Evolution Of Mating Behavior Research Articles

Female dispersion and sex ratios interact in the evolution of mating behavior: a computational model

The evolution of mating strategies is not well understood. Several hypotheses have been proposed to explain the variation in mating strategies, with varying levels of support. Specifically, female dispersion, adult sex ratio and mate guarding have been proposed as drivers of the evolution of monogamous strategies. In this study, we used an agent-based model (ABM) to examine how different mating behaviors evolve in a population under different conditions related to these putative drivers, looking to understand the interaction between them. We found an interaction among different factors in the evolution of social monogamy, and their impact is in this order: adult sex ratio (ASR), female dispersion and extra-pair copulation. Thus, when the adult sex ratio is male-biased, monogamous strategies are strongly favored. However, this is only the case if mate guarding is fully efficient, i.e., if there is no extra-pair copulation. On the other hand, in scenarios where the population is female-biased, or mate guarding is not efficient, we find that polygamous strategies are favored but proportionally to the dispersion of females. These results confirm previous findings regarding mate guarding and sex ratios, while also showing how female dispersion enters the dynamics.

Auditory brainstem responses in the Chinese tiger frog Hoplobatrachus chinensis (Osbeck, 1765) (Anura: Dicroglossidae) reveal sexually dimorphic hearing sensitivity

Hearing sensitivity affects survival and reproduction in animals that communicate vocally. The Chinese tiger frog exhibits sexual dimorphism in body size, reflecting the evolution of mating behaviour and life-history strategies. In this study, we recorded auditory brainstem responses (ABRs) to determine hearing sensitivity in both female and male frogs. We also compared male and female hearing characteristics with the shape of the tympanic membrane in light of previous studies showing that smaller middle ear cavities improve hearing sensitivity. We found that ABR thresholds differ significantly between males and females, with the greatest sensitivities in both sexes at frequencies close to the dominant frequency of male calls. ABR thresholds were significantly lower in females compared to males for frequencies in the 0.9–1.3 kHz range and at 1.6 kHz. The tympanic membrane diameter was significantly smaller in females (5.94 ± 0.87 mm) than in males (6.71 ± 0.49 mm). Our results indicate that sexual selection has in all likelihood differentially affected male and female hearing sensitivity as well as the shape of the tympanic membrane in frogs.

Evolution of mating behavior between two populations adapting to common environmental conditions.

Populations from the same species may be differentiated across contrasting environments, potentially affecting reproductive isolation among them. When such populations meet in a novel common environment, this isolation may be modified by biotic or abiotic factors. Curiously, the latter have been overlooked. We filled this gap by performing experimental evolution of three replicates of two populations of Drosophila subobscura adapting to a common laboratorial environment, and simulated encounters at three time points during this process. Previous studies showed that these populations were highly differentiated for several life-history traits and chromosomal inversions. First, we show initial differentiation for some mating traits, such as assortative mating and male mating rate, but not others (e.g., female mating latency). Mating frequency increased during experimental evolution in both sets of populations. The assortative mating found in one population remained constant throughout the adaptation process, while disassortative mating of the other population diminished across generations. Additionally, differences in male mating rate were sustained across generations. This study shows that mating behavior evolves rapidly in response to adaptation to a common abiotic environment, although with a complex pattern that does not correspond to the quick convergence seen for life-history traits.

Distinct behavioural strategies underlying asymmetric mating interactions between invasive and indigenous whiteflies

AbstractKnowledge of animal mating strategy may provide insight into the evolution of mating behaviour, speciation, and species competition interactions. Our previous study showed that asymmetric mating interactions between invasive and indigenous species of the worldwide distributed whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex contribute to invasion and displacement. Here, we reobserved in detail the video recordings of mating behaviour and behavioural interactions of a previous study and did an integrated analysis on the new data obtained here and some aspects of the data reported earlier. We compared the mating strategies of an invasive whitefly species and an indigenous congeneric competitor from each of two geographic regions, China and Australia. We found that in both regions, females of the invasive species had higher propensity to copulate than those of the indigenous species. In addition, females of the invasive species increased their frequency of copulation in response to increases in courting by males. Compared with males of the indigenous species, those of the invasive species were more likely to court per unit time as well as to interrupt courting pairs, and they also exhibited shorter durations of copulation. In addition, males of the invasive species exhibited post‐copulatory guarding behaviour, whereas those of the indigenous species did not. The different mating strategies exhibited by the invasive and indigenous species may be the evolutionary basis of their asymmetric mating interactions. Such differences in mating strategies confer on the invasive whitefly species the capacity to both invade and displace indigenous whitefly competitors.

