Multiple Mating

The nose or snout is an important anatomical structure of mammals. It is responsible for inspiration and expiration of gases into the lungs, temperature regulation and olfaction, and it is also essential for supporting navigation, foraging and immunological defence in animals. Snouts are also often used to differentiate and classify mammals. This review investigates the critical role of the snout and its accessory structures, and how it supports mammalian survival. We use wombats as a specific example, given their iconic status and that extant species are classified based on the appearance of their rhinarium, to identify gaps in our knowledge of the marsupial snout and its function.

In lek mating systems, females visit aggregations of displaying males and appear to have unrestricted opportunity to choose and mate with any male. Behavioral observations of lekking birds indicate that females generally mate once and that only a small percentage of males gain a majority of copulations. However, genetic analyses of paternity have revealed that multiple males sometimes sire young within one brood. We analyzed paternity of 25 broods of Greater Prairie-Chickens (Tympanuchus cupido pinnatus) breeding in an isolated population in central Wisconsin. We found multiple paternity in 44% of broods (1-4 sires brood -1 ) and a positive relationship between the number of sires and female home-range size prior to nesting. Multiple paternity was apparently not influenced by local breeding experience: native Wisconsin and translocated females from Minnesota did not differ in the likelihood of multiple mating. The high incidence of multiple paternity may reduce the variance in male reproductive success and increase the effective population size, which may be important for the maintenance of genetic diversity in small, isolated populations.

It has become increasingly evident that genomic recombination is an evolved trait that varies between and within species. The honey bee has an extremely high genomic recombination rate but the responsible mechanisms have not been studied. Based on the hypothesis that meiotic recombination and DNA damage repair share common mechanisms in honey bees, I predicted that oxidative stress leads to a further increase in recombination rate. This prediction was directly tested by subjecting honey bee queens to oxidative stress by paraquat injection and measuring the rates of genomic recombination in select genome intervals of their offspring before and after injection. Of 27 intervals compared only 13 experienced an increase in the rate of recombination in the post-injection sample set as compared to the pre-injection set, suggesting no significant experimental effect. This result was confirmed when the analysis was restricted to the 16 intervals whose pre-injection recombination fractions were within ±8% of the value that was predicted based on a pre-existing linkage map. Intervals did not see consistent upregulation in all colony sample sets where upregulation occurred either. Overall the evidence does not support the hypothesis that oxidative stress induces an increase in the rate of genomic recombination.

It has become increasingly evident that genomic recombination is an evolved trait that varies between and within species. The honey bee has an extremely high genomic recombination rate but the responsible mechanisms have not been studied. Based on the hypothesis that meiotic recombination and DNA damage repair share common mechanisms in honey bees, I predicted that oxidative stress leads to a further increase in recombination rate. This prediction was directly tested by subjecting honey bee queens to oxidative stress by paraquat injection and measuring the rates of genomic recombination in select genome intervals of their offspring before and after injection. Of 27 intervals compared only 13 experienced an increase in the rate of recombination in the post-injection sample set as compared to the pre-injection set, suggesting no significant experimental effect. This result was confirmed when the analysis was restricted to the 16 intervals whose pre-injection recombination fractions were within ±8% of the value that was predicted based on a pre-existing linkage map. Intervals did not see consistent upregulation in all colony sample sets where upregulation occurred either. Overall the evidence does not support the hypothesis that oxidative stress induces an increase in the rate of genomic recombination.

We have demonstrated that females of widespread phenomenon. The ability to discrimithe primitively eusocial tropical wasp Ropalidia nate kin from non-kin has been reported in marine marginata can discriminate nestmates from non-invertebrates, subsocial arthropods, sweat bees, nestmates outside the context of their nests. This honey bees, several species of ants and wasps, was accomplished by recording all behavioural in-fishes, frogs, toads, iguanas, birds and a variety teractions in a neutral arena and comparing toler-of mammals (reviews in Fletcher and Michener ance levels. In order for these wasps to make such 1986; Gadagkar 1985b; Gamboa et al. 1986a; a discrimination, howeyer, it was essential that Hepper 1986; Holldobler and Michener 1980; Linafter eclosion both the discriminated and the dis-senmair 1985; Sherman and Holmes 1985; Waldcriminating animals were exposed to their respec-man 1987); for the iguana see Werner et al. (1987); tive natal nests and nestmates. The results suggest for the fish see Quinn and Busack (1985); for the that both recognition labels and templates are ac-marine invertebrates see Grosberg and Quinn quired by the animals from sources outside their (1986) and Keough (1984). body, perhaps from their nest or nestmates. It is The mechanism of kin recognition has importhus unlikely that different genetic lines within a tant implications for the theory of kin selection colony can be distinguished. We conclude, there-(Gadagkar 1985b). Particularly compelling evifore, that genetic asymmetries created by haplodip-dence for this theory has been the strong correlaloi.dy, but often broken down by multiple mating tion between (a) haplodiploidy in the Hymenopand polygyny, are not restored by preferential al-tera, which creates asymmetries in genetic related-, truism towards full rather than half sisters by ness potentially favouring the evolution of sociality means of kin recognition. Hence we recommend and (b) the observed multiple origins of eusociality caution in ascribing the multiple origins of eusocia-in that insect order (Wilson 1971). This particular lity in the Hymenoptera to haplodiploidy. subset of kin selection can be called the haplodiploidy hypothesis. These asymmetries in genetic re-, latedness break down, however, if queens of soci~l insect colonies mate multiply and produce different patrilines of daughters using sperm from different

An important feature of insect societies is the presence of a sterile worker caste that makes it possible for the fertile queens to produce a large number of offsprings. The mechanism of evolution by natural selection of such sterility and similar, though less extreme, forms of altruism has long been considered as a paradox. In recent years a large body of theoretical ideas has accumulated that purports to explain altruistic behaviour within the framework of the theory of natural selection. With special reference to insect sociality three theories namely kin selection, parental manipulation and mutualism have been suggested. Some attempts have now been made to empirically test the mutually exclusive predictions arising out of these alternative theories. A somewhat different approach to empirically distinguishing between kin selection and parental manipulation is to measure sex-investment ratios. This approach was at one time believed to have provided overwhelming support in favour of the theory of kin selection. It has now been realised that several complicating factors such as local mate competition and multiple mating have to be considered before arriving at appropriate theoretical predictions of the two rival theories. I argue in this paper that rigorous quantitative studies on inter-individual variations in behavioural strategies in primitively eusocial insects constitutes yet another approach that is likely to help in understanding the forces that mould the evolution of insect societies.

