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ARS Home » Northeast Area » Newark, Delaware » Beneficial Insects Introduction Research Unit » Research » Research Project #429050

Research Project: Host Specificity and Systematics of Insect Biological Control Agents

Location: Beneficial Insects Introduction Research Unit

2015 Annual Report


1a. Objectives (from AD-416):
Objective 1: Determine the physiological, behavioral, ecological, and genetic basis of host ranges of noctuid moths and parasitoids of pest insects, such as soybean aphid, Russian wheat aphid, sugar cane aphid, and spotted-wing Drosophila, with a focus on using molecular genetic methods to elucidate factors responsible for the evolution of host specificity. Subobjective 1.1 – Determine the genetic basis of host ranges of noctuid moths and of parasitoids of pest insects. Subobjective 1.2 – Test whether bacterial endosymbionts affect acceptance and suitability of hosts and determine mechanisms of these effects. Subobjective 1.3 – Test whether the host specificity of Aphelinus species changes with stress or experience. Objective 2: Determine interactions between biological control and host plant resistance in their effects on survival, reproduction, and population dynamics of pest insects, such as soybean aphid, Russian wheat aphid, sugar cane aphid, and spotted-wing Drosophila, in laboratory and field experiments. Objective 3: Determine molecular phylogenetic relationships, test host specificity, and introduce parasitoids for biological control of pest insects, such as soybean aphid, Russian wheat aphid, sugar cane aphid, and spotted-wing Drosophila, and determine the impact of the introduced parasitoids on the abundance and distribution of target and non-target species. Subobjective 3.1 – Determine phylogenetic relationships among parasitoids whose members are candidates for biological control introductions. Subobjective 3.2 – Measure host specificity of parasitoids that are candidates for biological control introductions. Subobjective 3.3 – Introduce parasitoids to control pest insects, such as soybean aphid, Russian wheat aphid, sugar cane aphid, and spotted-wing Drosophila, and measure the impact of the introduced parasitoids on the abundance and distribution of target and non-target species.


1b. Approach (from AD-416):
We will use analysis of genomes for genes that are divergent in sequence or expression, QTL mapping, co-localization of probes for QTL markers and divergent genes with chromosomal fluorescence in-situ hybridization and allele genotyping, analysis of tissue-specific expression (antenna, ovipositor), and gene knock-out with CRISPR/Cas9 and RNAi technology to identify genes involved in host recognition and acceptance. To test whether defensive bacterial endosymbionts affect acceptance and suitability of hosts of parasitoids and to determine mechanisms underlying these effects, we will assay more species of parasitoids on more species of aphids with and without their defensive endosymbionts. To test whether host ranges of Aphelinus species are ever dynamic, we will test the effects of starvation, age, and experience on parasitism of sub-optimal hosts by parasitoid species with broad host ranges. We will do additional experiments on the interactions between host plant resistance and parasitism by Aphelinus species. Continued development of the molecular phylogeny of Aphelinus species will provide a framework for other results. We will conduct host specificity testing of parasitoids for release against D. noxia, M. sacchari and D. suzukii. We will introduce parasitoid species with narrow host ranges and monitor their impact on target and non-target species.


3. Progress Report:
No progress made; see annual/final report for 8010-22000-024-00D.


4. Accomplishments