A female sterilization method for use in field-based behavioral studies of the invasive Asian longhorned beetle (Anoplophora glabripennis)

Abstract

Asian longhorned beetle (Anoplophora glabripennis Motschulsky), a wood borer (Coleoptera: Cerambycidae) native to China, has been unintentionally and repeatedly introduced to North American and European landscapes as a stow-away in the wood packing material commonly used in international trade. Asian longhorned beetle causes extensive damage and mortality in multiple deciduous tree species and in response, countries in both North America and Europe have adopted policies of eradication. Models that integrate patterns of Asian longhorned beetle dispersal with records of infested trees are critical in optimizing survey and eradication efforts and tracking eradication progress. While these tools continue to be developed, they have been limited by the availability of experimental dispersal data. Existing data is restricted to observations made in the beetle's native range in China or based on inference of dispersal in invaded landscapes. Direct observation of beetle dispersal behavior in invaded landscapes could provide critical behavioral information, but the experimental release of gravid females has been incompatible with eradication program efforts. To fill this knowledge gap, there is a need to identify field-portable methods of effectively sterilizing mated females that do not alter ovipositional behavior. Here, we present a protocol for cauterizing a beetle's ovipositor to prevent successful oviposition. Results of lab trials demonstrate the efficacy of ovipositor cauterization in inhibiting successful oviposition without altering the egg-laying behavior of gravid Asian longhorned beetle females. This method enables research to inform models of beetle dispersal and infestation risk without adding to actual or perceived risk of exacerbating infestations in an eradication program.

Keywords: cauterization; eradication; exotic; pest management; wood borer.

Fig. 1.

A) During the cauterization sterilization procedure the beetle can be restrained with a microcentrifuge tube or towel to prevent movement and bites. B) The ovipositor is everted by putting gentle inward and downward force on the last abdominal sternite with the thumb. C) Then the posterior end of the ovipositor is cauterized with a battery-powered cautery pen to prevent the ovipositor from everting fully to deposit eggs under bark..

Fig. 2.

A) The anatomy of the posterior end of an adult female Asian longhorned beetle (Anoplophora glabripennis Motschulsky). B) To evert the ovipositor, pressure is applied to the last abdominal sternite in an inward and downward motion (dashed arrow), then the distal end of the ovipositor (highlighted) is cauterized with a cautery pen..

Fig. 3.

The rates of A) oviposition (eggs laid per day) and B) oviposition pit chewing (pits per day) before and after treatment for each group: a group that received ovipositor cauterization to prevent the oviposition of eggs under bark and a no-treatment control group.