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1

Divergent microclimates in artificial and natural roosts of the large-footed myotis (Myotis macropus)

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Campbell S., Coulson G., Lumsden L. F.
Acta Chiropterologica
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2010
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tom 12
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nr 1
The thermal environment of day roosts is considered one of the most influential factors affecting the survival, growth and reproduction of microbats. The use of torpor is a common energy saving strategy employed by microbats in temperate regions. The efficiency of entry into, and arousal from, torpor is governed by roost microclimate, primarily roost temperature. The large-footed myotis Myotis macropus roosts in both tree cavities and a man-made tunnel at Yan Yean reservoir in Victoria, Australia. We investigated the thermal properties of both roost types in comparison to available tree cavities and ambient temperature over four time periods from October 2003 to May 2005. Tree cavities and tunnel roosts remained significantly warmer at night, cooler during the day, and were more stable than ambient temperatures. In addition, roost tree cavities were significantly cooler between 10:00–13:00 h compared to available tree cavities, and there was a trend for roost tree cavities to be slightly warmer at night and slower to reach maximum temperature relative to available tree cavities during the breeding season (October–January). In contrast, there was little difference in roost and available tree cavity temperatures outside of the breeding season (April–May). Temperatures inside tunnel roosts were more stable and were significantly cooler during the afternoon compared to roost tree cavities during both the breeding and non-breeding seasons. Myotis macropus may actively trade-off the enhanced thermoregulatory benefits of warm roosts for reduced predation risk associated with the tunnel roosting environment.
2

Faecal Escherichia coli and Chlamydophila psittaci in the Superb Lyrebird Menura novaehollandiae: host sex and age effects

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Milne R. J., Poiani A., Coulson G., Auld R.
Acta Ornithologica
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2004
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tom 39
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nr 2
The Superb Lyrebird is a sexually dimorphic passerine that although is not considered endangered, it has been declining in population size since the 1940s due primarily to urban development. Recent reports suggest that lyrebirds may be threatened by chlamydial infection. We studied levels of faecal infection by two microparasites in lyrebirds: Chlamydophila psittaci and Escherichia coli in the Sherbrooke Forest, south-eastern Australia. Fresh faecal samples were obtained from 33 lyrebirds (15 adult females, 13 adult males and 5 juveniles) — estimated of 27.5% of the population, all of them tested negative to Ch. psittaci. E. coli prevalence was compared between adult males and females and no difference was found. This result is expected, for instance, if E. coli is sexually transmitted and lyrebirds are promiscuous. Trends for juveniles to be more parasitized than adults were detected, but they were statistically not significant. Behavioural analyses of video footage indicate that E. coli infected birds did not allocate more or less time to any of the activities considered than did non infected birds. This might suggest that E. coli infection in lyrebirds is relatively benign, and behavioural effects may thus be subtle. No significant differences were found in specific measurements of foraging behaviour but non infected birds tended to scratch more frequently than infected birds.
3

The effect of ectoparasites on the grooming behaviour of Gould's wattled bat (Chalinolobus gouldii): an experimental study

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Godinho L. N., Cripps J. K., Coulson G., Lumsden L. F.
Acta Chiropterologica
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2013
|
tom 15
|
nr 2
Grooming is an important behaviour for the control of ectoparasites in mammals but it is also energetically costly. Therefore, the time an animal allocates to grooming may be used to evaluate the potential cost of an ectoparasite to its host. Most mammals are host to more than one ectoparasite species, which may impose different costs. We experimentally evaluated the relative cost of three ectoparasite species by observing the grooming response of their host, Gould's wattled bat (Chalinolobus gouldii), to the manipulation of parasite load. The parasite that spent its entire lifecycle on the host, the mite Spinturnix novaehollandiae, triggered the greatest increase in grooming. A grooming response was not as evident for the other parasites (a smaller mite, Trichonyssus womersleyi, and a bat fly, Basilia troughtoni), possibly because part of their lifecycle occurred in the roost, which the host may avoid by discriminative roost selection. Grooming behaviour, although not significantly altered by parasites other than S. novaehollandiae, was performed by most bats, which maintained a baseline grooming rate even when relatively parasite free. This study suggests heterogeneity in the costs imparted on a host by members of its ectoparasite community and the potential importance of considering parasite life-history when evaluating the influence of parasites on the host.
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