Kin selection is a widely invoked mechanism to explain the origin and evolution of social behaviour in animals. Proponents of the theory of kin selection place great emphasis on the correlation between asymmetries in genetic relatedness created by haplodiploidy and the multiple origins of eusociality in the order Hymenoptera. The fact that a female is more closely related genetically to her full sister than to her daughters makes it more profitable for a Hymenopteran female, in terms of inclusive fitness, to raise full sisters rather than daughters or full siblings with a female biased sex ratio rather than offspring. This is sometimes referred to as the haplodiploidy hypothesis. In reality however, genetic relatedness between workers in social insect colonies and the reproductive brood they rear is far below 0075, the value expected for full sisters, often below 005 the value expected between mother and daughter and, not uncommonly, approaching zero. Such values are on account of queen turnover, multiple mating by queens or polygyny. This situation raises doubts regarding the haplodiploidy hypothesis unless workers can discriminate between full and half sisters and preferentially direct their altruism towards their full sisters only. This would still mean an effective coefficient of genetic relatedness of 0,75 between altruist and recipient. For this to be possible however, workers should be able to recognise their full sisters inspite of growing up with and being habituated to an assortment of full sisters, half sisters and perhaps other even less related individuals. Even outside the Hymenoptera, social animals may find themselves growing up together in the company of individuals of varying degrees of relatedness. An ability to tell apart the more and less related individuals under such circumstances should favour kin selection. Much effort is now going into assessing the abilities of animals to discriminate between kin and non kin. In every case studied carefully so far, animals appear to be capable of recognising their kin. Ants, wasps, sweat bees, honey bees, frogs, toads, mice, rats, voles, squirrels, monkeys and even humans appear to be able to recognise their kin in one circumstance or another. An ability to recognize true genetic relatedness requires genetically specified recognition labels and these must therefore be present. Recent findings of the role of the histocompatibility system provides some clues to the possible nature of recognition labels. An ability to recognise full sisters for example, inspite of being habituated to full and half sisters requires not merely genetically specified labels but also recognition templates which are based on the characteristics of the individual animals making the recognition and not templates based on all animals one grows up with. Some animals such as honey bees, tadpoles and ground squirrels appear to have such templates but others such as sweat bees and some mice appear not to. It is entirely possible that our inability to devise natural enough assays for recognition prevents us from understanding the full potential of the kin recognition abilities of many animal species. In any case, genetically specified labels and self based templates should greatly facilitate the evolution of social behaviour by kin selection.

Honey bees are significant pollinator species in both natural and agroecosystems. Among three honey bee castes, drones are often regarded as "lazy willi" and assumed merely to function as "flying sperm" in the honey bee colonies, this view is incorrect. During takeoff and landing, they always exhibit higher thermogenic capacity than workers, in addition to colony thermoregulation, they received higher attention for astonishing mating behavior. Honey bee queens are highly polyandrous and mate in mid-air with many drones from diverse genetic sources. Instrumental insemination is an essential tool that provides complete control of honey bee mating for breeding and research purposes. Controlled mating in honey bees helps to maintain economically valued traits that ensure colony productivity and sustainability. Ultimately, breeding and keeping better bees through instrumental insemination offer improved pollination that guarantees global food safety and security. The present review emphasizes mainly on the physiology and mating behavior of drones in the context of instrumental insemination.

The trade-off between current and future parental investment is often different between males and females. This difference may lead to sexual conflict between parents over care provisioning in animals that breed with multiple mates. One of the most obvious manifestations of sexual conflict over care is offspring desertion whereby one parent deserts the young to increase its reproductive success at the expense of its mate. Offspring desertion is a wide-spread behavior, and its frequency often varies within populations. We studied the consistency of offspring desertion in a small passerine bird, the Eurasian penduline tit Remiz pendulinus, that has an extremely variable breeding system. Both males and females are sequentially polygamous, and a single parent (either the male or the female) incubates the eggs and rears the young. About 28-40% of offspring are abandoned by both parents, and these offspring perish. Here we investigate whether the variation in offspring desertion in a population emerges either by each individual behaving consistently between different broods, or it is driven by the environment. Results: Using a three-year dataset from Southern Hungary we show that offspring desertion by females is consistent between nests. Male desertion, however, depends on ambient environment, because all males desert their nests early in the season and some of them care late in the season. Therefore, within-population variation in parental care emerges by sexually different mechanisms; between-individual variation was responsible for the observed pattern of offspring desertion in females, whereas within-individual variation was responsible for the observed pattern in males. To our knowledge, our study is the first that investigates repeatability of offspring desertion behavior in nature. The contrasting strategies of the sexes imply complex evolutionary trajectories in breeding behavior of penduline tits. Our results raise an intriguing question whether the sexual difference in caring/deserting decisions explain the extreme intensity of sexual conflict in penduline tits that produces a high frequency of biparentally deserted (and thus wasted) offspring.

is a journal primarily devoted to insect systematics, but articles can be published on any non-marine arthropod taxon. Manuscripts considered for publication include, but are not limited to, systematic or taxonomic studies, revisions, nomenclatural changes, faunal studies, book reviews, phylogenetic analyses, biological or behavioral studies, etc. Insecta Mundi is widely distributed, and referenced or abstracted by several sources including the Zoological Record, CAB Abstracts, etc. As of 2007, Insecta Mundi is published irregularly throughout the year, not as quarterly issues. As manuscripts are completed they are published and given an individual number. Manuscripts must be peer reviewed prior to submission, after which they are again reviewed by the editorial board to insure quality. One author of each submitted manuscript must be a current member of the Center for Systematic Entomology.

