Mating Options Research Articles

Light disrupts social memory via a retina-to-supraoptic nucleus circuit.

The formation of social memory between individuals of the opposite sex is crucial for expanding mating options or establishing monogamous pair bonding. A specialized neuronal circuit that regulates social memory could enhance an individual's mating opportunities and provide a parallel pathway for computing social behaviors. While the influence of light exposure on various forms of memory, such as fear and object memory, has been studied, its modulation of social recognition memory remains unclear. Here, we demonstrate that acute exposure to light impairs social recognition memory (SRM) in mice. Unlike sound and touch stimuli, light inhibits oxytocin neurons in the supraoptic nucleus (SON) via M1 SON-projecting intrinsically photosensitive retinal ganglion cells (ipRGCs) and GABAergic neurons in the perinuclear zone of the SON (pSON). We further show that optogenetic activation of SON oxytocin neurons using channelrhodopsin is sufficient to enhance SRM performance, even under light conditions. Our findings unveil a dedicated neuronal circuit through which luminance affects SRM, utilizing a non-image-forming visual pathway, distinct from the canonical modulatory role of the oxytocin system.

Poor reproductive success of polygynously mated female birds with obligatory bi-parental care: a result of deceptive behaviour of males?

Social polygyny usually benefits males by increasing the number of offspring, whereas it is detrimental for females as they must share the resources provided by their mate. An intersexual conflict may exist in animals with obligatory bi-parental care, such as birds of prey, in which females incubate and brood, whereas males provision food for their families. Long-term ringing data from Eurasian kestrels (Falco tinnunculus) breeding in nest-boxes and data on density indices of main prey animals (voles) were collected during 1985–2013 in western Finland to study polygynous behaviour. Of 1294 males, 54 (4.2%) were encountered at two (53) or three (1) nests during the same breeding season. Polygyny occurred more frequently during years of high vole abundance. The distances between nests of corresponding primary and secondary females were greater (median 1010 m) than the distances from nests of primary females to the nearest vacant nest-box (median 455 m). Twenty-eight (53%) of 53 secondary females had nearest available monogamous male within 2 km from their nest-boxes, indicating that mating options were available. Secondary females produced 30% less fledged offspring than simultaneously laying monogamously paired females. The abundance of prey animals is apparently alleviating the effort of males mating with multiple females. Spacing out the nests of primary and secondary females implies deceptive behaviour in the nest-site selection of polygynous males. Contradicting the polygyny threshold model, reproductive success of secondary females was significantly reduced in comparison to monogamous females laying simultaneously. These results show that secondary kestrel females apparently made a maladaptive choice, likely because they were deceived to accept polygynous mating status during the courtship feeding period.Significance statementAs dedicated parental effort of both the male and the female is vital to ensure the offspring survival amongst animals with obligatory bi-parental care, polygyny should be inherently a maladaptive mating strategy for females. However, regular social polygyny has been documented in at least 10% of bird species from ten orders. Previous studies on breeding success of polygynous birds of prey indicate reduced offspring production of secondary female partners with no apparent cause for females to choose polygynous males over other mating options. We showed that polygyny in Eurasian kestrels is frequent when food is abundant facilitating males to provision their two or more females during courtship feeding. Polygynous males space out their two nests thus attempting to hide their mating status from their secondary partners which suffer from their mate choice in form of poor reproductive success. Therefore, amongst the “cost of polygyny to females” hypotheses, the deceptive behaviour of males during courtship feeding appeared to be an apparent explanation for maladaptive mate choice of secondary females.

Inheritance and correlation of productive traits in wool-and-meat producing sheep of different genotypes

The effectiveness and competitiveness of sheep breeding directly depends on increasing the productivity of animals and improving the quality of products obtained from them, and this has been achieving by targeted breeding using the genetic potential of sheep breeds. The solution to this problem can be implemented through the rational use of breed resources of domestic and imported sheep breeding. Sheep breeding in Kazakhstan is the oldest branch of animal husbandry, which plays a major role in providing the national economy with specifi c types of raw materials and food. Sheep produce the largest amount of various products: wool for diff erent purposes, mutton, fat raw materials, sheep’s milk, sheep skin-fur-leather raw materials, lamb pelts. The whole of Kazakhstan and the West Kazakhstan region are characterized by a wide variety of natural, climatic and economic factors that have a specifi c infl uence on the development of sheep breeding in certain regions. In the West Kazakhstan region breeding work is carried out in a herd of Akzhaik wool-and-meat producing sheep to improve individual productive indicators by using the genetic potential of the gene pool of diff erent semifi ne-wool breeds, so breeding and improvement in order to increase the productivity of Akzhaik meat-wool sheep with double productivity is relevant and has great economic signifi cance. The inheritance and correlation of productive traits in Akzhaik wool-and-meat producing sheep obtained from diff erent mating options have been studied in the paper. It has been established that the inheritance of the main economically useful traits is additive in nature in an intermediate type with minor deviations towards one of the parent forms. The coeffi cients of heritability of live weight, clip, length and fi ber fi neness of wool are within the average values. The highest correlation coeffi cients (0,65–0,70) have been found in all groups between the length and fi ber fi neness of wool.

