MATING BEHAVIOUR AND MALE MATE CHOICE IN TRIBOLIUM CASTANEUM (COLEOPTERA, TENEBRIONIDAE) by LUDOVIC ARNAUD 1) and ERIC HAUBRUGE 2) (Unit of general and applied Zoology, Gembloux agricultural University, Passage des déportés, 2, B-5030 Gembloux, Belgium) (Acc. 2-XI-1998) Summary Mate choice by males has received less attention than female choice, despite the recognition that males can incur non-trivialreproductivecosts through mating. In this study we investigate male mate choice in the red our beetle, Tribolium castaneum. We determine whether male beetles have evolved sensitivity that enables them to discriminate between females and we then examine how males discriminate between females that present different reproductive potentials. Recently-emerged adult females are immature, and we investigate when egg- laying maturity develops, and whether male mating attempts with immature females provide reproductive pay-offs. We show that males are the sex most likely to initiate mating attempts (more than 85% of male-female contacts are male-initiated). Therefore, we test male mating initiationswhen presented with choices between: (i) immature and mature virgin females; (ii) mature virgin females and previously mated mature females; and (iii) mature females previously mated either with different male or with the test males. Last male sperm precedence exists in T. castaneum and females are polyandrous. Matings with immature femalesare thereforelikely to generate lower fertilizationsuccessesthan matings with mature females. Furthermore, males are likely to achieve higher total fertilizationsuccess when they mate if they precede a rival male’s sperm than if they precede their own sperm. Accordingly, we nd that: (i) males copulate more frequently with mature, than with immature females; (ii) males do differentiate between virgin and mated females; and (iii) males prefer females that have been inseminated by a different male to those previously inseminated by the test males themselves. The results demonstrate that male T. castaneum recognise female status, 1) E-mail address: arnaud.l@fsagx.ac.be 2) The authors gratefully acknowledge Peter Golob for the PRm strain and Andras Bozsik, Jennifer Moreman for correcting the manuscript, and George Lognay, Robin Wilkin, Matt Gage and the two anonymous referees for their comments on the manuscript. This research was supported by a PhD grant from the FRIA (Fonds pour la formation à la Recherche dans l’Industrie et dans l’Agriculture) to L. Arnaud. c ® Koninklijke Brill NV, Leiden, 1999 Behaviour 136, 67-77