OVIPOSITION BEHAVIOUR OF APHIDIINE WASPS (HYMENOPTERA: BRACONIDAE, APHIDIINAE): MORPHOLOGICAL ADAPTATIONS AND EVOLUTIONARY TRENDS

Abstract

AbstractWe examined oviposition behaviour in 49 species representing 19 genera of Aphidiinae. All species are solitary parasitoids of aphids (Hemiptera: Aphidoidea). Six general types are described that differ in oviposition time, behaviour, and morphology. The Ephedrini have the least specialized oviposition behaviour within the subfamily, with Praini and Aphidiini displaying various adaptations for host capture and oviposition. Use of the forelegs to grasp and orient aphids for oviposition has arisen twice, in Praini and, independently, in the genus Monoctonus Haliday (Aphidiini: Monoctonina). Morphological modifications of the terminal abdominal segments for host capture are found in Trioxina and in several species of Pauesia Quilis (Aphidiina). A “quick” sting is characteristic of species in the genus Aphidius Nees and related genera. The greatest degree of behavioural diversification occurred among Pauesia species, including cryptic behaviour, ant mimicry, and “sneak” oviposition. Acquired chemical camouflage and mimicry of the host’s cuticular hydrocarbon pattern to avoid detection by guarding ants is found in Aclitus obscuripennis Foerster, the genus Paralipsis Foerster, and the two closely related genera Adialytus Foerster and Lysiphlebus Foerster. It is suggested that the main driving forces in the evolution of parasitoid oviposition behaviour were aphid defensive behaviour and avoidance of aggression by trophobiotic ants. The results are compared with phylogenetic relationships inferred from morphological and molecular data.