New information on the evolution of mating behaviour in Sepsidae (Diptera) and the cost of male copulations in Saltella sphondylii

Here we describe the hitherto unknown details of the highly unusual mating behaviour of Saltella sphondylii—a widely cited model for male longevity costs caused by multiple copulations. When compared to the known mating behaviour of 28 sepsid species, we find five unique behavioural elements based on frame-by-frame analyses of video-recordings. These new behaviours are documented with video clips. We suggest that the male longevity costs could be due to copulation bouts that involve multiple insertions of a comparatively membranous phallus into the female. We compare the phallus of the Saltella sphondylii to those from three other species (Themira putris, Parapaleosepsis plebeia, Sepsis punctum).

Finding Safe Harbor: Buddhist Sexual Ethics in America

When the Buddha left home in search of spiritual understanding, he left behind his wife and presumably the pleasures of sex. After his enlightenment, he encouraged others to do the same: renounce the world of the senses to seek liberation from suffering. The monks and nuns that followed the Buddha's teachings formed a kind of sexless society, a society that did not reproduce itself biologically.' By abstaining from sexual relations, Buddhist monastics intended to reduce attachment and model an alternative to lay life. Buddhist society would continue via transmission of the teachings, a spiritual form of continuity not dependent on sex. But of course, the Buddha was teaching ordinary people with ordinary appetites for sexual contact. And these appetites could really get in the way of spiritual progress; thus we find no shortage of Buddhist commentary on sexuality and its ramifications. And despite 2,500 years of wisdom on this subject, Buddhist teachers and students are still blundering into sexual contacts that undermine their own progress and often the progress of others. Clearly this is not a human fallibility that can be corrected by setting up some simple rules. In fact, sexuality is one of the most deeply hard-wired neurological drives of the human organism, not easily uprooted even for lofty spiritual ideals. From a Buddhist perspective, working with sexuality is working with attachment. How can we understand that attachment in its biological origins? In A Natural History ofSex, Adrian Forsyth describes in vivid detail the ecology and evolution of mating behavior in the animal kingdom.2 In sixteen chapters that cover every biological strategy you can imagine-from incest to role reversal, infanticide to sex changethe author shows how costly sex can be to individual organisms. Though sex is not the only means of reproduction, it certainly involves the most complex behaviors, anatomical variations, social choices, and in a few cases, the risk of death. What can possibly merit such a great investment in momentary pleasure (if indeed it is pleasurable for some animals)? The evolutionary answer is, genetically variable offspring. Variation is the key to surviving calamity as a species. If all animals of a species were genetically identical, they would be terribly vulnerable to single events that exploited their weaknesses. But with variation, there is always a chance that some will make it

The sexual arms race and phenotypic correlates of mating success in the waterstrider,Aquarius remigis (Hemiptera: Gerridae)

Intersexual conflicts over mating decisions may have an important impact on the evolution of mating behaviours and strategies and may develop into an arms race between the sexes. In waterstrider species, where intersexual conflict is known to occur, the evolution of male traits that allow them to overcome female reluctance to mate is expected. Reproductively active waterstriders,Aquarius remigis, were videotaped in the laboratory to examine the influence of total body length and front femoral width of males, male: female body size ratio, and female reproductive condition (number of mature eggs) on three variables associated with mating success: duration of the premating struggle, duration of mating, and number of successful matings. None of these behaviors was significantly correlated with the size ratio of the mating pair. However, total body length was negatively correlated with premating struggle duration, male front femoral width was positively correlated with number of successful matings, and number of mature eggs in females was positively correlated with duration of both the premating struggle and the mating itself. The relative influence of male sexual armaments and female choice on the outcome of mating interactions is discussed.

