The role of physical cues in the regulation of host recognition and acceptance behaviour of Aphidius ervi Haliday (Hymenoptera:Braconidae).-

The role of color and shape in the host recognition and acceptance behavior of Aphidius ervi Haliday was studied. A quaqntitative analysis of the oviposition behavior of A. ervi was carried out with a computer-aided analysis of 150 video-recorded oviposition sequences on its natural host, Acyrthosiphon pisum (Harris). The importance of visual stimuli was assessed in a choice condition bioassay, observing the behavioral reaction of female parasitioids to various test material flame-sealed into glass capillaries. Glass beads 2 and 6 mm in diameter and a flat arena were coated with cornicle secretion of A. pisum, and their acceptance rates by both naïve and experienced female parasitoids were assessed under no-choice conditions. In most cases, A. ervi females switched from random searching to attack position when the host was within a range of 1 cm, suggesting that host recognition is regulated in part by cues acting before physical contact. The glass capillary bioassay indicated that visual cues are important factors in the host recognition and acceptance phases. Pea aphid color alone can elicit the oviposition response of naïve A. ervi females, and this response is enhanced when color is combined with aphid shape. The cornicle secretion of A. pisum stimulated an oviposition response Which was stronger in naïve females of A. ervi than in experienced ones and was not significantly affected by the glass bead size or flat surface. These results, along with those from previous studies, suggest that manipulation of the oviposition behavior of A. ervi is feasible under laboratory conditions

Cornicle secretion of Acyrtosiphon pisum (Harris) (Homoptera, Aphididae) as a contact kairomone for the parasitoid Aphidius ervi Haliday (Hymenoptera, Braconida

Females of the endophagous parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) respond positively to the cornicle secretion of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae). The parasitoid response has been assessed in a Petri dish choice test by presenting an aphid dummy consisting of a glass bead coated with cornicle secretion along with an untreated bead, which acted as a contro. Naive females responded similarly to the treated glass beads and aphids, while experienced females responded less to the treated beads than to aphids. The kairomonal activity of the cornicle secretion decreased as the wax dried. The behavioural response registered seems to be innate and not induced by associative learning