SEARCH · PubMed Health

Results for “mating systems”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

PubMed1999

The evolution of mating systems in tropical reef corals.

The life histories of tropical reef corals (Scleractinia) include two traits that can strongly bias mating systems towards inbreeding: (1) most species express both sexes simultaneously, creating the potential for self-fertilization; and (2) there is philopatric dispersal of planktonic or demersal larvae. Recent studies have confirmed that all hermaphrodite species with broad dispersal potential are either completely, or almost completely, self-incompatible. By contrast, species with limited dispersal potential have high, but variable, rates of self-fertilization. This interspecific variation in coral mating systems is similar to that found in terrestrial plants. Understanding the selective forces that drive mating-system variation in marine environments will undoubtedly broaden our understanding of the evolution of inbreeding and outbreeding in sessile plants and animals.

Journal Article↗

PubMed2006

Mitosis, stature and evolution of plant mating systems: low-Phi and high-Phi plants.

There is a long-recognized association in plants between small stature and selfing, and large stature and outcrossing. Inbreeding depression is central to several hypotheses for this association, but differences in the evolutionary dynamics of inbreeding depression associated with differences in stature are rarely considered. Here, we propose and test the Phi model of plant mating system evolution, which assumes that the per-generation mutation rate of a plant is a function of the number of mitoses (Phi) that occur from zygote to gamete, and predicts fundamental differences between low-Phi (small-statured) and high-Phi (large-statured) plants in the outcomes of the joint evolution of outcrossing rate and inbreeding depression. Using a large dataset of published population genetic studies of angiosperms and conifers, we compute fitted values of inbreeding depression and deleterious mutation rates for small- and large-statured plants. Consistent with our Phi model, we find that populations of small-statured plants exhibit a range of mating systems, significantly lower mutation rates, and intermediate inbreeding depression, while large-statured plants exhibit very high mutation rates and the maximum inbreeding depression of unity. These results indicate that (i) inbred progeny typically observed in large-statured plant populations are completely lost prior to maturity in nearly all populations; (ii) evolutionary shifts from outcrossing to selfing are generally not possible in large-statured species, rather, large-statured species are more likely to evolve mating systems that avoid selfing such as self-incompatibility and dioecy; (iii) destabilization of the mating system-high selfing rate with high-inbreeding depression-might be a common occurrence in large-statured species; and (iv) large-statured species in fragmented populations might be at higher risk of extinction than previously thought. Our results help to unify and simplify a large and diverse field of research, and serve to emphasize the importance that developmental and genetic constraints play in the evolution of plant mating systems.

Evolution, Molecular↗

PubMed2000

Mating system parameters in species of genus Prosopis (Leguminosae).

The section Algarobia of genus Prosopis involves important natural resources in arid and semiarid regions of the world. Their rationale use requires a better knowledge of their biology, genetics and mating system. There are contradictory information about their mating system. Some authors claim they are protogynous and obligate outcrosser. However, some evidence have been shown indicating that they might not be protogynous and that they might be somewhat self-fertile. The current paper analyses genetic structure and mating system parameters in populations of seven species of this section from South and North America based on isozyme data. In all species a significant homozygote excess was found in the offspring population but not in mother plant genotypes. Multilocus and mean single locus outcrossing rates (tm, ts) indicated that about 15% selfing can occur in the studied populations. The heterogeneity between pollen and ovule allele frequencies was low suggesting population structuration, in agreement with the estimates of correlation of tm within progeny (rt) and correlation of outcrossed paternity (rp). The difference of FIS estimates between offspring and mother plants suggest some selection favouring heterozygotes between seedling and adult stages.

Alleles↗

PubMed2004

Effective size of two feral domestic cat populations (Felis catus L): effect of the mating system.

A variety of behavioural traits have substantial effects on the gene dynamics and genetic structure of local populations. The mating system is a plastic trait that varies with environmental conditions in the domestic cat (Felis catus) allowing an intraspecific comparison of the impact of this feature on genetic characteristics of the population. To assess the potential effect of the heterogenity of males' contribution to the next generation on variance effective size, we applied the ecological approach of Nunney & Elam (1994) based upon a demographic and behavioural study, and the genetic 'temporal methods' of Waples (1989) and Berthier et al. (2002) using microsatellite markers. The two cat populations studied were nearly closed, similar in size and survival parameters, but differed in their mating system. Immigration appeared extremely restricted in both cases due to environmental and social constraints. As expected, the ratio of effective size to census number (Ne/N) was higher in the promiscuous cat population (harmonic mean = 42%) than in the polygynous one (33%), when Ne was calculated from the ecological method. Only the genetic results based on Waples' estimator were consistent with the ecological results, but failed to evidence an effect of the mating system. Results based on the estimation of Berthier et al. (2002) were extremely variable, with Ne sometimes exceeding census size. Such low reliability in the genetic results should retain attention for conservation purposes.

