Meeting Abstract
34.2 Wednesday, Jan. 5 Heart rate as an index of increased metabolic output in a bird with a complex courtship display BARSKE, Julia*; FUSANI, Leo; WIKELSKI, Martin; SCHLINGER, Barney; University of California, Los Angeles; University of Ferrara, Italy; Max Planck Institut for Ornithology, Radolfzell, Germany jbarske@ucla.edu
The golden-collared manakin (Manacus vitellinus) of Panamanian rainforests has a polygamous (lek) breeding system in which individual males perform a complex and physically intensive courtship display. Using a small arena created on the forest floor, male displays consist of rapid, acrobatic jumps between saplings accompanied by mechanical sounds produced by their wings. Males differ in the rate at which components of the display are performed and we have evidence that females can distinguish these subtle behavioral differences preferring males that perform faster and more frequently. We hypothesize that these properties of the display reflect male condition, hence they are an indicator of genetic quality and serve as the basis for female mate choice. We further hypothesize that males express a higher heart rate while courting, reflecting the higher metabolic rate associated with elevated displaying activity. If heart is increased during displaying, then courtship activity would represent a good proxy of condition for females. We monitored heart rate of wild breeding males over the course of one or more days. Birds were collected and miniature transmitters were attached that transmitted heart rate as frequency modulation of the carrier signal. After release, most males returned to their courtship arenas and appeared to behave normally. We obtained heart rates during discrete elements of their courtship display, recording rates up to 1300b/min compared to a mean of 563b/min when birds were at their courts but not displaying and approximately 350b/min at night. These data indicate that courtship displays are indeed highly energetically demanding consistent with the hypothesis that courtship displays serve as indicators to females of male condition and thus male quality.