Game theory approach to sterile release populations and replicator dynamics: Niche fragmentation and resilience

The sterile release technique liberates infertile individuals who mate with wilds. Consequently, wilds have two mating options: sterile or fertile individuals. This choice process can be framed in a theoretical game, typical in economic studies, between two opponents with the appropriate payoff (fitness). The game matrix is constructed depending on parameters such as wild growth rates and the influx rate of sterile individuals. A technique using replicator dynamics allows the equilibrium points to be determined, particularly, the (Nash) equilibrium resulting from the influx of the sterile population. Moreover, when population diffusion is considered, the niche of wilds becomes partitioned, defining a criterion for protecting biodiversity. The medfly, Ceratitis capitata, is regarded as an explicit example for parameter evaluations and numerical simulations.

Genetic Connectivity of the Sky Emperor, Lethrinus mahsena Populations Across a Gradient of Exploitation Rates in Coastal Kenya.

Marine-protected areas (MPAs) have the potential to enhance fisheries through transport of larvae or by a net emigration of adult and juvenile fish to adjacent fished areas. A network of appropriately located MPAs will have the potential to reseed fished areas and other MPAs. Connectivity studies are therefore important to assess the effectiveness of a network of MPAs and to determine the spatial scale necessary for spillover effects. The principal aim of this study was to determine the potential for Kenyan MPAs to reseed adjacent fishing zones by evaluating the levels of genetic differentiation of populations of Lethrinus mahsena, a commercially important fish, along a continuum of protected and nonprotected sites. Fish samples were collected from MPAs (Mombasa and Kisite Mpunguti Marine Parks) and the fished reserves adjacent to the two MPAs. Total length and weight of the fish from the sites and fin clips from one of the pectoral fins were collected and preserved in 90% ethanol. Genomic profiles for each sample were obtained through genotyping by sequencing using diversity array technology markers. Results from population structure, diversity, and admixture analyses indicated very low genetic differentiation (F ST = 0.00184, P > 0.05) and low population substructure between samples obtained from the study locations implying a free exchange of fish across protected and nonprotected sites. There was a high gene flow and multidirectional migration rate among the sampling sites. Inbreeding was moderately high (F IS = 0.15, P < 0.05) in the marine parks, indicating high relatedness and probably limited mating options for the species due to small population size or spatial restriction. The lack of genetic differentiation between protected areas and open fishing grounds is indicative of genetic connectivity for the sky emperor. This reinforces the significance of maintaining protected areas to serve as breeding and spawning grounds of fish without adversely affecting the livelihoods of communities that depend on the various fisheries linked to MPAs.

Marital Satisfaction in Spanish and Dominican Couples

Marriage is an appreciated worldwide institution, although nearly half of first marriages end in divorce. Thus, the relevance of understanding how people choose their partners and what features can predict a satisfactory relationship. More specifically, in search of data supporting similarity or complementarity approaches on marital satisfaction, the current study analyzes the association between different assortative mating options (homogamy, and heterogamy) and marital satisfaction in Spanish and Dominican couples. A stratified quota sampling of 600 participants was selected, corresponding to 300 married couples (50% Spanish and 50% Dominicans). Data were gathered by means of an interview with the 10-item scale on Marital Satisfaction and a 7-item scale on Status. Results suggest that spouses are matched by similarity in their health and education and by the perception of similarity in intelligence and the financial advantages of staying together. Dominican couples experienced higher marital satisfaction than Spanish couples. Findings on hypergamy reveals the persistence of some traditional roles’ distribution among Spanish speaking cultures. The association between status and marital satisfaction revealed that heterogamy rather than homogamy is associated to such satisfaction. These results stress the relevance of taking into account social and cultural differences, beyond biological and psychological factors, to fully understand couples’ satisfaction.