The rapid evolutionary divergence of male genital structures under sexual selection is well documented. However, variation in female genital traits and the potential for sexual conflict to drive the coevolution between male and female traits has only recently received attention. In many lepidopterans females possess genital teeth (collectively, signa). Comparative studies suggest these teeth, involved in the deflation of spermatophores, may have coevolved with male spermatophore thickness via sexually antagonistic coevolution in a contest over the rate of deflation of spermatophores within the reproductive tract. We tested the hypothesis that sexual conflict should generate coevolution between genital teeth and spermatophore morphology by examining these traits under experimental manipulation of sexual conflict intensity. Using micro-CT scanning, we examined spermatophore and teeth morphology in populations of the Indian moth, Plodia interpunctella, which had been evolving for 110 generations under different adult sex-ratio biases. We found divergence in female signa morphology in response to sexual conflict: females from female-biased populations (reduced sexual conflict) developed wider signa. However, we found no evidence of coevolution between signa traits and spermatophore thickness as reported from comparative studies.

The calculated nitrogen uptake data (Table ) were used to compare how species differ in their patterns of uptake across treatments. We emphasize that the data cannot be used to compare how species partition total nitrogen uptake within treatments because the total amount of 15 N uptake by each species strongly depends on the relationship between lateral rooting distance and the spacing of 15 N injections. In this experiment, where 15 N injections were spaced in a 7.5-cm grid, Ledum took up six times more 15 N across all treatments than Eriophorum ( 15 N data not shown). In a different experiment designed to determine species' lateral rooting distances, we injected a constant amount of 15 N (114 mg as a mixture of 25 mmol l -1 each of glycine, ammonium and nitrate) at different treatment radii (5, 10, 20, 40, 60 and 100 cm) around individual plants of Eriophorum and Ledum. That design allowed 15 N uptake data to be spatially integrated across all treatment radii, simulating how 15 N would be taken up from injections spaced in®nitely close together over an area with a radius of 100 cm. Although those results showed that the primary lateral radius of uptake (about 60% of total uptake) of Eriophorum was about half that of Ledum (5 versus 10 cm), Eriophorum took up almost twice as much 15 NasLedum when the data were extrapolated on a community basis (uptake per unit ground area) (R.B.M., unpublished data). The results of both experiments show that widely spaced tracer injections disproportionately label species with larger rooting areas but lower uptake capacities per unit ground area (for example, Ledum). In contrast, species' patterns of uptake across treatments (within rows), as presented here, should be relatively robust with respect to the spacing of tracer injections.

Life-history theory predicts trade-offs between resources invested in reproduction and other fitness-related traits. To date, most studies have focused on potential reproductive trade-offs in females. However, it is now generally accepted that reproduction is also costly for males, and thus males too may be subject to trade-offs. We examined the relationship between development time and the production of both fertile and non-fertile sperm in males of the African bush brown butterfly (Bicyclus anynana) selected for short or long pre-adult development time. Fast developing males ejaculated fewer non-fertile sperm on their first mating, suggesting that there could be a trade-off between ejaculate production and development time in this species. Contrary to predictions, slow developing males were smaller, produced fewer fertile sperm and took longer to mate. We discuss why this might be the case, and suggest that there may be a cost to the production of non-fertile sperm in the Lepidoptera.

Honey bees (Apis mellifera) have become a model system for studies on the influence of genetic diversity on disease. Honey bee queens mate with a remarkably high number of males—up to 29 in the current study—from which they produce a colony of genetically diverse daughter workers. Recent evidence suggests a significant benefit of intracolony genetic diversity on disease resistance. Here, we explored the relationship between the level of genetic diversity and multiple physiological mechanisms of cellular and humoral immune defense (encapsulation response and phenoloxidase activity). We also investigated an effect of genetic diversity on a measure of body condition (fat body mass). While we predicted that mean colony phenoloxidase activity, encapsulation response, and fat body mass would show a positive relationship with increased intracolonial genetic diversity, we found no significant relationship between genetic diversity and these immune measures, and found no consistent effect on...

Background: Phylogenetic analyses strongly associate nonsocial ancestors of cooperatively-breeding or eusocial species with monogamy. Because monogamy creates high-relatedness family groups, kin selection has been concluded to drive the evolution of cooperative breeding (i.e., the monogamy hypothesis). Although kin selection is criticized as inappropriate for modeling and predicting the evolution of cooperation, there are no examples where specific inclusive fitness-based predictions are intrinsically wrong. The monogamy hypothesis may be the first case of such a flawed calculation. Results: A simulation model mutated helping alleles into non-cooperative populations where females mated either once or multiply. Although multiple mating produces sibling broods of lower relatedness, it also increases the likelihood that one offspring will adopt a helper role. Examining this tradeoff showed that under a wide range of conditions polygamy, rather than monogamy, allowed helping to spread more rapidly through populations. Further simulations with mating strategies as heritable traits confirmed that multiple-mating is selectively advantageous. Although cooperation evolves similarly regardless of whether dependent young are close or more distant kin, it does not evolve if they are unrelated. Conclusions: The solitary ancestral species to cooperative breeders may have been predominantly monogamous, but it cannot be concluded that monogamy is a predisposing state for the evolution of helping behavior. Monogamy may simply be coincidental to other more important life history characteristics such as nest defense or sequential provisioning of offspring. The differing predictive outcome from a gene-based model also supports arguments that inclusive fitness formulations poorly model some evolutionary questions. Nevertheless, cooperation only evolves when benefits are provided for kin: helping alleles did not increase in frequency in the absence of potential gains in indirect fitness. The key question, therefore, is not whether kin selection occurs, but how best to elucidate the differing evolutionary advantages of genetic relatedness versus genetic diversity.

