We studied the hibernation behavior of the water frog Rana lessonae and its hybridogenetic associate R. esculenta in their natural habitat during three successive winters. Animals caught in pitfall traps at a fenced pond were individually
marked with PIT tags and some (n=36) were additionally equipped with radio transmitters. Of the animals caught, 85% left the fenced pond for hibernation.
More R. esculenta remained inside the fenced area compared to R. lessonae. R. lessonae emigrated earlier in autumn and came back later in spring than R. esculenta, but the distance to their hibernation sites did not differ. Both species left the fenced pond earlier in the year when ambient
temperatures were lower. All radio-tracked animals hibernated in woodland, 3–7 cm below the surface in soil, under moss, fallen
leaves or small branches. Soil temperatures at the actual hibernation sites were significantly higher than at randomly chosen
control sites. A surprising finding was that most frogs changed their hibernation sites during winter, and often more than
once. Movements were more frequent in the warmer first half of the winter than in the cooler second half, but some animals
were active even on days with mean temperatures below 1°C. These results show that both species do not spend the whole winter
torpid in one particular hibernation site but move around, especially at higher temperatures. Most of the animals lost weight
during the winter, and the weight loss was greater in females than in males and higher in warm than in cold winters. To what
extent weight loss and survival is influenced by the chosen hibernation sites and the amount of movement during winter, and
whether this contributes to the differences in species and sex ratios found in mixed populations, needs more investigation.
Received: 4 August 1999 / Accepted: 15 November 1999 相似文献
The initiation of innate immunology system could play an important role in the aspect of protection for sperms long‐term storage when the sperms got into oviduct of turtles and come into contact with epithelium. The exploration of TLR2/4 distribution and expression in oviduct during hibernation could help make the storage mechanism understandable. The objective of this study was to examine the gene and protein expression profiles in Chinese soft‐shelled turtle during hibernation from November to April in the next year. The protein distribution of TLR2/4 was investigated in the magnum, isthmus, uterus, and vagina of the turtle oviduct using immunohistochemistry, and the gene expression of TLR2/4 was analyzed using quantitative real‐time PCR (qRT‐PCR). The results showed positive TLR2 protein expression primarily in the epithelium of the oviduct. TLR4 immunoreactivity was widely observed in almost every part of the oviduct, particularly in the epithelium and secretory gland membrane. Analysis of protein, mRNA expression revealed the decreased expression of TLR2/4 in the magnum compared with the isthmus, uterus, and vagina during hibernation. The protein and mRNA expression of TLR2 in the magnum, isthmus, uterus, and vagina was decreased in April compared with that in November. TLR4 protein and mRNA expression in the magnum, isthmus, uterus and vagina was decreased in November compared with that in April. These results indicated that TLR2/4 expression might protect the sperm from microbial infections. In contrast to the function of TLR2, which protects sperm during the early stages of hibernation, TLR4 might play a role in later stages of storage. The present study is the first to report the functions of TLR2/4 in reptiles. 相似文献
The predation pressure of the greater horseshoe bat, Rhinolophus ferrumequinum, on the diapausing population of the noctuid moth, Goniocraspidum preyeri, was examined at an abandoned mine in central Japan. These bats did not prey on the moths in summer. The number of moths preyed on was largest in March. More than 60% of the diapausing moths were eaten by only three or four bats, which accounted for over 90% of all the moth deaths. This moth was an important source of food at the end of the hibernating period when the bat had already used most of its stored subcutaneous fat. The predation on G. preyeri may have raised the overwintering success rate of R. ferrumequinum. 相似文献
(1) The analysis of catecholamines revealed alterations in norepinephrine levels in the blood serum and the central nervous system of the Egyptian cobra during the different phases of the hibernation cycle. This may reflect an increased central demand for norepinephrine as a mediator for adaptive changes to cold.
(2) The low and variable concentration of dopamine suggests retarded synthesis during all the phases studied.
(3) Serotonin may be depleted or associated with increased activity of serotonergic neurons during cold acclimation. This increases the rate of turnover of serotonin to 5-hydroxy indole acetic acid.
(4) Cricannual measurements of cortisol and adrenocorticotrophic hormones revealed marked suppression that would clarify the direct effect of hibernation on higher centers. The decreased levels during prehibernation and hibernation were restored in normothermic animals when the pituitary–adrenal axis resumed its activity.
(5) The decline in thyroid hormone concentrations has its behavioural and physiological responses that lead to seasonal adjustments in the hibernating cobras.
The digestive tract is the largest endocrine organ in the body; the distribution pattern of endocrine cells varies with different pathological and physiological states. The aim of the present study was to investigate the distributed density of 5-hydroxytryptamine (5-HT), gastrin (GAS), somatostatin (SS) and vasoactive intestinal peptide (VIP) immunoreactive (IR) cells in the digestive tract of Alligator sinensis during the active and hibernating period by immunohistochemical (IHC) method. The results indicated that 5-HT-IR cells were distributed throughout the entire digestive tract, which were most predominant in duodenum and jejunum. The density increased significantly in stomach and duodenum during hibernation. GAS-IR cells were limited in small stomach and small intestine. The density decreased significantly in small stomach during hibernation, while increased in duodenum. What's more, most of the endocrine cells in duodenum were generally spindle shaped with long cytoplasmic processes ending in the lumen during hibernation. SS-IR cells were limited in stomach and small stomach. The density increased in stomach while decreased in small stomach during hibernation, meanwhile, fewer IR cells occurred in small intestine. VIP-IR cells occurred in stomach and small stomach. The density decreased in small stomach, while increased in stomach during hibernation. These results indicated that the endocrine cells in different parts of digestive tract varied differently during hibernation, their changes were adaptive response to the hibernation. 相似文献
Summary Immunocytochemical studies were performed to describe the characteristics of cell types and their distribution in the pars distalis of Japanese long-fingered bat, Miniopterus schreibersii fuliginosus, collected at various stages of the reproductive cycle. Six distinct cell types have been identified in the pars distalis by the unlabeled immunoperoxidase technique and by the ABC method. Growth hormone (GH) and prolactin (PRL) cells were immunostained with antisera against chicken GH and ovine PRL. The GH-immunoreactive cells were round or oval orangeophilic cells distributed throughout the pars distalis with prominent aggregation in the posterolateral region. The PRL cells were pleomorphic carminophilic cells that occurred in small groups within the central and dorsocaudal regions of the pars distalis. They were sparsely distributed in the central region of the pars distalis in the hibernating bats, but increased significantly in the pregnant and lactating bats. The adrenocorticotropic (ACTH) cells were large round or polygonal amphophilic cells in the rostroventral and ventrolateral regions of the pars distalis. The thyrotropic (TSH) cells were small rounded or polygonal and distributed mainly in the ventrolateral region of the pars distalis. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) cells were identified immunocytochemically with antisera against the specific beta subunits of ovine LH and rat FSH. There were two populations of LH and FSH cells, one aggregated in the zona tuberalis and the other scattered singly throughout the rest of the pars distalis. The aggregated cells were immunoreactive with both antisera directed to LH and FSH, while scattered cells were reactive solely with antiserum to either LH or FSH and exhibited seasonal variations. In females, the proportional volume of the pars distalis occupied by LH cells was significantly reduced during pregnancy and lactation. No evidence of involution was observed in pars distalis cells except for PRL cells in males or females during hibernation. 相似文献