A new method of distinguishing Daubenton's bats (<i>Myotis daubentonii</i>) up to one year old from adults

Richardson, Pat

doi:10.1111/j.1469-7998.1994.tb08590.x

Cited by 26 publications

(13 citation statements)

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“…Age was classed as either juvenile (born that year) or adult (born the previous year or earlier) [16]. The ‘chin-spot’ [17] was not used to distinguish between adults and juveniles as some individuals retained it for up to at least four years.…”

Section: Methodsmentioning

confidence: 99%

Sexual Segregation and Flexible Mating Patterns in Temperate Bats

2013

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Social structure evolves from a trade-off between the costs and benefits of group-living, which are in turn dependent upon the distribution of key resources such as food and shelter. Males and females, or juveniles and adults, may have different priorities when selecting habitat due to differences in physiological or behavioural imperatives, leading to complex patterns in group composition. We studied social structure and mating behaviour in the insectivorous bat Myotis daubentonii along an altitudinal gradient, combining field studies with molecular genetics. With increasing altitude the proportion of males in summer roosts increased and only males were present in the highest roosts. With increasing altitude environmental temperature decreased, nightly variation in temperature increased, and bat foraging activity decreased, supporting the hypothesis that the harsher, high elevation sites cannot support breeding females. We found that offspring in female-dominated lowland roosts had a very high probability of being fathered by bats caught during autumn swarming at hibernation sites, in contrast to those in intermediate roosts, which had a high probability of being fathered by males sharing the nursery roost with the females. Whilst females normally appear to exclude males from nursery colonies, for those in marginal habitats, one explanation for the presence of males is that the thermoregulatory benefits to the females may outweigh disadvantages, such as competition for food, and give some males an opportunity to increase their breeding success. We suggest that the environment, and its effects on resource distribution, thus determine social structure, which in turn determines the mating pattern that has evolved.

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Section: Methodsmentioning

confidence: 99%

Sexual Segregation and Flexible Mating Patterns in Temperate Bats

2013

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“…Such inconsistencies, relative to the pattern described for Pipistrellus pipistrellus, would explain the anomalous changes from mature to immature classi®cations of bats caught between 1978 and 1989 and classi®ed by Racey's (1974a) criterion. A recent study of Myotis daubentonii also suggested that the coloration of epididymides was not a valid indicator of sexual maturity in that species, since ®rst-year males (de®ned from the presence of black pigmented chin spots: Richardson, 1994), were found with spermatozoa in their testes and had undergone some epididymal distension, despite the presence of black caudae epididymides (Kokurewicz & Bartma Ânska, 1992). The present study suggested that, in P. auritus, the size and shape of the caudae epididymides were more appropriate indicators of sexual maturity than was colour.…”

Section: Determination Of Sexual Maturity In Malesmentioning

confidence: 95%

The reproductive cycle and determination of sexual maturity in male brown long‐eared bats, Plecotus auritus (Chiroptera: Vespertilionidae)

1998

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Observations of the external morphology of wild-caught and captive male brown long-eared bats (Plecotus auritus) revealed a marked seasonal pattern of spermatogenesis, similar to that established by histological examination of other temperate-zone vespertilionids, with a peak in testes size in August and a lag between testicular growth and epididymal distension. This was followed by complete cessation of spermatogenesis and shrinkage of the testes to prepubertal size. The period of peak spermatogenesis coincided with a reduction in the incidence of torpor and also a decline in body mass. This suggests that torpor and spermatogenesis may be incompatible in this species. Outside the season of testicular growth and epididymal distension, sexual maturity could not be con®dently determined in P. auritus by the pigmentation of the tunica vaginalis surrounding the epididymis, a characteristic which has become established in other species. Instead, the size and shape of the caudae epididymides appeared to be a better criterion for de®ning sexual maturity in this species. Most males underwent testicular growth and epididymal distension, and were assumed to have reached sexual maturity, at an age of 15 months. However, some individuals (29%), particularly those in good condition (relatively heavy individuals), showed a degree of testicular and epididymal development in their ®rst autumn, i.e. at 3 months of age, indicating that the onset of puberty may be dependent on body condition. Poor body condition was associated with delayed spermatogenesis in adult males.

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“…Sex was determined by visual inspection and young of the year were distinguished from adults based on the presence of unfused and translucent phalangeal epiphyses (Anthony 1988;Racey 1988) and a 'chin-spot' (Richardson 1994;Geiger et al 1996) in the former. Body mass was measured with a digital balance (Kern EM 150-1, BallingenFrommern, Germany) to the nearest 0.1 g. Reproductive status of females was classified as pregnant, non-pregnant, lactating, and post-lactating according to the methods described by Racey (1982).…”

Section: Capture Of Batsmentioning

confidence: 99%

Estimation of food intake and ingested energy in Daubenton’s bats (Myotis daubentonii) during pregnancy and spermatogenesis

Encarnação

Dietz

2006

Eur J Wildl Res

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We studied food intake of and estimated ingested energy in female and male Myotis daubentonii during the periods of pregnancy (period 1, 8 May-4 June) and of intense spermatogenetic activity (period 2, 24 July-22 August) over 8 years (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) in central Germany. We used radiotelemetry to determine the time spent foraging and marked animals with chemiluminescent light-sticks to determine prey attack rates. Body length, body mass, moisture content, and caloric content of chironomids, the main prey of Daubenton's bats, were measured to estimate the nightly food intake and, in consequence, energy intake. Pregnant females spent significantly more time foraging than males during period 1 and females during the post-lactation period. In contrast, male foraged longer during the period of highest spermatogenetic activity than during late spring and also significantly longer than post-lactating females. Based on a mean number of 8.3 prey attacks per minute, the time spent foraging, and a capture success rate of either 50 or 92%, calculated intake values with a feeding rate of 7.6 insects per minute (=92% capture success) were more consistent with literature data for other insectivorous bats than that of values calculated on the basis of a capture success rate of 50%. In the high capture-success model, calculated insect intake of female bats was 8.0 g during pregnancy and 4.9 g per day during post-lactation, providing 5.0 and 3.0 kJ of ingested energy per gram body mass per day. Calculated intake of male bats was 3.6 g insects per day during late spring and 8.0 g during period of intensive spermatogenesis, providing 2.6 and 5.7 kJ of ingested energy per gram body mass.

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A new method of distinguishing Daubenton's bats (Myotis daubentonii) up to one year old from adults

Cited by 26 publications

References 0 publications

Sexual Segregation and Flexible Mating Patterns in Temperate Bats

Sexual Segregation and Flexible Mating Patterns in Temperate Bats

The reproductive cycle and determination of sexual maturity in male brown long‐eared bats, Plecotus auritus (Chiroptera: Vespertilionidae)

Estimation of food intake and ingested energy in Daubenton’s bats (Myotis daubentonii) during pregnancy and spermatogenesis

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