Mate Guarding in a Millipede

Nyssodesmus python is a large (up to 100 mm--four inches--in length) millipede which is quite common in Costa Rican rainforests. Almost always seen in pairs, a male "rides" a female. This simple form of mate guarding prevents the female from mating with another male. Copulation occurs within a few hours of a male mounting the female, but the male and female may stay together for several days. Adolph and Geber (1995) found that 69% of these millipedes were paired at any given time, and that solitary animals were receptive for mating.

Nyssodesmus python are abundant and visually obvious. Predation seems, however, to be infrequent. A potent chemical secretion composed of cyanide and benzaldehyde protects them from would-be predators. In addition, their exoskeleton is calcified, making it much harder than that of a typical arthropod.


Adolph S. C., Geber M. A. 1995. Mate-guarding, mating success and body size in the tropical millipede Nyssodesmus python (Peters) (Polydesmida, Platyrhacidae). Southwestern Naturalist 40: (1) 56-61

Cooper M. I., Telford S. R. 2000 Copulatory sequences and sexual struggles in millipedes. Journal of Insect Behavior 3: (2) 217-230

Heisler, I. L. Nyssodesmus python. in Janzen, Daniel H. (Editor). 1983. Costa Rican Natural History. Chicago: University of Chicago Press

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copyright ©2001 Michael D. Breed, all rights reserved