Developmental time, potential food sources and predatory behaviour of the invasive pest species Thrips parvispinus

Biological control of invasive thrips is a challenge in many agricultural systems, partly because of a lack of knowledge about their life cycle and interactions with their environment. Thrips parvispinus Karny (Thysanoptera: Thripidae) is an invasive species causing damage to many crops worldwide and on which our knowledge is still limited. We studied the developmental time of T. parvispinus under three different fluctuating temperature regimes, its predatory behaviour against the eggs of a phytoseiid predatory mite and the effect of different food sources on its oviposition rate. We showed that T. parvispinus adult females and L2 larvae can feed on a limited number of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) eggs and that their predatory behaviour is significantly affected by the nutritional quality of the host plant and the presence of pollen. Additionally, the oviposition rate of T. parvispinus females over six days was not positively affected by the presence of Typha angustifolia pollen, Artemia cysts or prey mites on bean leaves. Finally, we showed that the developmental time of T. parvispinus is relatively fast and comparable to that of the invasive thrips species Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Our study provides further insight into the feeding behaviour of T. parvispinus as an omnivorous pest species and its interactions with its predators. Thrips parvispinus is unlikely to have a negative effect on phytoseiid mite populations and the use of supplementary food to support predatory mites in the crop does not seem to pose a risk of significantly increasing T. parvispinus populations.