Lack of evidence for a biological alarm clock in bats (Myotis spp.) hibernating under natural conditions

1993 ◽  
Vol 71 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Donald W. Thomas
Keyword(s):  
Eptesicus Fuscus ◽  
Myotis Lucifugus ◽  
Early Winter ◽  
Natural Conditions ◽  
Myotis Septentrionalis ◽  
Alarm Clock ◽  
Big Brown Bats ◽  
Free Running ◽  
The Mean ◽  
Activity Times

Noting that captive hibernating big brown bats (Eptesicus fuscus) aroused from bouts of torpor at precise times of the day (17:00–19:00), Twente and Twente (J. W. Twente and J. Twente. 1987. Can. J. Zool. 65: 1668–1674) hypothesized the existence of a temperature-compensated, non-free-running biological alarm clock that regulated the timing of arousals in bats. I tested this hypothesis in a natural hibernaculum used by little brown bats (Myotis lucifugus), northern long-eared bats (Myotis septentrionalis), and big brown bats (E. fuscus) by recording the timing of periods of activity with an ultrasonic detector and an electronic datalogger. Although there was significantly (2.5–4.0 times) more activity during the night than during the day, the pattern of activity did not conform with that observed in the laboratory. Bats were found to be active at all times of the day and there was little evidence of a concentration of activity around the period 17:00–19:00 as observed in the laboratory. Over three measurement periods in early winter and midwinter, the mean activity times were 18:54 ± 4.5 h, 23:48 ± 5.0 h, and 23:18 ± 5.2 h. The high variation around the mean times indicates that bats aroused and were active at most times of the night. If a biological alarm clock exists in bats, it is only weakly expressed under natural conditions.

Biological alarm clock arouses hibernating big brown bats, Eptesicus fuscus

1987 ◽  
Vol 65 (7) ◽  
pp. 1668-1674 ◽  
Author(s):  
John W. Twente ◽  
Janet Twente
Keyword(s):  
Laboratory Study ◽  
Eptesicus Fuscus ◽  
Continuous Darkness ◽  
Exogenous Variables ◽  
Alarm Clock ◽  
Big Brown Bats ◽  
Free Running ◽  
The Times ◽  
The Individual

This laboratory study showed that the individual averages of the times of day of arousal from hibernation of 55 big brown bats, Eptesicus fuscus, maintained in darkness, ranged from 14:05 to 20:50 (2:05 p.m. to 8:50 p.m.). The data were interpreted as representing a persistent but inexact 24-h rhythm that functioned as a biological alarm clock. This rhythm was, according to the parameters measured, apparent only on the day of arousal. The rhythm was determined to be independent of the length of time the bat had hibernated; independent of temperature; persistent and did not drift and become free-running in continuous darkness; unapparent in daily cardiac patterns or themogenic activity; and independent of obvious exogenous variables.

scholarly journals Hepatic lipid signatures of little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus) at early stages of white-nose syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evan L. Pannkuk ◽  
Nicole A. S.-Y. Dorville ◽  
Yvonne A. Dzal ◽  
Quinn E. Fletcher ◽  
Kaleigh J. O. Norquay ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Fatty Acid Distribution ◽  
Eptesicus Fuscus ◽  
Myotis Lucifugus ◽  
Pseudogymnoascus Destructans ◽  
Hepatic Lipid ◽  
Early Stages ◽  
White Nose Syndrome ◽  
Big Brown Bats ◽  
Little Brown Bats

AbstractWhite-nose syndrome (WNS) is an emergent wildlife fungal disease of cave-dwelling, hibernating bats that has led to unprecedented mortalities throughout North America. A primary factor in WNS-associated bat mortality includes increased arousals from torpor and premature fat depletion during winter months. Details of species and sex-specific changes in lipid metabolism during WNS are poorly understood and may play an important role in the pathophysiology of the disease. Given the likely role of fat metabolism in WNS and the fact that the liver plays a crucial role in fatty acid distribution and lipid storage, we assessed hepatic lipid signatures of little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus) at an early stage of infection with the etiological agent, Pseudogymnoascus destructans (Pd). Differences in lipid profiles were detected at the species and sex level in the sham-inoculated treatment, most strikingly in higher hepatic triacylglyceride (TG) levels in E. fuscus females compared to males. Interestingly, several dominant TGs (storage lipids) decreased dramatically after Pd infection in both female M. lucifugus and E. fuscus. Increases in hepatic glycerophospholipid (structural lipid) levels were only observed in M. lucifugus, including two phosphatidylcholines (PC [32:1], PC [42:6]) and one phosphatidylglycerol (PG [34:1]). These results suggest that even at early stages of WNS, changes in hepatic lipid mobilization may occur and be species and sex specific. As pre-hibernation lipid reserves may aid in bat persistence and survival during WNS, these early perturbations to lipid metabolism could have important implications for management responses that aid in pre-hibernation fat storage.