Adult sex ratios and partner scarcity among hunter-gatherers: implications for dispersal patterns and the evolution of human sociality.

Small populations are susceptible to high genetic loads and random fluctuations in birth and death rates. While these selective forces can adversely affect their viability, small populations persist across taxa. Here, we investigate the resilience of small groups to demographic uncertainty, and specifically to fluctuations in adult sex ratio (ASR), partner availability and dispersal patterns. Using 25 years of demographic data for two Savannah Pumé groups of South American hunter-gatherers, we show that in small human populations: (i) ASRs fluctuate substantially from year to year, but do not consistently trend in a sex-biased direction; (ii) the primary driver of local variation in partner availability is stochasticity in the sex ratio at maturity; and (iii) dispersal outside of the group is an important behavioural means to mediate locally constrained mating options. To then simulate conditions under which dispersal outside of the local group may have evolved, we develop two mathematical models. Model results predict that if the ASR is biased, the globally rarer sex should disperse. The model's utility is then evaluated by applying our empirical data to this central prediction. The results are consistent with the observed hunter-gatherer pattern of variation in the sex that disperses. Together, these findings offer an alternative explanation to resource provisioning for the evolution of traits central to human sociality (e.g. flexible dispersal, bilocal post-marital residence and cooperation across local groups). We argue that in small populations, looking outside of one's local group is necessary to find a mate and that, motivated by ASR imbalance, the alliances formed to facilitate the movement of partners are an important foundation for the human-typical pattern of network formation across local groups.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.

The Analogical Peacock Hypothesis: The Sexual Selection of Mind-Reading and Relational Cognition in Human Communication

This integrative review presents a novel hypothesis as a basis for integrating two evolutionary viewpoints on the origins of human cognition and communication, the sexual selection of human mental capacities, and the social brain hypothesis. This new account suggests that mind-reading social skills increased reproductive success and consequently became targets for sexual selection. The hypothesis proposes that human communication has three purposes: displaying mind-reading abilities, aligning and maintaining representational parity between individuals to enable displays, and the exchange of propositional information. Intelligence, creativity, language, and humor are mental fitness indicators that signal an individual's quality to potential mates, rivals, and allies. Five features central to the proposed display mechanism unify these indicators, the relational combination of concepts, large conceptual knowledge networks, processing speed, contextualization, and receiver knowledge. Sufficient between-mind alignment of conceptual networks allows displays based upon within-mind conceptual mappings. Creative displays communicate previously unnoticed relational connections and novel conceptual combinations demonstrating an ability to read a receiver's mind. Displays are costly signals of mate quality with costs incurred in the developmental production of the neural apparatus required to engage in complex displays and opportunity costs incurred through time spent acquiring cultural knowledge. Displays that are fast, novel, spontaneous, contextual, topical, and relevant are hard-to-fake for lower quality individuals. Successful displays result in elevated social status and increased mating options. The review addresses literatures on costly signaling, sexual selection, mental fitness indicators, and the social brain hypothesis; drawing implications for nonverbal and verbal communication.

“Although Quite Nice, I Was Somehow Not Attracted by That Person”

Individuals who are motivated to find a romantic partner do not only have to detect desirable mating options but also have to prevent becoming committed to attractive but unpromising contacts. We thus propose that an acquisition of highly positive evaluations of already romantically committed opposite-sex others is prevented by self-regulatory processes. In two experiments, positive evaluative conditioning (EC) effects were obtained for facial photos (conditioned stimulus) of other opposite-sex singles when these pictures were paired with positive trait adjectives or odors (unconditioned stimulus). In line with our hypothesis, however, this positive EC effect did not obtain for faces of other persons who were presented as being already involved in a romantic relationship. The results demonstrate that the acquisition of positive attitudes during mate searching is modulated by self-regulatory processes that inhibit the emergence of futile commitments.

Multiple mating opportunities boost protandry in a pied flycatcher population

Protandry, the earlier arrival of males than females to breeding areas, is widespread in birds, but its underlying mechanisms are far from well understood. The two, not mutually exclusive most highly supported hypotheses to explain avian protandry postulate that it has evolved from intrasexual male competition to acquire the best territories (“rank advantage” hypothesis) and/or to maximize the number of mates (“mate opportunity” hypothesis). We studied for two consecutive years the relative importance of both hypotheses in a population of pied flycatchers (Ficedula hypoleuca), a territorial songbird with a mixed mating strategy. We measured territory quality using a long-term dataset on nest occupation and breeding output, and we used molecular techniques to assess male fitness across the range of social and genetic mating options. Territory quality was unrelated to breeding date and had no influence on extra-pair paternity or social polygynous events. However, males breeding early increased their chances of becoming socially polygynous and/or of attaining extra-pair paternity and, as a consequence, increased their total reproductive success. These results support the “mate opportunity” hypothesis, suggesting that sexual selection is the main mechanism driving protandry in this population.