Analysis of Variance↗

PubMed2000

The mating system and gene dynamics of plateau pikas.

Evolutionary theory suggests that mating systems should have substantial effects on gene dynamics of local populations. In polygynous species, local 'breeding groups' may produce significant genetic structure, due to genetic differences among groups, and rate of loss of genetic variation from such populations may be considerably slowed. We examined possible influences of the variable mating system and family group structure on genetic properties of a population of plateau pikas (Ochotona curzoniae). Pika gene dynamics were examined via F-statistics and effective population sizes (N(e)), calculated from genetic correlations within and among individuals and families. Genetic correlations were estimated from mating patterns, population demography, and dispersal patterns. Substantial genetic structure within the population was indicated by a strongly positive F(LS). Genetic influence of natal dispersal out of pika families was indicated by a strongly negative inbreeding statistic (F(IL)=-0.34). Effective size of the population was not greatly different from the census population, whereas a traditional estimate of effective size of the population was much lower, indicating that the family structure of the pikas results in a slowed loss of genetic variation over time. Thus, even though mating patterns of plateau pikas were variable, family structure had a strong influence on pika gene dynamics.

Journal Article↗

PubMed2001

The genetic mating system and tests for cuckoldry in a pipefish species in which males fertilize eggs and brood offspring externally.

Highly variable microsatellite loci were used to study the mating system of Nerophis ophidion, a species of pipefish in which pregnant males carry embryos on the outside of their body rather than in an enclosed brood pouch. Despite this mode of external fertilization and brooding, otherwise rare in the family Syngnathidae, the genotypes of all embryos proved to be consistent with paternity by the tending male, thus indicating that cuckoldry by sneaker males is rare or nonexistent in this species. N. ophidion is a phylogenetic outlier within the Syngnathidae and its reproductive morphology is thought to be close to the presumed ancestral condition for pipefishes and seahorses. Thus, our genetic results suggest that the evolutionary elaboration of the enclosed brood pouch elsewhere in the family was probably not in response to selection pressures on pregnant males to avoid fertilization thievery. With regard to maternity assignments, our genotypic data are consistent with behavioural observations indicating that females sometimes mate with more than one male during a breeding episode, and that each male carries eggs from a single female. Thus, the polyandrous genetic mating system in this species parallels the social mating system, and both are consistent with a more intense sexual selection operating on females, and the elaboration of secondary sexual characters in that gender.

Animals↗

PubMed2000

Molecular ecology and biological control: the mating system of a marsupial pest.

Many studies in molecular ecology have focused on the use of repeat DNA markers to determine the nature of mating systems in a wide variety of animal species. Whilst these studies typically have focused on important issues such as the evolutionary consequences of fitness variation among males, genetic studies of mating systems are potentially also important because they can generate information of significance to wider issues in wildlife management. For example, genetically modified, sexually transmitted viral diseases have been suggested as potential agents for the control of vertebrate pest species. An understanding of the epidemiology of such agents requires an intimate knowledge of the sexual contact rates between individuals of the target species. Here, we report the use of minisatellite DNA profiling to reveal the mating system in two New Zealand populations of the introduced Australian brushtail possum. The brushtail possum is New Zealand's most important mammalian pest and a species for which control by a sexually transmitted immunocontraceptive has been proposed. Encouragingly, we report considerable variation in the reproductive success of males at both study sites, with one male siring offspring from four females in one year (mean no. of offspring/reproductively successful male/year at the two sites is 1.95-2.15), while many sired none. This bias in the pattern of reproductive success among males will probably facilitate the spread of an immunocontraceptive agent and thereby increase the power of this approach to biological control.

Animals↗

PubMed2000

Lek mating systems: a case study in the Little Bustard Tetrax tetrax.

