Female Mate Choice Research Articles

A genetic analysis of male-predominant pheromones in Drosophila melanogaster.

Chemical signals from males play an important role in stimulating Drosophila melanogaster females to mate, and male-predominant pheromones may influence a female's choice of mates. Male-predominant pheromones also inhibit courtship, thereby functioning as antiaphrodisiacs. Interstrain variation in the ratio of two male-predominant pheromones (7-tricosene and 7-pentacosene) has been reported, but the genetic basis for this potentially important variation has not been examined. In a series of crosses between strains that differ radically in the amounts of 7-tricosene and 7-pentacosene, we have identified both X-linked and autosomal contributions to interstrain variation in the amounts of these compounds. The X-linked loci act as enhancers for production of the compound predominant in the strain from which the X chromosome originated. Autosomal factors for each of the two compounds appear to segregate as high vs. low, with incomplete dominance of high 7-tricosene over low, and low 7-pentacosene over high. A significant negative correlation between the quantities of 7-pentacosene and 7-tricosene in the F2 and backcross progeny, but not in the F1s or parentals, indicates linkage between autosomal loci regulating the expression of each compound. However, the phenotypic distributions of the backcross progeny indicate that additional unlinked loci are also directly involved in the production of these two hydrocarbons.

Female Primate Sexual Behavior and Conception: Are There Really Sperm to Spare? [and Comments and Reply

Female Primate Sexual Behavior and Conception: Are There Really Sperm to Spare? [and Comments and Reply

Female choice of sites versus mates in a coral reef fish, Thalassoma bifasciatum

To understand the dynamics of sexual selection, one needs to identify the basis of female choice in mating. Daily censuses showed that most spawns of individual female bluehead wrasses, Thalassoma bifasciatum, occurred at one of several available mating sites, either in a group-spawning aggregation of small males or with a large territorial male. Most females were not located near their principal mating site during the non-spawning period of the day. Females were thus exposed to other males and sites and should have had the opportunity for choice. When a resident territorial male disappeared or was removed experimentally from a mating site, females did not alter their fidelity to that site. Furthermore, manipulations showed that when a territorial male changed the location of his mating activity to an adjacent site, females did not follow him but continued to mate at their customary site. Thus mating sites, rather than the males occupying them, appeared to be the objects of female choice. The bright coloration and courtship behaviour of larger males may demonstrate the safety of a particular site rather than indicating some aspect of male quality.

Do Nest Building and First Egg Dates Reflect Settlement Patterns of Females?

The order in which females settle on territories likely reflects patterns of female choice of territory and/or mates. Yet in most studies of female choice, settlement dates are usually only inferred from dates of nest initiation or first egg date. To test whether there is a close correlation between the order of female settlement and the initiation of nest building or egg laying, we determined the settlement date of female Tree Swallows (Tachycineta bicolor) through direct observation. The order of female settlement on territories was not significantly correlated with either the initiation of nest building or first egg date. The interval between settlement and egg laying shortened as settlement date advanced, and females began egg laying during a short period in May, regardless of when they had settled. Some females that we experimentally prevented from settling until early May began egg laying at the same time as females that settled in early April. We suggest that female Tree Swallows are under pressure to settle early due to intense competition for limited nesting sites, but then time their egg laying for mid-May to benefit from synchronous breeding and favorable environmental conditions. We predict that the order of settlement is not closely correlated with initiation of nesting activities by females in other species in which females breed synchronously and have a long interval between settlement and egg laying.

Consort Intrusion and Female Mate Choice in Japanese Macaques (Macaca fuscata)

AbstractConsort intrusion behavior has been proposed to largely function as a means of preventing or suppressing the reproductive activity of subordinate males. In the Japanese macaques of Arashiyama B troop this behavior was found to be ineffective in influencing female mate choice and affecting differential reproduction. Mainly directed towards the female of the pair intrusion resembled sexual solicitation and appeared to be an extension of consort behavior. Although the intruder male was almost always dominant over the other male, intrusion failed to provide priority of access to the estrous female as she most frequently chose to remain with her current partner. Copulations which were intruded upon were as likely to end in ejaculation as those which were undisturbed. Only a small proportion of intruder male‐female pairs mated. Pairs that did mate were likely to have been in consort before or during the period in which intrusion occurred. No significant correlation was found between male rank order and number of possible females impregnated. Individual young, middle to lower ranking males were estimated to have been reproductively the most successful.

Criteria for Female Choice of Mates: Courtship Feeding and Paternal Care in the Common Tern

Criteria for Female Choice of Mates: Courtship Feeding and Paternal Care in the Common Tern

Social preferences of domestic hens for domestic vs. red junglefowl males and females

The striking dimorphism of male and female junglefowl may have evolved in large part due to female choice of mates. However, domestic fowl hens consistently chose domestic, not junglefowl, males as well as females in preference tests. Either genetic predisposition to favor junglefowl morphological features over those of the domestic types utilized in these tests was overridden by experience or such genetic predisposition does not exist in the breed we tested.

