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Single Male (single + male)
Selected AbstractsMULTIVARIATE QUANTITATIVE GENETICS AND THE LEK PARADOX: GENETIC VARIANCE IN MALE SEXUALLY SELECTED TRAITS OF DROSOPHILA SERRATA UNDER FIELD CONDITIONSEVOLUTION, Issue 12 2004Emma Hine Abstract Single male sexually selected traits have been found to exhibit substantial genetic variance, even though natural and sexual selection are predicted to deplete genetic variance in these traits. We tested whether genetic variance in multiple male display traits of Drosophila serrata was maintained under field conditions. A breeding design involving 300 field-reared males and their laboratory-reared offspring allowed the estimation of the genetic variance-covariance matrix for six male cuticular hydrocarbons (CHCs) under field conditions. Despite individual CHCs displaying substantial genetic variance under field conditions, the vast majority of genetic variance in CHCs was not closely associated with the direction of sexual selection measured on field phenotypes. Relative concentrations of three CHCs correlated positively with body size in the field, but not under laboratory conditions, suggesting condition-dependent expression of CHCs under field conditions. Therefore condition dependence may not maintain genetic variance in preferred combinations of male CHCs under field conditions, suggesting that the large mutational target supplied by the evolution of condition dependence may not provide a solution to the lek paradox in this species. Sustained sexual selection may be adequate to deplete genetic variance in the direction of selection, perhaps as a consequence of the low rate of favorable mutations expected in multiple trait systems. [source] Notes on two species of the subgenus Lyrothorax Chaudoir (Coleoptera: Carabidae; genus Pterostichus), Pterostichus amagisanus Tanaka and Ishida and Pterostichus fujitai Tanaka and IshidaENTOMOLOGICAL SCIENCE, Issue 2 2009Kôji SASAKAWA Abstract Two species of the subgenus Lyrothorax Chaudoir (Coleoptera: Carabidae; genus Pterostichus), Pterostichus amagisanus Tanaka and Ishida and Pterostichus fujitai Tanaka and Ishida, were revised based on the male endophallus (inner sac everted from aedeagus). P. amagisanus was newly recorded based on a single male from Kyushu, southwest Japan, far from its known distribution (Honshu; the Fuji-Hakone-Izu volcano area), although additional materials are necessary to confirm this record. Despite a highly disjunct distribution, no conspicuous difference was recognized in either external or genital characters between the materials from Honshu and Kyushu. The nominal species P. fujitai was separated into two species, P. fujitai (Honshu) and Pterostichus eoyoritomus sp. nov. (Shikoku; type locality: Mount Jingayama); these two species have some significant differences in the endophallic structures. Character states in male genitalia suggest a sister relationship between P. eoyoritomus sp. nov. and Pterostichus yoritomus Bates. [source] Mating structure and male production in Vespa analis and Vespa simillima (Hymenoptera: Vespidae)ENTOMOLOGICAL SCIENCE, Issue 3 2007Jun-ichi TAKAHASHI Abstract We estimated queen mating frequency, genetic relatedness between workers and worker reproduction in the hornets Vespa analis and Vespa simillima using microsatellite DNA genotyping. The 20 V. analis colonies studied each contained a queen inseminated by a single male. Of the 15 V. simillima colonies studied, nine had a queen inseminated by a single male, four had a queen inseminated by two males, and two had a queen inseminated by three males. The estimated effective number of matings was 1.33 ± 0.74 (mean ± SD), with 75,85% of the offspring of the six multiply mated queens sired by single males. The values for genetic relatedness between the workers of V. analis and V. simillima were 0.739 ± 0.004 and 0.698 ± 0.013 (mean ± SD), respectively. We conclude that V. analis and V. simillima colonies are genetically monogynous and monandrous. When high relatedness between the workers occurs within colonies, kin selection theory predicts a potential conflict between queens and workers over male production. To determine whether males were derived from queens or workers, males from V. analis and V. simillima colonies were genotyped at four microsatellite loci and the level of ovary activation in workers was determined. None of the 787 V. analis workers and only 15 of 3520 V. simillima workers had developed ovaries. Furthermore, the genotyping identified no worker-produced males in any colony. The presence of reproductive workers correlated positively with the number of workers within the colony. These results suggest that eusocial colonies with an annual life cycle tend to break down socially when they become large and are close to dying. [source] Mating frequency and genetic relatedness of workers in the hornet Vespa analis (Hymenoptera: Vespidae)ENTOMOLOGICAL SCIENCE, Issue 3 2003Jun-ichi TAKAHASHI Abstract Mating frequency of Vespa analis queens and the genetic relatedness of their workers was analyzed by DNA