Evidence Of Reproductive Activity Research Articles

Update of the distribution of Lonchorhina aurita (Chiroptera), a vulnerable cave-dwelling bat in Brazil

Lonchorhina aurita is an insectivorous cave-dwelling bat, which roosts primarily in caves, and has been reported from three (Cave Pedra Branca, Cave Janela, and Cave Raposa) of the 94 natural caves registered in Sergipe by the National Register of Speleological Information/National Center for Cave Research and Conservation.The subfamily Lonchorhininae encompasses bats that can be distinguished from other phyllostomids by the presence of an extremely well-developed nasal leaf, which is as long as the ears. This study provides an update on the distribution of this species and reports its first record in the Caatinga for the state of Sergipe, northeastern Brazil. An adult female and an adult male with no evidence of reproductive activity were captured by mist nets in the surroundings of the Xingo Hydroelectric Reservoir, a region dominated by shrubby hyper xerophilous Caatinga vegetation, at the height of the dry season. The morphometric and morphological data were consistent with those recorded for the species in other South American countries. It is important to prioritize the investigation of these sites in order to better understand the abundance and distribution of the species in Sergipe, which is classified as threatened in Brazil.Keywords: bats, caves, distribution, Lonchorhininae, Tomes’s sword-nosed bat, threatened species.

Refining Aging Criteria for Northern Sea Otters in Washington State

AbstractMeasurement of skull ossification patterns is a standard method for aging various mammalian species and has been used to age sea otters Enhydra lutris from Russia, California, and Alaska. Cementum annuli counts have also been verified as an accurate aging method for sea otters in Alaska. In this study, we compared cementum annuli count results and skull ossification patterns as methods for aging the northern sea otter, E. l. kenyoni, in Washington State. We found significant agreement between the two methods, suggesting that either method could be used to age sea otters in Washington. We found that ossification of the squamosal–jugal suture at the ventral glenoid fossa can be used to differentiate male subadults from adults. To assist field biologists or others without access to cementum annuli or skull ossification analysis techniques, we analyzed a suite of morphologic, physiologic, and developmental characteristics to assess whether a set of these more easily accessible parameters could also predict age class. We identified tooth condition score, evidence of reproductive activity in females, and tooth eruption pattern as the most useful criteria for classifying sea otters in Washington. We created a simple decision tree based on characteristics accessible in the field or at necropsy, which can be used to reliably predict age class of Washington sea otters as determined by cementum annuli. These techniques offer field biologists and marine mammal stranding networks a replicable, cost-conscious methodology to gather useful biological information from sea otters.

Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean.

Whale sharks are generally associated with environmental factors that drive their movements to specific locations where food availability is high. Consequently, foraging is believed to be the main reason for the formation of whale shark aggregations. Feeding aggregations occur mainly in nearshore areas and are composed primarily of immature individuals. Conversely, aggregations of mature adults are rarely observed, and their occurrence is correlated with oceanic environments. Despite an increase in the number of whale shark studies, information on mating and parturition grounds is still lacking. In the present work, we assessed the ecological and behavioural aspects of the whale sharks that visit the archipelago of São Pedro and São Paulo (ASPSP), located ~1,000 km off the coast of Brazil in the equatorial Atlantic Ocean. Forty-nine whale sharks were recorded from February 2005 to May 2014. The estimated mean ± SD size was 8.27 ± 2.52 m (range: 2.5–14.0 m) with no significant differences in size across the year. The maturational stages were classified by size as immature (<8.0 m; 32.56%) and mature (>9.0 m; 46.51%); with almost half of the observed animals being mature specimens. The majority of sightings occurred between February and June. During this period, the ocean current weakens and the waters are enriched by eggs and larvae of fishes and invertebrates that attract marine life to forage. At the same time, evidence of reproductive activity in adult females (i.e. swollen abdomen and bite marks on the pectoral fins), and the potential mating behaviour exhibited by one male, suggest that the ASPSP area might also have a role in whale shark reproduction. Irrespective of its use for feeding or reproduction, this insular habitat serves as a meeting point for both juvenile and adult whale sharks, and may play an important ecological role for the species.

