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. Am. J. Primatol. 48:127–133, 1999. © 1999 Wiley‐Liss, Inc.     

Mating system shifts on the trailing edge

BACKGROUND: The trailing edges of species ranges are becoming a subject of increasing interest as the environment changes due to global warming. Trailing edge populations are likely to face extinction because of a decline in numbers and an inability to evolve new adaptations with sufficient speed. Discussions of character change in the trailing edge have focused on physiological, exomorphic and phenological traits. The mating pattern within populations has not been part of the discourse, in spite of the fact that the mating pattern may affect the ability of populations to respond to environmental change and to maintain their sizes. In this paper, the case is made that a substantial increase in self-fertilization rates may occur via plastic responses to stress. SCOPE AND CONCLUSIONS: Small populations on the trailing edge are especially vulnerable to environmental change because of inadequate levels of cross-fertilization. Evidence is presented that a deficiency of cross-seed production is due to inadequate pollinator services and a paucity of self-incompatibility alleles within populations. Evidence also is presented that if plants are self-compatible, self-fertilization may compensate in part for this deficiency through a stress-induced increase in levels of self-compatibility and stress-induced alterations in floral morphology that elevate self-pollination. Whereas increased self-fertility may afford populations the time to adapt to their changing environments, it can be concluded that increased selfing is not a panacea for the ills of environmental change, because it will lead to substantial reductions in genetic diversity, which may render adaptation unlikely.     

Mating system and laying date in birds

The hypothesis that polygynous species start breeding later in the season than monogamous ones was examined using two data sets, each with both monogamous and polygynous species—the eight species of wrens which breed in the USA, and five genera (15 species) of British passerines. Comparisons were made within each of 16 states in the USA from which data were available and for each genus in Britain. The hypothesis is supported for most subsets of data, but in some cases polygynous and monogamous species start breeding at the same time (but in no case do polygynous breed earlier than monogamous species). The late breeding of the polygynous species is probably an outcome of the fact that polygynous males tend to participate less in nest activities than monogamous ones.     

Mating system and brain size in bats

The contribution of sexual selection to brain evolution has been little investigated. Through comparative analyses of bats, we show that multiple mating by males, in the absence of multiple mating by females, has no evolutionary impact on relative brain dimension. In contrast, bat species with promiscuous females have relatively smaller brains than do species with females exhibiting mate fidelity. This pattern may be a consequence of the demonstrated negative evolutionary relationship between investment in testes and investment in brains, both metabolically expensive tissues. These results have implications for understanding the correlated evolution of brains, behaviour and extravagant sexually selected traits.     

Sexual selection and the mating system of Argusianus argus (Aves: Phasianidae)

A study of the Great Argus pheasant Argusianus argus is described. Cleared display sites are owned each by a single male which calls to attract females, while other adult and subadult males maintain no such sites. Evidence is presented to show that vocal differences between males at display sites are slight and unstable, and are therefore unlikely to be used by females in mate choice. No evidence was obtained to suggest that females wander from display site to site and mate with the best male chosen by visual comparison of subtle plumage variation, although the classical assumption has been that such choice accounts for the evolution of the males' extravagant plumage. Females may by chance meet males without display sites at random in the forest, but the displays of such males are probably insufficiently stimulating to induce the female to copulate. Choice between males with or without display sites, on gross plumage and display differences, provides an alternative explanation for the evolution of the males' plumage.     

Mating system of the meadow vole, Microtus pennsylvanicus

Previous studies on parental and spacing behavior of Microtuspennsylvanicus suggest a promiscuous mating system, but attemptsto find multiple paternity in single litters have been unsuccessful.In this paper we present evidence of multiple paternity in singlelitters conceived in the wild early in the breeding season.The proportion of litters sired by multiple males was estimated,by a conservative method, to be 33.1%.We argue that the presenceof promiscuity, rather than polygyny, in M. pennsylvanicus isthe result of two factors. First, overwintered breeding malesare similar in age and size, resulting in small variation incompetitive ability among males. This reduced variation in competitiveability reduces the possibility that some males defend severalfemales and others defend none. Second, the habitat structureof the meadow vole makes it difficult for a male to detect othermales nearby, and this reduces the possibility that one maleexcludes others from mating when a female comes into estrus.     

