Host instar preference and functional response of Aphidius transcaspicus, a parasitoid of mealy aphids (Hyalopterus species)

• Published in: BioControl (Dordrecht, Netherlands) Netherlands), 2012-10, Vol.57 (5), p.603-610
• Main Authors: Latham, Daniel R, Mills, Nicholas J
• Format: Article
• Language: English
• Subjects: Agriculture; Animal Biochemistry; Animal Ecology; Aphididae; Aphidiinae; Aphidius; Aphidius transcaspicus; Aphidoidea; Behavioral Sciences; Biological control; biological control agents; Biomedical and Life Sciences; Braconidae; Density; Entomology; Females; functional response; Hemiptera; Hyalopterus pruni; Hymenoptera; Insects; Instars; Leaves; Life Sciences; Orchards; Parasitoids; Plant Pathology; Preferences; Prunus domestica; Quarantine; Shoots; Success
• ISSN: 1386-6141; 1573-8248
• DOI: 10.1007/s10526-012-9440-8

Aphidius transcaspicus Telenga (Hymenoptera: Braconidae: Aphidiinae) has been selected for use as a biological control agent against Hyalopterus pruni Geoffroy (Hemiptera: Aphididae) in prune orchards in California. In this study we focus on the host instar preference and functional response of A. transcaspicus. Host instar preference was determined using laboratory arenas by allowing female parasitoids to attack aphids on field-collected leaves of Prunus domestica L. supporting a natural range of H. pruni instars. A relative preference index indicated that A. transcaspicus was 1.4 times more likely to attack intermediate instars (2–4) than 1st or adult instars. The functional response of A. transcaspicus to H. pruni density was determined on enclosed P. domestica shoots in a prune orchard. The functional response to host density was linear (Type I) at the lowest aphid densities, and the asymptotic number of aphids attacked at higher aphid densities was 64.3 ± 6.7 aphids day−1.