Physiological and genetic factors as sources of variation in locomotion and activity rhythm in a parasitoid wasp (Trichogramma brassicae)

F. Pompanon (1) , P. Fouillet (1, 2) , M. Bouletreau (1, 3)

1 LECA - Laboratoire d'Ecologie Alpine
2 LBBE - Laboratoire de Biométrie et Biologie Evolutive - UMR 5558
3 Génétique et évolution des interactions hôtes-parasites

The circadian rhythm of locomotor activity in the parasitoid Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) varies according to genetic and non-genetic factors. The physiological state of the adult influences the circadian rhythm of locomotor activity. Mating is responsible for a long-term decrease in the activity of males, while an increase in female activity is observed. In females, a previous oviposition reduces the spontaneous activity for 2 days. Food deprivation causes a 2-day increase in daily activity, followed by a strong decrease for both sexes. The daily amount of activity is much more affected by physiological variations of the parasitoid than the temporal distribution of the activity (i.e. phase and pattern of activity). In all experiments, variation in locomotor activity was related to path variations. Furthermore, comparison of inbred lines proved the genetic variability of these behavioural traits and of infestation capacity within a strain. Correlations between successive generations demonstrated their transmissibility. The genetic variability constitutes an evolutionary potential allowing the population to display an adaptive response to predictable (i.e. periodic) environmental variations. The behavioural plasticity resulting from physiological changes allows an individual response to unpredictable variations of the environment. Both mechanisms optimize resource exploitation by insect parasitoids.

Mots clés: Trichogramma; Life-history traits; flight activity; drosophila-melanogaster; hym; trichogrammatidae; reproductive strategy; evanescens westwood; foraging; behavior; food-deprivation; activity pattern; sex allocation; circadian rhythm; genetic variability; infestation capacity; locomotor; behaviour; mating; oviposition; parasitoid; starvation

Domaines: Biodiversité et Ecologie; Biodiversité; Ecologie, Environnement

F. Pompanon, P. Fouillet, M. Bouletreau. Physiological and genetic factors as sources of variation in locomotion and activity rhythm in a parasitoid wasp (Trichogramma brassicae). Physiological Entomology, 1999, 24 (4), pp.346-357. ⟨10.1046/j.1365-3032.1999.00150.x⟩. ⟨halsde-00295517⟩