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I develop Schoener's proposal that the amount of activity time allocated to foraging can be sex related; males more often than females should minimize foraging time, and females should often be foraging-time maximizers. Sexual differences in foraging-time allocation may be small when male mating success is limited by available energy for maximizing sperm production.The foraging-time patterns of the sexes were examined in three sequentially hermaphroditic (protogynous) hogfishes in the genus Bodianus (Family Labridae). The daily social and mating activities of males in each of these marine reef fishes are distinctly different: single males defend permanent, all-purpose territories that contain a harem of females (B. rufus; San Bias Islands, Panama), males defend temporary reproductive territories (B. diplotaenia; Gulf of California, Mexico), or males are not territorial and spawn together in groups (B. ec/ancheri; Galapagos Archipelago, Ecuador). Female hogfishes in all three species mate daily and spend relatively little time on social and mating activities. Fertilization is external, and parental care of young is absent in these species.Time budget analyses indicated that B. rufus males allocated a much smaller proportion of their time (39. 7%) to foraging than did conspecific females (76.8% ). Protogyny in B. rufus provided a unique opportunity to test the effect of sex on an individual's time budget experimentally. Sex change by the dominant female was initiated in the field by removing the dominant, territorial male from his harem group. All (N = 9) individuals tested decreased the amount of time spent foraging and increased time allocated to social and mating activities, after they became reproductively functioning males. Sequential removals within harems indicated that the reduction in time spent foraging decreased with the number of female mates remaining in the group. Bodianus diplotaenia males also spent less time foraging (45.9%) than did conspecific females (76.5%). Bodianus ec/ancheri males spent most (70.2%) of their time foraging, as did conspecific females (77.3%).It appears that males minimize foraging time when their reproductive success depends more upon time spent in social and mating activities than upon net energy gains, as in B. rufus and B. diplotaenia. The reproductive success of female hogfishes, and males that compete for mates by maximizing sperm production (B. ec/ancheri), appears to be limited primarily by energy available for gamete production and growth; these individuals spend relatively little time engaged in social and mating activities and spend most of their time foraging.

We propose that in some species, local population density can strongly affect the economic defendability of a mating territory. This is so because the numbers of females and potentially interfering males determine allocations of time and energy to reproduction and defense. At low densities, allocations to defense should be small and territorial mating success should initially rise with local density, reflecting the supply of females. If defense takes priority over mating, higher population densities can create a situation in which the time or energy devoted to defense against other males detracts from allocations to reproduction. Thus a point is reached where territorial mating success declines with increasing density, as a function of the number of nonterritorial males. We investigated these hypotheses by recording changes in the daily mating success of territorial males of the bluehead wrasse (Thalassoma bifasciatum) following experimental manipulations of local population size and composition. On large reefs, where mating population densities are already high, territorial mating success varied inversely with changes in overall population density and with changes in nonterritorial male numbers only; changes in female numbers had little effect. Thus at higher densities the demands of defense appear to be more important in determining mating success than the supply of available mates. Territorial mating success varied directly with population density changes only on the smallest experimental reff, where there were few nonterritorial males. The reduction of mating success at higher densities was correlated with a decreases in both the time spent in courtship and the efficiency of courtship itself. The effect of population density should be particularly important in species with short breeding periods and where the male contributes relatively little time or energy to each mating.

We studied short-tailed shearwaters Puff~nus tenuirostrjs foraging near the Pribilof Islands, Alaska, USA, during the summers of 1987, 1988, and 1989. Their foods were almost exclusively the euphausiid Thysanoessa raschii, which they obtained both from near-surface swarms and from epibenthic layers. Near-surface mating swarms of euphausiids occurred in areas of elevated phytoplankton standing stocks near inshore tldal fronts. Many of these euphausiids had attached spermatophores. Shearwaters also obtained euphausiids over shallow reefs and inshore of the fronts where euphausiids were trapped in water shallower than 40 m by lrreyulanties In bottom topography ('bathymetrlc traps'). We hypothesize that the largely inshore distribution of shearwaters in the southeastern Bering Sea described by previous workers is the result of attraction of shearwaters to frontal areas where euphausiids may forage on phytoplankton stocks throughout the summer. These areas, when shallower than 40 m, would also permit shearwaters to access epibenthic aggregations of euphausiids during daylight, when euphausiids not engaged in mating swarms usually migrate to depth.

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