Mating system of the lefteye flounder,Engyprosopon grandisquama

Underwater observations were conducted on the reproductive behavior and mating system of the lefteye flounder,Engyprosopon grandisquama, off Nagashima, southwest of Kyushu Island, Japan. Two types of males were found: large males, which defended territories against other large males, and small males, which did likewise but only against smaller males. Large males established territories which encompassed or ovelapped the home ranges of 1 or 2 cohabitant females. Territories of the small males, in which a smaller female often maintained a home range, overlapped those of large males. Pair spawning occurred around sunset. Mating of large males with cohabitant females was observed 36 times and that of a small male with a smaller female once. Pair formation was assorted by body size, paired males being larger than females in most cases. Thus, inE. grandisquama, gigamous large males were common, small males occurring within the former's erritorial boundaries mating with smaller females.     

Mating system variation in the hermaphroditic brooding coral, Seriatopora hystrix

Self-compatible, hermaphroditic marine invertebrates have the potential to self-fertilize in the absence of mates or under sperm-limited conditions, and outcross when sperm is available from a variety of males. Hence, many hermaphroditic marine invertebrates may have evolved mixed-mating systems that involve facultative self-fertilization. Such mixed-mating strategies are well documented for plants but have rarely been investigated in animals. Here, I use allozyme markers to make estimates of selfing from population surveys of reef slope and reef flat sites, and contrast this with direct estimates of selfing from progeny-array analysis, for the brooding coral Seriatopora hystrix. Consistent heterozygote deficits previously reported for S. hystrix suggests that inbreeding (including the extreme of selfing) may be common in this species. I detected significant levels of inbreeding within populations (F(IS)=0.48) and small but significant differentiation among all sites (F(ST)=0.04). I detected no significant differentiation among habitats (F(HT)=0.009) though among site differentiation did occur within the reef slope habitat (F(SH)=0.06), but not within the reef flat habitat (F(SH)=0.015). My direct estimates of outcrossing for six colonies and their progeny from a single reef flat site revealed an intermediate value (t(m) (+/-s.d.)=0.53+/-0.20). Inbreeding coefficients calculated from progeny arrays (F(e)=0.31) were similar to indirect estimates based on adult genotype frequencies for that site (F(IS)=0.38). This study confirms that the mating system of this brooding coral is potentially variable, with both outcrossing and selfing.     

Mating system and genetic variation in the endangered New Zealand takahe

The takahe (Porphyrio hochstetteri) is ahighly endangered flightless rail that isendemic to New Zealand. Only one remnantpopulation of takahe (120 adults) is left inthe wild in Fiordland, which has been thesource for introductions to four predator-freeislands. The objective of the present studywas to determine the mating system andamount of genetic variation in takahe usingmultilocus DNA profiling, in order to assist inthe management of the island populations. There was no evidence of extra-pair paternityfor the 27 (73%, n = 37) offspring towhich paternity could be resolved. Thepaternity of the remaining 10 offspring couldnot be resolved due to low levels ofminisatellite DNA variation, but in none wasthe resident male excluded. Overall, the DNAresults along with behavioral and life historyinformation indicate that extra-pairfertilizations should be rare or absent, andtakahe join a small but growing list oflong-lived species of birds that have beenshown to exhibit genetic monogamy. Inaddition, the levels of minisatellite DNAvariation detected in takahe are low relativeto those reported for most other known outbredavian populations, and are consistent with theevidence of the takahe's persistence as asmall, isolated population in Fiordland over atleast the last 100 years. The low geneticvariation is discussed in relation to possibleevidence of environment depended inbreedingdepression in translocated island populationsof takahe.     

