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Mating Pairs (mating + pair)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Scent-Marking of Giant Otter in the Southern Pantanal, Brazil

ETHOLOGY, Issue 3 2009
Caroline Leuchtenberger
Giant otters live in social groups, consisting of a mating pair and one or two litters. Groups are territorial and mark their territories often with scent-marks. Our objectives were to evaluate the frequencies of marking and over-marking according to the social status of the individuals and to define the different postures used during the marking. We observed four groups, totaling 25 individuals (five alpha males, four alpha females, seven adult females, one adult male and eight juveniles) with group size ranging between four and 13 individuals. The study was conducted between July 2006 and July 2007 in the Vermelho River and in a stretch of the Miranda River, in the Southern Pantanal. We observed the groups for a total of 2006 min and recorded 95 events of marking totaling 84.9 min. Time spent marking varied between groups and ranged from 4.3 to 44.7 min. The alpha males marked more frequently (62% of marking events, 55 min) than the alpha females (17% of marking events, 13.6 min). Of the 59 events of scent-marking by the alpha males, 32 over-marked the marks of other individuals from the group. Of the 16 events of scent-marking of the alpha females, five over-marked that of other females from the same group. When scent-marking, alpha males used the ,stepping' posture most frequently (63%), then ,fore-paw rubbing' (24%), ,latrine use' (7%), and ,body rubbing' (6%). Alpha females used the ,stepping' posture most frequently (65%), then ,latrine use' (19%) and ,fore-paw rubbing' (12%), with only one event of ,body rubbing' observed during marking. Subordinate females used the ,stepping' posture (76%) and ,latrine use' (24%) during marking. Scent-marking can play many roles in mammals and for giant otters, and the main roles appear to be communication of social and sexual status and territorial defense. [source]

Conjugative DNA metabolism in Gram-negative bacteria

FEMS MICROBIOLOGY REVIEWS, Issue 1 2010
Fernando De La Cruz
Abstract Bacterial conjugation in Gram-negative bacteria is triggered by a signal that connects the relaxosome to the coupling protein (T4CP) and transferosome, a type IV secretion system. The relaxosome, a nucleoprotein complex formed at the origin of transfer (oriT), consists of a relaxase, directed to the nic site by auxiliary DNA-binding proteins. The nic site undergoes cleavage and religation during vegetative growth, but this is converted to a cleavage and unwinding reaction when a competent mating pair has formed. Here, we review the biochemistry of relaxosomes and ponder some of the remaining questions about the nature of the signal that begins the process. [source]

Timing of sperm transfer in Diacamma pallidum

PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2007
DIANE ALLARD
AbstractDiacamma species (Hymenoptera, Formicidae) differ from other ants by the extremely long duration of copulation. By using histological sections through mating pairs of Diacamma pallidum (F. Smith), it is demonstrated that the transfer of sperm to the female genital tract only takes 2 min and is completed quickly after the onset of copulation, although the male and female will remain connected for many hours. Next to the two traditional hypotheses of mate guarding and mate manipulation commonly invoked to explain prolonged copulations, a new hypothesis is proposed linked to the interference of the nestmate workers with the mating pair, and suggestions for further research are given. [source]

Why are Male Columbian Ground Squirrels Territorial?

ETHOLOGY, Issue 11 2008
Theodore G. Manno
Male territorial defence is a component of many vertebrate mating systems and is often regarded as a tactic for acquiring mates. Traditionally considered within the context of overt site-specific defence, territoriality actually may have several components which encompass a variety of behavioural tactics (e.g. post-copulatory mate-guarding, defence of resources that females need, defence of area around females) that underlie a mating system. The purpose of our study was to evaluate such influences on the territorial behaviour of male Columbian ground squirrels in southwestern Alberta, Canada. Males were dominant and territorial if they defended a minimum convex polygon activity range by chasing other males more within the activity range than they were chased. Subordinate males had no territory and were chased throughout their ranges, but they competed for mates by increasing chases in their activity range when nearby females were oestrous. Dominant males exhibited conditional breeding tactics, tending to chase other dominant males from their territory when nearby females were oestrous, but travelling outside their activity ranges to chase subordinate males when females were not oestrous. Although females mated first with a dominant male on whose territory they resided (and in order from oldest to youngest if several territories overlapped), mating pairs were not exclusive, as females usually mated with additional males. Males also guarded females after copulation and defended females directly just before oestrus, rather than defending territory per se during those times. Thus, males possess a repertoire of behaviours that complement site-specific territoriality, and territory ownership serves to facilitate a first mating with females that live on the territory. [source]

Morphological and Molecular Data Reveal the Presence of the Invasive Artemia franciscana in Margherita di Savoia Salterns (Italy)

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 6 2006
Graziella Mura
Abstract Introduced populations of the American invasive Artemiafranciscana have been reported in Mediterranean countries except for Italy. A recent sampling at Margherita di Savoia revealed the presence of mating pairs in a saltwork known to host only parthenogens. An integrated approach, based on scanning electron microscopy of four morphological traits, discriminant analysis of 13 morphometric characters and 16S rRNA PCR-RFLP profiles of eight endonucleases was implemented for the identification of the invader. Patterns of variability in all assayed markers provided congruent and solid evidence that the allochthonous species is A. franciscana. Native parthenogens are still predominant (,98.4%) in this Italian site but they can be rapidly outcompeted by A. franciscana, as it occurred in similar cases throughout Europe and elsewhere. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Sex-biased natal dispersal and inbreeding avoidance in American black bears as revealed by spatial genetic analyses

