Understanding Of Mating Systems Research Articles

Brown bear skin-borne secretions display evidence of individuality and age-sex variation

Scent originates from excretions and secretions, and its chemical complexity in mammals translates into a diverse mode of signalling. Identifying how information is encoded can help to establish the mechanisms of olfactory communication and the use of odours as chemical signals. Building upon existing behavioural and histological literature, we examined the chemical profile of secretions used for scent marking by a solitary, non-territorial carnivore, the brown bear (Ursus arctos). We investigated the incidence, abundance, and uniqueness of volatile organic compounds (VOCs) from cutaneous glandular secretions of 12 wild brown bears collected during late and post-breeding season, and assessed whether age-sex class, body site, and individual identity explained profile variation. VOC profiles varied in the average number of compounds, compound incidence, and compound abundance by age-sex class and individual identity (when individuals were grouped by sex), but not by body site. Mature males differed from other age-sex classes, secreting fewer compounds on average with the least variance between individuals. Compound uniqueness varied by body site and age for both males and females and across individuals. Our results indicate that brown bear skin-borne secretions may facilitate age-sex class and individual recognition, which can contribute towards further understanding of mating systems and social behaviour.

Mating System Analysis of <i>Acacia auriculiformis</i> in First and Second Generation Orchard Populations

Acacia auriculiformis A.Cunn.ex Benth is one of the fast growing exotic timber species. Thorough understanding of mating systems is influencing towards an efficient tree breeding design. Thus plant mating systems play an important role in shaping the genetic composition of progeny generations. Institute of Forest Genetics & Tree Breeding (IFGTB), Coimbatore has established Seedling Seed Orchards of Acacia auriculiformis in Southern States (Tamil Nadu and Kerala) of India. Two successive generations of this species were studied for its mating system based on microsatellite markers. Five microsatellite loci were studied among the three hundred half-sib progenies of both first and second orchard populations. Out-crossing rate was estimated The range of the maternal, paternal genotypes among the individuals in the family was also studied in the orchards. The present study indicated high out-crossing rate in first and second generation orchards population and it reflects that this species is highly out-crossed. The gene frequency estimates of the first and second generation progenies were studied that there was no significant variation in the pollen and ovule gene frequency estimate in both generations. The range of the maternal genotypes was 1 to 2 among the individuals in the family. The high out-crossing rate (tm=0.98; SE= 0.05; tm=1.0; SE=0.02) in the orchards indicated that the species is predominantly out-crossed.

Mating compatibility and fertility studies in an herbaceous perennial Aster undergoing de novo domestication to enhance agroecosystems

De novo domestication has received recent attention because of the potential to produce new crop species with additional agroecosystem functions and useful products for climate-resilient agricultural systems of the future. However, there are often traits in wild species that make them difficult to domesticate. One key domestication trait selected by early farmers and modern plant breeders in many crops is the ability to self-pollinate. Benefits include higher seed set and more reliable seed production, as well as more efficient selection during breeding because it allows for unmasking of recessive traits and enforcement of favorable gene interactions. Similarly, interspecific hybridization has been used to add to the genetic diversity of many crop species. We evaluated self-pollination and interspecific hybridization in Silphium integrifolium and S. perfoliatum to learn the extent of possible gene flow between the species and its usefulness in cultivar development and the potential for fixation of favorable domestication genes by self-pollination. Our results indicate that Silphium interspecific hybrids can be easily developed, potentially facilitating movement of otherwise invariable traits from one species to another. Further, we showed, for the first time, that self-pollination is also possible in both species and their interspecific hybrids, but the rate varies among genotypes. This has profound implications in optimizing plant breeding methods for the study and improvement of these species and adds more evidence to our understanding of mating systems in Asteraceae, an underutilized family of plants with great potential for additional domesticated species.

Polygamy and an absence of fine-scale structure in Dendroctonus ponderosae (Hopk.) (Coleoptera: Curcilionidae) confirmed using molecular markers.

