Meeting Abstract
P1.114 Sunday, Jan. 4 Cost of male courtship: Using whole group metabolic rate to assess cost of courtship FRIESEN, Chris/R.; POWERS, Donald/R*; MASON, Robert/T; Oregon St. Univ.; George Fox Univ.; Oregon St. Univ. friesenc@science.oregonstate.edu
Reproductive effort is an important aspect of life history, as reproductive success is arguably the most important component of fitness. Females of most sexually reproducing organisms invest more in the production of offspring than do males. Males then tend to compete for access to females and in the process expend their energetic capital on mate searching, male-male competition and courtship rather than directly on offspring. Red-sided garter snakes (Thamnophis sirtalis parietalis) are an exceptional model for the study of energetic costs of courtship and mating as they fast during the spring mating season segregating the cost of energy acquisition from the cost of courtship and mating. However, in this species measuring an individual males metabolic rate during courtship is complicated by the fact that male courtship behavior in red-sided garter snakes is dependent on the detection of female sexual attractiveness pheromones, and facilitated courtship, i.e., vigorous courtship is only exhibited in the presence of other males. Thus, traditional techniques of masking individuals prevents male courtship behavior, and single animals placed in a flow-through chamber would not yield ecologically realistic levels of courtship, which are only seen in the context of a group or mating ball. Because of these difficulties, we placed groups of males in a flow-through metabolic chamber together with a single female whose respiratory gases were vented outside the chamber to yield a whole group metabolic rate during competitive courtship. Conservative estimates of peak group metabolic rates during courtship are 10-20 times higher than resting group metabolic rates. These measurements indicate that costs of male courtship are high for males and may have implications for the evolution of alternative male mating strategies in this system.
