Lekking males are thought to face strong directional selection on secondary sexual traits. How variation in male traits can persist under these conditions remains problematic (the lek paradox). Here, we present several game-theoretic models that show that avoidance of costly and mobile...

Both male and female Wellington tree weta, Hemideina crassidens, use cavities in trees as diurnal shelters. That these galleries are often limiting in nature offers males the opportunity to increase their reproductive success by monopolizing galleries and the females residing in them. Male H....

Males may allocate a greater proportion of metabolic resources to maintenance than to the development of secondary sexual characters when food is scarce, to avoid compromising their probability of survival. We assessed the effects of resource availability on body mass and horn growth of bighorn...

We examined interspecific female mating preferences in four closely related species of cichlid belonging to the Pseudotropheus zebra species complex of Lake Malawi. These species differ in coloration but are similar in other respects, suggesting that male color patterns may be important to...

Female mating decisions that are based on condition-dependent traits, such as male nutritional state, may be associated with a female's own condition. In the swordtail fish, Xiphophorus birchmanni, females prefer the chemical cues of well-fed males to cues of food-deprived males. Here we show...

Defense of territories in many animal species involves the advertisement of territory holder quality by acoustic signaling. In the sac-winged bat Saccopteryx bilineata, males engage in territorial countersinging when reoccupying their day-roost territories in the morning and in the evening...

Why do females increase parental effort when caring for the offspring of attractive males? First, attractive males may be poor fathers so that their females are compelled to increase their own contribution in order to fledge some young (the partner-compensation hypothesis). Second, females mated...

Multispecies choruses represent a promising but uninvestigated forum for public information. Although frogs exposed to a potential predator call more readily in the presence of conspecific calls than in their absence, none are known to make comparable use of heterospecific calls. To test for...

The morphology of male genitalia often suggests functions besides sperm transfer that may have evolved under natural or sexual selection. In several species of sexually cannibalistic spiders, males damage their paired genitalia during mating, limiting them to one copulation per pedipalp. Using a...

Although costs of mating have been widely documented in females, intrinsic costs of copulation have been poorly documented in males, and there is little evidence that such costs constrain male mating success under natural conditions. Male sagebrush crickets, Cyphoderris strepitans, offer females...