An understanding of mating systems and fine-scale spatial genetic structure is required to effectively manage forest pest species such as Dendroctonus ponderosae (mountain pine beetle). Here we used genome-wide single-nucleotide polymorphisms to assess the fine-scale genetic structure and mating system of D. ponderosae collected from a single stand in Alberta, Canada. Fine-scale spatial genetic structure was absent within the stand and the majority of genetic variation was best explained at the individual level. Relatedness estimates support previous reports of pre-emergence mating. Parentage assignment tests indicate that a polygamous mating system better explains the relationships among individuals within a gallery than the previously reported female monogamous/male polygynous system. Furthermore, there is some evidence to suggest that females may exploit the galleries of other females, at least under epidemic conditions. Our results suggest that current management models are likely to be effective across large geographic areas based on the absence of fine-scale genetic structure.

Sexual size dimorphism, mating system and seasonality of a Neotropical damselfly,Telebasis carmesina(Coenagrionidae)

Our understanding of mating systems is highly skewed toward temperate examples. This study investigated the mating system, sexual size dimorphism and seasonal variation in local distribution and abundance of male and female Telebasis carmesina, a common damselfly in Brazilian tropical savanna. In a natural reserve, daily census and behavioral observations were made throughout 1 year at the edges of a permanent pond. Males were more abundant during the rainy season, when mating and oviposition by females occurred. The operational sex ratio at the pond was heavily male biased, c. 1\female: 19\male. Males were smaller than females but were larger in the dry season than in the wet season, when they were more abundant at the pond. Females were larger in the dry months of July to September than in the rainy season. Both males and females principally used the macrophyte Eleocharis sp. as perches and for oviposition. Males exhibited polygynous, scramble mate competition, as in most coenagrionids that have been st...

Promiscuous mating in the harem‐roosting fruit bat,Cynopterus sphinx

Observations on mating behaviours and strategies guide our understanding of mating systems and variance in reproductive success. However, the presence of cryptic strategies often results in situations where social mating system is not reflective of genetic mating system. We present such a study of the genetic mating system of a harem-forming bat Cynopterus sphinx where harems may not be true indicators of male reproductive success. This temporal study using data from six seasons on paternity reveals that social harem assemblages do not play a role in the mating system, and variance in male reproductive success is lower than expected assuming polygynous mating. Further, simulations reveal that the genetic mating system is statistically indistinguishable from promiscuity. Our results are in contrast to an earlier study that demonstrated high variance in male reproductive success. Although an outcome of behavioural mating patterns, standardized variance in male reproductive success (I(m)) affects the opportunity for sexual selection. To gain a better understanding of the evolutionary implications of promiscuity for mammals in general, we compared our estimates of I(m) and total opportunity for sexual selection (I(m) /I(f), where I(f) is standardized variance in female reproductive success) with those of other known promiscuous species. We observed a broad range of I(m) /I(f) values across known promiscuous species, indicating our poor understanding of the evolutionary implications of promiscuous mating.

Genetic mating system of the brown smoothhound shark (Mustelus henlei), including a literature review of multiple paternity in other elasmobranch species

Although an understanding of mating systems is thought to be an important component of long-term population management, these life history characteristics are poorly known in sharks. Here, we employ polymorphic microsatellite markers to test for the occurrence and prevalence of multiple paternity in a population of the brown smoothhound shark, Mustelus henlei. We analyzed litters from 14 females sampled from the Pacific coast of Baja California Sur. The minimum number of sires ranged from one to three with an average of 2.3 sires per litter. Regression analyses did not indicate a relationship between female body size and number of sires, or female body size and size of the litter. A review of the existing literature on genetic mating systems in sharks suggests that polyandry may be common and that reproductive behavior may have evolved from conflicting selection pressures between the sexes.

Novel microsatellite loci for the compost earthworm Eisenia fetida: A genetic comparison of three North American vermiculture stocks

