Advances on the group composition, mating system, roosting and flight behaviour of the European free-tailed bat (Tadarida teniotis)

Mammalia ◽  
2018 ◽  
Vol 82 (5) ◽  
pp. 460-468
Author(s):  
Alfonso Balmori

AbstractWe investigated a large colony of European free-tailed bats (Tadarida teniotis) in Spain, using a combination of capture-mark-recapture data and direct observations. Its social and reproductive organisation is complex and the mating system fits a “resource defence polygyny” model. In spring and autumn, aggressive interactions in flight, defence of roosts and mating songs of males to attract females occurred. According to our results,T. teniotisis organised in “harems” consisting of a dominant male and a variable number of females. In addition the sexual cycle displayed a bimodal reproductive pattern (this is unique and remarkable for European bats). The bimodal pattern coincided with peaks in food availability (moths) at high altitudes. Presumably, roost-guarding activities (patrolling, advertising…) make males less prone to move away (e.g. at higher altitudes and longer distances) from roosts, resulting in differences in prey selection and in altitudinal segregation between sexes. This provides a plausible explanation for the differences in diet (predation of more sedentary vs. high-flying migratory moths) between males and females that has been found in published studies.

2012 ◽  
Vol 90 (6) ◽  
pp. 736-743 ◽  
Author(s):  
Philip H. Jones ◽  
Jeffrey L. Van Zant ◽  
F. Stephen Dobson

The imbalanced reproductive success of polygynous mammals results in sexual selection on male traits like body size. Males and females might have more balanced reproductive success under polygynandry, where both sexes mate multiply. Using 4 years of microsatellite DNA analyses of paternity and known maternity, we investigated variation in reproductive success of Columbian ground squirrels, Urocitellus columbianus (Ord, 1815); a species with multiple mating by both sexes and multiple paternity of litters. We asked whether male reproductive success was more variable than that of females under this mating system. The overall percentage of confirmed paternity was 61.4% of 339 offspring. The mean rate of multiple paternity in litters with known fathers was 72.4% (n = 29 litters). Estimated mean reproductive success of males (10.27 offspring) was about thrice that of females (3.11 offspring). Even after this difference was taken into account statistically, males were about three times as variable in reproductive success as females (coefficients of variation = 77.84% and 26.74%, respectively). The Bateman gradient (regression slope of offspring production on number of successful mates) was significantly greater for males (βM = 1.44) than females (βF = 0.28). Thus, under a polygynandrous mating system, males exhibited greater variation in reproductive success than females.


Author(s):  
Leigh W. Simmons

‘Mating systems, or who goes with whom, and for how long’ examines the variation in how males and females associate during the breeding season, ranging from brief couplings with multiple partners to lifelong monogamy. It also shows how the discovery that females mate with many partners, even in supposedly monogamous species such as songbirds, was made possible by modern genetic techniques. Variation in mating systems holds considerable implications for the operation of sexual selection. The way that animal mating systems have been explained historically is outlined before considering how a more contemporary understanding of genetic and social relationships has reshaped our thinking and how understanding a species’ mating system can have practical applications.


Author(s):  
Danillo Barroso ◽  
Douglas Fernandes Rodrigues Alves ◽  
Gustavo L. Hirose

The aim of the present study is to test the resource economic monopolization hypothesis and the hypothesis of monogamy using the shrimpAlpheus estuariensisas a model. The shrimps were collected in two areas in the Vaza-Barriz estuary, north-east Brazil, from August to November 2016. The average abundance of refuges was obtained through 30 random replicates. The shrimp presented a random distribution in both areas. Males and females found together showed a weak relation between their sizes, with males being larger than females. In addition, the cheliped of males grows proportionally more than that of females. The great abundance of refuges present in the environment, added to the aforementioned results, do not support the idea of refuge-guarding behaviour or monogamy. These results, which are in disagreement with those already found for some shrimps of the same family, genus, and even species, reinforce the idea that Alpheidae can be used as a model in the study of how environmental conditions are capable of shaping the social behaviour of a species.


