Cost of mating in male Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae)

Mating and reproduction not only provide benefits but can also incur substantial costs. An increasing number of recent studies have indicated that mate searching, mating, and ejaculate production requires large amount of energy which can result in high cost to males. Here, we examine the effect of number of matings of males and mating duration on mating and reproductive success in Menochilus sexmaculatus (Coleoptera: Coccinellidae) by subjecting them to 3 consecutive matings of 30, 60, 90 min, and complete mating (a) with no interval and (b) with interval of 24 hr between the matings. The results reveal a reduction in reproductive performance for both the setup and reduction is more when mating is consecutive without gap. This shows that between subsequent matings males require time to recuperate the sperm/ejaculate. As a male engages in a greater number of matings, the time it takes to begin mating when paired with a female increases and the overall duration of mating decreases. However, frequent mating attempts made by males result in reduction in their body weight. Thus, in this ladybird beetle mating and related physiological process consume lots of energy and the body weight of males tend to decrease which further modifies their reproductive performance. The study helps us to identify the cost of mating from male's perspective and indicates that males need to rejuvenate between the matings.