Abstract Earthworms are important components of soil ecosystems worldwide, and have been used extensively as indicator species in ecotoxicology studies. Our understanding of mating systems, population structure, and genetic diversity in earthworms is limited by the current lack of available genetic tools. To address this gap, we developed 16 novel microsatellite markers for the compost earthworm Eisenia fetida, one of the most widely studied earthworm species. We tested the new markers in 3 putative populations of worms from commercial vermiculture operations in Canada and the U.S.A. All 16 loci were variable in at least one population, with the number of alleles per locus ranging from 3 to 10, observed heterozygosity from 0.000 to 0.783, and polymorphic information content from 0.032 to 0.587. One group had significantly reduced heterozygosity compared to the other 2, but overall there were only minor genetic differences among the tested suppliers, suggesting a possible bottleneck for this species in North America. The microsatellite loci we describe here will be extremely useful tools for future field and laboratory studies of E. fetida. Body size and condition in adult worms varied significantly by supplier, and breeding success and cocoon production were significantly higher in breeding pairs from one supplier compared to the other two. In the absence of evidence for genetic divergence among populations, our results suggest that the early rearing environment may be an important factor affecting adult breeding performance. We caution that the source of worms may affect the outcome of laboratory experiments involving growth and reproduction.

Multiple paternity and maintenance of genetic diversity in the live-bearing rockfishes Sebastes spp.

The understanding of mating systems is key to the proper management of exploited spe- cies, particularly highly fecund, r-selected fishes, which often show strong discrepancies between census and effective population sizes. The development of polymorphic genetic markers, such as codominant nuclear microsatellites, has made it possible to study the paternity of individuals within a brood, helping to elucidate the species' mating system. In the present study, paternity analysis was performed on 35 broods, representing 17 species of the live-bearing scorpaenid genus Sebastes. We report on the finding of multiple paternity from several species of Sebastes and show that at least 3 sires can contribute paternity to a single brood. A phylogenetically and ecologically diverse sample of Sebastes species was examined, with multiple paternity found in 14 of the 35 broods and 10 of the 17 examined species, we suggest that this behavior is not a rare event within a single species and is likely common throughout the genus. Despite high variance in reproductive success, Sebastes spp., in general, show moderate to high levels of genetic diversity. We suggest that multiple paternity may be a form of bet hedging that serves to maximize genetic diversity within broods and that, regardless of the selective value at the level of individual fitness, the net effect at the population level may be a genetic buffer to the consequences of severe overexploitation.

Habitat, Niche, and Evolution of Sirenian Mating Systems

Lek polygyny, monogamy and scramble promiscuity have been reported in the two families and five species of Recent sirenians. Evidence for lek mating in the dugong or "sea pig" (Dugong dugon), monogamy in Steller's sea cow (Hydrodamalis gigas), and scramble promiscuity in the three manatees or "river cows" (Trichechus manatus, Trichechus senegalensis, and Trichechus inunguis), as well as in one dugong population, is reviewed. Sirenians are long-lived "K-strategists" with precocious young, few potential young per female lifetime, high female investment in a few young, little apparent opportunity for post-copulatory male investment, and "paenungulate" reproductive physiologies that appear to increase uncertainty as to female receptivity and assurance as to paternity. Common features notwithstanding, diverse habitats, climates, and niches may account for mating system diversity. Scenarios for evolution of diverse mating systems, based on our understanding of mating systems in terrestrial herbivores, are presented. The dugong retains the ancestral low latitude marine, seagrass dependent, bottom-feeding, niche characteristic of diverse, tusked, Oligocene and Miocene sirenian faunas. With a long breeding season and high polygyny potential, retention of tusks by male dugongs in the absence of any foraging function suggests that tusks may have always had social functions and lekking may be of ancient origin. The sea cow lineage, isolated on the shoreline of the northeastern Pacific as seagrasses declined, turned to surface foraging on chemically undefended kelps and lost both tusks and molar teeth. As it followed kelps northwards, adaptation to a cold-temperate climate compressed the breeding season, limited the polygyny potential, and, in conjunction with incentives for paternal investment, favored pair bonding and the monogamous mating system postulated by George Steller (1751). Manatees, evolving in botanically-rich fresh waters of the Amazon basin as an aberrant offshoot of the marine dugongid line, remained in the tropics and retained a high polygyny potential, but became generalist foragers in the upper few meters of the water column. Labyrinthine river systems provided little opportunity for male aggregation and display (or rhizome foraging) and tusks were lost as the uncertainty of female inseminability drove the mating system toward scramble promiscuity and sperm competition. An observation of manatee-like behavior in a dense and sedentary dugong population in eastern Australia suggests plasticity in sirenian mating, and the likelihood that a form of scramble promiscuity may exist where no suitable site for lekking is available, where large group size makes female defence impossible, or where vulnerability of territorial males to hunting has resulted in extirpation of a lekking tradition. Dugong and manatee life history characteristics conform to expectations based on observed differences in mating systems.

