DEEPON CHAKRABORTY, UNIVERSITY OF CALCUTTA
Boreal bats, A resident of high latitudes of Southwestern Finland, Norway and North America, are generally insectivorous. As they are living in high altitudes, they face enormous fluctuations in seasonal food availability. So, they have to come up with this seasonal challenge, specifically, the chilling winter to survive. For that reason, they have generally two choices, either migrating to warmer areas, where food is occasionally available throughout the winter or to hibernate in-situ by utilising fat reserves which are accumulated before the winter.
The Boreal bats generally preferred the second way most likely. The underground hibernation sites are called hibernacula. Hibernation consists of extended Bouts of Torpor, during which bats lower their body temperature close to the ambient temperature of their hibernaculum. They also lower their metabolic rate for energy conservation. As the winters are prolonged in high latitudes, bats must shift their microclimate preference towards colder ambient temperature and longer torpor bouts to preserve energy.
But under some circumstances, during hibernation, they also need to relocate new hibernaculum due to disturbances, unfavourable changes in abiotic condition. Bats also detect the change in barometric pressure in hibernacula and they can use these in many circumstances. As Finland has a huge glacial history, there is a strong chance that these hibernation sites are associated with a variety of rock formation, crevice formation, outcrops etc. As the bats sometimes shift places during hibernation, Acoustic monitoring could provide the best means to gather information on the nature of these sites.
Acoustic monitoring on some suitable sites which are perfect for the hibernation of Norway, Southwestern Finland, North America reveals that more activity of bats is observed in studied hibernation sites during winter months compared to sites that do not have a suitable structure for hibernation. It is also found that the activity of bats is seen more in warm nights. Low barometric pressure also affects bat activity though it is a positive effect, that is low barometric pressure increases bat activity. Another interesting thing is that, during winter months, this barometric pressure can function as a substitute rather proxy for the mild outside temperature.
Some species like E.nissonii, P.auritus are more active during the winter compared to Myotis species. This is because they both have a larger body size and for that reason, they can accumulate more fat resources for the activity. So, we can conclude that for the conservation of those bat species – those rock outcrops, rock crevices, are more suitable as conservation sites and their utilities are newly acknowledged currently.
Also read:PHOSPHO1 AS A POTENTIAL TREATMENT FOR OBESITY AND DIABETES?
REFERENCES:https://www.biorxiv.org/content/10.1101/2020.10.19.345124v1
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