Regional differences in winter activity of hibernating greater horseshoe bats (Rhinolophus ferrumequinum) from Korea

Abstract

Background: Hibernating bats exhibit ubiquitous winter activity in temperate zones, but there is considerable between-and within-species variety in their intensity and purpose. Bats may fly during winter for sustenance or travel to other hibernacula. This study compared inter-regional variation in the winter activity of the greater horseshoe bat (Rhinolophus ferrumequinum). We predicted that weather and hibernacula-environmental conditions would influence winter activity patterns. Results: Winter activity patterns differed between regions. In the Anseong area, we confirmed movement inside the hibernaculum, but in Hampyeong, we observed movement both inside and between hibernacula. The two regions differ by 4°C in average winter temperatures. Anseong experiences 22 days during which average daily temperatures exceeded 5°C, whereas Hampyeong experienced 50 such days. During the hibernating period, bat body weight decreased by approximately 17-20% in both regions. Conclusions: Ambient temperatures and winter-roost environments appear to be behind regional differences in hibernating bat activity. As winter temperatures in Korea do not favor insect activity, feeding probability is low for bats. However, bats may need to access water. At Anseong, underground water flows inside the hibernaculum when the reservoir outside is frozen. At Hampyeong, the hibernaculum does not contain a water source, but the reservoir outside does not freeze during winter. In conclusion, water-source location is the most likely explanation for regional variation in the winter activity of hibernating bats.

Urinary creatinine varies with microenvironment and sex in hibernating Greater Horseshoe bats (Rhinolophus ferrumequinum) in Korea

“…In contrast, the mean daily RH was lower and the variance was greater in H1 than A1. Given that these microenvironment parameters were consistent with a previous study conducted in the same place [ 30 ], the higher creatinine concentrations in H1 might be related with higher TA and lower RH in H1 that could cause higher evaporative water loss [ 37 ]. However, we could not rule out the possibility that the higher creatinine concentrations in H1 were related to frequent or longer arousal that can result in increase of glomerular filtration rate and an increase in the accumulation of urinary creatinine in bladder [ 13 ].…”

“…However, we could not rule out the possibility that the higher creatinine concentrations in H1 were related to frequent or longer arousal that can result in increase of glomerular filtration rate and an increase in the accumulation of urinary creatinine in bladder [ 13 ]. In addition, as hibernating greater horseshoe bats can shift their roosting location within and between hibernacula [ 30 , 38 ], the urinary creatinine differences between A1 and H1 might not result solely from microenvironment differences. Further investigation on arousal frequency and metabolic rate between the two mineshafts will elucidate the reason for the creatinine differences between the two hibernacula.…”

“…Greater horseshoe bats arouse once a week on average during hibernation in the UK [ 29 ]. This arousal may be related to the need for water or energy intake [ 29 ], movement between hibernacula [ 30 ], or mating behaviours [ 31 , 32 ]. However, the reasons for arousal during hibernation have not yet been fully elucidated from a physiological perspective.…”

Three-Dimensional and Histological Observations on Male Genital Organs of Greater Horseshoe Bat, Rhinolophus ferrumequinum

“…Similar plugs are known to exist in other mammals, such as rodents, lipotyphlans, and marsupials (Austin and Short 1972;Rochel et al 2007;Martin et al 2011). It has been reported that R. ferrumequinum can interrupt hibernation (Sano 2001;Kim et al 2019). In the Japanese R. cornutus species, evidence of forced mating during hibernation periods has been recently reported, and the functional significance of the vaginal plug for deterring other males during hibernation period has been pointed out (Sato 2019).…”

Wintering of an urban bat (Pipistrellus kuhlii lepidus) in recently occupied areas

“…The percentage of body mass lost (17-20%) by P. k. lepidus over three months of winter hibernation is similar to that of many underground hibernators such as Myotis daubentonii, Barbastella barbastellus and Rhinolophus ferrumequinum (e.g. Lesinski 1986;Kokurewicz 2004;Kim et al 2019).…”