Male influence on oestrous cycles in female woolly opossum (Caluromys philander)

Plasma progesterone concentrations and the occurrence of oestrous cycles were studied in isolated woolly opossums subsequently subjected to male influences during a 40-day period. Pairing (N = 48) or exposure to male urine (N = 15) resulted in all females exhibiting oestrous during the stimulation phase, providing evidence that the activation of ovarian activity in the woolly opossum involves pheromonal cues from males. The latency of occurrence of oestrous in stimulated females depended upon their sexual state before male stimulation. In anoestrous females, the mean latency was 20.7 +/- 0.9 days (N = 35), a value which agrees with the duration of the follicular phase. In females which first entered oestrous before male stimulation, the latency of induced oestrous was inversely correlated to the date of occurrence of the previous oestrous. The inter-oestrous interval was normal (38.1 +/- 1 days, N = 5) when females were in oestrous at the beginning of male stimulation. In contrast, the inter-oestrous interval was significantly shortened (28.7 +/- 2 days, N = 7) or lengthened (51.1 +/- 1.7 days, N = 16) depending on whether females were in the luteal or follicular phases at the beginning of male stimulation. During pairing several females became pregnant and gave birth 24 +/- 0.9 days (N = 13) after copulation. In the woolly opossum, the response to male influences involves mechanisms similar to those observed in eutherians and results in enhancement and synchronization of oestrous cycles in females. Pheromonal interactions could play an important role in synchronizing oestrous cycles in wild females during the dry season, a period when animals regroup to feed on spatially localized food resources.     

Carpal ontogeny in Monodelphis domestica and Caluromys philander (Marsupialia)

Carpal bones have experienced numerous changes during marsupial evolution, even though their diversity and development remain poorly studied. The aim of this work was to document adult form and the pattern of mesenchymal tissue condensation and formation of chondrification and ossification centers in the hand of two marsupials. Two fundamental questions were asked: whether the loss of embryonic precursors was associated with the loss of adult elements, or whether there were developmental signs of ancestral mammalian elements that have been fused or lost in marsupial taxa. We were also interested to find out whether there is sexual dimorphismus in the carpals, as has been reported for some didelphids. Histological sections, cleared and stained specimens and macerated skeletons representing an ontogenetic series of Monodelphis domestica were used to document carpal development. Comparisons were made with perinatal stages of Caluromys philander and with adult specimens of other marsupials. A prenatal M. domestica in the 13th day after conception has a cell condensation that because of its position is homologized with a centrale, which is at birth already lost or fused. Neonatal M. domestica and C. philander have the number and arrangement of their adult carpal anatomy. Trapezium and trapezoid start ossification later than most other carpals, while pisiform and prepollex are the last to do so. Adult males of M. domestica have relatively larger and more robust pisiforms, compared to other carpals, than females. This sexual dimorphism develops relatively late as it was not recorded in male specimens around 160 days old. An extra sesamoid bone located just distal to the radius and proximo-palmar to the scaphoid was recorded in specimens of C. philander, C. derbianus and Didelphis virginiana.     

Use of zygodactylous grasp by Caluromys philander (Didelphimorphia: Didelphidae)

The present report aims to quantify the use of zygodactylous (opposability of digits II to III) grasping in relation to positional modes and support size and orientation, in the highly arboreal, walking/climbing woolly opossum, Caluromys philander. For this purpose, four captive adult C. philander were intensively video-recorded and their positional behavior, hand grasp, and support size and orientation use were analyzed frame-by-frame. Overall, C. philander used a zygodactylous grasp in 81.3±1.2% of bouts. In terms of support features, this grasp was particularly common on (a) supports that could be wholly and partly held by the animals’ hand and (b) vertical supports in particular. In a comparable manner, zygodactyly dominated during above-support positional modes, but was significantly less used during bridging and suspension. The results show that zygodactyly provided an above-support secure and steady grasp on relatively unstable arboreal supports, by aligning the hand with the main axis of the support. This very likely assisted in controlling over the applied torques during cautious quadrupedal and climbing activities with extended hand contact that characterizes the locomotor strategy of C. philander. These observations need to be further tested by more detailed kinetic studies and on a larger sample of arboreal didelphids.     

Serum chemistry concentrations of captive woolly monkeys (Lagothrix lagotricha)