Mating preferences of Saint Croix rams to related or unrelated ewes

Fifty mating tests were performed comparing the mating preferences of Saint Croix rams to unrelated ewes or their daughters. In each test, two ewes were induced into oestrus and restrained by the use of portable metal stanchions holding the head of the ewes, at equal distances from the point of entrance of 10 rams. The rams were individually tested with an unrelated ewe and his daughters as mating options in each test. No difference in mating preference was found in the choices that rams made regarding firstly the approach to the ewe, the number of approaches to each ewe, and the ewes mated. It was concluded that in Saint Croix rams, genetic relatedness did not influence the choice of mating partner.

Bigamous Trios in the Black-winged Stilt Himantopus himantopus himantopus: I. Pathways to form Bigamous Trios

Six cases of bigamous trios in the Black-winged Stilt Himantopus himantopus himantopus were studied during 1997-2006. One cause for the occurrence of bigamous trios is that postbreeding groups composed of a parent and a female offspring of the previous year, or that of a family and an unrelated female, have not dissolved by the next breeding season. Under conditions of a female-biased sex ratio in the non-breeding season, some females may chose bigamous trios as one of three mating options. In one trio, one female left the trio just before egg-laying, after they began to defend the nesting territory. Two bigamous trios made a joint nest, respectively. One bigamous trio made two simultaneous nests. One bigamous trio made a joint nest in one year and two simultaneous nests the following year. One bigamous trio made three nests successively.

Producing and using genetic evaluations in the United States beef industry of today1

The overall motivation for the development of an information system for beef cattle improvement is the belief that knowledge of breeding values and heterosis effects allows one to determine the consequences of alternative selection and mating options. With this information, livestock managers can easily shift populations in a desirable direction. The foundation principles for establishing a sound breeding program, including the prediction of animal performance for economically relevant traits and their incorporation into a single index of aggregate economic merit, have been well established over the last half century. Rather than this goal-based approach, the industry adopted a data-driven approach to the production of genetic evaluations that has been characterized by an overemphasis on the evaluation of productive traits, notably BW at various ages, with inadequate regard for other economically important traits, such as reproduction, animal health, and feed requirements. Production of evaluations is breed association centered, and this has delayed the introduction of national across-breed evaluations for all breeds and crosses of cattle. The computational aspects of producing evaluations are now migrating from land-grant universities to breed associations, but not yet to a single entity. The introduction of genomic information in the form of high-density SNP panels will introduce threats, challenges, and new opportunities for the production of evaluations, and represents the largest force to alter the structure of the beef improvement industry since the advent of AI. The use of evaluations has, until recently, stopped short of the provision of index merit as a basis for selection. Accordingly, the value propositions associated with annual improvement or the selection of alternative sires has not been well communicated. Technology, along with economic and other issues related to stakeholder acceptance, will collectively determine the future nature of the industry in terms of the production and use of evaluations.

Factors affecting individual participation in group-level aggression among non-human primates

Abstract Group members do not always act cohesively when facing extra-group rivals. When benefits such as group-defence are not monopolizable, it poses an economics problem: who should contribute to public goods and who should freeload? A collective action framework compliments existing theoretical explanations for cooperation, and provides testable hypotheses about group-level behaviour based on individual costs and benefits. Using this approach, we review research on intergroup encounters in non-human primates published over the last 20 years, focusing on participation by different classes of individuals. While food- and mate-defence explain much between-sex variation in participation, rank and reproductive access frequently explain within-sex variation. In some species, individuals may use intergroup interactions to survey potential transfer locations and mating options, which might coincidently intimidate rivals. Experimental evidence suggests that when intergroup dominance is based on relative number of fighters, individual participation still varies with sex, rank, companion behaviour and dependent offspring presence. Relatively few studies have examined how factors such as relationships within and between groups or individual temperament mediate aggression. Long-term studies of multiple habituated groups and methodological advances (e.g., playback experiments) will continue to improve our understanding of how complex group-level patterns are predictable when viewed from an individual perspective.