MOLECULAR ECOLOGY, Issue 21 2008
CECILY M. COSTELLO
Abstract We tested the hypothesis that sex-biased natal dispersal reduces close inbreeding in American black bears, a solitary species that exhibits nearly complete male dispersal and female philopatry. Using microsatellite DNA and spatial data from reproductively mature bears (, 4 years old), we examined the spatial genetic structure of two distinct populations in New Mexico from 1993 to 2000. As predicted, relatedness (r) and the frequency of close relationships (parent,offspring or full siblings) decreased with distance among female dyads, but little change was observed among male or opposite-sex dyads. Neighbouring females were more closely related than neighbouring males. The potential for inbreeding was low. Most opposite-sex pairs that lived sufficiently close to facilitate mating were unrelated, and few were close relatives. We found no evidence that bears actively avoided inbreeding in their selection of mates from this nearby pool, as mean r and relationship frequencies did not differ between potential and actual mating pairs (determined by parentage analysis). These basic patterns were apparent in both study areas despite a nearly two-fold difference in density. However, the sex bias in dispersal was less pronounced in the lower-density area, based on proportions of bears with male and female relatives residing nearby. This result suggests that male bears may respond to reduced competition by decreasing their rate or distance of dispersal. Evidence supports the hypothesis that inbreeding avoidance is achieved by means of male-biased dispersal but also indicates that competition (for mates or resources) modifies dispersal patterns. [source]

Timing of sperm transfer in Diacamma pallidum

Sperm transfer during mating in the pharaoh's ant, Monomorium pharaonis

PHYSIOLOGICAL ENTOMOLOGY, Issue 3 2006
D. ALLARD
Abstract Sperm transfer in the pharaoh's ant Monomorium pharaonis (L.) is studied by making longitudinal sections through the gasters of mating pairs fixed in copula. Sperm is transferred inside a spermatophore similar to those found in two other ants, Diacamma sp. from Japan and Carebara vidua. Sharp teeth-ridges are present on the penis valves and, during copulation, these teeth make contact with a thick and soft cuticular layer covering the bursa copulatrix. This ensures an attachment long enough for the successful transfer of the spermatophore to the right position inside the female oviduct. The thick cuticle also protects the queen from serious damage by the male's sharp claspers. After a first successful copulation, sperm is still present inside the male's seminal vesicles, suggesting that males can mate multiply. Additional experiments, where single, initially virgin males are presented to several virgin females, confirm this. [source]

Effect of mate selection on fuzzy selective mating criteria in closed dairy multiple ovulation and embryo transfer nucleus programs

ANIMAL SCIENCE JOURNAL, Issue 3 2002
Atsushi NAKAMURA
ABSTRACT In order to control rates of response and inbreeding, mate selection using fuzzy selective mating criteria (FMC) was investigated in adult multiple ovulation and embryo transfer nucleus schemes for dairy cattle. Stochastic simulation was used to model the closed nucleus scheme. This mate selection was examined in four alternative mating and male selection schemes: (i) a hierarchical scheme; (ii) a hierarchical sibship scheme (two males per sibship); (iii) a factorial scheme (two sires per dam); and (iv) a factorial sibship scheme (two males per sibship and two sires per dam). Genetic response and inbreeding rate tended to be reduced by increasing the trade-off parameter of FMC between the expected breeding value and inbreeding of progeny. Inbreeding rates in all schemes were reduced by reducing the variance of family size through selection and the average coancestry of mating pairs through mate allocation. [source]

Mating behaviour and alternative oviposition sites for male eggs in the heteronomous hyperparasitoid Coccophagus gurneyi Compere (Hymenoptera: Aphelinidae)

AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2001
GT Parkes
Abstract The aphelinid parasitoid Coccophagus gurneyi Compere has unusual sex-related host relationships. Females are diploid and develop internally within mealybugs Pseudococcus calceolariae (Maskell). Males, in contrast, are haploid and hyperparasitic, developing on primary parasitoid larvae within the mealybugs. Furthermore, males have been claimed to be capable of either internal or external development, depending on the precise site of deposition of the haploid egg. This diversity of developmental pathways could indicate the existence of a sibling-species complex. We therefore quantified the mating and ovipositional behaviour of C. gurneyi, for comparison with that of an undescribed sibling species. We also checked whether the females deposit male eggs in alternative sites. The pattern of mating was found to be typical of mating behaviour in Coccophagus spp. and was consistent among all mating pairs, suggesting that the colony comprised one species. Further, the mating behaviour was significantly different from that of the undescribed sibling species. The site of male egg deposition varied and is apparently dictated by two factors; whether the mealybug is parasitised and, if so, the size of the parasitoid it contains. If the mealybugs were unparasitised or if the parasitoids within the mealybugs were small (< 0.53 mm), male eggs were deposited within the mealybug haemocoel. If the parasitoids were large (> 1.05 mm), male eggs were deposited within the parasitoids. These results support the claim of alternate host relationships and developmental pathways within males of C. gurneyi. [source]