FEMALE MATE ASSESSMENT TACTICS IN A SUBSOCIAL DESERT BEETLE - A TEST OF JANETOS MODELS

The subsocial desert tenebrionid beetle Parastizopus armaticeps is mon ogamous and nocturnal, with division of labour and female mate selecti on for large male body size. Mate choice is time-constrained and must take place during the night following sporadic heavy rainfall since pa irs can only dig breeding burrows when the sand is moist. Beetles cour t in small, widely-separated groups. The four tactics proposed by JANE TOS (1980), through which females could assess potential mates before coming to a decision, were tested experimentally. Approximately 20% of females adopted the ''fixed-threshold'' tactic to assess males, all o thers opting for the ''best of n males'' tactic. These tactics are con sidered to be the most advantageous ones when time is limited and the number of prospective mates that can be assessed low, as is the case f or P. armaticeps. Females used multiple assessments in ''the best of n males tactic'', suggesting that evaluation is constrained by female i nformation retention and integration ability, one of the constraints o n sequential comparisons. This tactic also has the highest expected fi tness benefits.