The infl1uence of physical clutter and noise on the activity of bats over water

1989 ◽  
Vol 67 (5) ◽  
pp. 1167-1170 ◽  
Author(s):  
Robin L. Mackey ◽  
Robert M. R. Barclay
Keyword(s):  
Myotis Lucifugus ◽  
Foraging Efficiency ◽  
Prey Detection ◽  
Foraging Activity ◽  
Natural Conditions ◽  
Running Water ◽  
Big Brown Bats ◽  
Calm Water ◽  
Bodies Of Water ◽  
Turbulent Water

To determine why some bats concentrate their activity over calm water rather than turbulent water, we studied the effects of surface clutter and running-water noise on the foraging activity of Myotis lucifugus (little brown bats), which commonly fly within 0.5 m of the water surface, and Eptesicus fuscus (big brown bats), which forage at greater heights, in southwestern Alberta, Canada. In paired experiments over calm water, artificial clutter reduced the activity of M. lucifugus, but not that of E. fuscus, compared with natural conditions. Playbacks of the sound of turbulent water reduced the activity of both M. lucifugus and E. fuscus in paired experiments over calm water. Clutter is an obstacle to flight and produces extraneous background echoes that must be discriminated from prey echoes. Water noise may also interfere with prey detection. The result may be reduced foraging efficiency by bats and a preference for calm bodies of water over turbulent ones.

The influence of roost closure on the roosting and foraging behaviour of Eptesicus fuscus (Chiroptera: Vespertilionidae)

1986 ◽  
Vol 64 (5) ◽  
pp. 1128-1133 ◽  
Author(s):  
R. Mark Brigham ◽  
M. Brock Fenton
Keyword(s):  
Reproductive Success ◽  
Direct Observation ◽  
Foraging Behaviour ◽  
Eptesicus Fuscus ◽  
Maximum Distance ◽  
Radio Tracking ◽  
Site Specific ◽  
Big Brown Bats ◽  
Specific Factors ◽  
Foraging Flight

We used radio tracking and direct observation to determine the effect of roost closure on the roosting and foraging behaviour of big brown bats (Eptesicus fuscus) in maternity colonies near Ottawa. Individuals were site loyal, but after eviction they moved short distances to new roosts where they tended to produce fewer offspring. The time spent on the first foraging flight, the maximum distance travelled, and the use of feeding areas did not change with exclusion. The results suggest that bats roost to take advantage of site-specific factors that may increase reproductive success.

scholarly journals The differential transmissibility of myxoma virus strains of differing virulence grades by the rabbit flea Spilopsyllus cuniculi (Dale)

1975 ◽  
Vol 75 (2) ◽  
pp. 237-247 ◽  
Author(s):  
A. R. Mead-Briggs ◽  
J. A. Vaughan
Keyword(s):  
Host Resistance ◽  
Oryctolagus Cuniculus ◽  
Selective Advantage ◽  
Myxoma Virus ◽  
Laboratory Studies ◽  
Natural Conditions ◽  
Male And Female ◽  
The Mean ◽  
Virus Strains ◽  
Sampling Times