Leks have recently been defined as male display aggregations that females attend primarily for the purpose of mating. This is an extended version of previous definitions, as a clear-cut definition of leks is difficult to obtain. Four criteria should be verified to identify a lekking species: (i) there is no male parental investment beyond the sperm; (ii) males aggregate at specific sites for display; (iii) the only resource females find on the lek is the male, i.e. the male genes; (iv) females can select her mate(s), although the necessity of this latter condition for lekking species has been highly debated. We applied these criteria to the endangered little bustard Tetrax tetrax, a species that is claimed to show an exploded lek mating system, but for which this has never been fully investigated. We monitored a population of little bustards in western France during 2 years to investigate the two central criteria in the assessment of their mating system: male aggregation in arenas and lack of consistent resources in male territories. We analysed the spatial distribution of little bustard male territories, the individual variation in size, and the land use characteristics of male territories, with particular attention to the habitats that may be considered as defensible resources. Displaying males showed an aggregated spatial distribution over the study area during the 2 years of survey. Male territories were rather large (19+/-16 ha), but a large among-male variability in territory size was observed. Land use within the territories included mainly permanent and semi-permanent crops. The variability in land use among territories suggests also that resources found within male territories were selected according to male needs (food and display) rather than to female needs (permanent crops that are more appropriate for reproduction). The mating system of the little bustard seems to match the general (and extended) definition of leks, at least in some populations. However, limits between resource defence polygyny and extreme exploded or resource-based leks are thin and unclear, and the little bustard is a good example of how lek definitions may be difficult to apply in non clear-cut empirical situations.

Journal Article↗

PubMed2003

Mating system and the evolution of sex-specific mortality rates in two nymphalid butterflies.

Life-history theory predicts that organisms should invest resources into intrinsic components of lifespan only to the degree that it pays off in terms of reproductive success. The benefit of a long life may differ between the sexes and different mating systems may therefore select for different sex-specific mortality rates. In insects with polyandrous mating systems, females mate throughout their lives and male reproductive success is likely to increase monotonously with lifespan. In monandrous systems, where the mating season is less protracted because receptive females are available only at the beginning of the flight season, male mating success should be less dependent on a long lifespan. Here, we show, in a laboratory experiment without predation, that the duration of the mating season is longer in the polyandrous comma butterfly, Polygonia c-album, than in the monandrous peacock butterfly, Inachis io, and that, in line with predictions, male lifespan is shorter than female lifespan in I. io, whereas male and female lifespans are similar in P. c-album.

Aging↗

PubMed2004

The effects of mating system and genetic variability on susceptibility to trematode parasites in a freshwater snail, Lymnaea stagnalis.

The amount and distribution of genetic variability in host populations can have significant effects on the outcome of host-parasite interactions. We studied the effect of mating system and genetic variability on susceptibility of Lymnaea stagnalis snails to trematode parasites. Mating system of snails from eight populations differing in the amount of genetic variability was manipulated, and self- and cross-fertilized offspring were exposed to naturally occurring trematode parasites in a controlled lake experiment. Susceptibility of snails varied between populations, but mating-system treatment did not have a significant effect. Heterozygosity of snails was negatively correlated with the probability of trematode infection, however, suggesting that parasitic diseases may pose a serious threat to populations lacking genetic variability.

Analysis of Variance↗

PubMed2007

Mating system of Brazilian Oryza glumaepatula populations studied with microsatellite markers.

BACKGROUND AND AIMS: A knowledge of natural populations' breeding systems is important in order to implement in situ and ex situ management and conservation practices. Using microsatellite markers, three Oryza glumaepatula populations from Brazil were studied to determine the breeding system and genetic structure parameters of this species. METHODS: Each population represented by ten families with ten individuals per family was studied using eight microsatellite primers. Families of the Rio Xingu population (XI) were obtained from the greenhouse, whereas families from Rio Solimoes (SO) and Rio Paraguay (PG) were collected from the wild. Amplified products electrophoresed on non-denaturing polyacrylamide gels were visualized with a silver staining procedure. The mating system parameters were analysed based on the mixed mating model (software MLTR) while genetic structure analyses of the three populations and their families were performed using the FSTAT software. KEY RESULTS: The mean numbers of alleles per loci were 2.5, 3.9 and 2.5, respectively for the XI, PG and SO populations. Compared with their families, higher values for the observed heterozygosity and gene diversity were estimated for the parental populations. The subdivision (based on R(ST)) and inbreeding (F(IS)) in the SO and PG populations had similar effects, while inbreeding was the main effect in the families. Multilocus outcrossing rates varied from 0.011 to 0.223 in the three populations, indicating divergence in the outcrossing rates among O. glumaepatula populations. For the species (considering SO and PG populations together) an intermediate value was observed (tm = 0.116). Biparental inbreeding varied from 0.008 to 0.123, contributing to the selfing rate in these populations. More than 50 % of the outcrossing occurred between related individuals. CONCLUSIONS: The results indicated divergence in the mating system among O. glumaepatula populations, with consequences for conservation practices. The mating system of this species was classified as mixed with a predominance of self-fertilization.

