Material benefits from multiple mating in female mealworm beetles (Tenebrio molitor L.)

In yellow mealworm beetles (Tenebrio molitor), females are sexually recepti ve throughout their adult lives. We examined how access to mates affected f emale fecundity by varying the number of matings per female and quantifying cumulative egg production. Also, we dissected females at successive interv als after a single mating to assess the relationship among time since matin g, sperm supplies, egg load, and oviposition rate. Females that mated at in tervals greater than 2 days did not produce as many eggs as females that ma ted every 2 days or were allowed to mate ad libitum. Dissections showed tha t the amount of sperm remaining in a female spermatheca was correlated with the number of eggs she had laid recently, which suggests sperm replenishme nt as the material benefit gained through multiple mating. However, females mate more frequently than necessary for sperm replenishment, and therefore material benefits alone may not fully explain the continuous receptivity o f T. molitor females.