MATING BEHAVIOUR AND MALE MATE CHOICE IN TRIBOLIUM CASTANEUM (COLEOPTERA, TENEBRIONIDAE)

Mate choice by males has received less attention than female choice, despite the recognilion that males can incur non-trivial reproductive costs through mating. In this study we investigate male mate choice in the red flour beetle, Tribolium castaneum. We determine whether male beetles have evolved sensitivity that enables them to discriminate between females and we then examine how males diseriminate between females that present different reproductive potentials. Recently-emerged adult females are immature, and we investigate when egglaying 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 mille-initiated). Therefore, we test male mating initiations when 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. castanenm and females are polyandrous. Matings with immature females arc therefore likely to generate lower fertilization sueecsscs than malings with mature females. Furthermore, males are likely to achieve higher total fertilization success when they mate if they precede a rival maleʹs sperm than if they precede their own sperm. Accordingly, we find that: (i) males copulate more frequently with mature, than with immature females; (ii) males do differenliale between virgin and mated females; and (iii) males prefer females that have been msemmaled by a different male to those previously inseminated by the test males themselves. The results demonstrate that male T. castaneum recognise female status,