Table 3.

Selection-based hypotheses often advanced to explain unexpectedly high levels of polyandry in various species (42)

Nature of the fitness benefit	Representative example or review
Direct material benefits	43
Courtship feeding (nutritional support)	44, 45
Better territories (more resources)	46
Reduced risk of sexual harassment	48
More parental care	50
Better immediate mate compatibility	51
Indirect genetic benefits	42
Fertilization insurance	52
Better genes via sperm competition	53, 54
Better genes via cryptic female choice	47, 55
Enhanced offspring viability
Sons with more competitive sperm	49
Reduced risk of incompatible sperm	56
Higher genetic diversity within a brood	57, 58
Bet-hedging in unpredictable settings	59
Compatible genes for self or progeny	60

Many of these hypotheses overlap and are not mutually exclusive.