microsatellite genotyping. Of 20 colonies studied, 18 had a queen inseminated by a single male and two had queens each inseminated by two males. The estimated effective number of matings was 1.05 ± 0.037 (mean ± SE), with 75,85% of the offspring of the two multiply mated queens sired by a single male. The pedigree relatedness between nestmate workers averaged over the 20 colonies was estimated to be 0.74 ± 0.008, almost identical to the predicted value of 0.75 for colonies headed by a singly mated queen. Multiple matrilines; that is, the presence of workers not related to the current queens, were detected in six colonies, suggesting that queen replacement occurred via usurpation of the founding queens in these six colonies. These results demonstrate that the kin structure of V. analis is similar to that reported in other vespid species. [source] Male Competition over Access to Females in a Spider with Last-Male Sperm PrecedenceETHOLOGY, Issue 5 2003Daniela Schaefer Agonistic behaviour between male cellar spiders (Pholcus phalangioides) was investigated to test whether (1) size difference determines which male achieves access to the female, (2) males are able to monopolize access to the female until egg laying and whether (3) female resource value increases before egg laying because of last-male sperm precedence. We further investigated whether (4) there is variation in time and energy spent on courtship and copulation depending on the degree of sperm competition, i.e. with or without rival present. In three experimental settings we introduced two males of either different or similar sizes, or a single male to a female. The mating units were constantly video-observed until the females produced their first egg sac. Experience, ownership and female resource value in terms of body size was controlled. Our results show that larger males achieve almost exclusive access to females. Size symmetrical settings resulted in increased fighting activity and duration but dominance did not influence mating success. If copulations were disturbed by the rival male, copulations were terminated earlier in symmetrical settings compared with asymmetrical settings. In 94.8% of trials only one copulation took place, suggesting that the copulating male successfully monopolized access to the female. Males confronted with a rival copulated longer but courted significantly shorter than lone males. Although the last male to copulate sires 88% of the offspring in P. phalangioides, neither fighting nor courtship activity increased before the female laid a batch of eggs. This suggests that males have no indication of the timing of oviposition. [source] Effects of Pair-Bond and Social Context on Male,Female Interactions in Captive Titi Monkeys (Callicebus moloch, Primates: Cebidae)ETHOLOGY, Issue 12 2000Eduardo Fernandez-Duque In monogamous species, an abiding relationship between a specific adult male and a specific adult female is a defining feature of the social system. The interactions between these individuals are influenced by many factors, including not only the history of their relationship (for example, development of a mutual bond), but also the immediate effects of the prevailing social context (for example, presence and sex of extra-pair conspecifics). In this study we examined the effects of an existing bond and of social context on interactions between adult heterosexual pairs of the monogamous titi monkeys (Callicebus moloch). Twelve adult males and 12 adult females were tested with their cagemates and with an unfamiliar partner of the opposite sex in five social contexts: (1) mated male,female pair; (2) unfamiliar pair; (3) single female; (4) single male; and (5) empty stimulus cage. Results show that mated pairs were more affiliative than unfamiliar pairs and differentiated social contexts more sharply. Males were more responsive to context than females. Distance between mates was less and physical contact was more frequent in the presence of male,female pairs or a single male, than in the presence of a single female or an empty cage. These findings suggest that the presence and sex of strangers have a stronger influence on male,female interactions when the pair has an existing relationship. [source] Factors influencing the evolution of clutch size in a gregarious insect parasitoidJOURNAL OF ANIMAL ECOLOGY, Issue 6 2000Tania Zaviezo Summary 1.,In this study we examined the clutch size of Hyssopus pallidus (Askew) (Hymenoptera, Eulophidae), a gregarious ectoparasitoid of codling moth (Lepidoptera, Tortricidae) larvae that is characterized by a host handling time of 2 days approximately. 2.,Clutch size increased asymptotically with host larval size (fresh weight) to a maximum of 32 eggs. A single male developed from each clutch, brood survival was 83% and pupal size of female offspring was 0·45 mg, all independent of clutch size. 3.,A comparison of the response of both experienced and naïve adult parasitoids to varying host larval size, indicated that experience was not necessary for H. pallidus to be able to accurately estimate host size. 4.,Clutch size increased by 50% for medium size host larvae (30,40 mg) and 83% for large host larvae (60,76 mg) when the encounter rate was reduced from one host every second day to one every seventh day. A significantly lower clutch size was produced on the last day at the highest encounter rate for large host larvae, suggesting exhaustion of the egg supply for H. pallidus. 