1st Place: Assessing interspecific competition between two specialist predators of hemlock woolly adelgid, Laricobius spp. and Leucotaraxis spp.

Monday, November 14, 2022

8:12 AM – 8:24 AM PT

Location: Vancouver Convention Centre, Meeting Room 217/218/219

Presenting Author(s)

OA

Olivia K. Andrews (she/her/hers)

Graduate Student
Virginia Polytechnic Institute and State University
Blacksburg, Virginia

Co-Author(s)

AM

Albert E. Mayfield

Research Entomologist
USDA-Forest Service
Asheville, North Carolina
SS

Scott S. Salom

Professor
Virginia Polytechnic Institute and State University
Blacksburg, Virginia
CY

Chin-Cheng Yang

Virginia Polytechnic Institute and State University
Blacksburg, Virginia
MW

Mark Whitmore

Senior Extension Associate
Cornell University
Ithaca, New York

In the last decade, rearing and release of predators for hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae) has focused on two Laricobius spp. (Coleoptera: Derodontidae). More recently, Leucotaraxis flies (Diptera: Chamaemyiidae) have also been studied and released. They are present during the second generation of HWA (in the spring) when Laricobius spp. drop to the soil to complete development, and thus, have the potential to help regulate HWA populations in combination with the Laricobius beetles. With the release of these flies into the environment, where the already established predator Laricobius is present, it is important to understand if and to what extent the two predators compete. Leucotaraxis argenticollis and Laricobius osakensis were looked at alone and in combination in a laboratory setting. Three treatments were assessed: conspecific 4 sexual pairs of Laricobius, conspecific 6 sexual pairs of Leucotaraxis and heterospecific 2 sexual pairs of Laricobius and 3 sexual pairs of Leucotaraxis. There were four replicates for each treatment including controls due to Laricobius nigrinus present on the branches used that were brought in from the field. Assessment of competition between the two species was measured by comparing the net reproduction of the predators (survivorship of progeny) and the predation rate by looking at ovisac disturbance. Results from this overview lab study will help us design more intensive behavioral experiments for the future.