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Mating Tactics (mating + tactic)
Kinds of Mating Tactics Selected AbstractsOn the analysis of non-linear allometriesECOLOGICAL ENTOMOLOGY, Issue 1 2009ROBERT J. KNELL Abstract 1.,Non-linear allometries are those where a log,log scatterplot of trait size against body size deviates from simple linearity. These are found in many insects, including the horns of beetles, the forceps of earwigs, and the heads of certain castes of ant. 2.,Non-linear allometries are often associated with polyphenism that is itself related to behaviour: for example, the alternative mating tactics displayed by many species of beetle are widely associated with dimorphisms in horn size. 3.,This paper critically reviews the current techniques used to analyse these datasets. 4.,Recommendations include the use of scatterplots and assessment of the goodness of fit of simple linear models as an initial screen for non-linear allometry. The use of recently developed algorithms for ,segmented' regression to analyse continuous allometric relationships, and a pragmatic approach to the analysis of discontinuous relationships that recognises that there is no simple way to distinguish between morphs in some cases, and that all of the proposed methods for doing so have some drawbacks. 5.,Worked examples of the analysis of two sets of data from animals that have been the subject of controversy regarding the nature of their allometric relationships are given: further worked examples are provided as online Supporting Information. [source] Effects of Social Structure on the Behaviour and Performance of Alternative Reproductive Phenotypes in Male Rock Shrimp, Rhynchocinetes typusETHOLOGY, Issue 4 2008Stefan Dennenmoser Males that adopt alternative mating tactics within a conditional strategy often undergo costly morphological changes when switching to the next phenotype during ontogeny. Whether costs of changing to a subsequent reproductive phenotype are outweighed by a higher mating probability may depend on the frequencies of different phenotypes in a group of competitors. Benefits and costs associated with different phenotype frequencies depend on interactions within and between alternative phenotypes, but the underlying behavioural mechanisms have rarely been studied. Herein, we used the rock shrimp Rhynchocinetes typus as a model: ontogenetic male stages of this species differ in morphological and behavioural traits that indicate alternative reproductive phenotypes. The small, subordinate, male stage (typus) develops via several intermediate stages (intermedius) to the dominant male stage (robustus): in competitive interactions the typus males usually employ the sneaking tactic, while the robustus males invariably employ the monopolizing fighter tactic. In laboratory experiments, we manipulated phenotype frequencies to examine whether there are frequency-dependent effects on searching behaviour, aggressiveness and mating probability. With increasing frequency of robustus males, the rate of aggressive interactions among them increased. Furthermore, robustus males increased walking velocity when more than one robustus male was present. In contrast, typus males did not adjust their searching or aggressive behaviour. The increase of aggressive interactions among robustus males provided more opportunities for typus males to seize a temporarily unguarded female. While typus males exploit fights among robustus males that produce mating opportunities for them, robustus males benefit from typus males, which reveal the presence of receptive females. We suggest that each phenotype benefits from the presence of the other phenotype and suffers costly interference among individuals of the same phenotype. Whether frequency-dependent effects on the mating probability of subordinates also affect their ontogenetic switchpoint should be examined in future studies. [source] Operational Sex Ratio and Alternative Reproductive Behaviours in Chinese Bushcricket, Gampsocleis gratiosaETHOLOGY, Issue 4 2006Yong Gao The effects of operational sex ratio (OSR) on male mating tactics in the Chinese bushcricket Gampsocleis gratiosa were investigated in male- and female-biased environments. We measured fresh and dry spermatophore contents and copulation duration, and counted sperm numbers of each copulation. The fresh weight of spermatophore and spermatophylax was positively correlated with male body weight. The males in a strongly male-biased environment produced significantly heavier fresh ampulla and more sperm per ejaculation, which were likely tactics for successful matings under the competition of rivals. The spermatophore might function as a structure to protect the fertilization potential of the ejaculate from rival males. [source] Toward a New Sexual Selection Paradigm: Polyandry, Conflict and Incompatibility (Invited Article)ETHOLOGY, Issue 12 2003Jeanne A. Zeh Darwin's recognition that male,male competition and female choice could favor the evolution of exaggerated male traits detrimental to survival set the stage for more than a century of theoretical and empirical work on sexual selection. While this Darwinian paradigm represents one of the most profound insights in biology, its preoccupation with sexual selection as a directional evolutionary force acting on males has diverted attention away from the selective processes acting on females. Our