Natal dispersal and parental escorting predict relatedness between mates in a passerine bird

Although relatedness between mates is of considerable evolutionary and ecological significance, the way in which the level of relatedness is determined by different behavioural processes remains largely unknown. We investigated the role of behaviour in predicting mate relatedness in great tits using genotypic markers and detailed observations. We studied how mate relatedness is influenced by natal dispersal, inbreeding/outbreeding avoidance after natal dispersal and a behaviour not previously considered that influences membership to social aggregations, namely family escorting behaviour by parents. Among locally born individuals, the level of mate relatedness decreased with natal dispersal distance for females, but not for males. In contrast, mate relatedness was negatively related to the extent of family movements for males, but not for females. However, family movements did not predict dispersal distance for either sex. Local recruits were more related to their mates than immigrants, but this was only significant for females. No evidence was found for inbreeding/outbreeding avoidance after dispersal. Our results suggest that, in highly mobile species, mating options are spatially and/or socially limited, and that parents influence mating options of their offspring before dispersal.

The Frequency and Timing of Courtship and Copulation in Blackbirds, Turdus Merula, Reflect Sperm Competition and Sexual Conflict

AbstractIn a long-term field study we estimated the number of copulations per pair in blackbirds at 24.2 in a single reproductive cycle. Thus it seems unlikely that the only function of copulation behaviour is just to guarantee fertilization. We considered three other hypotheses which might explain frequent pair copulation: (1) as an effect of sperm competition, (2) cooperation between pair members aiming at increasing joint production of offspring; or, (3) sexual conflict resulting in female manipulation of allocation of time and energy of the male. We found no positive correlation between the copulation frequency and reproductive performance, a result that essentially falsifies the cooperation hypothesis. Only two extra-pair copulations were recorded. However, attempts at forced extra-pair copulation were very common and a high pair copulation rate might have evolved in response to sperm competition. Alternately, relatively high copulation rate in the pre-fertile stage of the reproductive cycle and female control over timing and frequency of copulation (via solicitation of copulation and/or rejection of courtship by the male) also supports the sexual conflict scenario. We suggest that our findings support the idea that the female prolongs the period of sexual activity to induce her partner to guard her (which reduces sexual coercion from other males) and to monopolise his parental effort (the male while mate guarding cannot pursue extra-pair activity or search for better mating options).

Bill morphology reflects female independence from male parental help.

The study of territorial polygyny in birds has been influential in the development of the theory of social mating systems. Alternative female mating options have been studied within the framework of the polygyny-threshold model and later as the outcome of conflicts of interest between individuals. However, little attention has been given to variations between individual females, and how this affects their mating behaviour. Here, we test the hypothesis that some females are better adapted to raise nestlings without male assistance, and thus to mate polygynously. Specifically, we investigate whether intraspecific variation in female bill morphology is related to mating behaviour. This hypothesis is derived from earlier studies showing that, in both intra- and interspecific comparisons, uniparental care by females is correlated with the catching of larger prey items than when both parents provision the young. Using the polygynous dusky warbler (Phylloscopus fuscatus) as a model species, we found that, in accordance with our prediction, females with deep bills were more likely to mate as a secondary female. Moreover, regardless of mating status, females with deep bills settled in territories with more food and they received less male assistance in feeding their offspring. We argue that females with stronger bills are better adapted to exploit the abundance of large food items in rich territories and thus to raise young on their own. Our results demonstrate the importance of studying variations between individual females, and provide evidence for an extended version of the 'constrained-female hypothesis'. As bill depth is a highly heritable trait, our study strongly suggests that variation in female mating behaviour is not only related to ecological factors and female condition (as shown elsewhere) but also to heritable morphological traits.

Theoretical Consequences of Heterogeneous Transport Conditions for Pollen Dispersal by Animals