Heritable variation is essential for evolution by natural selection. In Neotropical army ants, the ecological role of a given species is linked intimately to the morphological variation within the sterile worker caste. Furthermore, the army ant Eciton burchellii is highly polyandrous, presenting a unique opportunity to explore heritability of morphological traits among related workers sharing the same colonial environment. In order to exploit the features of this organismal system, we generated a large genetic and morphological dataset and applied our new method that employs geometric morphometrics (GM) to detect the heritability of complex morphological traits. After validating our approach with an existing dataset of known heritability, we simulated our ability to detect heritable variation given our sampled genotypes, demonstrating the method can robustly recover heritable variation of small effect size. Using this method, we tested for genetic caste determination and heritable m...

— Drones of Apis dorsata had an average of 2.46•10 6 spermatozoa in their vesiculae seminales. Two queens had 3.67•10 6 spermatozoa in their spermathecae. In A adreniformis, drones had an average of 0.13•10 6 and the spermathecae of 2 queens contained 0.98 and 1.09•10 6 spermatozoa. In both A dorsata and A andreniformis the spermathecae of queens contained more sper- matozoa than the vesiculae seminales of a single drone of either species. Therefore, we conclude that multiple mating occurs in both species as is the case for A mellifera, A cerana and A florea. multiple mating / spermatozoon / Apis andreniformis / Apis dorsata *

Which task a social insect worker engages in is influenced by the worker's age, genotype and the colony's needs. In the honeybee, Apis mellifera, genotype influences both the age a worker switches tasks and its propensity of engaging in specialist tasks, such as water collecting, which only some workers will perform. In this study, we used colonies with natural levels of genetic diversity and manipulated colony age demography to drastically increase the stimuli for the generalist tasks of foraging and nursing, which all workers are thought to engage in at some point in their lives. We examined the representation of worker patrilines engaged in nursing and foraging before and after the perturbation. The representation of patrilines among foragers and nurses differed from that of their overall colony's population. In the case of foraging, over-and underrepresentation of some patrilines was not simply due to differences in rates of development among patrilines. We show that replacement foragers tend to be drawn from patrilines that were overrepresented among foragers before the perturbation, suggesting that there is a genetic component to the tendency to engage in foraging. In contrast, the representation of patrilines in replacement nurses differed from that in the unperturbed nursing population. Our results show that there is a genetic influence on even the generalist tasks of foraging and nursing, and that the way patrilines in genetically diverse colonies respond to increases in task stimuli depends upon the task. The possible significance of this genetic influence on task allocation is discussed.

The evolution of polyandry is a general problem in behavioral ecology that has attracted particular interest in the social insects. Most social insects are monandrous (i.e., females are inseminated by a single male), but approximately a third of species have evolved polyandry (i.e., females are inseminated by multiple males), which can reach extreme levels. One of the leading explanations for polyandry is that genetically diverse colonies may have improved division of labor because of genotypic variation in the propensity of workers to engage in particular tasks. Here we investigate whether there may also be genotypic variation in the ability to carry out a task, by examining the effect of genotype, as well as caste and age, on the foraging performance of workers of the leaf-cutting ant Acromyrmex subterraneus. Larger ants cut larger fragments of orange-impregnated parafilm, and did so more quickly than smaller ants, whereas older ants also cut larger fragments but were slower to transport them. Most importantly, we found that patrilines within colonies differed significantly in the size of fragment cut, and the speed of cutting and transporting fragments when controlling for both ant size and fragment size in the analyses. Certain patrilines were better foragers, often in multiple ways, whereas other patrilines were significantly worse at foraging. Genotype can therefore affect the ability of social insect workers to carry out tasks as well as their previously shown propensity to engage in them, providing an additional mechanism by which genetic diversity may be beneficial to social insect colonies.

The evolution of permanent inquiline social parasites in ants has been conjectured to be facilitated by secondary poly gyny, that is, the re-adoption of new queens into existing mature colonies. This idea was first formulated by Wasmann, Wheeler, and Emery more than a century ago. Emery predicted that inquilines should be the sister-lineages of their hosts, which prompted Alfred Buschinger to propose that they evolve by sympatric speciation. However, these scenarios hinge on two vital conditions that have not been quantitatively documented: 1. That host sister species are secondarily polygynous and primarily recruit close kin, and 2. That such adoptions are prone to occasional mistakes that would select for the condition-dependent expression of exploitative traits and reproductive isolation by disruptive selection. Here, we use a long-term data set on the leaf-cutting ant Acromyrmex echinatior (Forel, 1899), known to have a closely related inquiline social parasite A. insinuator Sch...

Understanding the evolution of the alternative mating strategies of monandry and polyandry is a fundamental problem in evolutionary biology because of the cost-benefit trade-offs associated with mating for females. The problem is particularly intriguing in the social insects because queens in most species appear to be obligately monandrous (i.e., only a single male fathers their offspring), while those in a minority of species have evolved high, and sometimes extreme, polyandry. One group which may shed particular insight is the ant subfamily Myrmeciinae (Myrmecia and Nothomyrmecia). Here we examine the population and colony genetic structure of the bulldog ant Myrmecia pavida CLARK, 1951 by genotyping offspring workers from 45 colonies. We find little evidence of geographic structuring or inbreeding in the population, indicating that the species outbreeds, most probably in mating swarms. We also find that queens of M pavida show moderately high polyandry, with 84% having mated with...

