The object is to saturate an area with so much synthetic pheromone that the males are unable to locate calling females.
Social monogamy has evolved in nonhuman mammals where breeding females are intolerant of each other and female density is low, suggesting that it represents a mating strategy that has developed where males are unable to defend access to multiple females.
In addition, since ice is less stable then solid land, breeding sites change location each year, and males are unable to predict where females will stay during the breeding season.
Females can usually move freely between territories and males are unable to coerce them, but in some species such as the northern fur seal, South American sea lion and Australian sea lion, males can successfully contain females in their territories and prevent them from leaving.
In other cases, sperm depletion is permanent, where males are unable to replenish their sperm once it is used [13].
Therefore, unlike males of the remaining Gerridae, G. gracilicornis males are unable to commence copulation even after coercively overcoming female resistance to mounting, and despite positioning their genitalia against the female's abdominal tip (the gonocoxae).
Instead of rejecting mounting males, females actively halve the number of matings by producing an andromorphous mucous trail that result in males being unable to discriminate between female and male trails of this species, as is possible in closely related species (Johannesson et al. subm).
In the high-density species, however, males fail to discriminate between male and female trails, not because males are unable to identify female trails (which we show using heterospecific females), but because females do not, as the other species, add a gender-specific cue to their trail.
