Activity and shelter selection by Myotis myotis and Rhinolophus hipposideros hibernating in the Kateřinská cave (Czech Republic)

In 1992–1993, the bat species Myotis myotis and Rhinolophus hipposideros hibernating in the Kateřinská cave were investigated by means of regular censuses without any handling and marking of the animals. Three basic parameters of their shelters were recorded (position in cave, type and relative height). In total, during 26 checks we registered 1141 findings of nine bat species. Movement activity, expressed as percentage of new findings during a particular visit, was registered during the whole winter season. Its level fluctuated in different ways and the hibernation period of R. hipposideros could be divided into three different parts, while the level of M. myotis movement activity was relatively high during all season. The shelter selection of R. hipposideros was not dependent on the part of cave where the bats were hibernating, and it did not change during the season. Hibernating specimens of R. hipposideros most frequently used exposed places, in which they were always hanging free. Myotis myotis was registered in all types of shelter with one exception. Rhinolophus hipposideros used mainly the middle part of the cave at a distance between 121 and 180 m from the entrance. The most preferred part of the cave by M. myotis was a small segment of Corridor (between 21 and 30 m), i.e., the entrance part of the cave. Rhinolophus hipposideros is a highly specialized species which prefers parts of the cave with very stable microclimatic conditions and, on the contrary, M. myotis appears to be indifferent to all parameters studied, and it uses the shelters indiscriminately.     

超氧化物歧化酶同工酶分析法用于兽类分类的试探

本文以蝙蝠的5种组织和鼠类的红细胞为材料,从方法上探讨SOD同工酶的分析比较对于兽类分类的价值和意义。实验结果表明SOD同工酶的泳动速度和区带的分布组成,种与种之间有明显的区别,作为一个辅助的工具酶对于兽类的演化和物种的鉴定比较适用。此外,同种的个体间以及同个体的组织间未发现明显区别,这预示在分类工作中不必强调被分析个体数的多寡,也不必进行各组织的全面分析,有利于取材不易的或不能杀死取材的珍稀兽类物种间的比较分析。     

Reduced Neurophysin Immunoreactivity in Rat Suprachiasmatic Nucleus Parallels Dissociation of Circadian Feeding Rhythm in Constant Light

Several distinct neuronal populations can be outlined in the suprachiasmatic nucleus (SCN) by employing immunohistochemistry. Understanding their interaction may serve as the key to the processes involved in the generation of circadian rhythms by the SCN. 15 adult rats were exposed to constant dim light (LL) and 3 animals as controls to an LD 12:12 light schedule over 140 days. When sacrificed 10 of the LL-animals had lost their circadian feeding rhythm while 5 were free-running and the controls kept an entrained rhythm. The brains were immunohistochemically stained for myelin basic protein, neurophysin (NPH), vasoactive intestinal peptide, neuropeptide Y, synaptophysin and the leucocyte epitopes FAL and HNK-1. Demarcation of intensely and very intensely stained NPH-positive areas by subjective gray-level-discrimination and computerized area measurement revealed that in rhythmic rats (n=8) the areas containing the stained material were twice as large (0.06 ± 0.03 mm2 vs. 0.028 ± 0.027 mm2; p=0.05) than in arrhythmic animals. It is hypothesized that low NPH-contents in arrhythmic animals reflect arrest of the ‘clockwork’ in the SCN at circadian time 12:00.     

Effect of intrinsic and extrinsic factors on the variability of echolocation pulses of Myotis nigricans (Schinz, 1821) (Chiroptera: Vespertilionidae)

Bats may exhibit plasticity in echolocation pulses as response to intrinsic and extrinsic factors, and the estimation of the magnitude of such variation can provide confidence in acoustic monitoring. Myotis nigricans (Schinz, 1821) is a widely distributed but relatively understudied Neotropical species for which, during fieldwork, we found maternity colonies in the Lagunas de Montebello National Park, in Chiapas, South-east Mexico, and no previous information in the area. Therefore, we aimed to provide an acoustic characterization on the basis of intraspecific variability for its recognition using bat detectors. For this purpose, we examined the moulding of shape, frequency-based and time-based acoustic parameters, specifically by the effect of age group (sub-adults vs. adults) and acoustic environment (open space vs. background vegetation). By graphic comparison of echolocation pulses between acoustic environments, we observed changes in shape by an increase in bandwidth and steeper modulation along background vegetation. Statistically, on univariate basis, we did not find a significant effect of age group, but we did of acoustic environment, specifically on highest frequency (higher average), duration (shorter average) and interpulse interval (shorter average) along background vegetation. On multivariate basis, we confirmed shorter average interpulse interval along background vegetation. The overall classification accuracy was relatively high (82.22%): 80% in open space and 84% along background vegetation. Our work reinforces previous knowledge about sound constraints imposed by vegetation clutter, and provides a reliable framework for acoustic monitoring of this species across structurally variable, and hence acoustically variable, environments in the area.     

A Comparison of mucosal surface area and villous histology in small intestines of the Brazilian free‐tailed bat (Tadarida brasiliensis) and the mouse (Mus musculus)

Studies on birds have led to the hypothesis that increased intestinal absorption between enterocytes (paracellular) evolved as a compensation for smaller intestinal size in fliers, which was perhaps selected to minimize the mass of digesta carried. This hypothesis predicts that bats will also exhibit relatively reduced intestinal size and high paracellular absorption, compared with nonflying mammals. Published studies on three bat species indicate relatively high paracellular absorption. One mechanism for increasing paracellular absorption per cm² small intestine (SI) is increased number of tight junctions (TJs) across which paracellular absorption occurs. To our knowledge, we provide the first comparative analysis of enterocyte size and number in flying and nonflying mammals. Intestines of insectivorous bats Tadarida brasiliensis were compared with Mus musculus using hematoxylin and eosin staining method. Bats had shorter and narrower SIs than mice, and after correction for body size difference by normalizing to mass^3/4, the bats had 40% less nominal surface area than the mouse, as predicted. Villous enhancement of surface area was 90% greater in the bat than in the mouse, mainly because of longer villi and a greater density of villi in bat intestines. Bat and mouse were similar in enterocyte diameter. Bats exceeded mice by 54.4% in villous area per cm length SI and by 95% in number of enterocytes per cm² of the nominal surface area of the SI. Therefore, an increased density of TJs per cm² SI may be a mechanistic explanation that helps to understand the high paracellular absorption observed in bats compared to nonflying mammals. J. Morphol. 276:102–108, 2015. © 2014 Wiley Periodicals, Inc.     

Fruit digestion time,integrity and germination of seeds defecated by Artibeus lituratus (Olfers, 1818) (Chiroptera: Phyllostomidae)

We evaluated the effects on the integrity, germinability and mean germination time of three Ficus species eaten by Artibeus lituratus in captivity. The passage of seeds through the digestive tract of the animal did not interfere in the germinability and the mean germination time of F. organensis; however, it increased the germination of F. guaranitica and reduced the mean germination time of F. glabra. The mean time of digestion of A. lituratus presented no significant difference for Ficus species. The results showed that A. lituratus has a good potential for dispersal and can modify the germination of some Ficus species.