5.,Manipulation of parasitoid clutch size on constant size host larvae did not influence sex ratio (single male) or brood survival (93%), but produced a linear trade-off between clutch size and the size (fresh weight) of female pupae. Longevity, lifetime fecundity, total number of hosts attacked, and clutch size all increased linearly with the adult size (female pupal weight). 6.,The observed clutch size in newly emerged H. pallidus is consistent with a strategy of maximizing lifetime fitness gain rather than the gain from individual hosts (Lack clutch size) despite a significant investment in the time required to attack each host. [source] Daily energy expenditure of singing great reed warblers Acrocephalus arundinaceusJOURNAL OF AVIAN BIOLOGY, Issue 4 2008Dennis Hasselquist According to honest signalling theory, signals must be costly to produce to retain information about the signaller's quality. The song produced by male birds during breeding is a vocal "ornament" used for intra- and inter-sexual purposes. The energetic cost of this vocal signal remains a contentious issue. We used the doubly labelled water method to measure field metabolic rate by estimating CO2 production and then convert this to daily energy expenditure (DEE) in great reed warbler males singing under natural conditions (10 at low to moderate intensity and 7 at very high intensity from dawn to dusk). There was a significant positive relationship between singing intensity and DEE. From this relationship we extrapolated the average DEE for intensely singing males (i.e., males producing song sounds 50% of the time and hence sitting at their elevated song post in the top of a reed stem more or less continuously throughout the ,20 h of daylight) to 3.3×BMR (basal metabolic rate) and for non-singing males to 2.2×BMR. The mean DEE measured for the seven males singing with very high intensity was 3.1×BMR. The maximum measured DEE for a single male was 3.9×BMR, i.e. close to the maximum sustainable DEE (4×BMR), and the minimum DEE was 2.1×BMR for a male singing at very low intensity. These results imply that producing intensive advertising song in birds may incur a substantial cost in terms of increased energy expenditure. [source] The reproductive biology and ecology of the Port Jackson shark Heterodontus portusjacksoni in the coastal waters of eastern AustraliaJOURNAL OF FISH BIOLOGY, Issue 10 2008D. M. Powter The reproductive biology and ecology of the Port Jackson shark Heterodontus portusjacksoni was investigated at three locations on the central and southern coast of New South Wales (NSW), Australia from January 2002 to December 2005 using underwater visual census surveys and samples obtained from a commercial fishery. Adults displayed sexual dimorphism in total length (LT) at sexual maturity, with males maturing between 762 and 772 mm LT and females between 902 and 905 mm LT. The mean ovarian fecundity was estimated at 16 offspring per female but was unrelated to female LT. Male gonado-somatic (IG) and hepato-somatic (IH) indices and female IG declined from July to November as did maximum ovarian follicle diameter and the diameter of the three largest follicles. Adults were absent from inshore reefs between December and July. Hence, H. portusjacksoni has a synchronous annual breeding season in NSW, which occurs between July and November (the austral winter to spring), with a peak in oviposition from August to October. Heterodontus portusjacksoni copulatory and ovipository behaviour are reported for the first time. Copulation was observed and involved oral grasping of the female's pectoral fin by a single male, which wrapped his body around hers to insert one clasper. Ovipositing females appeared to search crevices in the reef prior to delivering a single capsule, which was washed into the crevice by water movement, with the female departing very soon after oviposition. This study represents the first rigorously quantitative analysis of H. portusjacksoni reproductive biology and ecology in NSW waters. [source] Sexual development and reproductive seasonality of hogfish (Labridae: Lachnolaimus maximus), an hermaphroditic reef fishJOURNAL OF FISH BIOLOGY, Issue 5 2007R. S. McBride The seasonality, size, age, colour phases and sexual dimorphism of 13 reproductive classes of hogfish Lachnolaimus maximus are described. Analysis of histological sections of gonads (n = 1662) confirmed earlier conclusions that L. maximus is a monandric, protogynous hermaphrodite. Sex change was initiated at the end of the spawning season and over a broad range of sizes and ages. It occurred after a functional female phase (postmaturation) and proceeded more slowly (months) than previously believed. Eventually all individuals changed sex to a terminal male