Quantitative Genetic Studies of Behavioral Evolution

This text examines the theory and methods of quantitative genetics and presents case studies that illustrate the many ways in which the methods can be applied. The author brings together current theoretical and empirical studies to show how quantitative genetics can illuminate topics as diverse as sexual selection, migration, sociality and aggressive behaviour. Nearly half of the chapters focus on conceptual issues, ranging from quantitative genetic models to the complementary roles of quantitative genetic and optimality approaches in evolutionary studies. Other chapters illustrate how to use the techniques by providing surveys of research fields, such as the evolution of mating behaviour, sexual selection, migration and size-dependent behavioural variation. The balance of the volume offers case studies of territoriality in fruit flies, cannibalism in flour beetles, mate-attractive traits in crickets, locomotor behaviour and physiology in the garter snake, and cold adaptation in the house mouse. Taken together, these studies document both the benefits and pitfalls of quantitative genetics. This book aims to show the advanced student and scholar of behavioural evolution and genetics the many powerful uses of quantitative genetics in behavioural research.

Patterns of Sperm Storage in Relation to Sperm Competition in Passerine Birds

Using a technique for observing sperm storage tubules (SSTs) in whole-mount preparations of oviduct tissue, we estimated the number and length of SSTs across 20 species of passerine birds in seven subfamilies. The average number of SSTs per female varied ninefold across the species examined and was correlated positively with body mass and relative egg size, suggesting that much of the interspecific variation in the number of SSTs may be a consequence of allometry. However, after controlling for body mass, the number of SSTs per female was also negatively correlated with the average length of SSTs and we suggest this pattern could result from selection for greater sperm length when access to sperm storage sites is limited by females. SST length varied eight-fold across the species examined but unlike the number of SSTs, SST length was not correlated with body mass. Instead, SST length was strongly and positively correlated with sperm length, suggesting a history of coevolution between male gametes and sperm storage sites in females that is independent of body size. Neither mating system nor any of four other morphological variables (testis length, oviduct length, clutch size, sperm storage capacity) was consistently correlated with either the number or size of SSTs. Variation between species in the potential for sperm layering within an SST, however, indicates that the pattern of sperm precedence (i.e., the pattern of paternity relative to mating order) may vary from species to species. We propose that a conflict of interest between the sexes with respect to sperm storage could lead to an arms race between sperm length and SST length and may help explain both the diversity in sperm storage patterns among species and the influence of sperm storage on the evolution of mating behavior in birds.

PARENTAL BEHAVIOR IN LAPWINGS (CHARADRIIDAE) AND ITS RELATIONSHIPS WITH CLUTCH SIZES AND MATING SYSTEMS.

It is generally assumed that parental behavior is much less demanding in birds that do not feed their young than in those that do (e.g., Graul, 1973; Wiley, 1974; Emlen and Oring, 1977; Welty, 1982 p. 293). That is, parental behavior requires less effort, or at least imposes fewer constraints on time and energy budgets, in the former. This assumption seems plausible, not only because parental feeding is lacking, but also because the young of such species are nidifugous and precocial, and hence relatively self-reliant. The assumption that parental behavior is less demanding in precocial birds is important because of its critical role in theories about clutch sizes and mating systems. If young are not fed, other parental behaviors are thought to constrain clutch size very little, so that additional factors, notably ability of females to form eggs, limit clutches to sizes below those at which parents might begin to have difficulty providing adequate care (Lack, 1968; see also Bengtson, 1971; von Haartman, 1971; Ricklefs, 1974; Rahn et al., 1975; Andersson, 1976). Mating system theory attributes the relatively high incidence of polygamy among birds that do not feed young to the lesser demands of parental behavior in these species (Lack, 1968 p. 150; Orians, 1969). In the evolution of mating behavior, the advantage, measured in number of additional offspring produced, of acquiring multiple mates is weighed against the decrease in the viability of those