Social insect castes represent some of the most spectacular examples of phenotypic plasticity, with each caste being associated with different environmental conditions during their life. Here we examine the level of genetic variation in different castes of two polyandrous species of Acromyrmex leaf-cutting ant for the antibiotic-producing metapleural gland, which has a major role in defence against parasites. Gland size increases allometrically. The small workers that play the main role in disease defence have relatively large glands compared with larger workers, while the glands of gynes are substantially larger than those of any workers, for their body size. The gland size of large workers varies significantly between patrilines in both Acromyrmex echinatior and Acromyrmex octospinosus . We also examined small workers and gynes in A. echinatior , again finding genetic variation in gland size in these castes. There were significant positive relationships between the gland sizes of ...

Multiple mating by females with different males (polyandry) is difficult to explain in many taxa because it carries significant costs to females, yet benefits are often hard to identify. Polyandry is a derived trait in social insects, the evolutionary origins of which remain unclear. One of several leading hypotheses for its evolution is that it improves division of labour by increasing intra-colonial genetic diversity. Division of labour is a key player in the ecological success of social insects, and in many successful species of ants is based on morphologically distinct castes of workers, each with their own task specialisations. Atta leaf-cutting ants exhibit one of the most extreme and complicated forms of morphologically specialised worker castes and have been reported to be polyandrous but with relatively low mating frequencies (~2.5 on average). Here, we show for the first time that there is a significant genetic influence on worker size in Atta colombica leaf-cutting ants. We also provide the first estimate of the mating frequency of Atta cephalotes (four matings) and, by analysing much higher within-colony sample sizes, find that Atta are more polyandrous than previously thought (approximately six to seven matings). The results show that high polyandry and a genetic influence on worker caste are present in both genera of leaf-cutting ants and add weight to the hypothesis that division of labour is a potential driver of the evolution of polyandry in this clade of ants.

Females mating with multiple males (polyandry) is taxonomically widespread but is hard to explain in many animals in which it has no obvious direct benefits. In some, of which social insects are the best example, it is suggested that females benefit from the increased genetic diversity of their offspring. Social insect colonies express division of labor, and if genotypes behave differently (genetic polyethism), then genetically diverse colonies may be fitter. However, unequivocal evidence of genetic polyethism is only known from honey bees. Here, we show that such a genetic influence on behavior is also present in the leaf-cutting ant Acromyrmex echinatior. In 2 of the 3 colonies examined, we found that the offspring of some fathers (patrilines) were more likely to engage in waste management, whereas other patrilines were more likely to engage in foraging. When we increased the stimulus for waste management, the representation of patrilines in the ants that responded was the same as normally engaged in waste management in 2 colonies but differed in the third colony. The leaf-cutting ant A. echinatior therefore shows genetic polyethism. Although other factors such as disease resistance may have also played a role in the evolution of polyandry, the results suggest that genetic polyethism may be widespread in social insects and potentially of general importance in the evolution of polyandry.

Courtship behavior has been studied extensively in the wolf spider Schizocosa ocreata (Hentz) (Araneae, Lycosidae). While much research has tested predictions of sexual selection theory regarding male traits and female mate choice, some critical assumptions about female behavior remain untested. To determine if females mate more than once, and to what degree copulation influences subsequent female mating, a multiple mating experiment was conducted. Virgin females were paired randomly with males in laboratory containers. If mating occurred, females were paired with a second male within 24 hr, after 3 days, or after 30 days (enough time for an egg sac to be produced). Of the 101 females tested, 83 (82%) mated with the first male they encountered. The probability of a female mating the first time was not influenced by female size, male size, or male age, but varied significantly with female age post-maturity. Of the 18 males that failed to mate, 3 were cannibalized. Of the 83 males that did mate, 12 were cannibalized after mating. There was no difference between re-mating treatments (1 d, 3 d and 30 d), and analysis of pooled data showed a highly significant difference in the proportion of virgin and mated females accepting males; most females mated only once (93%). In contrast, males appeared to court and attempt mating with every female encountered (virgin and mated), and a majority of males paired with more than one virgin female mated more than once (64.5%). Results suggest that female S. ocreata are essentially monandrous, while males are polygynous, and are discussed in the context of potential conflicts-of-interest between the sexes.

The calculated nitrogen uptake data (Table ) were used to compare how species differ in their patterns of uptake across treatments. We emphasize that the data cannot be used to compare how species partition total nitrogen uptake within treatments because the total amount of 15 N uptake by each species strongly depends on the relationship between lateral rooting distance and the spacing of 15 N injections. In this experiment, where 15 N injections were spaced in a 7.5-cm grid, Ledum took up six times more 15 N across all treatments than Eriophorum ( 15 N data not shown). In a different experiment designed to determine species' lateral rooting distances, we injected a constant amount of 15 N (114 mg as a mixture of 25 mmol l -1 each of glycine, ammonium and nitrate) at different treatment radii (5, 10, 20, 40, 60 and 100 cm) around individual plants of Eriophorum and Ledum. That design allowed 15 N uptake data to be spatially integrated across all treatment radii, simulating how 15 N would be taken up from injections spaced in®nitely close together over an area with a radius of 100 cm. Although those results showed that the primary lateral radius of uptake (about 60% of total uptake) of Eriophorum was about half that of Ledum (5 versus 10 cm), Eriophorum took up almost twice as much 15 NasLedum when the data were extrapolated on a community basis (uptake per unit ground area) (R.B.M., unpublished data). The results of both experiments show that widely spaced tracer injections disproportionately label species with larger rooting areas but lower uptake capacities per unit ground area (for example, Ledum). In contrast, species' patterns of uptake across treatments (within rows), as presented here, should be relatively robust with respect to the spacing of tracer injections.

