Potential citric acid exposure and toxicity to Hawaiian hoary bats (Lasiurus cinereus semotus) associated with Eleutherodactylus frog control

Free-flying individual Lasiurus cinereus semotus were observed as they foraged near incandescent lights on the island of Kauai, Hawaii. Two types of vocalizations were recorded from the bats: an echolocation–hunting signal with peak frequency of 27.8 kHz and an agonistic social signal, emitted while the bats were in aggressive pursuit of one another, with a peak frequency of 9.6 kHz. The tendency to vocalize agonistically increased with increased numbers of bats in the foraging area and increased as the density of insects available to the hunting bats decreased. Our observations suggest that the bats may gather echolocation information from their social signals. The bats at the site foraged under most weather conditions, including fog, moderate rain, strong winds, and temperatures as low as 13 °C. Groups of up to eight animals were common, although bats hunted in airspaces that were vigorously defended against other individuals. Small flies and small moths (< 10 mm body length) were the most common insects available as prey, but larger moths (16–20 mm) made up the bulk of the bats' diet. Moths larger than 20 mm were available but not fed on by the bats. This unique study site provides a rare opportunity to compare both prey availability to prey consumption in a population of bats. Our results suggest that this bat, at least on a short-term basis, exhibits a high degree of selectivity in its foraging, a behaviour similar to the mainland subspecies.

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Acoustic Evidence of Hoary Bats (Lasiurus Cinereus) on Newfoundland, Canada

Northeastern Naturalist ◽

10.1656/045.027.0315 ◽

2020 ◽

Vol 27 (3) ◽

pp. 567

Author(s):

Darrian P. Washinger ◽

Raymond Reid ◽

Erin E. Fraser

Keyword(s):

Lasiurus Cinereus ◽

Hoary Bats

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Flight muscle carnitine palmitoyl transferase activity varies with substrate chain length and unsaturation in the hoary bat (Lasiurus cinereus)

Canadian Journal of Zoology ◽

10.1139/cjz-2013-0141 ◽

2014 ◽

Vol 92 (2) ◽

pp. 173-176 ◽

Cited By ~ 3

Author(s):

E.R. Price ◽

L.P. McGuire ◽

M.B. Fenton ◽

C.G. Guglielmo

Keyword(s):

Fatty Acids ◽

Fatty Acid Composition ◽

Fatty Acid ◽

Acid Composition ◽

Substrate Preference ◽

Acid Oxidation ◽

Transferase Activity ◽

Carnitine Palmitoyl Transferase ◽

Lasiurus Cinereus ◽

Hoary Bats

Fat is an important fuel for bats to support high metabolic rates in extended periods of flight. The fatty acid composition of adipose stores could affect whole animal exercise performance, as fatty acids vary in rates of mobilization and oxidation. A key step in the fatty acid oxidation pathway is transporting fatty acids from the cytosol into mitochondria, mediated by the enzyme carnitine palmitoyl transferase (CPT). Therefore, understanding the substrate preference patterns of CPT in bats is important for interpreting the consequences of adipose fatty acid profiles. We measured CPT activity with eight different fatty acyl CoA substrates (16:0, 16:1ω7, 18:0, 18:1ω9, 18:2ω6, 18:3ω3, 20:4ω6, and 22:6ω3) in the pectoralis muscle of migrating and nonmigrating hoary bats (Lasiurus cinereus (Beauvois, 1796)). The pattern of substrate preference was similar to the patterns previously reported for birds and rats and was not affected by migration. Generally, activity increased with the number of double bonds and was higher with 16 carbon fatty acids compared with 18 carbon fatty acids. Given the observed substrate variation in CPT activity, there is no evidence to suggest that recently reported seasonal changes in the adipose fatty acid composition of migrating hoary bats would lead to increased lipid oxidation rate, and may instead be a consequence of seasonal shifts in diet.

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Inconspicuous echolocation in hoary bats ( Lasiurus cinereus )

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.0441 ◽

2018 ◽

Vol 285 (1878) ◽

pp. 20180441 ◽

Cited By ~ 11

Author(s):

Aaron J. Corcoran ◽

Theodore J. Weller

Keyword(s):

Model Organisms ◽

Mating Season ◽

Sensory Stimuli ◽

Sound Energy ◽

Lasiurus Cinereus ◽

Echolocation Calls ◽

Call Type ◽

Acoustic Modelling ◽

Infrared Cameras ◽

Hoary Bats

Echolocation allows bats to occupy diverse nocturnal niches. Bats almost always use echolocation, even when other sensory stimuli are available to guide navigation. Here, using arrays of calibrated infrared cameras and ultrasonic microphones, we demonstrate that hoary bats ( Lasiurus cinereus ) use previously unknown echolocation behaviours that challenge our current understanding of echolocation. We describe a novel call type (‘micro’ calls) that has three orders of magnitude less sound energy than other bat calls used in open habitats. We also document bats flying close to microphones (less than 3 m) without producing detectable echolocation calls. Acoustic modelling indicates that bats are not producing calls that exceed 70–75 dB at 0.1 m, a level that would have little or no known use for a bat flying in the open at speeds exceeding 7 m s −1 . This indicates that hoary bats sometimes fly without echolocation. We speculate that bats reduce echolocation output to avoid eavesdropping by conspecifics during the mating season. These findings might partly explain why tens of thousands of hoary bats are killed by wind turbines each year. They also challenge the long-standing assumption that bats—model organisms for sensory specialization—are reliant on sonar for nocturnal navigation.

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