PCB 4674 Lecture Notes - Lecture 25: Ceratitis Capitata, 18 Months, Heritability
21 Dec 2016
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Document Summary
Because claiming and holding a territory requires combat, bigger males tend to win. Mean size of males that actually got to copulate was significantly larger than the mean size of all males that tried to copulate. If we assume that body size is heritable in marine iguanas, then we have variation, heritability, and differential mating success: good explanation for why male marine iguanas get so much bigger than the optimal size for survival. Marine iguanas- small males are only rarely successful, but they do get about 5% of the mating in the colony. Small males are far more likely to be disrupted in copulation before they have had time to ejaculate- which typically takes about 3 minutes. So they solve this problem by ejaculating ahead of time: use the stimulation of an attempted copulation (or even seeing a hot female walking by) to induce ejaculation, which they then store in their cloacal pouches.