2015 ◽  
Vol 75 (1) ◽  
pp. 224-228
Author(s):  
FA. Alves-Costa ◽  
AP. Wasko

Differential Display (DD) is a technique widely used in studies of differential expression. Most of these analyses, especially those involving fish species, are restricted to species from North America and Europe or to commercial species, as salmonids. Studies related to South American fish species are underexplored. Thus, the present work aimed to describe DD technique modifications in order to improve outcomes related to the isolation of DETs (Differentially Expressed Transcripts), using Leporinus macrocephalus, a large commercially exploited South American species, as a fish design. Different DDRT-PCR approaches were applied to brain samples and the products of the reactions were analyzed on 6% polyacrylamide gels stained with 0.17% Silver Nitrate (AgNO3). The use of PCR reactions under high stringency conditions and longer oligonucleotides based on VNTR (Variable Number of Tandem Repeats) core sequences led to better results when compared to low stringency PCR conditions and the use of decamer oligonucleotides. The improved approach led to the isolation of differentially expressed transcripts on adult males and females of L. macrocephalus. This study indicates that some modifications on the DDRT-PCR method can ensure isolation of DETs from different fish tissues and the development of robust data related to this approach.


Author(s):  
Joaquim Olinto Branco ◽  
Alexander Turra ◽  
Flávio Xavier Souto

This study was conducted between January and December 1995 at Armação do Itapocoroy, Penha, Santa Catarina, southern Brazil. Monthly samples were carried out in the morning, afternoon, and evening using two over-trawls with 6 m at the opening, 3·0-cm mesh at the outer part and 2·0-cm mesh in the bag. Dardanus insignis was collected year round but with higher densities in September and October. The hermit crabs were more abundant during the evening than the afternoon but no differences were recorded between morning and both evening and afternoon. Females were slightly more abundant than males but the sex ratio did not differ from 1:1. Females were more abundant in the smallest size-classes (<1·8 cm) while males outnumbered females in the largest ones (>2·2 cm). The individuals of this population of D. insignis have a mean cephalothoracic length of 1·89±0·40 cm (range 1·00 to 3·90 cm) and a mean weight of 40·26±27·06 g. The size distribution showed an unimodal pattern, with males being larger than ovigerous females, which, in turn, were larger than non-ovigerous females. Dardanus insignis showed a seasonal reproductive pattern with a peak from September to November and complete absence of ovigerous females from April to August. The von Bertalanffy growth function (VBGF) with temporal oscillation fitted for this population of D. insignis had the following parameters: L∞=4·40 cm, K=0·60, C=0·95, WP=0·35. Recruitment was estimated to start in September and was extended to the following months. Estimates of longevity ranged from 20 to 62 months. A mortality rate of 2·21 was estimated based on the length converted catch curve. The cephalothoracic length of males and females showed, respectively, positive and negative allometry with both cephalothoracic width and crab weight.


2010 ◽  
Vol 67 (8) ◽  
pp. 1221-1231 ◽  
Author(s):  
Justin J. Meager ◽  
Jon Egil Skjæraasen ◽  
Anders Fernö ◽  
Svein Løkkeborg

Atlantic cod ( Gadus morhua ) are being increasingly farmed in net pens adjacent to coastal populations that are currently at historic lows. One concern is that farmed escapees enter local spawning shoals and mate with wild cod. We tested for the potential of escaped farmed cod to interact and hybridize with wild fish by examining the spatial dynamics of, and associations between, fish tagged with ultrasonic transmitters. Based on these data, we also investigated the basic mating system of cod in the field. The spawning ground was best described as a lekking arena. Wild males aggregated near the seafloor and associations between individuals were frequent. Wild females had a pelagic and dispersed distribution and rarely associated with each other. Associations between individual wild males and females were also infrequent. Farmed males rarely associated with wild fish and had core usage areas above the wild males, suggesting that they were not admitted into the spawning arena. Farmed females were over the spawning arena more frequently than wild females and often associated with wild males at the depth of the spawning arena, indicating potential mating with wild males and the possibility of courtship interference. Hence, hybridization between escaped farmed and wild cod is likely.


