Territorial behavior in Taiwanese kukrisnakes (Via Herp Digest)

Territorial behavior in Taiwanese kukrisnakes (Oligodon formosanus)(Snakes protecting and eating sea turtle eggs)

Wen-San Huanga,b, Harry W. Greeneb, Tien-Jye Changc, and Richard Shined,1
aDepartment of Zoology, National Museum of Natural Science, Taichung 404, Taiwan; bDepartment of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-2701; cDepartment of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan; and dBiological Sciences A08, University of Sydney, Sydney, NSW 2006, Australia
Edited by David B. Wake, University of California, Berkeley, CA, and approved March 22, 2011 (received for review January 31, 2011)

Proceedings of the Nationla Academy of Society of the United States (PNAS), April 19, 2011, 108 (16)


The independent evolutionary origin of a complex trait, within a lineage otherwise lacking it, provides a powerful opportunity to test hypotheses on selective forces. Territorial defense of an area containing resources (such as food or shelter) is widespread in lizards but not snakes. Our studies on an insular population of Taiwanese kukrisnakes (Oligodon formosanus) show that females of this species actively defend sea turtle nests by repelling con- specifics for long periods (weeks) until the turtle eggs hatch or are consumed. A clutch of turtle eggs comprises a large, long-lasting food resource, unlike the prey types exploited by other types of snakes. Snakes of this species have formidable weaponry (mas- sively enlarged teeth that are used for slitting eggshells), and when threatened, these snakes wave their tails toward the ag- gressor (an apparent case of head-tail mimicry). Bites to the tail during intraspecific combat bouts thus can have high fitness costs for males !
(because the hemipenes are housed in the tail).

In combination, unusual features of the species (ability to inflict severe damage to male conspecifics) and the local environment (a persis- tent prey resource, large relative to the snakes consuming it) ren- der resource defense both feasible and advantageous for female kukrisnakes. The (apparently unique) evolution of territorial be- havior in this snake species thus provides strong support for the hypothesis that resource defensibility is critical to the evolution of territoriality.

PDF of full paper
http://intl.pnas.org/content/early/2011/04/13/1101804108.full.pdf+html?sid=4be759cc-6d2c-4edf-a4a8-05c6ae87537f.