Females of many species mate with more than one male (polyandry), yet the adaptive significance of polyandry is poorly understood. One hypothesis to explain the widespread occurrence of multiple mating is that it may allow females to utilize post-copulatory mechanisms to reduce the risk of fertilizing their eggs with sperm from incompatible males. Selfish genetic elements (SGEs) are ubiquitous in eukaryotes, frequent sources of reproductive incompatibilities, and associated with fitness costs. However, their impact on sexual selection is largely unexplored. In this review we examine the link between SGEs, male fertility and sperm competitive ability. We show there is widespread evidence that SGEs are associated with reduced fertility in both animals and plants, and present some recent data showing that males carrying SGEs have reduced paternity in sperm competition. We also discuss possible reasons why male gametes are particularly vulnerable to the selfish actions of SGEs. The widespread reduction in male fertility caused by SGEs implies polyandry may be a successful female strategy to bias paternity against SGE-carrying males.

Direct costs and benefits to females of multiple mating have been shown to have large effects on female fecundity and longevity in several species. However, with the exception of studies examining genetic benefits of polyandry, little attention has been paid to the possible effects on offspring of multiple mating by females. We propose that nongenetic effects of maternal matings on offspring fitness are best viewed in the same context as other maternal phenotype effects on offspring that are well known even in species lacking parental care. Hence, matings can exert effects on offspring in the same way as other maternal environment variables, and are likely to interact with such effects. We have conducted a study using yellow dung flies (Scathophaga stercoraria), in which we independently manipulated female mating rate, number of mates and maternal thermal environment and measured subsequent fecundity, hatching success, and offspring life-history traits. To distinguish between direct effects of matings and potential genetic benefits of polyandry we split broods and reared offspring at three different temperature regimes. This allowed us to demonstrate that although we could not detect any simple benefits or costs to matings, there are effects of maternal environment on offspring and these effects interact with female mating regime affecting offspring fitness. Such interactions between female phenotype and the costs and benefits of matings have potentially broad implications for understanding female behavior.

Butterflies show considerable variability in female mating frequency, ranging from monandrous species to females mating several times in their lifetime. Degree of polyandry also varies within species, with some females only mating once and others mating multiply. Previous studies have shown that one reason for female multiple mating is to obtain nutritious male donations that both increase the longevity of females and result in higher lifetime fecundity. Despite the presence of male nutrient donations, some females of the green-veined white butterfly (Pieridae: Pieris napi) never mate more than once. In this study, we examined this apparent paradox. We assessed to what degree polyandry is under genetic control by a full-sib analysis, and we also estimated the broad sense heritability of female lifetime fecundity in singly mated females. Both polyandry and lifetime fecundity have a genetic component. However, degree of polyandry appears to be traded off against reduced longevity when denied the opportunity to mate more than once. It is possible that female P. napi display different reproductive strategies, with some females relying on male donations to realize their potential fecundity and others relying on their own resources for egg production. In nature, polyandrous females may be prevented from mating multiply due to unfavorable weather. We discuss the possibility that the trade-off between degree of polyandry and life span when singly mated may affect the maintenance of genetic variability in female mating frequency in this species. Possible reasons for these different reproductive strategies are discussed.

Sexual conflict has been suggested to be important in the evolution of reproductive traits, with much recent theoretical and empirical evidence emphasizing its role in generating sexually antagonistic coevolution in the context of promiscuous mating. Here we shift attention to the role of sexual conflict in a monogamous mating context. Conflicts can arise, for example, when males are successful in imposing monandry at a cost to female fitness, or when females impose monogyny on males. Conflict over remating can also generate monogamy. For example, when males invest heavily in attempting to impose female monandry, the cost of their investment may prevent them from securing additional mates. We emphasize that sexual conflicts need not always generate sexually antagonistic coevolution, and that it is important to consider whether mating decisions are controlled primarily by males or females. Finally, we briefly discuss approaches to distinguish between conflict and classical modes of s...

