FEEDING, REPRODUCTIVE, AND NESTING BEHAVIOR OF CANTHON BISPINUS GERMAR (COLEOPTERA: SCARABAEIDAE: SCARABAEINAE)

摘要

The food relocation, reproductive, and nesting behaviors of Canthon bispinus Germar were studied in terraria at ambient conditions outdoors with three food resources. Individuals fed upon fish meat and dog dung but did not use cow dung. Five kinds of food manipulation behavior were observed: rolling balls, rolling dung pellets, rolling small pieces of fish, direct burial, and stationary rotation of food. To attract females, males adopt the typical headstand position for the emission of sexual pheromones beside the food source or next to a rolled ball. Males make two sizes of balls to attract females: small balls (<= 10 mm) and large balls (>= 11 mm). Small balls are always abandoned intact or lightly bitten after mating; they are regarded as nuptial gifts offered by males only to copulate. Most often, sexual encounters occur at the food source or, less frequently, while the male is rolling a ball without the previous emission of pheromones. Only carrion-provisioned large balls (11-21 mm maximum diameter) are used for nesting. Males assume the principal role in making and rolling the ball. Most nests are telecoprid, compound, and shallowly buried. Parental care is performed by the couple; the male remains in the nest up to 10 days, while the female usually remains for 30 to 32 days, just a few days prior to the emergence of the progeny. Survival rate was 92%. The carrion-provisioned brood balls are shaped like a figure eight or a pear. The egg chamber is separated from the provision chamber by a partition of soil material. As larval development advances, small excretions appear, increasing in number outside the ball.