Mating system and population structure in the desert ant Cataglyphis livida

We investigated population genetic structure, mating system, worker reproduction and thelytokous parthenogenesis in the desert ant Cataglyphis livida. Pedigree analyses at polymorphic microsatellite loci show that colonies are headed by a single queen, and that queens are mated with two to eight males. No inbreeding was found in the population sampled. Colonies are genetically differentiated and exhibit no isolation-by-distance pattern, consistent with independent foundation of new colonies. Workers do reproduce and lay haploid (arrhenotokous) eggs in queenless colonies; conversely, we found no evidence of worker reproduction in queenright nests. In contrast with C. cursor, where new queens are produced by thelytokous parthenogenesis, female sexuals and workers of C. livida arise from classical sexual reproduction. We discuss the parallels and contrasts between the mating system and population structure in C. livida and the other Cataglyphis species studied so far.     

Mating system shifts and transposable element evolution in the plant genus Capsella

Background

Despite having predominately deleterious fitness effects, transposable elements (TEs) are major constituents of eukaryote genomes in general and of plant genomes in particular. Although the proportion of the genome made up of TEs varies at least four-fold across plants, the relative importance of the evolutionary forces shaping variation in TE abundance and distributions across taxa remains unclear. Under several theoretical models, mating system plays an important role in governing the evolutionary dynamics of TEs. Here, we use the recently sequenced Capsella rubella reference genome and short-read whole genome sequencing of multiple individuals to quantify abundance, genome distributions, and population frequencies of TEs in three recently diverged species of differing mating system, two self-compatible species (C. rubella and C. orientalis) and their self-incompatible outcrossing relative, C. grandiflora.

Results

We detect different dynamics of TE evolution in our two self-compatible species; C. rubella shows a small increase in transposon copy number, while C. orientalis shows a substantial decrease relative to C. grandiflora. The direction of this change in copy number is genome wide and consistent across transposon classes. For insertions near genes, however, we detect the highest abundances in C. grandiflora. Finally, we also find differences in the population frequency distributions across the three species.

Conclusion

Overall, our results suggest that the evolution of selfing may have different effects on TE evolution on a short and on a long timescale. Moreover, cross-species comparisons of transposon abundance are sensitive to reference genome bias, and efforts to control for this bias are key when making comparisons across species.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-602) contains supplementary material, which is available to authorized users.     

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.     

Mating system variation and morph fluctuations in a polymorphic lizard

In polymorphic male painted dragon lizards (Ctenophorus pictus), red males win staged contests for females over yellow males, and yellow males have greater success in staged sperm competition trials than red males. This predicts different reproductive strategies in the wild with red males being more coercive or better mate guarders than yellow males. Yellow males would be expected to sire more offspring per copulation and have a greater proportion of offspring from clutches with mixed paternity. However, here we show using microsatellites that the frequency of mixed paternity in the wild is low (< 20% on average across years), that all morphs on average have the same number of offspring sired per year, and that mating system variation (polyandry vs. monandry) is strongly correlated with perch density on male territories. Furthermore, a logistic regression on male successful vs. unsuccessful mate acquisition showed that red males were under negative selection when they dominated the population, which suggests ongoing frequency dependent selection on male colouration.     

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.     

Keratan-sulphate-containing proteoglycans in human osteochondrophytic spurs of the femoral head

Newly synthesized and endogenous proteoglycan was isolated from human femoral head osteochondrophytic spurs. 35SO4-containing keratan sulphate was measured by its susceptibility to endo-beta-D-galactosidase (keratanase) and comprised 15-17% of the two subpopulations of a proteoglycan monomer fraction (D1) resolved by Sepharose CL-2B chromatography (Kav (I), 0.22; (II), 0.78). The size of the newly synthesized keratan sulphate in these fractions was large (Mr greater than 7,000). The hydroxylamine cleavage product of a proteoglycan aggregate fraction (A1) which eluted in the void volume of a Sepharose CL-2B column was immunoreactive with an anti-keratan sulphate monoclonal antibody, 5-D-4. Unlike the proteoglycan aggregate A1 fraction from bovine nasal cartilage, immunoreactivity against 5-D-4 was also found in chromatographic fractions retarded by Sepharose CL-2B. These results lend additional support to our assertion that the osteophyte extracellular matrix consists of hyaline cartilage-type proteoglycan. Stimulation of osteophyte proliferation may be useful as a repair mechanism for resurfacing denuded areas of osteoarthritic femoral heads.     