Woolly monkeys (Lagothrix sp.) are threatened species and numerous zoos have failed to sustain successful populations. The most common causes of death in captive woolly monkeys are related to pregnancy and hypertension. The objective of this retrospective study was to evaluate serum concentrations of a large number of captive woolly monkeys to establish baseline means and compare these concentrations with their closest related species to determine potential abnormalities. Serum analyses from 30 woolly monkeys housed at two institutions (Apenheul, The Netherlands and The Louisville Zoo, KY, USA) over 12 yr were collected. The statistical model included gender, age group (young, 0–4 yr of age; middle, 5–9 yr; and old, 10+ yr), and zoological institution. All panel result means were similar to previously reported concentrations for howler (Alouatta sp.) and spider monkeys (Ateles sp.) with the possible exception of alanine aminotransferase and γ‐glutamyl‐transferase being higher, whereas creatinine and phosphorus were lower. The serum glucose mean of 6.7 mmol/L is above the baseline range for humans and spider monkeys. Alkaline phosphatase (ALP), alanine aminotransferase, and sodium (Na) were higher in females and magnesium (Mg) was higher in males (P<0.05). ALP, Mg, and phosphorus were highest (P<0.05) and calcium and sodium tended to be highest (P<0.10) in the oldest animals. Ferritin tended to be highest (P<0.10) in the oldest animals. Albumin, ALP, chloride, Na, and total bilirubin were higher for Zoo A, whereas γ‐glutamyl‐transferase, glucose, and lactate dehydrogenase were lower for Zoo A (P<0.05). Areas of potential woolly monkey health risk were noted and discussed. Future studies are needed to determine free‐ranging serum concentrations to elucidate parameters that contain aberrant concentrations and decrease health status. Zoo Biol 27:188–199, 2008. © 2008 Wiley‐Liss, Inc.     

Behavior and maintenance of the woolly opossum (Caluromys) in captivity

Circadian activity, general behavior, dietary requirements, and reproductive activity were recorded in a small laboratory colony (four females, six males) of two species of the woolly opossum (Caluromys lanatus and C derbianus) over a period of 3 years. The two species were indiscernable in all aspects of their behavior. Both were completely nocturnal and rarely active during daylight hours. General behavior was apparently related to many variables, particularly individual temperament and cage size. Even docile individuals were more excitable when housed in small cages. Although the woolly opossum is reported to prefer a meat diet, the opossums in this study remained healthy on a meat-egg-fruit diet, and showed a special liking for fruit, especially bananas. Vaginal smears indicated that females of the colony were cyclic, but all attempts to breed them were unsuccessful. Sexual behavior included pre-mount, pelvic-thrust displays on the part of the male, with complete repulsion by all females.     

Plasma progesterone, androstenedione and testosterone concentrations in freemartin heifers.

Plasma concentrations of testosterone, androstenedione and progesterone in freemartins, and normal cyclic and non-cyclic heifers were studied. The plasma testosterone concentrations were in general less than 10 pg/ml in all animals. The mean androstenedione concentration of 28 pg/ml in 10- to 12-month-old freemartins was significantly lower than the mean of 58 to 60 pg/ml for normal 10- to 12-month-old heifers. At 24 months of age the mean androstenedione concentration in the freemartins had risen significantly to 65 pg/ml.     

Variations of chromosomal structures in Caluromys philander (Didelphimorphia: Didelphidae) from the Amazon region

Caluromys is considered to be one of the most ancient genera of extant marsupials and is positioned among the basal taxa of the family Didelphidae. At least two species occur in Brazil, C. philander and C. lanatus, both of which have 2n = 14 chromosomes. For the first time, we present evidence of an intrapopulation polymorphism of the sexual chromosome pair in C. philander females from the Central Amazon region. Detailed cytogenetic results of animals from three localities on the Amazon region were analyzed using classical cytogenetics (NOR, C-Band and G-Band) and molecular techniques (18S rDNA and telomere probes). Similar to other conspecific individuals, the diploid number of these animals is 2n = 14, and their fundamental number is 24, with NOR present on the 6th autosomal pair. The X chromosome presented variation detectable by G banding, suggesting a pericentric inversion.     

Chest-rubbing in captive woolly monkeys (Lagothrix lagotricha)

The correlates of chest-rubbing were studied in a captive group of woolly monkeys (Lagothrix lagotricha) to assess possible functions of territorial marking, spacing among competing groups or competing males, reproductive communication, marking to identify familiar environments, selfanointing, and displacement activity. Chest-rubbing was observed only in sexually mature monkeys and was a predominantly male activity. Females increased chest-rubbing when the original adult male died. Chest-rubbing by the first adult male was more common during the two months that he was mating with two females and at times when keepers were likely to be at the exhibit. The results suggest a reproductive function for chest-rubbing in both males and females. There is also support for chest-rubbing as a spacing activity.     

Highly conserved d-loop sequences in woolly mouse opossums Marmosa (Micoureus)

This study reports the occurrence of highly conserved d-loop sequences in the mitochondrial genome of the woolly mouse opossum genus Marmosa subgenus Micoureus (Mammalia, Didelphimorphia, Didelphidae). Sixty-six sequences of Marmosa (Micoureus) demerarae, Marmosa (Micoureus) constantiae, and Marmosa (Micoureus) paraguayanus were amplified using universal d-loop primers and virtually no genetic differences were detected within and among species. These sequences matched the control region of the mitochondrial marsupial genome. Analyses of qualitative aspects of these sequences revealed that their structural composition is very similar to the d-loop region of other didelphid species. However, the total lack of variability has not been reported from other closely related species. The data analyzed here support the occurrence of highly conserved d-loop sequences, and we found no support for the hypothesis that these sequences are d-loop-like nuclear pseudogenes. Furthermore, the control and flanking regions obtained with different primers corroborate the lack of variability of the d-loop sequences in the mitochondrial genome of Marmosa (Micoureus).     