Brazil↗

PubMed2004

Water turbidity by algal blooms causes mating system breakdown in a shallow-water fish, the sand goby Pomatoschistus minutus.

Eutrophication as a result of human activity has resulted in increased algal blooms and turbidity in aquatic environments. We investigated experimentally the effect of algal turbidity on the mating system and sexual selection in the sand goby, Pomatoschistus minutus (Pallas), a marine fish with a resource-defence mating system and paternal care. Owing to male-male competition and female choice, large males can monopolize multiple mates, while some males do not achieve mating at all. We show that the number of eggs laid was the same in both turbid and clear tanks but that mating success was more evenly distributed among males in turbid than in clear water. The opportunity for sexual selection was lower in turbid conditions. In turbid conditions mating success was less skewed towards large males. Our results suggest that increased turbidity can change mating systems and decrease the opportunity for sexual selection as well as selection intensity.

Animals↗

PubMed1999

Mating system of Microcebus murinus.

Microcebus murinus, a small nocturnal lemur from Madagascar, has retained features of ancient primates. Based on these ancestral traits, its social organization has often been used as a model for early primate social systems. In captivity it breeds polygynously, i.e., one male mates with several females, while females usually copulate only with the dominant male. The present project tested whether or not sexual size dimorphism, spatial distribution, and relative testis size of M. murinus correspond with predictions of the sexual selection theory concerning polygynous mating systems. The study was combined with a mark-recapture study and radio tracking of 12 animals in 1993 in a dry deciduous forest of western Madagascar at the end of the dry season. Large overlapping home ranges in males, lack of sexual size dimorphism, and relatively large testes suggest a multi-male mating system, i.e., one that is promiscuous rather than polygynous.

Adaptation, Biological↗

PubMed2004

Primate mating systems and the evolution of immune response.

White blood cell (WBC) and red blood cell (RBC) counts were examined in a sample comprising 762 specimens, representing 25 genera and 38 species of captive non-human primates. Animals suffering from illnesses exhibited higher WBC counts than healthy specimens sampled during routine health checks. Analysis of basal WBC counts in healthy animals confirmed a positive correlation between higher cell counts and occurrences of multiple partner mating. This finding remained statistically significant after use of comparative analysis of independent contrasts (CAIC) to control for possible phylogenetic biases in the dataset. These findings were confirmed when using relative testis size as an independent index of mating system. By contrast, RBC counts were not significantly affected by health or correlated with mating systems. These studies confirm a correlation between WBC counts and primate mating systems, and extend the findings to include a positive correlation between WBC counts and relative testis size. However, the findings do not prove that a causal relationship between these variables exists. Further research is required to establish the evolutionary causation of basal WBC counts in primates.

Animals↗

PubMed2000

Sexually transmitted diseases in polygynous mating systems: prevalence and impact on reproductive success.

Studies of disease in relation to animal mating systems have focused on sexual selection and the evolution of sexual reproduction. Relatively little work has examined other aspects of ecological and evolutionary relationships between host social and sexual behaviour, and dynamics and prevalence of infectious diseases; this is particularly evident with respect to sexually transmitted diseases (STDs). Here, we use a simulation approach to investigate rates of STD spread in host mating systems ranging from permanent monogamy to serial polygyny or polyandry and complete promiscuity. The model assumes that one sex (female) is differentially attracted to the other, such that groups of varying size are formed within which mating and disease transmission occur. The results show that equilibrium disease levels are generally higher in females than males and are a function of variance in male mating success and the likelihood of a female switching groups between mating seasons. Moreover, initial rates of disease spread (determining whether an STD establishes in a population) depend on patterns of host movement between groups, variance in male mating success and host life history (e.g. mortality rates). Male reproductive success can be reduced substantially by a sterilizing STD and this reduction is greater in males that are more 'attractive' to females. In contrast, females that associate with more attractive males have lower absolute fitness than females associating with less attractive males. Thus, the potential for STDs to act as a constraint on directional selection processes leading to polygyny (or polyandry) is likely to depend on the details of mate choice and group dynamics.

