April « 2012 « Chiroblog

Archive for April 2012

Link between the fungus Geomyces destructans and White Nose Syndrome (WNS): experimental evidence.

Wednesday 11 April 2012

It is in “Proceedings of National Academy of Science” (PNAS), an American magazine, that the study has been published (the 10 April 2012). The original manuscript was submitted to the newspaper 9 January 2012 by Canadian researchers at the University of Manitoba in Winnipeg. This experimental work has allowed verification of the original 3rd postulate of Koch, that the inoculation of the organism causes disease isolated. More, According to these authors, White Nose Syndrome (WNS) and fatal features are observed in bats (Myotis lucifugus) inoculated and then placed in hibernation, regardless of the geographical origin of the strain used (European or American). The results of this study are in favor of the hypothesis of an invasive species of European origin that the systematic progression of the fungus to the American West and its wide distribution already seemed to describe European. This perspective appears sufficient to explain, to date, the difference in sensitivity observed populations of American and European bat. An ancient evolutionary history of the fungus with bats of the Old World, which have not benefited those in the new world where the fungus was introduced some years ago, would have favored the adaptation of species of the old continent and helped limit the pathology associated with the presence of the fungus. The latter hypothesis would be verified if the genetic mechanisms of resistance to infection by the fungus could be detected in European bats while they are absent, or much less represented, bat populations in the U.S.. The validation of this possibility and / or experimental evidence would undoubtedly minimize the risk associated with Geomyces destructans for European bat populations.

Meriadeg

Source:Warnecke, The. et al., 2012. Inoculation of Bats with European Geomyces Destructans Supports the Novel Pathogen Hypothesis for the Origin of White-Nose Syndrome. Proceedings of the National Academy of Sciences. Available at: http://www.pnas.org/content/early/2012/04/03/1200374109 [Accessed April 10, 2012].

 

Africhiro : chiroptérologique an expedition in Africa

Sunday 8 April 2012

There are still many to be understood about the chiroptérofaune of West Africa, including the distribution and ecology of these mammals. With the agreement of local authorities and the scientific support of Jakob Fahr, a survey of a period of 5 November 2010 to March 2011, in three countries in West Africa was conducted. Collaboration was developed in Mauritania with the park authority, in Senegal with the Ministry of Water and Forests and the International Mission LPO and Mali with the Ministry of Forestry and Thousand Traces in France based in Vercors.

So, 407 individuals on 54 evenings capture, of 34 different species have been captured (with the proper permissions), measured and identified in this study. More, 25 houses with colonies of bats have been described. Results on the genetics and the acoustics of bats are being studied.

If the job of acquiring knowledge about the species of bats is needed in West Africa, will be essential to couple a development program protection of some deposits, especially notable numbers of colonies. More, an awareness of these mammals with the local population remains an unavoidable aspect of the conservation of bats in West Africa, especially for species troglophiles.

More for the blog created for this project : africhiro.canalblog.com

Nicolas & Vanessa

Colonies of Rhinolophus fumigatus of 1200 individuals within a baobab in Senegal, in the region of Joal-Fadiouth.

A flagship species of chiroptérofaune of West Africa: Lavia frons or bat-winged orange.

 

Why bats are nocturnal ?

Tuesday 3 April 2012

Despite the many species of bats (+ of 1200 around the world), they are almost all active almost exclusively at night ! Only a few animals of oceanic islands such as Noctule des Açoresare known for their diurnal behavior and occasionally, other species of temperate and tropical zones were observed in activity in the light of day. These observations, however, remain relatively rare.

During the day, several problems for bats. First of all, these are in competition with insectivorous birds like swallows (Hirundininae) or swifts (Apodidae). Hunt at night would allow bats to exploit an ecological niche not exploited by birds. Then, bats flying in daylight are likely to be attacked by predators such as birds of prey (Accipitridae, Falconidae). This risk of predation is also the night (former: owls, Hawks) but is much lower. A third assumption is powered in a recent article while Voigt et al. (2011). Sunlight absorbed by the wings of bats would cause an increase in the cost of flying in the light of day. Hunting days would be beneficial only if the energy gain is relative and that the elevated risk of predation is low. The authors propose an evolution of wing color to darker tones that would make the bat less detectable by predators, thus trapping bats in the darkness of the night.

Yann et Meriadeg

C. C. Voigt and D. Lewanski (2011). Trapped in the darkness of the night: thermal and energetic constraints of daylight flight in bats. Proceedings of the Royal Society B. Biological Sciences, 278 (1716) 2311-2317.

http://rspb.royalsocietypublishing.org/content/278/1716/2311.short

Bat, Tags bright and flight direction

Monday 2 April 2012

Were you familiar with the use of tags for light to track bats ?
Older models have helped to track animals and record their acoustic emissions.

A new generation of light tags is now under review, them in the air leaving a luminous trail
for a few moments. The material is still in development but here are exclusively the flight path of a common Pipistrelle (Pipistrellus pipistrellus), equipped and monitored near Lake Constance in Germany. A pathway for the most atypical !
Future trials will learn about strategies for the use of space bats.

For the team Chiroblog, Yann and Dorian

;-)