1993 ◽  
Vol 20 (4) ◽  
pp. 405 ◽  
Author(s):  
TM Bubela ◽  
DCD Happold

Mastacomys fuscus is a grass-eating rodent of south-eastern Australia that lives mainly in subalpine habitats where snow covers the ground for about four months of the year. Radiotelemetry revealed that in summer the females were territorial. Home ranges of males were larger than those of females and overlapped extensively with the home ranges of other males and with the home ranges of up to three females. In winter, males and females huddled together in communal nests. The locations of nest sites, cover, water and grass also determined the spatial organisation of individuals. The evidence suggests that M. fuscus is not monogamous, but there were insufficient data to determine whether polygyny or promiscuity is the preferred mating system. The social organisation of this species, solitary in summer and communal in winter, is a response to the cold snowy winters and the limited time for reproduction in summer. The social organisation of M, fuscus is different from that of the other conilurine rodents of Australia, but similar to that of rodents that live in other alpine regions of the world.


Zootaxa ◽  
2017 ◽  
Vol 4312 (1) ◽  
pp. 92 ◽  
Author(s):  
FREDERIC DIETER BENEDIKT SCHEDEL ◽  
ULRICH KURT SCHLIEWEN

Hemibates koningsi, new species, is described from southern Lake Tanganyika (Republic of Zambia) as the second species of Hemibates Regan, 1920. Males of the new species are easily distinguished from H. stenosoma (Boulenger, 1901) based on their adult color pattern, i.e. black vertical bars on the anterior flanks part and posterior horizontal bands on a silvery-whitish body coloration vs. an anterior flank color pattern of black blotches of variable number, size and shape and posterior horizontal bands. Males and females of the new species are further distinguished by their longer lower pharyngeal jaw (37.6–38.2% HL vs. 27.8–32.5% HL) with a characteristically curved keel, which is straight or only slightly curved towards the tips in H. stenosoma. The new species has on average fewer gill rakers on the first gill arch than its only congener (33–37 vs 35–43). 


1995 ◽  
Vol 46 (3) ◽  
pp. 617 ◽  
Author(s):  
SH Hooker ◽  
RG Creese

An examination of the reproductive condition of a population of paua, H. iris, at Leigh in north-eastern New Zealand during 1986-87 revealed a long breeding season extending from late summer through autumn and winter and into early spring. Within this period, a sharp decrease of over 60% in the gonad index for both males and females indicated major spawning events in July and October. A smaller decrease in the gonad index in March suggested a third, minor spawning. These spawning events were confirmed by regular examination of histological sections of gonadal material. This breeding pattern is different from that previously described for southern localities in New Zealand, where spawning activity is limited to a four-month period from late summer into autumn. Paua in this northern population had a sex ratio slightly biased towards males (1 female to every 1.3 males) and achieved reproductive maturity between the sizes of 48 and 60 mm shell length. These features are also different from those described for southern populations of H. iris. These findings highlight the need to take regional differences in reproductive pattern into account when describing the population dynamics of marine gastropods.


1996 ◽  
Vol 44 (1) ◽  
pp. 9 ◽  
Author(s):  
H Frederick ◽  
CN Johnson

This study examined association patterns and reproductive behaviour in a sexually monomorphic potoroid marsupial, the rufous bettong, Aepyprymnus rufescens. A total of 29 individuals was marked, and 22 of these were observed regularly over a six-month period; these 22 individuals accounted for almost all the animals using the study area. Rufous bettongs at this site were predominantly solitary (71% of sightings were of single animals) and groups, when they formed, were generally small (maximum of six individuals). Most groups of two were male-female pairs, and unisex groups occurred significantly less often than expected. These male-female groups formed as a result of sexual investigations of females by males, and were shore-lived. Analysis of the frequency with which particular males and females were seen together (excluding occasions when females were in oestrus) showed that most males did not persistently associate with any particular female. Instead, they appeared to maintain transitory contact with as many females as possible. However, three pairs were regularly seen together, suggesting that some males may maintain especially close contact with particular females. Females as they approached oestrus were followed continually by several males, with one male following very closely and preventing others from approaching. In two well-studied cases, the male who defended priority of access to the female was the same individual who had most often associated with that female when not in oestrus. These males demonstrated intimate knowledge of the nesting locations of the females and were able to join them very early each evening, and defended them against other males with little overt aggression. The mating system in this population appears to be promiscuous, but with a hint of monogamy arising from the tendency of some males to persistently investigate and ultimately to guard sexual access to certain individual females.


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