Image Credit: arian.suresh
Blister beetles, wedge-shaped beetles, checkered beetles (Meloidae (Lytta+), Rhipiphoridae (all), Cleridae (Trichodes)) – parasitic on pollenivores. All these beetles are nest parasites/predators of mature larval bees (& wasps). Though they attack the bee by generally giving live-birth to their own young on the flower surface, the new-born larva hitches a ride on a bee’s back to its nest where upon it waits until the larvae are mature, then it kills and eats them. Throughout the North Temperate Zone there are several genera of blister-beetles that successfully attack large bees (Bumblebees and Digger bees); in this case, all the young are born live at the same time and hundreds climb together onto a plant stalk; then they produce a chemical scent that attracts the female bees upon which the leap in large numbers. This strategy can decimate an entire hive.
The blister-beetle Meloe is distinctly uncommon; the females are extremely robust since they give birth to dozens of active “triungulin larvae”. Wedge-shaped beetles resemble a large tumbling-flower beetle; they are extremely rare. The checkered beetle, Trichodes ornatus, is abundant and widespread; it is an important parasite in the alfalfa-bee industry.
Triungulin larvae (see center) are born active and have to be phoretic on flower-visiting bees in order to successfully parasitize the bee’s offspring in the nest. Note the triungulin on the right-hand waist of the spring on the left.