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At least 1,315 records · Page 73Linked to original sources
PubMed1979

Female reproductive patterns in nonhibernating bats.

The major reproductive events in the oestrous cycles of nonhibernating mega- and microchiropteran species are reviewed. However, special attention is given to the reproductive biology of the temperate North American species, Tadarida brasiliensis mexicana (Molossidae), the Mexican free-tailed bat, which expresses dextral uterine and ovarian dominance. Only the larger right ovary is capable of producing an ovulatory follicle and the left has long been considered atrophic. In order to elucidate the normal oestrous cycle and define the structural and functional characteristics of the ovaries of this nonhibernating bat several analytical technique were utilized. These included light microscopic analysis, histochemical localization of delta 5-3 beta-hydroxysteroid dehydrogenase (HSD) activity, and radioimmunoassay of seasonal plasma progesterone levels. Interstitial tissue was found in both ovaries, but the left was almost entirely an interstitial organ. Histochemical analysis demonstrated that the gonads have seasonally varying amounts of delta 5-2 beta-HSD localized either in the thecal cells of the Graafian follicle or in the interstitium. The corpus luteum persisted throughout gestation, reaching maximum development just prior to parturition. Circulating progesterone levels correlated directly with luteal gland size and peaked at 106 ng/ml when the corpus luteum was largest.

Animals↗
PubMed1987

Prolonged receptivity to the male and the fate of spermatozoa in the female black mastiff bat, Molossus ater.

Observations were made on the reproductive biology of black mastiff bats maintained in a laboratory colony. Many of the females were inseminated within 24 h after the introduction of the males, and most exhibited a period of 10-50 days during which spermatozoa were present in their vaginal smears almost every day. The frequency of sperm-positive smears began to fall off around the time of implantation, but some smears taken much later in pregnancy were positive. The extent to which spermatozoa in the smears came from reservoirs in the female tract could not be thoroughly investigated, but evidence was obtained that the females have more than a limited period of oestrus. Female courtship behaviour and new copulations were sometimes observed many days after the start of the breeding activity. Also, histological studies of the reproductive tracts of females which had recently mated revealed that many were not in a periovulatory condition. Intact spermatozoa were usually found in the uterine horns and distal oviducts of preovulatory bats and those carrying tubal ova. Spermatozoa were absent from the oviducts of animals bearing early uterine embryos, and were much less abundant in the uterine horns after the start of implantation. Many of the excess spermatozoa appeared to have been expelled into the upper cervix where phagocytic leucocytes were commonly observed in the lumen. Some sperm components were also taken up by epithelial cells in the oviducts and uterine horns.

Animals↗
PubMed1987

Changes in progesterone concentrations in the Japanese long-fingered bat, Miniopterus schreibersii fuliginosus.

In the Japanese long-fingered bat, when compared with the baseline values during non-pregnancy in the autumn, plasma progesterone concentrations were not significantly elevated during the delayed implantation stage that begins before the bats enter hibernation. However, progesterone concentrations were significantly lower during the delayed development stage that occurs during hibernation and rose significantly during the rapid embryogenesis that occurs after arousal from hibernation in the spring. Changes in the corpus luteum volume corresponded closely with those of plasma progesterone values. Maintenance of gravid females at 25 degrees C for 2 weeks in winter resulted in significant increases in the plasma progesterone concentration and the corpus luteum volume.

Animals↗
PubMed1987

Reproduction in Schlieffen's bat, Nycticeius schlieffenii, in the eastern Transvaal lowveld, South Africa.

The present study is based on 153 Schlieffen's bats collected over a 2-year period from September 1983 to September 1985. Spermatogenesis extends over a 10-month period with the first signs of spermatozoa in the epididymides by the end of April. Spermatozoa were present in the epididymides from the end of April until the beginning of September. Copulation begins during June (early winter) and the females have spermatozoa in the uterine horns from then until the end of August (late winter) when ovulation occurs. These bats are seasonally monoestrous with the great majority of births occurring during November. The number of conceptuses varied; a maximum of 5 pre-implanted embryos was recorded, but the maximum number of fetuses observed was 3.

Animals↗
PubMed1988

Fetal development, and placental and maternal plasma concentrations of progesterone in the little brown bat (Myotis lucifugus).