phase. Females were batch spawners, spawning as often as every day during winter and spring. There was no evidence of precocious sperm crypts in active females, sperm competition or other alternative male sexual strategies. Mating has been reported elsewhere to be haremic. The sexual development of L. maximus appears to be adaptive in terms of Ghiselin's size-advantage model, which links monandric protogyny and polygyny. The slow rate of sex change, however, poses problems when fishing pressure is high because harvest of a single male has the potential to reduce the reproductive output of an entire harem. [source] How female reed buntings benefit from extra-pair mating behaviour: testing hypotheses through patterns of paternity in sequential broodsMOLECULAR ECOLOGY, Issue 9 2006KAREN M. BOUWMAN Abstract Extra-pair paternity is an important aspect of reproductive strategies in many species of birds. Given that in most species females control whether fertilization occurs, they are expected to benefit in some way from the extra-pair matings. In this study we use patterns of extra-pair paternity (EPP) in broods of individual reed buntings (Emberiza schoeniclus), both within and between seasons, to test four hypothesized female benefits: (1) assessing potential future partners and seeking (2) genetic diversity (3) good genes, or (4) compatible genes. Reed buntings are socially monogamous, multibrooded passerines with extremely high levels of extra-pair paternity. We studied a population of reed buntings in the Netherlands in 2002 and 2003; 51% of offspring in 74% of nests were extra-pair. We showed that patterns of EPP did not support the first and second hypotheses, since females did not form a pair with previous extra-pair partners, EPP was not evenly distributed among broods and more broods than expected were sired by a single male. Furthermore, there was no relation between a male's within- and extra-pair fertilization success, no consistency in EPP between breeding attempts, no effect of parental relatedness on EPP and several cases of reciprocal paternity. These patterns do not support the good genes hypothesis and are most consistent with the genetic compatibility hypothesis. However, our previous finding that older males are more successful in gaining EPP, suggests some effect of good genes. These hypotheses need not be mutually exclusive, as females may select compatible males above a certain quality threshold (e.g. old males). [source] Investigation of the population genetic structure and mating system in the ant Pheidole pallidulaMOLECULAR ECOLOGY, Issue 9 2002Denis Fournier Abstract The origin of eusociality in haplo-diploid organisms such as Hymenoptera has been mostly explained by kin selection. However, several studies have uncovered decreased relatedness values within colonies, resulting primarily from multiple queen matings (polyandry) and/or from the presence of more than one functional queen (polygyny). Here, we report on the use of microsatellite data for the investigation of sociogenetic parameters, such as relatedness, and levels of polygyny and polyandry, in the ant Pheidole pallidula. We demonstrate, through analysis of mother,offspring combinations and the use of direct sperm typing, that each queen is inseminated by a single male. The inbreeding coefficient within colonies and the levels of relatedness between the queens and their mate are not significantly different from zero, indicating that matings occur between unrelated individuals. Analyses of worker genotypes demonstrate that 38% of the colonies are polygynous with 2,4 functional queens, and suggest the existence of reproductive skew, i.e. unequal respective contribution of queens to reproduction. Finally, our analyses indicate that colonies are genetically differentiated and form a population exhibiting significant isolation-by-distance, suggesting that some colonies originate through budding. [source] Spawning success in Atlantic salmon (Salmo salar L.): a long-term DNA profiling-based study conducted in a natural streamMOLECULAR ECOLOGY, Issue 4 2001J. B. Taggart Abstract Spawning success of Atlantic salmon (Salmo salar L.) was investigated, under near-natural conditions, in the Girnock Burn, an 8-km long tributary of the River Dee in Scotland. Employing minisatellite-based DNA profiling, mating outcomes were resolved over three spawning seasons by assigning parentage to progeny samples removed from spawning nests (,redds'). While individual spawning patterns differed markedly, consistent trends were present over the 3 years studied. Multiple spawning was found to be prevalent. More than 50% of anadromous spawners of both sexes contributed to more than one redd. Up to six redds for a single female and seven for a single male were detected. Both sexes ranged extensively. Distance between redds involving the same parent varied from a few metres to > 5 km. Distances > 1 km were common. Both males and females ranged to a similar extent. Range limit was not correlated to fish size. Pairs were not monogamous, both males and females mating with different partners at different