Infidelity as a transaction between social mates

Why are some females faithful to their mates, whereas others are promiscuous, and why do males tolerate cuckoldry, raising both their own and the young of another male? Determining these answers is central to our understanding of mating systems and sexual selection. The past decade has been marked by an infusion of molecular analyses of paternity, revealing enormous variation in cuckoldry rates across species, populations and even individuals. Arguments have been waged about the underlying determinants of the levels of cuckoldry and female infidelity. In many species, females might be largely in control of which male or males they mate with. Understanding promiscuous behaviour might, therefore, be achieved best by examining the costs and benefits of cuckoldry to females. Until now, however, no formal framework existed that simultaneously took into account both female and male interests to provide a comprehensive explanation of how these costs and benefits might interact to shape the evolution of infidelity.Janet Shellman-Reeve and H. Kern Reeve 1xExtra-pair paternity as the result of reproductive transactions between paired mates. Shellman-Reeve, J.S and Reeve, H.K. Proc. R. Soc. London B Biol. Sci. 2000; 267: 2543–2546Crossref | Scopus (16)See all References1 have now developed a mathematical model similar to transactional (optimal skew or concession) models in which cuckoldry in broods receiving biparental care is viewed as emerging from a transaction between the mated pair. The model assumes that a female can obtain good genes (i.e. better genes than from her current mate) by mating with a second male. The model also assumes that males can assess their potential risk of being cuckolded, but might not be able to recognize their own young within the brood. If they suspect, however, that their paternity is sufficiently low, they might choose to abandon both their mate and the brood. Conversely, a female can choose to divorce her mate and raise a brood comprised entirely of cuckolded young on her own. This elegant model provides the first formal framework for evaluating how good genes can tradeoff with good care in determining the frequency of cuckoldry. The model shows that a female is expected to become more promiscuous when the value of the care of her mate (in terms of offspring survivorship) becomes lower or when the genetic quality of a potential cuckolder male becomes higher relative to that of the current mate of the female. Given such circumstances, a paired male can only demand the small amount of paternity that a female is willing to give him before she discounts his value altogether and chooses to raise cuckolded young on her own.Cuckoldry and parental care is perhaps best studied in birds, and the transactional model of Shellman-Reeve and Reeve provides a remarkably unified explanation for all of the major empirically observed predictors of cuckoldry rates in birds that provide biparental care. Perhaps most importantly, the model makes an important connection between the extensive theory of transactions and theory of mate choice and parental investment. It is probable that, given the depth of transactional theory, many more insights will arise from this new association. For example, ‘tug-of-war’ models might be amendable to address cuckoldry and parental care in mating systems in which males have more control of paternity, such as might be the case in external fertilizers, or systems where males are larger than females. Nevertheless, it appears that transactional theory might provide the basis for a truly unifying theory of social interactions.

A METHOD TO COLLECT AND PROCESS SKIN BIOPSIES FOR CELL CULTURE FROM FREE‐RANGING GRAY WHALES (ESCHRICHTIUS ROBUSTUS)

AbstractFor researchers studying mysticere whales few methods for determining gender or for collecting biochemical and genetic information from unrestrained animals are available. The objective of this study was to develop a reliable method for collecting viable tissue samples for establishing continuous cell cultures from skin biopsies of free‐ranging whales. A method to collect and process these samples is presented. Six of seven skin biopsies from gray whales were established in cell culture. Our results suggest that the viability of the samples is improved by (1) sterile processing in the field, (2) minimizing the time between collection and delivery to the cell culture facility, (3) reducing the concentration of antifungal agent, and (4) placing tissue explants under a coverslip. While the results reported in this paper are based on a small sample size, we believe that if the procedures are followed, they will increase the probability of successfully culturing cetacean tissue. Established cell lines can supply replenishable material from identified whales still living in the wild. These cultures can then be used for determination of sex from karyotypes, and for assessing genetic relationships of cetaceans from inherited protein, chromosomal and DNA polymorphisms. These much needed analytical tools can be used to determine familial and populational relationships, leading to a better understanding of mating systems, stock identification and effective population sizes of wild cetaceans.