Asian Longhorned Beetle Life Cycle

Life Stages of Asian Longhorned Beetle

The life cycle of the Asian longhorned beetle has four stages of development called complete metamorphosis. Complete metamorphosis development includes four stages of development: egg, larva, pupa and adult. The egg is laid by the female Asian longhorned beetle in a notch that she chews into the bark of a tree.

life cycle chart

After burrowing, the female beetle then lays a single egg. A single female will lay eggs at multiple sites, with the possibility of one laying up to 100 eggs. When the egg hatches, the newly emerged larva feeds upon the inner tissues of the tree and branch trunks in the vicinity of the burrow site. As it increases in size, the growing larva turns and burrows its way into the heart of the tree. The Asian longhorned beetle larva has 5 stages of development known as “instars.” They can grow up to 5 cm prior to entering the pupation stage into adulthood. The adults exit from the tree through holes they chew.  The holes are irregularly oval, circular, oblong or even linear in shape and over a centimeter in diameter. Infestation by Asian longhorned beetles can be determined by the locations of these burrows or holes. Slight infestations have shown that these holes only appear toward the tops of the tree trunks and branches, where heavy infestation shows holes throughout the tree from the ground up.

The life cycle of the Asian longhorned beetle crosses from one development season into the next, with the insect overwintering as a larva in the heart of the tree. The larva then enters the pupation stage and emerges in the adult form after a month. Adults will continue to develop from the tree until the weather turns cooler or the first hard frost of the fall occurs. In northern areas, eggs laid in the late season may overwinter as eggs. Before pupating, the larvae turn and make their way toward the exterior bark of the infested tree, where they establish into a pupal cavity where they will finish development into the adult form.

The adult beetles will reproduce when they emerge from the tree until the first frost of the season occurs. Once in adult form their feeding habits decrease in that they do not feed as much as when in the stages of development. Once mating has occurred, the female will start the chewing process into the tree to lay the egg. The male is present until this process occurs.

The only known way that these beetles are eliminated or eradicated is through destruction of the infested tree or trees. Burning, chipping and removal of the tree eliminates the possibility of transfer of eggs, larvae and adults.