sites. Size assortative mating was apparent among 1991 spawners but was not detected for 1992 or 1995. Redd superimposition was found to be common (17,22% of redds over the 3 years), although it was not correlated to the number of anadromous spawners present. High levels of nonanadromous mature parr mating success (40,50% of total progeny sampled) were recorded, and these likely contribute greatly to the effective population size. The relevance of these findings at the individual and population level is discussed, with particular reference to management implications. [source] Male mating tactics in spider monkeys: sneaking to competeAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2010K. Nicole Gibson Abstract I investigated the mating system and male mating tactics for a population of wild spider monkeys (Ateles belzebuth chamek), to identify the behaviors males used to achieve and maintain access to sexually receptive females, and to examine if some males used more tactics than other males and/or had differential access to females. Results show that the mating system mostly involved scramble competition polygyny and that males used a range of mating tactics and behaviors, previously unreported for spider monkeys. The most unusual feature of spider monkey mating behavior was the secretive nature of copulations,nearly all copulations were clandestine, but a few were in the presence of other group members. Fifteen sexually mature males were observed to copulate 43 times. These data provide the first opportunity to evaluate how female availability influences male,male competition. First, the operational sex ratio was highly skewed toward males because usually only one female was receptive in each community per month. Second, females only mated with a few males in their community in any one mating period, but some females mated over the course of multiple consecutive mating periods, eventually mating with most or all of the males in their community. Across all communities, 9 (21%) of the 43 copulations involved a single male,female partner, 20 (47%) involved four males mating with the same female, and males mated with from one to four different females. Fourteen of the 16 total adult males and 1 subadult male (10 total) copulated. One or two males in each community were successful in monopolizing access to receptive females, and these males did not usually have the highest rates of copulation. In this system, clandestine copulations are one behavioral solution to the complex problem of gaining mating exclusivity and, probably, exercising mate choice. Am. J. Primatol. 72:794,804, 2010. © 2010 Wiley-Liss, Inc. [source] Genotyping from semen of wild Japanese macaques (Macaca fuscata)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2004Xavier Domingo-Roura Abstract The noninvasive collection of animal cells is crucial for DNA analyses in wild populations that cannot be disturbed by capture. We describe the collection of 68 semen samples following copulation and masturbation events in wild habituated and nonhabituated troops of Japanese macaques on the protected island of Yakushima. We used this DNA to amplify 390 base pairs (bp) of the mitochondrial DNA control region in 16 individuals from eight troops, and found a monomorphic pattern in agreement with the low variability imposed by geographic isolation and female philopatry. We also amplified two microsatellite loci from samples collected after the resident males of a focal troop had copulated with different females. We found several different allele combinations in samples collected after the observed mating of a single male, indicating the presence of contaminant DNA, presumably from males that had previously mated with the same female. This discovery made it impossible to assign a given sample to a specific male except when the samples were recovered after masturbation events. Thus, it was not possible to test for kinship or estimate allele frequencies from the semen samples. The mixing of semen, and the pattern of sample collection observed in morphologically identified individuals support the notion that strong mating and sperm competition exists among resident and nonresident males. Am. J. Primatol. 62:31,42, 2004. Copyright © 2004 John Wiley & Sons, Ltd. [source] Spawning behaviour, early development and first feeding of the bluestriped angelfish [Chaetodontoplus septentrionalis (Temminck & Schlegel, 1844)] in captivityAQUACULTURE RESEARCH, Issue 9 2010Ming-Yih Leu Abstract Successful natural spawning of Chaetodontoplus septentrionalis in captivity from 19 March to 11 May, 2008 is described for the first time. A single male dominates a harem of two females, spawning with each at dusk, from 10 min before to 20 min after sunset. Each female laid an average 119 × 103 eggs during the spawning period. Fertilized eggs were spherical, buoyant and had a diameter of 0.83 ± 0.02 mm (mean ± SD). Embryonic development lasted 15,18 h at 28.1 °C. Newly hatched larvae were 1.60 ± 0.07 mm in total length (TL) with 27 myomeres. Larvae completed yolk absorption within 3 days post hatching (ph) at 3.01 ± 0.08 mm TL. Ten days ph, the larvae had attained 3.95 ± 0.12 mm TL. Larvae were fed either 100% s-type rotifers (Brachionus rotundiformis), 100% copepods (Microsetella sp.), a combination of the two (50%:50%) or without live feed (starved control) to determine the effect of live feed on the survival rate. The survival was significantly (P<0.001) higher in larvae fed a combination of diet than the others. These results indicate that C. septentrionalis is a potential species for captive breeding programs and the use of a combination of diet (s-type rotifers and copepods) may be a suitable first food for the larvae. [source] Male infertility, female fertility and extrapair copulationsBIOLOGICAL REVIEWS, Issue 2 2009Oren Hasson ABSTRACT Females that are socially bonded to a single male, either in a social monogamy or in a social polygyny, are often sexually polyandrous. Extrapair copulations (EPC) have often been suggested or rejected, on both empirical and theoretical grounds, as an important mechanism that enables females to avoid fertility risks in case their socially bonded male is infertile. Here, we explore this possibility in two steps. First, we present a mathematical model that assumes that females have no precopulatory information about male fertility, and shows that a female EPC strategy increases female reproductive success only if certain specific conditions are upheld in the nature of male infertility. In particular, these conditions require both (i) that fertile sperm precedence (FSP) is absent or incomplete within ejaculates of the same male (i.e. that an infertile male is, at least partly, truly infertile), and (ii) the existence of FSP among ejaculates of different males (such that infertile spermatozoa of the infertile male are at a disadvantage when competing against spermatozoa of a fertile male). Second, to evaluate their potential role in the evolution of female EPC, we review the abundance and FSP patterns of the different male infertility types. The conclusion is drawn that some common infertility types, such as poor sperm count or motility, contribute to the evolution of female EPC, whereas other common infertility types, such as sperm depletion or allocation in a social monogamy (but not in a social polygyny), and in particular male driven polyspermy, do not. Also, a deeper look at the arms race between sperm fertilization efficiency and female barriers to sperm may answer the non-trivial question: "why are some types of infertility so common?" [source] Injury and alcohol: a hospital emergency department studyDRUG AND ALCOHOL REVIEW, Issue 2 2001ANN M. ROCHE Abstract A pilot survey was undertaken of injury presentations to a public hospital emergency department to determine patterns of alcohol use in this population. Of the 402 injury presentations in the study period, a total of 236 injury cases were interviewed, of whom 45% (n = 107) and 29% (n = 69) had consumed alcohol 24 and 6 hours prior to injury. Mean age for all injury presentations was 35.1 years, and 32.6 years for alcohol injury cases. For both injury groups, males were significantly younger than females. Recent alcohol ingestion was three times more common among male than female injury presentations, but with females drinking at significantly lower levels. Of males who had consumed alcohol 6 hours prior to injury, nearly 70% were drinking at NHMRC harmful levels and 61% had drunk more than eight standard drinks. Overall, alcohol-involved injury cases commonly occurred among low-income, single males around 30 years of age who were regular heavy drinkers who were drinking heavily in licensed premises prior to their injury, and who sustained injury through intentional harm. In addition, one in five of the alcohol-involved injury cases were aged 15,18 years, i.e. below the legal age of purchase. The high proportion of hazardous and harmful drinkers among those who had consumed alcohol within the last 6 hours, and the injury sample overall, highlights the need for further research to explore the relationship between the occurrence of injury and the drinking patterns and environments associated with injury. Further research is also required to assess the efficacy of early and brief interventions for alcohol and drug use within the emergency ward setting. This information would enable appropriate public health interventions to be initiated. [source] Mating structure and male production in Vespa analis and Vespa simillima (Hymenoptera: Vespidae)ENTOMOLOGICAL SCIENCE, Issue 3 2007Jun-ichi TAKAHASHI Abstract We estimated queen mating frequency, genetic relatedness between workers and worker reproduction in the hornets Vespa analis and Vespa simillima using microsatellite DNA genotyping. The 20 V. analis colonies studied each contained a queen inseminated by a single male. Of the 15 V. simillima colonies studied, nine had a queen inseminated by a single male, four had a queen inseminated by two males, and two had a queen inseminated by three males. The estimated effective number of matings was 1.33 ± 0.74 (mean ± SD), with 75,85% of the offspring of the six multiply mated