Female choice of mates in a polygynous insect, the whitespotted sawyer Monochamus scutellatus

Adult female whitespotted sawyers Monochamus scutellatus (Coleoptera: Cerambycidae) were placed on succeeding days with two males differing visibly in size. Females showed a significant preference for the larger of two males. The rate of oviposition was significantly higher when the female was paired with the larger male. Both the rate of movement by the paired female and her rate of indicating non-receptivity were significantly lower when the female was paired with the larger male. This species exhibits resource defense polygyny, and females appear to choose mates mainly on the basis of the quality of resources defended. This study suggests, however, that when resource quality is constant, females choose mates on the basis of their size.

Sexual selection in gallus: Effects of morphology and dominance on female spatial behavior

Sexual selection has received a great deal of attention from field and laboratory researchers for over a century, but hard evidence of female choice of mates in mixed-sex groups remains scarce. Dominant males typically mate much more often than subordinants but evidence that females “choose” such males is elusive. In Gallus , which includes junglefowl and their domestic fowl descendants, females stay near and mate with dominant, territorial males. We demonstrate here that Gallus females in mixed-sex flocks who have no information about the social dominance status of males orient to, approach and stay near males with larger than average combs whereas females which do not have information about male dominance orient toward and stay near high ranking males. We verify that comb size correlates with male social rank. Hence, Gallus females do actively respond to “high quality” males; they apparently identify such males by male physical characteristics and, if available, information concerning male-male interactions.

Mate Choice by Females of the Lizard, Anolis carolinensis

Mate choice by female Anolis carolinensis was evaluated under conditions simulat- ing the normal long-term association between males and females of territorial lizards. One-third of the females tested exhibited a significant preference for one of two males and two-thirds of the females associated with males randomly. Preference or non-preference by females was not related to their body size or to the rate at which they laid eggs. Females associated with males more frequently than necessary for the fertilization of eggs. Significant preferences by females were independent of the relative size of the two males. Because male body size is strongly correlated with dominance in interactions between males, females thus did not prefer to associate with dom- inant males. Sexual dimorphism in body size and the brightly colored dewlaps and elab- orate displays of males suggest that so- cial and sexual selection has played an important role in shaping the life his- tories of Anolis lizards (West-Eberhard, 1983). However, the relative impor- tance of competition between males and of female choice of mates is yet to be resolved (Trivers, 1972; Andrews, 1979; Stamps, 1983). On the one hand, body size is strongly associated with domi- nance in interactions among male ano- les (Greenberg and Noble, 1944; Rand, 1967). Concomitantly, large adult males have larger territories and harems than small adult males (Rand, 1967; Trivers, 1972, 1976). Moreover, sexual dimor-

Song repertoire size and female preferences in song sparrows

Captive female song sparrows (Melospiza melodia), after treatment with estradiol, perform copulation solicitation displays when presented with songs of conspecific males. Females respond more strongly to eight song types than to four, and to sixteen song types than to eight. These results are consistent with the hypothesis that female song sparrows prefer large repertoires, rather than preferring normal or natural repertoire sizes (5 to 13 song types). The results with captive females might be taken to imply that females in the field prefer as mates those males with the largest repertoire sizes. This hypothesis was tested by observing pairing in a field population. In each of 2 years, there was no significant correlation between male repertoire size and date of initial pair formation. Furthermore, there was no correlation between repertoire size and the speed with which a second mate was acquired after removal of the first. It is concluded that repertoire size does not have an important influence on female choice of mates in song sparrows.

The Development of Mate Choice in Zebra Finch Females

Abstract SONNEMANN & SJÖLANDER (1977) found that zebra finch females raised by their own species (Zz females) differ in mate preference from females raised by Bengalese finches (Zb females) when given the choice between a Z male and a B male. Their data also showed an own species bias (Zz females strongly preferred Z males, whereas Zb females showed about equal interest in Z and B males). Several authors mentioned the existence of a preference for species-specific characteristics independent of early experience (a so called 'innate' preference) as a cause for an own species bias. This conclusion can be doubted for theoretical and methodological reasons and the question for the processes leading to an own species bias in zebra finch females seems completely open. We investigated several possible causes of the own species bias. Our experiments suggest that the final preference in Z females may be influenced by three independent processes. First, visual stimuli are involved. Information on these seems to stem exclusively, or at least largely from parental influence. No initial preference for visual characteristics, independent of experience with Z or B has to be assumed. Second, experiments indicate that a preference for actively courting males is present. The process underlying this is unknown but seems independent of the one giving rise to a preference for visual stimuli. Third, during the period between raising and testing (during which the females were visually isolated) the preference changes with age. Here too, the underlying process is unclear. Several possible causes for this change are discussed. The process underlying it is probably different from the other two. Altogether the results indicate that the own species bias may be the result of several independent developmental processes, which in combination led to a bias in testing.

Sexual selection and reproductive success in males of the bicolor damselfish, Eupomacentrus partitus (Pisces: Pomacentridae)

Relative reproductive success of male bicolor damselfish, Eupomacentrus partitus, was measured as the number of egg batches obtained per week per male during a 14-month field study. Large and consistent differences in spawning success, observed in seven colonies containing 23 males, demonstrated that mating was non-random. Various physical and behavioural characteristics of males were also monitored. Significant correlations ( P<0.05) were found between reproductive success and four variables: frequency of courtship, inter- and intraspecific aggression, and total length. The importance of other factors such as size and location of male territories and time allotment to various activities was also considered. The interactions between these variables, as well as preliminary observations of spawning, suggest that intersexual selection, that is female choice of mates, is the dominant process in sexual selection in this species.