Pollination governs a plant’s mating options by establishing the diversity and intensity of male-gamete exchange between plants. For animal-pollinated plants, the pattern of pollen dispersal arises from the pollinator’s interactions with floral organs during each flower visit and with the pollen it carries during transport. These interactions typically cause some portions of a flower’s pollen to experience different transport conditions than other portions. We model three classes of heterogeneous transport conditions to assess their effects on pollen dispersal. Two classes occur when the pollen carried by individual pollinators becomes spatially structured. “Horizontal” structure arises when areas of a pollinator’s body differ in their frequency or intensity of contact with anthers and/or stigmas. Alternatively, “vertical” structure develops when pollinators do not disturb their pollen load, causing pollen to accumulate on the pollinator’s body in layers, so that much pollen is temporarily inaccessible to stigmas. The third class of heterogeneity occurs when the pollinators that visit a flower differ consistently with respect to pollen transfer from pollinator to stigmas. These classes of heterogeneous transport produce similar mean patterns of pollen dispersal, which differ from that expected if transported pollen acts as a homogeneous population. In particular, near and far recipient flowers receive proportionately more of the donor pollen reaching stigmas than predicted for a single population. Reanalysis of data in the literature illustrates that predictions based on heterogeneous transport conditions are more representative of observed dispersal patterns than predictions of the traditional characterization of pollen dispersal. We also demonstrate that stochastic variation between flowers in pollen donation and receipt does not affect the arithmetic mean pattern of pollen dispersal, although it does reduce the geometric mean. Although the different types of heterogeneous transport conditions produce similar mean patterns of pollen dispersal, the influences of specific floral and pollinator characteristics on dispersal can depend on the type(s) of heterogeneity involved. In particular, pistil characteristics should affect dispersal independently of stamen characteristics when horizontal heterogeneity governs transport dynamics, but not when pollen accumulates in layers. This relation is likely reflected in many aspects of floral divergence among related taxa pollinated by different vectors and convergent design among unrelated taxa served by similar vectors.

THEORETICAL CONSEQUENCES OF HETEROGENEOUS TRANSPORT CONDITIONS FOR POLLEN DISPERSAL BY ANIMALS

Pollination governs a plant’s mating options by establishing the diversity and intensity of male-gamete exchange between plants. For animal-pollinated plants, the pattern of pollen dispersal arises from the pollinator’s interactions with floral organs during each flower visit and with the pollen it carries during transport. These interactions typically cause some portions of a flower’s pollen to experience different transport conditions than other portions. We model three classes of heterogeneous transport conditions to assess their effects on pollen dispersal. Two classes occur when the pollen carried by individual pollinators becomes spatially structured. “Horizontal” structure arises when areas of a pollinator’s body differ in their frequency or intensity of contact with anthers and/or stigmas. Alternatively, “vertical” structure develops when pollinators do not disturb their pollen load, causing pollen to accumulate on the pollinator’s body in layers, so that much pollen is temporarily inaccessible to stigmas. The third class of heterogeneity occurs when the pollinators that visit a flower differ consistently with respect to pollen transfer from pollinator to stigmas. These classes of heterogeneous transport produce similar mean patterns of pollen dispersal, which differ from that expected if transported pollen acts as a homogeneous population. In particular, near and far recipient flowers receive proportionately more of the donor pollen reaching stigmas than predicted for a single population. Reanalysis of data in the literature illustrates that predictions based on heterogeneous transport conditions are more representative of observed dispersal patterns than predictions of the traditional characterization of pollen dispersal. We also demonstrate that stochastic variation between flowers in pollen donation and receipt does not affect the arithmetic mean pattern of pollen dispersal, although it does reduce the geometric mean. Although the different types of heterogeneous transport conditions produce similar mean patterns of pollen dispersal, the influences of specific floral and pollinator characteristics on dispersal can depend on the type(s) of heterogeneity involved. In particular, pistil characteristics should affect dispersal independently of stamen characteristics when horizontal heterogeneity governs transport dynamics, but not when pollen accumulates in layers. This relation is likely reflected in many aspects of floral divergence among related taxa pollinated by different vectors and convergent design among unrelated taxa served by similar vectors.

Plumage Characteristics as an Indicator of Male Parental Quality in the American Kestrel

How females pair with respect to the plumage and provisioning characteristics of males, and its fitness consequences, was studied in the American Kestrel Falco sparverius in east central Pennsylvania, USA. Within a 100 km2 area where pairing was studied, on the day females formed a pair bond they had approximately 3.4 unmated males to choose from. No male trait was clearly related to the time males had to wait before obtaining females. Indeed, the scarcity of unmated males together with extremely fast pairing (the pairs were usually formed within a day of males' arrival) suggest limited mating options for females. Male plumage brightness was related to age, adult males being brighter than yearlings. Early laying by females was associated with bright plumage of males, and high hatching success and food provisioning rate to nestlings were negatively correlated with the width of the subterminal band of yearling males. Males with bright plumage and a narrow subterminal tail band produced the most fledglings. This study indicates that plumage characteristics may reveal males' parental quality; plumage brightness predicts age and thus experience, and a narrow subterminal tail band predicts foraging ability especially of young, inexperienced males. Consequently, females mated to males with bright plumage color or with narrow subterminal tail band gain reproductive success. The results support the direct process of sexual selection, even though indirect processes may also exist.