The longhorn beetle family (Cerambycidae) is widespread.The family is typically characterized by their extremely long antennae, which are often as long as or longer than the beetle’s body.This is a large family with over 26,000 described species.Several species are considered to be serious pests for their wood boring activities as larvae.Many species are brightly colored and typically feed on flowers.Some species mimic Hymenoptera (wasps, bees, and ants), but most are cryptically colored and nocturnal.Some species make squeaking noises when disturbed.Such a large and diverse family has led insect taxonomists to recognize several subfamilies and tribes, but not without some disagreement among authorities.
The genus Prionus is native to the American west, and is often a pest in orchards and vine crops.Most of its life is spent underground in the larval stage feeding on the roots of trees and shrubs (the adults are not known to feed).The adults emerge from the soil from late June to early August.The males are smaller than the females and have more strongly serrated antennae.They fly at night in search of mates: the males are more active, but the females produce a pheromone to attract males.The life span of the adult Prionus is about 10-20 days.After mating the females lay eggs a few centimeters below the soil surface near the roots of suitable plant hosts.
Prionus larvae are strongly segmented and seek out roots shortly after hatching.They furrow and tunnel through roots as they consume tissue, and move upward and inward, often killing the apical region of the root where primary growth occurs.As the larvae age and grow the eventually reach the root crown.Prionus pupates near the soil surface in a cell constructed of soil and root material.The tunneling habits of the larvae can contribute to the death of infested trees either directly by the girdling of the root cambium (the region of secondary growth in plants), or indirectly as a weakened plant host is more susceptible to other diseases.
Twig girdlers (Oncideres) lay eggs beneath the bark near the tips of living branches of many deciduous trees.But before an egg is deposited, the beetle gnaws a deep groove around the twig, girdling it; the twig eventually dies and drops to the ground, and the larvae completes its metamorphosis in the twig.