Progesterone concentrations measured in plasma samples from 280 bats captured during pregnancy or early lactation were related to fetal attributes indicative of stage of pregnancy. Fetal weight increased exponentially from 40 mg at crown-rump length of 6 mm to 2000 mg at 23 mm (term). Fetal weights at term accounted for up to 35% of the weight of intact pregnant animals. Progesterone concentrations increased from less than 5 ng/ml at 2 mm estimated crown-rump length to plateau values of approximately 65 ng/ml (geometric means) from 16 mm crown-rump length until the most advanced stages of pregnancy. Mean concentration in 8 post-partum bats, most of which were actively lactating, was 8.4 ng/ml; 11.6 ng/ml was measured in one animal that was carrying a wet neonate when sampled yet was still pregnant when captured 5 h earlier. Placental concentrations of progesterone ranged from 43 to 964 ng/g wet weight of tissue and mean values increased in a similar fashion though were about 4-fold greater than changes in plasma concentrations of the steroid. The concentrations in placental tissue were at least 15- to 20-fold higher than could be expected from blood contamination, indicating that placental steroidogenesis is likely to occur in this species.

Animals↗
PubMed1988

Plasma progesterone concentrations in female little brown bats (Myotis lucifugus) during hibernation.

Monthly collections of hibernating little brown bats contained (1) nulliparous females with small uteri and no antral follicles, (2) nulliparous females with swollen uteri and mature follicles, and (3) parous females, which, despite obvious differences in reproductive status, had equivalent plasma progesterone values. During the principal study season, mean monthly progesterone concentrations (measured by radioimmunoassay) showed recurrent increases with an apparent periodicity of about 60 days, but limited data obtained in the subsequent season did not. However, comparison of activity patterns in the two seasons with monthly progesterone concentrations suggests that ovarian activity during hibernation is affected by variations in metabolic level. We saw no evidence that nulliparous bats with small uteri developed antral follicles during hibernation. Despite their apparent immaturity, however, they had cornified vaginae and most were demonstrably inseminated. These indications of oestrus and the lack of differences between their plasma progesterone concentrations and those of patently mature females suggest that they were physiologically post-pubertal but failed to complete folliculogenesis before entering hibernation.

Animals↗
PubMed1991

Plasma progesterone and luteinizing hormone concentrations and the role of the corpus luteum and LH gonadotrophs in the control of delayed implantation in Schreibers' long-fingered bat (Miniopterus schreibersii).

In Schreibers' long-fingered bat from South Africa (approximately 33 degrees S) copulation, ovulation and fertilization occurred in April and May, implantation was delayed until August, and parturition occurred in December. Delayed implantation coincided with winter, during which the bats remained active, only entering prolonged periods of torpor during particularly cold spells. Plasma progesterone concentration was low during non-pregnancy (1.54 ng/ml) and during delayed implantation (1.67 ng/ml), and thereafter increased to reach a peak mean of 64.82 ng/ml in late pregnancy. Changes in size and ultrastructure of the luteal cells indicated periods of steroidogenesis just after formation of the corpus luteum, and for about 2 months after implantation; reduced steroidogenic activity during delayed implantation; and luteolysis in the last 2 months of pregnancy. Plasma luteinizing hormone (LH) concentration and pituitary LH-beta immunoreactivity were highest during follicular development and peaked just before ovulation. During early delayed implantation, plasma LH concentration was low, and both plasma LH and pituitary LH-beta immunoreactivity increased from July, reaching peaks in late pregnancy. LH may be required to activate the corpus luteum and terminate delayed implantation, or, as in some small carnivores, it may be required for luteal maintenance.

Animals↗
PubMed1992

Oxygen consumption and evaporation during parturition in a vespertilionid bat (Pipistrellus pipistrellus).

Oxygen consumption and evaporation were measured in a single pregnant pipistrelle bat during labour and parturition of twins, using an open-flow respirometry system. During 233 min of measurements, three distinct phases were noted, which we suggest represent prelabour, labour and grooming or suckling the young. On the basis of this hypothesis, during labour and parturition, oxygen consumption was a maximum of 8.9% of daily energy expenditure, evaporation was 2.7% of daily water turnover, and total water loss was 5.5% of daily water turnover in free-living bats in early lactation. We estimated that, for the mother and young combined, oxygen consumption associated with grooming and suckling would be equivalent to 37.5% of daily energy expenditure of the mother, if carried out continuously. Similarly, evaporation due to grooming and suckling would be equivalent to 16.4% of daily water turnover. In terms of daily energy expenditure and daily water turnover, labour and parturition are therefore cheap, but grooming and suckling (even ignoring costs in terms of losses in the milk) are expensive.

Animals↗
PubMed1992

Seasonal reproduction of a tropical bat, Anoura geoffroyi, in relation to photoperiod.