Je souhaite en premier lieu remercier mes directeurs de thèse, les Dr François Criscuolo et Dr Frédéric Bouillaud. François, tout d'abord merci de m'avoir choisie et fait confiance pour ce projet, merci pour ton écoute, ta bienveillance en période(s) de doute, et ton aide précieuse malgré la distance des deux premières années. Et pour finir, merci pour ta contribution à ce manuscrit. Frédéric, je te remercie pour ton accueil sur Paris, ton expertise précieuse, notamment dans la relecture des manuscrits et l'interprétation des résultats. Martin, Antman, je te suis également reconnaissante. Sans toi le projet n'aurait pas existé, et tu t'es toujours rendu disponible pour répondre à mes questions. Je tiens à remercier l'équipe parisienne dans laquelle je suis restée pendant deux ans : Renaud, Clotilde, Carina et l'adorable Véronique. Je salue également ceux qui n'étaient que de passage, ou qui ont quitté l'institut, comme Céline et Noureddine. Big up aux anciennes stagiaires qui sont devenues de bonnes copines, Khawla et Sarah. Et bien sûr je ne t'oublie pas Angèle ! On aura partagé une table de bureau pendant deux années, on aura ri, pleuré (un peu quand même), testé des trucs (à la paillasse comme à la salle ^^). A défaut d'avoir trouvé un protocole valable d'isolation de mitochondries de fourmis sur Paris, j'ai trouvé une très bonne amie . Bon courage pour tes derniers mois, mouvement du pied et « Attitude » ! Je tiens également à exprimer ma reconnaissance aux plateformes de l'institut Cochin, et notamment Thomas qui m'a formée et assistée dans les tests de microscopie en temps de vol. Le monde de la recherche implique de se faire des relations, et pas mal de collaborations. J'ai eu la chance de pouvoir profiter du réseau de Céline Cansell pour faire respirer mes fourmis, merci ! J'ai également profité de la gentillesse d'Hervé Colinet, et des doctorantes du laboratoire EcoBio, qui nous ont accueillies mes fourmis et moi pendant une semaine pour des mesures de respiration discontinue. Je remercie également Benoît Pinson pour ses mesures Ô combien précieuses de l'AEC, et sa disponibilité. Et un petit coucou à Steffi, copine du M2 et doctorante au MnHn, contrebandière et guide à ses heures ;-) Un peu plus à l'Est maintenant, ce sont les personnes du bâtiment 60 de l'IPHC que je souhaiterais remercier : en particulier Elisabeth, qui aura dû composer avec mon ordre de mission permanent bloquant mon compte etamine pendant deux ans (oups), et qui pour la science se sera mise au polonais le temps d'une commande de fourmis ; Sandrine qui veille dans les labos et qui est iii toujours là en cas de besoin ; les animaliers Hélène, David, Aurélie et Nicolas, qui s'occupent des colonies de fourmis; Astolfo, pour sa gentillesse ; JP, pour sa bonne humeur et sa playlist de fin de semaine. Un grand merci aux collègues doctorants, et une pensée pour mes colocataires de bureau Maëlle, Camille et Lilia, que je quitte bientôt et qui vont beaucoup me manquer. Maëlle, Cyrielle, mille mercis pour votre écoute et vos encouragements ! Je salue le travail de mon stagiaire, Valentin (et par la même occasion Julien Pétillon), pour son beau travail et son implication dans les mesures de respiration de mitochondries d'araignées. Je profite des lignes restantes pour remercier Fabrice, du département de Chimie Analytique, pour l'organisation des mesures, et ses nombreux retours sur le projet et les drafts. Je n'oublie pas Valériane, qui a récupéré mes isolations de mitochondries et les a préparées pour la protéomique, après avoir dû créer une nouvelle base de données ! Enfin, parce qu'une thèse est également une affaire de famille, j'exprime toute ma gratitude envers mes parents qui me soutiennent depuis toujours, c'est-à-dire longtemps. Merci Mamounette pour tes corrections de mails, et tes encouragements énergiques répétés (c'est un euphémisme), merci Papa d'être toujours là. Je remercie ma « chère soeur » Pauline (à lire à haute voix avec l'intonation de Mme Bennet), mon petit frère Quillian alias Quiqui la Quiche ou Tête de Baleine (si on veut l'énerver, mais à éviter maintenant qu'il frôle le 1m90), ainsi que tous les amis à quatre pattes de la maison, qui sont le meilleur remède contre le spleen (Maïka Macha Machkaïa, Dame Hiris, Maximilien Maximus Magnus I er de la Barbotine et Niambé). J'ai une pensée toute particulière pour mes grands-parents, ma tendre Mamie Gloue et mon Popen, les deux personnes au monde que je souhaitais le plus rendre fières, et qui m'ont toujours aimée, accompagnée et soutenue de toutes les manières possibles dans les étapes clés de la vie. Je regrette seulement qu'ils ne puissent pas voir l'aboutissement de ces trois ans de thèse. At last but not least, je tiens à remercier mon neveu Kymani, avec qui je n'ai pas besoin de me tenir, et faire semblant d'être adulte. Minou, mon copain de foot, le Neymar de Bretagne, le dormeur du Louvre, et moteur de mes premières recherches sur les mitochondries, ce manuscrit est pour toi. Merci au jury d'avoir accepté de me relire

Mating is one aspect of behaviour that has been much ignored in mosquito biology. Yet, the success of a transgenic release strategy depends on normal, competitive mating between introduced and wild individuals. An overview is presented of current knowledge of mating behaviour in Culicidae, including timing of mating, means of sperm transfer, refractory behaviour and multiple mating. Most lacunae were found in mate finding: it is known that some species use swarming while other mate on or near the vertebrate host. At short range males locate females by acoustic signals, but there is no knowledge how the sexes locate each other from a distance. It is argued that mass rearing of mosquitoes for sterile-insect release or transgenic release should include steps to safeguard male fitness. A series of challenges for future studies are discussed, including cues that control swarming behaviour, mate-finding behaviour and identification of genes that control mating behaviour.

Variation in paternity frequency in colonies of eusocial insects has profound effects on the relatedness among offspring and on the genetic diversity of colonies. Data on queen ‘mating-frequency’ in eusocial Hymenoptera vary in both quality and the phase of the ‘mating’ process they address. Some are observational studies of the range or maximum number of copulations; others are derived from estimates of the number of sperm in males and queens; others use genetic techniques to determine the paternity of different males among female offspring. Only the latter data can be used to calculate relatedness among offspring females. Previous reviews drew attention to these problems, but their results have established the impression that high paternity frequencies are common, largely because multiple copulations are frequently observed. For ants, we show that: (i) the range of observed copulations overestimates effective paternity frequency; and (ii) the mean effective paternity frequency in ...

Copulation behavior has often been shaped by sexually selected sperm competition or cryptic female choice. However, manipulation of previously deposited ejaculates is unknown in the social Hymenoptera and the degree to which sperm competes after insemination or is actively selected by females has remained ambiguous. We studied the mating process in the leaf-cutting ants Atta colombica and A. cephalotes, which belong to one of the few derived social insect lineages where obligate multiple mating has evolved. As copulations often occur at night and in remote places, direct observations were impossible, so we had to reconstruct the sequential copulation events by morphological analysis of the male and female genitalia and by tracking the process of sperm transfer and sperm storage. We show that Atta male genitalia have two external rows of spiny teeth, which fit into a specialized pouch organ in the female sexual tract. Reconstruction of the sperm storage process indicated that sperm is transferred to the spermatheca during or immediately after ejaculation and without being mixed with sperm and seminal fluids from other males. A convergent mechanism of direct sperm transfer to the spermatheca of queens is known from two species of dwarf honeybees. Direct sperm transfer may restrict female control over the sperm storage process and the number of males that contribute to the stored sperm.