Exploiting boom times. Southern Boobook OwlNinox novaeseelandiaediet during a rodent irruption in central Australia

Populations of Australian desert rodents are known to undergo booms in response to resource pulses following periods of high rainfall. Australia's arid-adapted Tyto owls have been recorded responding functionally and numerically to these small mammal booms, though it is not known whether Southern Boobook Ninox novaeseelandiae is able to respond similarly. We aimed to determine whether Southern Boobooks could find and exploit a localised rodent irruption in the western Simpson Desert, in a location with few roost trees and no tree hollows. Boobook owls immigrated to the site from an estimated distance of ≥ 32 km and appeared to be resident over a period of ≥ 4 months, coinciding with a localised irruption of Plains mice Pseudomys australis. Dietary analysis confirmed that the owls specialised on small mammals, with rodent and dasyurid species accounting for c. 98% of prey items and > 99% of prey biomass. There was no evidence of reproductive activity among the owls and they vacated the area as the small mammal irruption subsided. Although a dietary generalist across its range, our results indicate the Southern Boobook is capable of specialising on small mammals during population irruptions.

Extant population of the Critically Endangered central rock-rat Zyzomys pedunculatus located in the Northern territory, Australia

AbstractThe central rock-rat Zyzomys pedunculatus is categorized as Critically Endangered on the IUCN Red List. Over the last 50 years the species had only been recorded from 14 sites within a 600 km2 area of the West MacDonnell National Park and immediate surroundings in the Northern Territory, Australia. The central rock-rat disappeared from monitoring sites in 2002, coincident with the onset of drought conditions and extensive wildfires. With concern growing for the survival of the species, we sought to locate an extant population. During 2009–2012 we surveyed sites throughout the western sector of the West MacDonnell National Park, including sites where rock-rats had previously been recorded. From a total of 55 sites and 5,000 trap nights we located eight central rock-rats from only five sites (overall detection rate = 0.16 rock-rats per 100 trap nights). All sites were on two mountain-top locations, both of which are over 1,250 m altitude. Evidence of reproductive activity was observed at both locations but the subpopulations were relatively localized and no individuals were captured at any of the sites from which the species was known previous to these surveys. Although the rugged mountains may provide the central rock-rat with some refuge from predation and wildfires, more research is needed to understand better the factors suppressing and constraining the species at the population and landscape scales. Immediate management priorities are prescribed burning to limit the extent and severity of wildfires and trialling a baiting programme with 1080 to target feral cats in the mountains.

Histological evidence of reproductive activity in lizards from the APM Manso, Chapada dos Guimarães, Mato Grosso State, Brazil

The construction of dams causes major impacts on fauna by changing or eliminating irreversibly their habitats. The resulting changes lead to deep potential modifications on reproductive biology and population structure of lizards, snakes and amphisbaenas. The reservoir in the Multiple Use Area of Manso (APM-Manso) is located near to Chapada dos Guimaraes National Park, in Mato Grosso State. We analyzed comparatively the male gonads of Anolis meridionalis, Colobosaura modesta, Cercosaura ocellata, Cnemidophorus ocellifer, Hoplocercus spinosus, Bachia bresslaui, Mabuya frenata, Micrablepharus atticolus and Tropidurus oreadicus, from APM-Manso, aiming to verify possible changes in the reproductive success according to environmental changes. Before the impoundment A. meridionalis, Colobosaura modesta, Cercosaura ocellata, M. atticolus and T. oreadicus showed up reproductive. However, during the impoundment period they presented changes in seminiferous tubules, evidenced by the absence of spermatids and spermatozoids. B. bresslaui and M. frenata had no differences in the seminiferous tubules before and after the impoundment, being reproductive in both moments. The damming and the formation of the lake of Manso reservoir may have interfered on the reproduction of some lizards species, especially if the reproductive cycle is regulated by the rainfall of the habitat.