Anoura geoffroyi (Chiroptera, Phyllostomidae, Glossophaginae), Geoffroy's hairy-legged long-tongued bat, were collected from September 1984 to August 1985, and these bats were found to breed seasonally in the wild on Trinidad, West Indies, at 10 degrees N latitude. Histological examination of these samples indicated that females became pregnant in July or August, and young were born in late November or early December. The testes and epididymides were small from September to mid-April, increased threefold in weight between mid-April and late May, reached a peak weight in July, and decreased in weight in August. Spermatogenesis occurred throughout the testes of males captured from May to August. In 1990, the timing of parturition in females that gave birth in the laboratory to young conceived in the wild was similar to the timing in the field in 1984-1985. Groups of 10-13 males were subjected in the laboratory to (i) a gradually changing, civil twilight photoperiod that mimicked the natural cycle of annual change at 10 degrees N latitude, (ii) the same gradually changing cycle of photoperiod accelerated to a six-month period, or (iii) a constant photoperiod (light 12:54 h: dark 11:06 h). These treatments began in mid-December, four months before the initiation of testicular recrudescence in the wild. In all three groups, testicular volume remained low until April, and then increased two- to threefold between late April and late June, rising to a peak in July, as occurred in the wild.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

Stability of the sperm plasma membrane of hibernating bats (Myotis velifer) compared with other mammals.

Previous experiments have established that the long-lived spermatozoa of hibernating bats are resistant to the acrosome reaction and fertilization in vitro conventional techniques. We tested the hypothesis that the membranes of these spermatozoa are more resistant to perturbation than those of other mammals. We exposed them to non-specific bilayer destabilizing agents and abrupt changes in incubation temperature and tested their response by observing their status (motility and viability) after a time interval compared with other mammals (golden hamster, rabbit, human). The results did not support the hypothesis. The inherent longevity of bat spermatozoa may thus be a function of some component other than unique resilience of their plasma membrane.

Animals↗
PubMed1996

High androgen production by ovarian thecal interstitial cells: a mechanism for delayed ovulation in a tropical vespertilionid bat, Scotophilus heathi.

The steroid hormone profile of Scotophilus heathi, and Indian tropical vespertilionid bat, was studied, with special reference to the period of delayed ovulation. The results show unusually high concentrations of circulating androstenedione and testosterone during the first half of the period of delayed ovulation, whereas the concentrations of progesterone and oestradiol were relatively low during this period. Androstenedione, testosterone and oestradiol concentrations were high during the period of ovarian recrudescence (October-November). The oestradiol concentration increased, whereas androstenedione and testosterone declined significantly, before ovulation. Studies in vitro showed that the ovary secrets more androstenedione and testosterone than does the adrenal. A histological study showed that a major part of the ovary of S. heathi was occupied by hypertrophied interstitial cells. An immunocytochemical study showed ovarian thecal interstitial cells as the major site of high androgen synthesis in the ovary. During the period of delayed ovulation the bat ovaries thus resemble the ovaries from women with polycystic ovaries in which abnormally high androgen secretion from hypertrophied interstitial cells prevent ovulation.

Androgens↗
PubMed2001

Gut morphology and morphometry in the epauletted Wahlberg's fruit bat (Epomophorus wahlbergi, Sundevall, 1846).

The morphological adaptations of the fruit bat small intestine to which the high functional efficiency could be related and the possible landmarks delineating the various parts of the gut were examined. The stomach was the carnivorous type with large rugae spanning the entire luminal aspect down to the pyloric sphincter, which was reflected internally as a prominent fold. Externally, the intestine was a continuous tube uninterrupted by any structures. The cranial fifth of the small gut had long, branching and anastomosing villi, which caudally turned to finger-like discrete structures that became rather short and stumpy and diminished at the beginning of the colon. The colon had longitudinal folds that were macroscopically discernible from the mucosal aspect of the opened intestine and that continued into the rectum. The small gut formed 94% of the whole intestinal length, the colon and the rectum taking 4 and 2%, respectively. Ultrastructurally, the enterocyte showed a prominent brush border and the lateral membranes were modified into numerous tortuous interdigitating processes. Adjacent enterocytes were joined by these processes through desmosomes. The processes also participated in pinocytotic fluid uptake from the intercellular spaces with resultant numerous intracellular vacuoles of varied sizes. Solutes absorbed into the cells were probably first passed into the intercellular compartment to create a concentration gradient thus enhancing further absorption into the cell. We conclude that the uniquely elaborate ultrastructure of the enteric epithelium coupled with the vast microvillous surface areas reported elsewhere are partly responsible for the very high absorption rates reported in the fruit bat small intestine.

Animals↗
PubMed2002

Seasonal changes in thyroid activity in the female sheath-tailed bat, Taphozous longimanus (Chiroptera: Emballonuridae).

