Low-ranking Males Research Articles

The Influence of Nests on the Social Behaviour of Males in Manorina Melanocephala, a Communally Breeding Honeyeater

Manorina melanocephala is a communally breeding honeyeater in which several males feed the offspring of a single female. A free-living population of colour-banded birds was observed from 1971 to 1974 in southern Queensland.Males visiting nests were frequently attacked by males previously dominant at that place. Immatures from a female’s previous broods in the same year were driven away from the nest by adult males. Sometimes males displayed towards the eggs in the nest and often drove off the incubating female before such display. Females almost never visited the nests of other females and only rarely fed their fledged offspring. Females appeared to learn to leave the nests at the approach of a male and thus incubation could possibly be considerably interrupted when many males visit. Every nest watched had a complement of visiting males, whose number increased as the nest advanced. At least twenty-two males were known to visit one successful nest. Feeding rates of nestlings by males reaching fifty-five per hour; of fledgelings eighty per h our. Females’ contributions were additional to these. Males did not restrict their activities to a single nest but often had a much more active role at one. The largest recorded complement (banded males only) attending successive nests of a single female in the same breeding period numbered twenty-four. Spaces in which females were active showed no clustering nor were they confined to the area occupied by a coterie of males. Of nests built by fourteen banded females, an average of 5-2 were visited by thirty-three banded males during systematic watches. The mean number of females visited was 3'8. Males ranking highest in visiting any female also visited more nests and more females than did lower ranking males. No male ranked highest with more than one female. Often females were visited by males from more than one coterie but then always from an adjacent one. When a female nested within the area of a coterie, most visiting males originated there. When a female nested near the common boundary of one or more coteries, males from each visited. Visiting males tended to show a linear relation between rank in visiting activity and distance of their space of activity from a nest. The social system, in general, is complex and unlike any previously described for birds. Although observations of early nests in the breeding period suggest synchrony between close females, analysis did not support widespread synchrony of reproductive activity within a colony.

Male dominance and aggression in Japanese macaque reproduction.

Dominant males have been reported to mate more frequently than lower-ranking males in multimale troops of baboons (DeVore, 1965), rhesus monkeys (Carpenter, 1942; Kaufman, 1965), and Japanese macaques (Tokuda, 1961–2; Hanby et al., 1971). Such behavior would appear to have selective advantages for fostering genetic traits that contribute to the phenotype of high-ranking males, e.g., perhaps a low threshold for instituting attack, a high tolerance of pain, and a high social intelligence. However, Rowell (1966) has argued that dominance in caged baboons is a social construct that is maintained by the behavior of lower-ranking animals and that female primate sexual receptivity is not necessarily related to ovulation. Therefore, she concluded it would be difficult for traits that contribute to dominance to be selected through reproductive success.KeywordsJapanese MacaqueDominance RankDominant MaleJapanese MonkeyPapio UrsinusThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Territoriality and the Influence of Females On the Spacing of Males in the Cockroach, Nauphoeta Cinerea

Abstract(I) The first aim of the study was to extend earlicr observations on the effect of density on social structure and in particular to see if all males in a group became territorial at very low density. The second aim was to determine the social organisation of females in relation to territorial males. (2) Most males were observed to become territorial at very low density but there was a definite limit to the tendacy to spread out. A few males were not territorial and the behaviour of these animals is described. (3) The females formed a group, usually but not always, on a male-occupied territory. Unreceptive, virgin females introduced into the observation tank remained inactive for the first few days. In these females activity and exploration were correlated with the onset of receptivity. Some females mated at this time and then moved on until they joined the female group. Others joined the female group immediately and mated with the territory owner if one was present. Once females had joined the group they did not leave except for brief sallies or to give birth to their young. The female group did however move en masse and sometimes moved the entire length of the tank. (4) One of the most obvious effects of the females was on the pattern of male territory holding. Competition for territory centred round the female group and several males took up residence with the females during the day. Either one of these males became a despot or a hierarchy of dominance developed. At night the top-dominant chased the others off his territory. These males, with the exception of a few very low-ranking males, then set-up territories on adjacent rest-sited and made occasional attempts to rejoin the female group. This sequence of events was repeated each day. (5) The second obvious effect of the females was on the amount of fighting. Males were alone more often than they were with females but when females were present there was more fighting. (I) The relationship between hierarchy and territory is discussed and conclusions are drawn about the function of territory and the limitations of the territorial system in Nauphoeta.