Sexual Differences in Parental Activities of Breeding Black Skimmers

Sexual Differences in Parental Activities of Breeding Black Skimmers

Female Choice of Mates: A General Model for Birds and Its Application to Red-Winged Blackbirds (Agelaius phoeniceus)

A model of female choice in birds is developed with special reference to red-winged blackbirds. Characteristics of the male are related to female fitness, and it is argued that these characteristics should influence mate choice only if they (a) have an important effect on female fitness, (b) are variable, and (c) are accurately assessable prior to mating. Using these criteria, it is concluded that female choice in redwings (1) should not be influenced by the female's estimate of the male's future nest defense effort because nest defense seems to have little effect on the severity of predation and parasitism losses; (2) should not be influenced by an estimate of the male's future time investment in feeding the young because this investment is small in redwings, and the female's estimate must be inaccurate; (3) should be influenced by the vulnerability of the territory to predation because predation rates are high, variable from area to area, and predictable; (4) should not be influenced by the vulnerability of the territory to cowbird parasitism because parasitism losses are lower and less predictable than predation losses; and (5) should be influenced by the availability of food to a female on the territory because starvation rates are substantial, marshes are known to be variable in productivity, and productivity should be predictable before mating. Male genetic quality could also influence female choice, but the importance of this factor cannot be evaluated as it is not known how strongly the fitness of offspring is influenced by male genetic quality nor how accurate is the female's estimate of genetic quality. Empirical tests indicate that territory quality influences female choice more than male genetic quality and that male defense effort has little influence.

The Evolution of Mating Systems in Grouse

The evolution of polygyny in birds has been clarified by recent theory based on female choice of mates (Verner 1964, Orians 1969), but the evolution of promiscuity has remained difficult to explain (Selander 1972). Wiley (1974) recently suggested that promiscuity evolved in grouse as a consequence of delayed maturation of males. This hypothesis reverses the usually accepted causal relationship between delayed breeding and polygamy. It also emphasizes the optimization of male rather than female reproductive tactics. Therefore, the intent of this paper is to examine Wiley's (1974) hypothesis and present an alternative based on the assumption that female choice determines the evolution of grouse mating systems. Polygamy must normally be advantageous to both sexes before it can evolve. The only known exceptions occur when females cannot determine the true mated status of potential mates (Wittenberger 1976). According to sexual selection theory, polygamy should nearly always be advantageous to males because males -can usually increase their fitness by copulating with as many females as possible (Bateman 1948). In contrast, females usually gain little advantage by copulating with more than one male per season because their reproductive output is limited by energetic constraints rather than ability to get eggs fertilized. In addition, females risk losing a much larger investment of time and energy than males when they accept a mate (Orians 1969). As a result, males generally compete among themselves for mates, while females generally select their mates from an array of competing males. According to this principle of female choice, factors affecting female success should normally determine the type of mating system that evolves (Orians 1969). The Orians-Verner model follows directly from the female choice principle. It predicts that polygyny should evolve only when some females can be more successful as second mates of already mated males than as first mates of any remaining unmated males (Verner 1964, Orians 1969). This can occur whenever habitat differences between male terri-

Territoriality and Male Mating Success in the Green Frog (Rana Clamitans)

Territorial behavior of Rana clamitans was studied in an enclosed experimental pond. Males maintained territories from June through August. Most ♂ ♂ occupied more than one site during the breeding season. Most sites were occupied for &lt; 1 wk before changing ownership, but some were occupied by a single ♂ for up to 7 wk. Large ♂ ♂ remained at individual sites longer and spent more total time in territories than small ♂ ♂. The smallest of ♂ ♂ usually acquired territories only after other ♂ ♂ had abandoned them, while larger ♂ ♂ sometimes ousted residents with aggressive behavior. Males sometimes adopted a satellite role in the territories of other ♂ ♂ and waited for sites to become available. Individual territory sites were ranked by relative quality based on the physical structure of the sites. Female choice of mates appearerd to be related to territory quality, and especially to density of vegetation in the water. Males that spent the most time in high quality territories acquired the largest number of mates. The social system of the green frog probably evolved as a result of intense ♂— ♂ competition for mates. This in turns is probably related to its prolonged summer breeding season.

The Roles of Female Mate Choice and Predation in the Mating Systems of Some Tropical Labroid Fishes

AbstractThe highly differentiated patterns of courtship and spawning of 3 tropical wrasses are described. We show how (a) the ability of a ♀ to freely choose her mates, and (b) risks of predation on the spawning fishes and their zygotes, affect the structure of courtship interactions and the spawning act itself. We also discuss how both these factors affect the spatial location and diurnal timing of spawning. The significance of variability in the expression of sexual dichromatism in these and other wrasses and parrotfishes is considered from the same viewpoints.