The present study was designed to investigate changes in thyroid activity during the reproductive cycle in Taphozous longimanus. Thyroid gland showed marked seasonal variation in weight and secretory activity. It was inactive in quiescence and early to mid-winter dormancy and active during recrudescence and breeding period during late winter dormancy. The serum 3,5,3'-triiodothyronine (T3) and thyroxine (T4) concentrations showed significant variation and closely coincided with thyroid activity. The T3 and T4 concentrations were higher in recrudescence, late winter dormancy and minimum in quiescence and initial stages of first pregnancy. The body weight (r = 0.56), ovary weight (r = 0.73), and thyroid weight (r = 0.70) showed correlation with each other and with T3 and T4 concentrations. The correlation between body weight, thyroid weight and T3 and T4 concentrations in non-pregnant bats was higher when compared with pregnant bats. The T3 and T4 levels remained low during the initial stages of development in first pregnancy when compared with the initial stages of second pregnancy. The scant food supply and low levels of T3 and T4 and low temperature during initial stages of first pregnancy might be responsible for differential rate of fetal development in two successive pregnancies in T. longimanus.

Animals↗
PubMed1996

Outbreak of vampire bat biting in a Venezuelan village.

An outbreak of 154 cases of vampire bat biting in a four-month period in the gold mine of Payapal, a Venezuelan village, is reported. All patients were bitten during the night and the most bites were on their toes. No complication attributed to the bite was reported. Diagnoses of rabies virus made by means of immunofluorescence were negative. A possible reason for this outbreak may been the development of mining areas, with the inhabitants providing an alternative food source for the bats.

Adolescent↗
PubMed1998

[Isolation of rabies virus from an insectivorous bat, Nyctinomops macrotis, in southeast Brazil].

The rabies virus was isolated from an insectivorous bat, Nyctinomops macrotis, trapped in Diadema, SP, Brazil, in a public building near a water supply reservoir. Fluorescent antibodies against rabies virus were detected in cerebral tissue and the viral isolation was made after the inoculation of cerebral tissue and salivary gland suspension in mice. There have been no recorded cases of animal rabies in Diadema since 1982, and this is the first isolation of the rabies virus in an insectivorous bat in the city.

Animals↗
PubMed2003

[Comments on models for studying human rabies outbreaks from bats].

This paper analyzes which of the possible public health models could contribute to an understanding of human rabies outbreaks transmitted by bats. First, we present a short review of the most common pertinent models. Second, we present an investigation of a human rabies outbreak transmitted by bats based on the socio-epidemiological model. The same outbreak is analyzed again using the complex system theory as a theoretical framework, as both a theoretical-practical exercise seeking an approximation to this theory and a model to study this problem.

English Abstract↗
PubMed2001

Bat ectoparasites from the Trans-Pecos region of Texas, including notes from Big Bend National Park.

Ectoparasites of 13 species of molossid, mormoopid, and vespertilionid bats from the Trans-Pecos region of Texas were studied, as follows: Antrozous pallidus (LeConte), Corynorhinus townsendii (Cooper), Eptesicus fuscus (Palisot de Beauvois), Lasiurus cinereus (Palisot de Beauvois), Mormoops megalophylla (Peters), Myotis thysanodes G. S. Miller, Myotis velifer (J. A. Allen), Myotis volans (H. Allen), Myotis yumanensis (H. Allen), Nyctinomops femorosaccus (Merriam), Nyctinomops macrotis (Gray), Pipistrellus hesperus (H. Allen), and Tadarida brasiliensis (I. Geof. St.-Hilaire). The bats were netted, examined for ectoparasites and released. Ectoparasites recovered included three species of flea, three species of streblid, three species of nycteribiid, two species of cimicid, two species of tick, and 17 species of mite. New ectoparasite records are given for hosts in seven instances and for the Trans-Pecos region of Texas in three instances.

Animals↗
PubMed2002

Acari ectoparasites of bats from Minas Gerais, Brazil.

Ectoparasites were recovered from Brazilian bats captured from April to November 1997 at or near Parque Estadual do Rio Doce, State of Minas Gerais, southeastern Brazil. Sixty bats were collected, representing three families and 13 species. Five Acari families were recorded: Myobiidae, Trombiculidae, Labidocarpidae, Macronyssidae, and Spinturnicidae. The macronyssid Radfordiella desmodi Radovsky (71 specimens) and the spinturnicid Periglichrus iheringi Oudemans (45 specimens) were the most abundant mite species. They were mainly recorded on Desmodus rotundus (Geoffroy) and Artibeus litratus (Ofers), respectively. Among trombiculid chiggers, the genus Colicus Brennan (55 specimens) was predominant and found mainly on Carollia perspicillata (L.). The current study presents new data about host-parasite relationships and increases the understanding of geographical distribution for some mite and chigger species.

Animals↗