areas) you might want to treat it. The adults aren't a problem and birds love to eat them, and keep their numbers down for the most part. In rural areas they can be a problem in peak years.

Oncopeltus fasciatus

Oncopeltus fasciatus, the milkweed bug, is a wide-ranging lygaeid bug that feeds on several milkweed species (and dogbane) througout North America (although not commonly in the Rocky Mountains or the Pacific Northwest). It can be fairly abundant and chances are, you’ve seen one before. They share the same host plant as monarch butterfly larvae and milkweed beetles.

 In California, they can be found every month of the year. I found these individuals just south of King’s Canyon National Park in September this year (at about 3,500 feet).

The habitat was mixed pine / oak forest.

Ampedus occidentalis

Ampedus occidentalis is a medium-sized click beetle (about a centimeter long) that lives much of its life in the decaying wood of fallen pines. I found this one under the bark of a dead ponderosa pine several miles east of Jackson, California a couple of weeks ago.

There are several species of Ampedus that have this general color pattern - of the black body with pale (almost orange) wing covers. Many of the species have a black spot at the end of the body. In A. occidentalis, the black spots normally do not touch the sides of the wing covers.

The grove of trees where I found it was a mixed conifer forest of ponderosa pine, white fir and incense cedar (with the occasional oak as well) in El Dorado County at about 4,300’ elevation.