understanding of female reproduction has been further confounded by discreet female mating tactics that have perpetuated the illusion of the monogamous female and masked the potential for conflict between the sexes. With advances in molecular techniques leading to the discovery that polyandry is a pervasive mating strategy, recognition of these shortcomings has brought the study of sexual selection to its current state of flux. In this paper, we suggest that progress in two key areas is critical to formulation of a more inclusive, sexual selection paradigm that adequately incorporates selection from the female perspective. First, we need to develop a better understanding of male × female and maternal × paternal genome interactions and the role that polyandry plays in providing females with non-additive genetic benefits such as incompatibility avoidance. Consideration of these interaction effects influencing natural selection on females is important because they can complicate and even undermine directional sexual selection on males. Secondly, because antagonistic coevolution maintains a balance between opposing sides that obscures the conflict itself, many more experimental evolution studies and interventionist investigations (e.g. gene knockouts) are needed to tease apart male manipulative adaptations and female counter-adaptations. It seems evident that the divisiveness and controversy that has plagued sexual selection theory since Darwin first proposed the idea has often stalled progress in this important field of evolutionary biology. What is now needed is a more pluralistic and integrative approach that considers natural as well as sexual selection acting on females, incorporates multiple sexual selection mechanisms, and exploits advances in physiology and molecular biology to understand the mechanisms through which males and females achieve reproductive success. [source] Environmental Predictors of Geographic Variation in Human Mating PreferencesETHOLOGY, Issue 4 2002Kevin J. McGraw Sexual selection theory classically posits consistent and directional mate-preferences for male traits that provide benefits to females. However, flexible mate-choice tactics may persist within a species when males display multiple desirable features that confer different benefits to females under variable environmental conditions. Ecological factors such as population density, resource demand, and sex ratio can influence the value that female animals place on certain male characteristics across mating environments. In this study, I used human mate-preference data from `lonely hearts' advertisements in the newspapers of 23 cities in the USA to assess geographic differences in female preferences for male traits (e.g. physical attributes, resource-holding potential, emotional characteristics, personal interests) in relation to these ecological parameters. I found that females placed more emphasis on the resource-accruing ability of prospective mates in densely populated cities and cities having greater resource demands (higher cost of living). In contrast, women from densely populated or resource-demanding cities placed less emphasis on the emotional aspects or personal interests of males. Preferences for physical features were not environmentally linked, but instead were a function of the degree to which females advertised their own physical attractiveness. Collectively, these results suggest that certain mate-choice criteria employed by women are sensitive to variation in local environmental conditions and that variable levels of resource or mate availability may favor different mating tactics across human populations. [source] Social biology of rodentsINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2007Jerry O. WOLFF Abstract Herein, I summarize some basic components of rodent social biology. The material in this paper is summarized and condensed from a recent book "Rodent Societies: An Ecological and Evolutionary Perspective" edited by J. O. Wolff and P. W. Sherman (2007). I describe the four basic spacing patterns and illustrate how female territoriality is a function of offspring defense and male mating tactics are a function of female defensibility. The vulnerability of young to infanticide shapes female spacing and mating behavior. Food does not appear to be a defensible resource for rodents, except for those species that larder hoard nonperishable items such as seeds. Philopatry and the formation of kin groups result in genetic sub-structuring of the population, which in turn affects effective population size and genetic diversity. Dispersal is male biased and typically involves emigration from the maternal site to avoid female relatives and to seek unrelated mates. Scent marking is a major form of communication and is used in reproductive competition and to assess prospective mates, but it is also eavesdropped by predators to locate prey. Females do not appear to alter the sex ratio of litters in response to maternal condition but among arvicoline rodents daughters appear to be favored in spring and sons in autumn. Rodents are relatively monomorphic; however, females tend to be larger than males in the smallest species and smaller in the larger species. Predation risk results from an interaction among foraging time and vulnerability and in turn affects behavioral and life history characteristics. [source] Geographic variation