Lily and company spotted this mass of beetles from the Clark Fork River. Lily first thought they were galls of some type but on closer inspection they were these beauties! As far as beetles go, these guys are pretty small (ranging from 1/16 to a whopping 1/4 of an inch). Thanks to oversized hind legs, they are good jumpers — hence the name “Flea Beetle,” and can make a hasty retreat when threatened. Flea beetles are plant eaters. Some species are considered crop pests while others are considered “beneficial” since they feed on weeds. The beetles pictured here (one of two different species that are nearly indistinguishable) are feeding on their host of willow. The adults emerge in August and will group up at this time of year to overwinter as a group in the soil / leaf litter under the host plant. Come spring, they will be active again.
Photo by Lily Cobble a few weeks ago in Missoula, MT