Mating system and pollen gene flow in Mediterranean maritime pine

Mating systems define the mode of gene transmission across generations, helping to determine the amount and distribution of genetic variation within and among populations of plant species. A hierarchical analysis of Mediterranean maritime pine mating system (61 mother trees from 24 plots, clustered in three populations) was used to identify factors affecting mating patterns and to fit pollen dispersal kernels. Levels of ovule and seed abortion, multi- and single-locus outcrossing rates and correlated paternity were estimated from progeny arrays and correlated with ecological stand variables and biometric tree measures. Pollen dispersal kernels were fitted using TwoGener and KinDist indirect methods and simulations were carried out to identify relevant factors affecting correlated paternity. Maritime pine showed high outcrossing rates (t(m) and t(s) approximately 0.96) and relatively low levels of correlated paternity [an r(p) of 0.018 (Ritland's estimate) or 0.048 (Hardy's estimate)], although higher than in other anemophilous tree species. Mating system parameters had high variation at the single-tree level (99-100%) but no stand or population effect was detected. At the single-tree level, outcrossing rates were correlated with tree (diameter and height) and crown size. In addition, correlated paternity showed a significant negative correlation with tree height, height to crown base and height to the largest crown width, probably reflecting the importance of the trees' 'ecological neighborhoods'. Indirectly estimated pollen dispersal kernels were very leptokurtic (exponential-power distributions with beta<0.5), with mean dispersal distances from 78.4 to 174.4 m. Fitted dispersal kernels will be useful in building explicit simulation models that include dispersal functions, and which will contribute to current conservation and management programs for maritime pine. Nevertheless, the numerical simulations showed that restricted dispersal, male fertility and phenological overlap could only partially explain the observed levels of correlated paternity; so other factors may also be relevant for the management of this valuable forest tree species.     

Mating system and reproductive success in eastern Pacific harbour seals

Harbour seals sometimes breed along inland travel corridors where females become clustered in space and time and males establish underwater acoustic display territories similar to terrestrial arenas known as resource-based leks. Under these conditions, we predicted that higher levels of polygyny would be observed than has been previously reported for this species mating in open coast environments without travel corridors. Reproductive success (RS) of 70 males was measured using 20 microsatellite DNA loci and likelihood-based paternity analysis of 136 offspring collected over 3 years. Most males were assigned either zero or one paternity with 80% confidence. The greatest number of pups assigned to one male in a season was two. Variance in RS was higher for males than females (which are biologically limited to one offspring per year) indicating low to mild polygyny. In addition, distributions of relatedness values among pups within year classes did not differ significantly from a simulated distribution with R = 0, indicating that half-siblings were uncommon. Overall, polygyny levels were low relative to terrestrial pinniped mating systems and similar to observations from a harbour seal population along an open coast. Due to large confidence intervals associated with our results, we cannot rule out the hypothesis that a travel corridor might increase the degree of polygyny skew relative to that observed in open coast environments. Habitat appeared to influence male strategies as the most successful males in open coast environments patrolled offshore, while the most successful male in this study defended a territory along the travel corridor.     

Neuronal correlates of the activation of the brain-reinforcing system in dogs

In analysis of neuronal activity of g. proreus of dogs brain in response to positive and differentiation conditioned cutaneous stimuli, in 44% of 78 studied neurons "late responses" appeared in the form of impulse activity intensification elicited by a positive conditioned stimulus after the end of eating and by a differentiation one--during conditioned signal action; it persisted in different neurones for 30--60 s. By means of various functional tests it has been shown that these reactions are a neurophysiological correlate of animals emotional state gradient.     

雉科8种中央尾羽分类特征探究

观察348个标本的中央尾羽,测量其性状并统计,结果表明:1)雉科8种中央尾羽色斑格局不相同:2)中央尾羽长、内翈宽、外翈宽都存在显著差异(P<0.05),以白冠长尾雉中央尾羽(118,3±18,89)cm最长,内翈(2.44±0.21)cm最宽,以红腹锦鸡外翈(2.80±0.82)cm最宽,而灰胸竹鸡的中央尾羽(9.51±0.78)cm最短,内翈(1.02±0.13)cm和外嘲(0.99±0.10)cm最窄.以上有助于分辨雉科此8种鸟类.