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Student 10-Minute Presentation

Plant-Insect Ecosystems

Student

Student Competition

Grad 10-min Competition: P-IE, Invasive Species

Nature’s avengers: Functional and numerical response studies of Leucotaraxis spp., predators of hemlock woolly adelgid

Monday, November 11, 2024
9:00 AM – 9:12 AM MST
Location: Phoenix Convention Center, 121 C, PCC
Oral Presentation Student Competition
The focus for biological control of the invasive hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae) has been two predators in the genus Laricobius (Coleoptera: Derodontidae). For two decades, rearing and releases of these two predatory species has resulted in their establishment throughout the eastern U.S. and demonstration of impact on the first generation of HWA. However, the beetles drop to the soil to complete development and are not present during the second generation of HWA in the late spring. Due to HWA being parthenogenic and the absence of a predator during the second generation, populations can bounce back. Other specialized predators of HWA on western hemlock, Tsuga heterophylla (Raf.) Sarg., in the Pacific Northwest, are two fly species, Leucotaraxis argenticollis and Le. piniperda (Diptera: Chamaemyiidae). To better understand their potential for biological control of HWA-infested eastern hemlock, Tsuga canadensis (L.) Carrière, we conducted laboratory studies to assess the functional and numerical responses of both predators in response to changing HWA densities. Prey densities of 3, 6, 12, 24, and 48 HWA ovisacs were used to assess the egg laying ability of both fly species. Prey densities of 3, 6, 12, 24, and 36 HWA ovisacs were used to assess the feeding potential of L. argenticollis. L. piniperda was not successfully reared to the larval stage so functional response for this species could not be assessed.