The evolution of mating systems in eusocial Hymenoptera is constrained because females mate only during a brief period early in life, whereas inseminated queens and their stored sperm may live for decades. Considerable research effort during recent years has firmly established that obligate multiple mating has evolved only a few times: in Apis honeybees, Vespula wasps, Pogonomyrmex harvester ants, Atta and Acromyrmex leaf-cutting ants, the ant Cataglyphis cursor, and in at least some army ants. Here we provide estimates of queen-mating frequency for New World Neivamyrmex and Old World Aenictus species, which, compared to other army ants, have relatively small colonies and little size polymorphism among workers. To provide the first overall comparative analysis of the evolution of army ant mating systems, we combine these new results with previous estimates for African Dorylus and New World Eciton army ants, which have very large colonies and considerable worker polymorphism. We show that queens of Neivamyrmex and Aenictus mate with the same high numbers of males (usually ca. 10-20) as do queens of army ant species with very large colony sizes. We infer that multiple queen mating is ancestral in army ants and has evolved over 100 million years ago as part of the army ant adaptive syndrome. A comparison of army ants and honeybees suggests that mating systems in these two distantly related groups may have been convergently shaped by strikingly similar selective pressures.

The seminal fluid that accompanies sperm in ejaculates has been shown or suggested to affect sperm competition and paternity success of insects by preventing female remating, inducing oviposition, and forming mating plugs. In Atta leafcutter ants, queens have multiple mates but never remate later in life, although they may live and produce fertilized eggs for several decades. The mating biology and life history of these ants therefore suggests that the major function of seminal fluid is to maximize sperm viability during copulation, sperm transfer, and initial sperm storage. We tested this hypothesis by comparing the viability of testis sperm and ejaculated sperm (mixed with seminal fluid) and found a significant positive effect of seminal fluid on sperm viability. We further quantified this positive effect by adding accessory gland secretion (a major component of seminal fluid) in a dilution series, to show that minute quantities of accessory gland secretion achieve significant increases in sperm viability. Sperm stored by queens for 1 year benefited in a similar way from being exposed to accessory gland compounds after dissection in control saline solution. Our results provide the first empirical evidence that seminal fluid is important for the production of viable ejaculates and that the accessory glands of Atta males-despite their small size-are functional and produce a very potent secretion.

Mutual policing is an important mechanism for maintaining social harmony in group-living organisms. In some ants, bees, and wasps, workers police male eggs laid by other workers in order to maintain the reproductive primacy of the queen. Kin selection theory predicts that multiple mating by the queen is one factor that can selectively favor worker policing. This is because when the queen is mated to multiple males, workers are more closely related to queen's sons than to the sons of other workers. Here we provide an additional test of worker policing theory in Vespinae wasps. We show that the yellowjacket Vespula rufa is characterized by low mating frequency, and that a significant percentage of the males are workers' sons. This supports theoretical predictions for paternities below 2, and contrasts with other Vespula species, in which paternities are higher and few or no adult males are worker produced, probably due to worker policing, which has been shown in one species, Vespula vulgaris. Behavioral observations support the hypothesis that V. rufa has much reduced worker policing compared to other Vespula. In addition, a significant proportion of worker-laid eggs were policed by the queen.

Direct costs and benefits to females of multiple mating have been shown to have large effects on female fecundity and longevity in several species. However, with the exception of studies examining genetic benefits of polyandry, little attention has been paid to the possible effects on offspring of multiple mating by females. We propose that nongenetic effects of maternal matings on offspring fitness are best viewed in the same context as other maternal phenotype effects on offspring that are well known even in species lacking parental care. Hence, matings can exert effects on offspring in the same way as other maternal environment variables, and are likely to interact with such effects. We have conducted a study using yellow dung flies (Scathophaga stercoraria), in which we independently manipulated female mating rate, number of mates and maternal thermal environment and measured subsequent fecundity, hatching success, and offspring life-history traits. To distinguish between direct effects of matings and potential genetic benefits of polyandry we split broods and reared offspring at three different temperature regimes. This allowed us to demonstrate that although we could not detect any simple benefits or costs to matings, there are effects of maternal environment on offspring and these effects interact with female mating regime affecting offspring fitness. Such interactions between female phenotype and the costs and benefits of matings have potentially broad implications for understanding female behavior.

A database containing 24 key production measurements was created by abstracting data files of 673 U.S. farms which participated in the PigCHAMP data-share program in 1995. Summary statistics for breeding-herd performance data were presented for the Cornbelt and the South or Eastern regions. Eight models were built to assess the association between production system, operation management factors and productivity outcomes. Lactation length, percentage of multiple matings, parity of culled sows, percent gilts in the breeding-female inventory, and female culling rate were the management factors identified as having important associations with productivity outcomes. For example, shorter lactation length, higher percentage of multiple matings, and lower culling rate were associated with more pigs weaned per mated female per year. In addition, a lower percentage of gilts in the breeding-female inventory and a higher percentage of multiple matings were associated with fewer average non-productive female days. We recommend that producers change their management systems to decrease lactation length, the percentage of gilts in the breeding-female inventory, and female culling rate, and increase percentage of multiple matings in order to improve breeding-herd productivity on swine farms. # 1998 Elsevier Science B.V.