in sperm traits reflects predation risk and natural rates of multiple paternity in the guppyJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2010K. E. ELGEE Abstract Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high-predation populations compared to low-predation populations. Here, we assess the possible evolutionary consequences of these patterns by asking whether variation in sperm traits reflect differences in predation intensity among four pairs of Trinidadian populations: four that experience relatively low levels of predation from a gape-limited predator and four that experience relatively high levels of predation from a variety of piscivores. We found that males in high-predation populations had faster swimming sperm with longer midpieces compared to males in low-predation populations. However, we found no differences among males in high- and low-predation populations with respect to sperm number, sperm head length, flagellum length and total sperm length. [source] Response of territorial males to the threat of sneaking in the three-spined stickleback (Gasterosteus aculeatus): a field studyJOURNAL OF ZOOLOGY, Issue 1 2003Steven C. Le Comber Abstract Alternative mating tactics are found in many species, and may have important implications for population genetics and speciation. The existence of such alternative mating tactics is well-documented in the three-spined stickleback Gasterosteus aculeatus, and sneaking and egg-stealing may occur in a significant proportion of matings under natural conditions. Sneaking can impose high costs on territorial males, both in terms of reduced reproductive output and caring for unrelated offspring. We ask whether territorial males adjust their behaviour in response to the risk of sneaking. In a field study of three-spined sticklebacks on the Isle of Arran, Scotland, territorial males were presented with glass bottles containing either a male, a female or neither, to address whether territorial males were more aggressive to other males in the presence of a female, and whether territorial males courted females less in the presence of another male. Behavioural observations showed that territorial males did not behave more aggressively towards rival males in the presence of a female, but did reduce their rate of courtship towards females in the presence of rival males. We conclude that territorial males adopt behavioural strategies that may reduce their risk of reproductive parasitism. [source] A genetic assessment of parentage in a natural population of dollar sunfish (Lepomis marginatus) based on microsatellite markersMOLECULAR ECOLOGY, Issue 9 2002M. MacKiewicz Abstract We employ microsatellite markers to assess mating tactics in Lepomis marginatus. Genetic assignments for 1015 progeny in 23 nests indicate that about 95% of the offspring were sired by their respective nest-guardians, a finding consistent with the apparent absence of a brood parasitic morphotype in this species. Allopaternal care was documented in two nests, one resulting from a nest takeover, the other from cuckoldry by an adjoining nest-tender. Clustered de novo mutations also were identified. About 2.5 females (range 1,7) contributed to the offspring pool within a typical nest. Results are compared to those for other Lepomis species. [source] Male mating tactics in spider monkeys: sneaking to competeAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2010K. Nicole Gibson Abstract I investigated the mating system and male mating tactics for a population of wild spider monkeys (Ateles belzebuth chamek), to identify the behaviors males used to achieve and maintain access to sexually receptive females, and to examine if some males used more tactics than other males and/or had differential access to females. Results show that the mating system mostly involved scramble competition polygyny and that males used a range of mating tactics and behaviors, previously unreported for spider monkeys. The most unusual feature of spider monkey mating behavior was the secretive nature of copulations,nearly all copulations were clandestine, but a few were in the presence of other group members. Fifteen sexually mature males were observed to copulate 43 times. These data provide the first opportunity to evaluate how female availability influences male,male competition. First, the operational sex ratio was highly skewed toward males because usually only one female was receptive in each community per month. Second, females only mated with a few males in their community in any one mating period, but some females mated over the course of multiple consecutive mating periods, eventually mating with most or all of the males in their community. Across all communities, 9 (21%) of the 43 copulations involved a single male,female partner, 20 (47%) involved four males mating with the same female, and males mated with from one to four different females. Fourteen of the 16 total adult males and 1 subadult male (10 total) copulated. One or two males in each community were successful in monopolizing access to receptive females, and these males did not usually have the highest rates of copulation. In this system, clandestine copulations are one behavioral solution to the complex problem of gaining mating exclusivity and, probably, exercising mate choice. Am. J. Primatol. 72:794,804, 2010. © 2010 Wiley-Liss, Inc. [source] | |||||||||||||||||||