queens sired by single males. The values for genetic relatedness between the workers of V. analis and V. simillima were 0.739 ± 0.004 and 0.698 ± 0.013 (mean ± SD), respectively. We conclude that V. analis and V. simillima colonies are genetically monogynous and monandrous. When high relatedness between the workers occurs within colonies, kin selection theory predicts a potential conflict between queens and workers over male production. To determine whether males were derived from queens or workers, males from V. analis and V. simillima colonies were genotyped at four microsatellite loci and the level of ovary activation in workers was determined. None of the 787 V. analis workers and only 15 of 3520 V. simillima workers had developed ovaries. Furthermore, the genotyping identified no worker-produced males in any colony. The presence of reproductive workers correlated positively with the number of workers within the colony. These results suggest that eusocial colonies with an annual life cycle tend to break down socially when they become large and are close to dying. [source] Habitat selection and reproductive success of Ortolan Buntings Emberiza hortulana on farmland in central Sweden , the importance of habitat heterogeneityIBIS, Issue 3 2008ÅKE BERG Many granivorous birds have shown severe population declines in Europe during recent decades. The aim of the present study was to analyse habitat preferences and reproductive success of one such species, the Ortolan Bunting Emberiza hortulana, in different farmland habitats in south-central Sweden. Four seemingly different land-use types were preferred: permanent set-asides, short rotation coppice, and grazed and unmanaged semi-natural pastures. Territories and random sites differed considerably in the proportion of these preferred land-use types; 39% of territories had > 70% preferred habitat (at the 100-m scale) compared to 5% of random sites. In contrast, 22% of territories and 65% of random sites had no preferred habitats. All the preferred habitats had heterogeneous ground vegetation characterized by patches with bare ground, or at least sparse ground vegetation, intermixed with patches with taller vegetation. Ortolan Buntings also preferred a heterogeneous habitat structure with occurrence of field islets, shrubby edges, barns and electric wires, which could act as song posts or suitable nest-sites, in 88% of territories. At a larger (1-km square) scale, territories occupied by pairs aggregated strongly in areas with high proportions of preferred habitats. The number of territories with single males correlated positively with the number of pairs, which suggests that conspecific attraction may influence territory distribution. No measured habitat factors were related to reproductive success. However, due to habitat preferences and the higher proportion of paired males in one habitat type (set-aside), the production of young (fledglings/ha) is expected to be higher in set-asides, as well as in short-rotation coppices and semi-natural pastures. Thus, these habitats are important for the conservation of the Ortolan Bunting. Large areas with habitat structures such as field islets are especially important because the Ortolan Bunting breeds in aggregations in these areas. [source] Community Structure of Large Mammals in Tropical Montane and Lowland Forest in the Tenasserim-Dawna Mountains, ThailandBIOTROPICA, Issue 3 2008Robert Steinmetz ABSTRACT Montane evergreen forest in SE Asia is structurally and floristically different from lowland habitats. The response of large mammals to this variation is largely unexplored. We used sign transects to compare community structure of large mammals in montane (>1100 m), and lowland (<1100 m) forest types over 4 yr in western Thailand. Relative abundance of most ungulate species was significantly higher in lowland forest, except for elephant (Elephas maximus) and tapir (Tapirus indicus), which were most abundant in montane forest (based on chi-square tests of sign encounter rates). Sexual segregation was apparent for gaur (Bos gaurus): breeding herds were concentrated in the lowlands, whereas single males were most abundant in montane forest. Large cat abundance was similar in both elevation zones. Tapir, single gaur, and bears (Ursus spp.) characterized the montane mammal community, whereas most other ungulate species and social groups were indicative of lowland forest (based on discriminant function analysis). Results pertain only to the dry season; seasonal movements could alter the patterns we observed. Differences in community structure between elevation zones are hypothesized to result from differences in habitat structure, resource availability, and human impacts. Lowland forests provide bamboo, grass, and mineral licks, probably accounting for higher ungulate densities despite higher levels of hunting. These resources are scarce in montane forest. However, montane forest functions as a refuge for at least three globally threatened large mammal species, because commercial hunting is concentrated in the more accessible lowlands. [source] | |||||||||||||