Plasma corticosterone concentrations in wild and captive juvenile tuatara (Sphenodon punctatus)

Abstract

High mortality and abnormal growth patterns commonly found in captive juvenile tuatara were hypothesised to be due in part to the effects of long‐term chronic stress of captivity. This study compared plasma concentrations of the reptilian adrenal steroid, corticosterone, in wild juvenile tuatara on Stephens Island, Cook Strait, and in captive juveniles of Stephens Island origin, held in New Zealand institutions, in February and August 1992. Seasonal variation in plasma concentration of corticosterone in wild juveniles in four seasons of the year was also examined. This is the first study of seasonal cycles in plasma corticosterone in a wild juvenile reptile. Plasma corticosterone concentrations were significantly higher in captive juvenile females (4.21 ± 0.27 ng/ml; mean ± SE) compared with wild juvenile females (2.44 ± 0.42 ng/ml) in February (P < 0.05), but not in August, and there was no difference in concentration between captive and wild juvenile males in either month. There was significant seasonal variation in plasma corticosterone in wild juvenile females (P < 0.05). However, there was no seasonal variation observed in wild juvenile males, and the magnitude of the variation in plasma corticosterone was low in both sexes (1.28 ± 0 ng/ml ‐4.65 ±3.41 ng/ml). Although mean plasma corticosterone was higher in captive juvenile females compared with wild juvenile females in February 1992, the value in captive females was within the range of mean plasma corticosterone concentrations observed in the seasonal study, and may be therefore due to asynchronicity of seasonal cycles, rather than stress. Further research is required; however, lack of correlation between plasma corticosterone concentrations and either growth rate or density indicate that captive juvenile tuatara in New Zealand are not suffering from pronounced chronic stress.     

Food preferences of captive gray short-tailed opossums (Monodelphis domestica)

The gray short-tailed opossum has been a subject in behavioral and biomedical studies for the last quarter century, but researchers know little about its preferred diet. The authors describe a study designed to determine food preferences of this species for the purpose of identifying suitable rewards to be used in behavioral studies.     

Bird predation by captive woolly monkeys (Lagothrix lagotricha)

Vertebrate predation has not been reported for woolly monkeys (Lagothrix lagotricha) in their natural habitat. However, bird predation has been observed in captivity. The present report is based on 15 incidents of bird predation that occurred during a 1-year observational study of the nine woolly monkeys at the Louisville Zoo. All identified captures were by females. The captor and her prey were frequently pursued by the other monkeys. Social rank was related to attempts to steal the prey. Consumption was characterized by much chewing and frequent alternation between the prey and highly fiberous substances. Predation was not characterized by stereotypical behaviors for pursuit or killing of prey, but instead suggested opportunistic capture by a generalized organism. The low frequency of bird predation by captive woolly monkeys may indicate that a similar level of predation has gone undetected in the study ofLagothrix in the wild.     

Plasma aldosterone concentrations in wild and captive western spotted frogs (Rana pretiosa)

Plasma aldosterone concentration (1.33 ± O.10 ng/ml) was substantially lower in a wild population of Rana pretiosa than in frogs from the same population held in captivity for three weeks (4.48 ± 0.55 ng/ml). The aldosterone value for the wild population was much lower than circulating levels previously reported for laboratory amphibians but higher than those reported for other vertebrates.     

Plasma concentrations of progesterone, oestrogens, testosterone and LH-like activity during the oestrous cycle of the camel (Camelus dromedarius)

Peripheral plasma concentrations of progesterone, total oestrogens and testosterone (measured by RIAs) and LH (monitored by the mouse Leydig cell bio-assay) were measured in 8 female camels for a complete oestrous cycle (23.1 +/- 1.2 days). The absence of an LH surge and a low concentration of progesterone (less than 1 ng/ml) during oestrus (5 days) and throughout the cycle indicated a failure of spontaneous ovulation and absence of a subsequent luteal phase in this species. High concentrations of testosterone and oestrogens indicated that the oestrous cycle in the camel is mostly follicular and that the increasing values of the two hormones during follicular development (5 days) is probably the stimulus to behavioural oestrus.     

Diurnal variations in serum testosterone concentrations of captive adult male chacma baboons (Papio ursinus)

Captive adult male chacma baboons (Papio ursinus) housed with natural lighting exposure and blood sampled at 3-hr intervals showed significant diurnal variations in serum testosterone concentrations. Low mean concentrations were found at 0800 hr approximately 1 hr after sunrise and mean concentrations were their highest at 2000 hr approximately 1 ¼ hr after sunset.     

Plasma progesterone concentrations in the female Natal clinging bat (Miniopterus schreibersii natalensis)

Plasma progesterone concentrations measured by radioimmunoassay in the Natal clinging bat remained below 2.01 ng/ml during lactational anoestrus but increased significantly during the period of delayed implantation. Values peaked at implantation but were followed by a significant decrease thereafter. Concentrations remained low (less than 6.0 ng/ml) during the initial period of fetal development (153-180 days post coitum) and attained peak values (85.6-181.3 ng/ml) 216-222 days after fertilization. The marked post-implantation increase in progesterone concentrations coincided with a significant increase in placental weight.     

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.