Sexual behavior in the Northern Elephant seal Mirounga angustirostris.

AbstractThe mating behavior of Northern elephant seals, Mirounga angustirostris, was studied during the I968, I969 and I970 breeding seasons at Año Nuevo Island, I9 miles north of Santa Cruz, California. Copulation takes place primarily on land, from January to March; it is initiated and terminated by the male and lasts approximately 5 minutes. A few males do most of the breeding and the higher a male's rank in the social hierarchy, the more frequently he copulates. Some bulls may maintain high rank and participate in mating for 3 breeding seasons. Low ranking males are kept out of the harem so they attempt to copulate with females on the periphery or in the water with departing females. Males prevent subordinates from mounting females and disrupt copulations in progress. The higher a male's rank, the more freedom he has to copulate without interference, and the more frequently he interferes with the copulation of others. The highest ranking males interrupt their own copulations prematurely to attack other males and prevent them from copulating. Males mount weaned pups, yearlings, and non-estrous females in addition to estrous females; the latter are mounted most frequently. Females come into estrus 24 days after parturition. They are receptive for about 3 days (range I-I3 days), during which they may copulate several different times with one or more males. Females are usually in estrus when they leave the rookery and return to sea. The greatest difference in the copulatory pattern of the elephant seal, a true seal, and members of the sea lion family, is that the former interfere with the copulations of other males while the latter do not. This may he due to differing social systems, a social hierarchy in elephant seals and a territorial system in sea lions. In elephant seals, where copulations are interrupted, mating may be incomplete. This is not as likely with sea lions where copulations are never interrupted because males honor the boundaries of their neighbors. The differences in female behavior and sexual physiology - a long promiscuous estrous period in elephant seals as opposed to a brief estrus with only one copulation in sea lions - may have evolved as a compensation for the consequences of the social behavior of males.

Canine teeth and rank in Japanese monkeys (Macaca fuscata)

Canine teeth were extracted from seven adult male Japanese monkeys. Observations over the next four years led to the conclusion that canines are not essential for either the attainment or maintenance of high rank, but that they may play an important part in the self-defense of low-ranking males.

A Three‐Year Study of Mating Behavior in a Freeranging Band of Rhesus Monkeys

The mating behavior of a freeranging band of rhesus monkeys in an island colony near Puerto Rico was studied for three consecutive years. From approximately July through December females had repeated cycles of estrous behavior in which they associated closely with males, groomed with them, and engaged in copulation. About one—half of the females which conceived had postconception estrous periods, including copulation. The average number of estrous periods per female was two, each period lasted an average of 11 days, and most estrous cycles lasted about 28 days. An average of three males associated with a female during one period. Most females began breeding when they were three years old and there was no significant difference between the mating activity of females three, four, and five years old. Six—year—old females showed a definite increase in mating activity, and females seven years old showed a still greater increase. No significant increase was apparent after the females reached seven. The females' rank in the dominance hierarchy apparently had no effect on their mating activity. The quantity of the males' sexual activity was generally correlated with their dominance rank. The highest male was the most active by far, the first to become active, and the only male to form many exclusive consort relationships with individual females. Progressively lower ranking males were usually less active, but low—ranking males were active early and late in the mating season. The findings concerning average period and cycle length, number of males associating with females, and the relation between the males' rank and mating activity agree closely with those of C. R. Carpenter (1942) on Cayo Santiago in 1940. Though several promising lines of inquiry have been opened, much work remains to be done before we can explain the relation between rhesus mating behavior and its physiologic basis, or explain variations in reproductive periodicity.