Sex‐Related Foraging Behavior in Sequentially Hermaphroditic Hogfishes (Bodianus Spp.)

Abstract

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.

Foraging activities and diets of males and females in a haremic sandperch (Pisces: Pinguipedidae)

“…My data on activity time allocation in male and female Parapercis polyophthalma were concordant with the predictions of Schoener (1971), Hixon (1982Hixon ( , 1987 and Hoffman (1983) in that the amounts of time allocated to foraging and nonforaging activities can be sex related. Males spent much less time feeding and more time on territorial and social activities than did females, because males would be able to gain increased mating success by defending their territories, maintaining social dominance over females, and securing mates.…”

“…Schoener (1971), Hixon (1982) and Hoffman (1983) predicted 3 general patterns of sex-related foraging behavior (or net energy gain) in mating systems where total male parental investment is lower than female investment, particularly in species showing no parental care. First, males tend to minimize foraging time when their reproductive success is limited more by the amount of time spent in social and mating activities than by foraging activities.…”

“…According to these predictions, a sexual difference in foraging time should be found in fish species with a social system based on male territoriality and a male-dominated harem (Hoffman 1983, Hixon 1987. Since single dominant males of such species can mate with almost all females within their territories (e.g.…”

“…In the case of fishes in which males are not territorial and spawn in groups, foraging time is expected to be similar between the sexes. Both sexes maximize reproductive success by gaining greater energy and maximizing gamete production (Hoffman 1983).…”

Predators and the Distribution and Abundance of Blennies on Offshore Petroleum Platforms

“…Bodianus rufus was recorded in three observation periods at 10 m and one at 15 m. Rooker et al (1997) found B. rufus less common at depths < 9 m, a distribution not consistent with the expected distribution if this predator was limiting the distribution of P. marmoreus. Bodianus rufus are territorial (Hoffman 1983) and additional observations indicated this species consistently frequented parts of the platform that offer some cover (where diagonal and vertical members meet). Such a territorial behavior would limit the potential for this predator to restrict a prey species on areas of the structure that are not a part of its territory.…”