SUMMARYLaboratory studies showed that few rabbit fleas (Spilopsyllus cuniculi (Dale)) transmitted myxomatosis after removal from wild rabbits (Oryctolagus cuniculus (L)) that had been infected for fewer than 10–12 days, irrespective of the virulence of the myxoma virus strain involved. Rabbits infected with fully virulent (Grade I) strains died within 10–15 days and few fleas from these hosts became infective; averaging all the samples taken, 12% of the fleas were infective. Also, few fleas acquired infectivity on individual rabbits which recovered from infection with attenuated strains; the mean was 8% infective. Rabbits which died between 17 and 44 days after infection had higher proportions of infective fleas at all sampling times; the mean was 42% infective. Male and female fleas transmitted virus with equal efficiency.For rabbits infected with any of the attenuated virus strains the mean percentage of infective fleas was inversely related to the survival time of the host. Rabbits infected with moderately attenuated strains (Grades IIIA and IIIB) had, on average, the highest proportion of infective fleas; hence such strains have a selective advantage and have become predominant under natural conditions in Britain. The changes that might occur if there is an increase in host resistance to myxomatosis are discussed.

scholarly journals Sampling Blood from Big Brown Bats (Eptesicus fuscus) in the Field with and without Anesthesia: Impacts on Survival

2006 ◽  
Vol 42 (4) ◽  
pp. 849-852 ◽  
Author(s):  
Laura E. Ellison ◽  
Thomas J. O'Shea ◽  
Jeffrey Wimsatt ◽  
Roger D. Pearce ◽  
Daniel J. Neubaum ◽  
...  
Keyword(s):  
Eptesicus Fuscus ◽  
Big Brown Bats

Genetic relationships between roost-mates in a fission–fusion society of tree-roosting big brown bats (Eptesicus fuscus)

2007 ◽  
Vol 62 (7) ◽  
pp. 1043-1051 ◽  
Author(s):  
Jackie D. Metheny ◽  
Matina C. Kalcounis-Rueppell ◽  
Craig K. R. Willis ◽  
Kristen A. Kolar ◽  
R. Mark Brigham
Keyword(s):  
Genetic Relationships ◽  
Eptesicus Fuscus ◽  
Big Brown Bats

A record of Siamese twinning in bats

1969 ◽  
Vol 47 (1) ◽  
pp. 154-154 ◽  
Author(s):  
R. L. Peterson ◽  
M. Brock Fenion
Keyword(s):  
Eptesicus Fuscus ◽  
Royal Ontario Museum ◽  
Big Brown Bats ◽  
Siamese Twin

Specimens of Siamese twin big brown bats (Eptesicus fuscus) now in the Royal Ontario Museum appear to represent the first reported occurrence among bats.

scholarly journals A Comprehensive Assessment of Tropical Stratospheric Upwelling in Specified Dynamics CESM1.2.2 (WACCM)

2019 ◽  
Author(s):  
Nicholas A. Davis ◽  
Sean M. Davis ◽  
Robert W. Portmann ◽  
Eric Ray ◽  
Karen H. Rosenlof ◽  
...  
Keyword(s):  
Best Practices ◽  
Climate Models ◽  
Climate Model ◽  
Meridional Circulation ◽  
Trace Gas ◽  
Mean Meridional Circulation ◽  
Community Earth System Model ◽  
Free Running ◽  
The Mean ◽  
Wave Momentum

Abstract. Specified dynamics (SD) schemes relax the circulation in climate models toward a reference meteorology to simulate historical variability. These simulations are widely used to isolate the dynamical contributions to variability and trends in trace gas species. However, it is not clear if trends in the stratospheric overturning circulation are properly reproduced by SD schemes. This study assesses numerous SD schemes and modeling choices in the Community Earth System Model (CESM) Whole Atmosphere Chemistry Climate Model (WACCM) to determine a set of best practices for reproducing interannual variability and trends in tropical stratospheric upwelling estimated by reanalyses. Nudging toward the reanalysis meteorology as is typically done in SD simulations expectedly changes the model’s mean upwelling compared to its free-running state, but does not accurately reproduce upwelling trends present in the underlying reanalysis. In contrast, nudging to anomalies from the climatological winds or from the zonal mean winds and temperatures preserves WACCM’s climatology and better reproduces trends in stratospheric upwelling. An SD scheme’s performance in simulating the acceleration of the shallow branch of the mean meridional circulation from 1980–2017 hinges on its ability to simulate the downward shift of subtropical lower stratospheric wave momentum forcing. Key to this is not nudging the zonal-mean temperature field. Gravity wave momentum forcing, which drives a substantial fraction of the upwelling in WACCM, cannot be constrained by nudging and presents an upper-limit on the performance of these schemes.

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