Bulletin of Entomological Research

Original Articles

Comparative life history studies of Frankliniella occidentalis and Thrips tabaci (Thysanoptera: Thripidae) on cucumber

Paul C.J. van Rijna1 c1, Chris Mollemaa2 and Greet M. Steenhuis-Broersa2

a1 Department of Pure and Applied Ecology, University of Amsterdam, The Netherlands

a2 DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Wageningen, The Netherlands

Abstract

Shortly after its invasion into Europe, the western flower thrips, Frankliniella occidentalis (Pergande), became a more severe pest of greenhouse crops than the onion thrips, Thrips tabaci Lindeman. To test whether this differential pest status was due to a larger capacity of population increase, a comparative life history study was carried out on cucumber (Cucumis sativus cv. Corona). Experiments at 25°C showed that the egg-to-egg period of F. occidentalis was shorter, but its peak ovipositional rate was lower and its offspring sex ratio more male biased. These differences resulted in a slightly lower intrinsic rate of population increase (rm) for F. occidentalis than for T. tabaci (0.166 vs. 0.176/day). It was shown experimentally that between 15 and 28°C, developmental rate of F. occidentalis is linearly related to temperature, with a theoretical threshold temperature similar to the value reported for T. tabaci (10.9 vs. 11.5°C). It is argued that the rm-value of F. occidentalis will not be higher than that of T. tabaci for any temperature within this range. Alternative explanations for the difference in pest status between the two thrips species are discussed.

(Accepted October 04 1994)

Correspondence:

c1 P.C.J. van Rijn, University of Amsterdam, Department of Pure and Applied Ecology. Kruislaan 320, 1098 SM Amsterdam, The Netherlands.