Animals↗

PubMed2006

Impact of mating systems on patterns of sequence polymorphism in flowering plants.

A fundamental challenge in population genetics and molecular evolution is to understand the forces shaping the patterns of genetic diversity within and among species. Among them, mating systems are thought to have important influences on molecular diversity and genome evolution. Selfing is expected to reduce effective population size, Ne, and effective recombination rates, directly leading to reduced polymorphism and increased linkage disequilibrium compared with outcrossing. Increased isolation between populations also results directly from selfing or indirectly from evolutionary changes, such as small flowers and low pollen output, leading to greater differentiation of molecular markers than under outcrossing. The lower effective recombination rate increases the likelihood of hitch-hiking, further reducing within-deme diversity of selfers and thus increasing their genetic differentiation. There are also indirect effects on molecular evolutionary processes. Low Ne reduces the efficacy of selection; in selfers, selection should thus be less efficient in removing deleterious mutations. The rarity of heterozygous sites in selfers leads to infrequent action of biased conversion towards GC, which tends to increase sequences' GC content in the most highly recombining genome regions of outcrossers. To test these predictions in plants, we used a newly developed sequence polymorphism database to investigate the effects of mating system differences on sequence polymorphism and genome evolution in a wide set of plant species. We also took into account other life-history traits, including life form (whether annual or perennial herbs, and woody perennial) and the modes of pollination and seed dispersal, which are known to affect enzyme and DNA marker polymorphism. We show that among various life-history traits, mating systems have the greatest influence on patterns of polymorphism.

Evolution, Molecular↗

PubMed2001

Different types of oestrous cycle in two closely related South American rodents (Cavia aperea and Galea musteloides) with different social and mating systems.

A comparative approach was used to investigate two closely related South American rodent species: the wild cavy (Cavia aperea) and the yellow-toothed cavy (Galea musteloides). These species of wild guinea-pig inhabit different habitats and show divergent social and mating systems. Cavia have a polygynous mating system, whereas in Galea promiscuous mating occurs. These observations correspond to functional variations in sperm characteristics, which might be interpreted as adaptations to different reproductive patterns in the females of both species. Twenty-two female C. aperea and G. musteloides (11 of each species) were investigated to elucidate differences in the characteristics of the oestrous cycles. The experimental design consisted of three stages, in which the degree of contact between the sexes was successively changed. During these stages, the reproductive cycle of the females was monitored by examining the condition of the vaginal closure membrane, analysing vaginal smears and determining serum concentrations of oestrogens and progesterone. The results revealed different types of oestrous cycle in the two species. Female C. aperea showed periodical cycles with spontaneously occurring oestrous periods, ovulation and corpus luteum activity. In contrast, in female G. musteloides, oestrus was exclusively induced by the presence of a male. However, after the induction of oestrus, ovulation and corpus luteum activity occurred spontaneously without stimuli from copulation. To date this type of oestrous cycle has not been described for any other mammalian species. Thus, these data indicate that differences in the reproductive patterns of the females may have shaped the evolution of different sperm characteristics in the males.

Animals↗

PubMed2005

Reproductive compensation in the evolution of plant mating systems.

Reproductive compensation, the replacement of dead embryos by potentially viable ones, is known to play a major role in the maintenance of deleterious mutations in mammalian populations. However, it has received little attention in plant evolution. Here we model the joint evolution of mating system and inbreeding depression with reproductive compensation. We used a dynamic model of inbreeding depression, allowing for partial purging of recessive lethal mutations by selfing. We showed that reproductive compensation tended to increase the mean number of lethals in a population, but favored self-fertilization by effectively decreasing early inbreeding depression. When compensation depended on the selfing rate, stable mixed mating systems can occur, with low to intermediate selfing rates. Experimental evidence of reproductive compensation is required to confirm its potential importance in the evolution of plant mating systems. We suggest experimental methods to detect reproductive compensation.

Biological Evolution↗