Gametogenesis and spawning periodicity in the fan worm Sabellastarte spectabilis (Polychaeta: Sabellidae)

The sabellid polychaete Sabellastarte spectabilis (Grube 1878) was collected at approximately monthly intervals from January 2002 to December 2003 from intertidal and subtidal reefs near the Hawaii Institute of Marine Biology in Kane’ohe Bay, Hawaii, USA (21°N, 157°W). Gametogenesis and spawning periodicity were investigated using histological techniques and induction of spawning trials. Worms were characterized into four discrete reproductive stages based on histological evidence: (1) No evidence of reproductive activity in the coelom (sex cannot be determined), (2) Only coelomocytes present in the coelom (sex cannot be determined), (3) Some gametes present in the coelom (sex can be determined) and (4) Coelom densely packed with gametes (sex can be determined). The small hermaphroditic portion of the population was not used in this study. Stage 4 worms were present over an extended period of time (females, March–December and males, March–November) indicating a potentially broad reproductive season. No correlation between day length and maturation stages in S. spectabilis was detected. However, the statistical model Y = ([394.26 × X] − [7.793 × X2]) − 4960.781 where Y the % frequency of Stage 4 worms and X the mean monthly water temperature explained 44% of the variation between water temperature and % frequency of Stage 4 worms. Maturation appeared to coincide with water temperatures of 24–25°C (March–September) after which there is a reduction in the % frequency of stage 4 individuals. Induction of spawning trials conducted between May and January showed the month of October with a significantly higher percent success than any other month investigated. According to all available information (e.g., natural spawning in water tables, histological data, induction of spawning trials, correlation of maturation stages with observed changes in average monthly water temperature.), there is an apparent peak in reproductive activity (spawning) within a broad maturational season, which may be influenced by water temperature.

Seasonality and reproduction in wild-living cats in Scotland

The definition of the wildcatFelis silvestris Schreber, 1775 in Scotland is contentious, in light of long-term interbreeding with domestic catsF. catus Linnaeus, 1758. Two morphological groupings (Group 1 and Group 2) have previously been proposed to explain the variation found in wild-living cats in Scotland, with Group 1 cats closest to wildcats and Group 2 cats to domestic cats. Data from the reproductive tracts of 185 wild-living cat carcasses and evidence of reproductive activity in 31 live cats were analysed in order to compare reproductive activity between the morphological groups, and in relation to seasonality and existing data on wildcats and domestic cats. For males, Group 2 cats had a greater mean relative testes size than Group 1 cats. Estimated from corpora lutea, there was a suggestion that Group 1 females showed more seasonality in oestrous than Group 2 cats. In all wild-living cats, the mean litter size was 4.3 and estimated birth dates were throughout the year, but least in winter. A high number of pseudopregnancies were recorded. The results were consistent with the hypothesis that Group 2 cats are closer to domestic cats. However, the variation observed in the sample of wild-living cats reported here, suggested that reproduction was neither strictly seasonal nor outside the range observed in some feral cat populations.

Comparative ecology of catfishes of the Upper Zambezi River floodplain

An 8‐month survey of the Upper Zambezi River, its associated floodplain and marginal upland habitats yielded 16 catfish (Siluriformes) species, among which Schilbe intermedius comprised over half of the 3534 specimens. Generally catfishes were most abundant in floodplain and river channel habitats, but three species (Clariallabes platyprosopos, Synodontis macrostoma, S. nigromaculatus) were most abundant in the river channel, and three species (Amphilius uranoscopus, Chiloglanis neumanni, Leptoglanis rotundiceps) were most abundant or restricted within small tributary streams. Diet analysis revealed low pairwise dietary overlaps, but there was no statistically significant pattern of community‐wide niche segregation based on prey type. The 16 catfishes fell into four size/trophic guilds: large carnivores (Clarias gariepinus, C. ngamensis), medium‐sized carnivores (C. stappersii, C. theodorae, Parauchenoglanis ngamensis, Clariallabes platyprosopos, Schilbe intermedius), medium‐sized omnivores (Synodontis leopardinus, S. nigromaculatus, S. woosnami, S. sp. cf. woosnami), and small omnivores (S. macrostigma, S. macrostoma, Amphilius uranoscopus, Chiloglanis neumanni, Leptoglanis rotundiceps). No evidence of reproductive activity was detected in any of the catfishes during the survey period of falling and low water conditions. Although catfishes are not as highly valued for food as cichlid fishes, three species are significant components of local commercial and subsistence fisheries: the two large Clarias by virtue of their size, and Schilbe by virtue of its great abundance. Abundances of the heavily exploited Clarias gariepinus and C. ngamensis stocks appear to be lower in the Upper Zambezi compared with the Okavango floodplain system.

