PSYC 3201 Lecture Notes - Lecture 55: Handicap Principle, Goby, Crested Auklet
25 Dec 2016
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Sperm is very cheap (males make a lot of it), but eggs are costly because females don"t make that many. For this reason, females need to be choosey. Sexual dimorphism (most colorful are best providers of resources) they are used solely for reproductive success, They only exist among males that court in daytime. Colors are oriented toward female during courtship. Long-tailed widow bird males are either kept long-tailed or have tails cut off and attached to make a super-long tail. The super long tails were chosen more frequently than the normal and short tails. Light, short mains usually means submissive while longer, darker manes is dominant. Dark, long-maned males have higher testosterone, longer reproductive life-span, and high offspring survival. But dark, long-maned males are costly because of thermal stress which leads to abnormal sperm and lower food intake in heat. Handicap principle: if a trait has costs, it must be really beneficial (like lion example)
