Environmental and physiological factors for diapause induction and termination in the aphid parasitoid, Aphidius ervi (Hymenoptera: Aphidiidae)

• Published in: Journal of insect physiology Vol. 45; no. 4; pp. 357 - 364
• Main Authors: Christiansen-Weniger, Petra, Hardie, Jim
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-1999
• Subjects: Aphid; Aphididae; Aphidiidae; Aphidius ervi; Diapause; Parasitoid; Aphidius ervi; Parasitoid; Aphid; Diapause
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/S0022-1910(98)00134-6

In the aphid parasitoid
Aphidius ervi Haliday, the incidence of diapause around the critical photoperiod was dependent on temperature. At a photoperiod of 12 h light:12 h dark, a significantly higher proportion of diapausing individuals was found at 12°C than at 15°C. The second larval stage of the parasitoid was most sensitive to photoperiod and localised-illumination experiments showed that the parasitoid responded independently of the aphid host. The sex ratio of the population which emerged after rearing in short-days and/or after diapause was male biased. Topical application of the juvenile hormone-mimic, pyriproxyfen, before or during diapause delayed emergence of
Aphidius ervi but did not induce diapause or influence its termination. The ecdysteroid mimic RH 5849 induced diapause in a few treated individuals but did not affect diapause termination.