Seasonal Changes in Mass and Reproductive Condition of the Corn Mouse (Calomys musculinus) on the Argentine Pampa

Gross morphological and histological examinations of gonads were used to assess seasonal and age-related reproductive condition of Calomys musculinus captured in cultivated areas of the pampa of central Argentina. All females >5 weeks of age showed evidence of reproductive activity during the spring and summer; 86% of similar-aged males had fully mature gonads during the same period. The male reproductive system appeared to be most sensitive to the unfavorable environmental conditions of autumn and winter, yet a low level of reproduction was observed throughout the winter and was attributable to animals in older age classes that did not undergo gonadal regression. Commonly used external indicators of sexual maturity were relatively poor measures of underlying physiological conditions: 80% of mature, nulliparous females captured throughout the year had closed vaginal orifices and 19% of those with past or present pregnancies were nonperforate; 10% of fully mature males (mostly captured in winter) had nonscrotal testes. Aging by eye-lens weight showed that the large number of individuals of low body mass that were captured during the winter did not represent autumn and winter recruitment, but were older animals that had grown slowly or lost mass in response to unfavorable environmental conditions.

Reproductive tactics of Ameiva ameiva (Lacertilia: Teiidae) in a seasonally fluctuating tropical habitat

The reproductive ecology of Ameiva ameiva was studied for 12 months in a caatinga habitat of northeast Brazil. Even though rainfall was seasonal, the female reproductive cycle was not associated with this seasonality. Females reproduced year-round, with peak reproductive periods during August–October and January–February. Clutch size ranged from one to nine and was correlated to female size but egg size was constant. Males showed evidence of reproductive activity throughout the year. Fat body mass of males and females varied greatly among individuals. There was no association between fat storage and wet–dry seasonality. In females, fat body mass tended to decrease during peak reproductive periods. Most striking was the observation that 97.8% of all adult Ameiva possessed enlarged fat bodies, suggesting that resource periods low enough to affect reproduction did not exist during 1977–1978. The reproductive tactics of Ameiva were similar to those of other tropical macroteiids, regardless of their distribution, but very different than reproductive tactics of sympatric iguanid lizards. Compared with iguanid lizards, resources may be less limiting for macroteiids because their widely foraging behavior for prey acquisition may allow them to find rich patches of resources which would be unavailable to habitat specific sit-and-wait foragers, like most iguanid lizards.

MOULT IN FIVE SPECIES OF CORVIDAE IN BRITAIN

SUMMARYThis paper presents objective methods for measuring moult and uses them to describe the pattern and rate of the complete moult as a component of the annual cycle in Corvus corone, C. frugilegus, C. monedula, Pica pica and Garrulus glandarius in Britain.The basis of the methods used to measure the rate of moult was the dry weight of the whole plumage and its component tracts and feathers. Within whole tracts of flight feathers showing diversity of size, the longer feathers grew in length a little faster than the others by accumulating feather material very much faster. Thus, for the flight feathers at least length by itself was a poor indicator of size, but, if first related to weight, could be used to predict weight. Hence, to enable realistic comparisons to be made between different flight feathers and tracts of flight feathers on a given individual bird or on individuals of different species, a ‘units’ system was created which would take account of such variations in size. This information provided a standard against which the growth of new flight feathers in a specimen collected in the field could be measured. The progress of moult in each tract was indicated by the sum of the units. In addition, for both the flight feathers and all other tracts, the duration of moult was measured from the start and finish in each tract as indicated by the proportion of birds having either growing or entirely fully‐grown feathers in each tract.In the annual cycle body weight and abdominal fat weight were at a maximum in mid‐winter and at a minimum in mid‐summer in Corvus; variations in these items were apparently absent in G. glandarius. In Corvus probably only post‐second‐year birds breed, but in P. pica some second‐year individuals do so as well; also, increase in testes size in second‐year males was greatest in P. pica.The patterns of the relative seasonal timing of the start and finish of moult in each tract were most similar in the three Corvus species, in which moult in the whole plumage began in the primary tract and finished in tracts on the body; P. pica differed principally in the extended growth of the secondary tract; G. glandarius differed in that moult began in the dorsal tract. By summing the data from individual tracts, a measure of the rate of growth in the whole plumage was obtained: all five species moulted at essentially the same time of year.In the primary, secondary, tertiary and rectricial tracts the seasonal accumulation of dry weight of feather material in each tract followed a sigmoid pattern; in the alula tract dry weight increased most rapidly at the beginning. These patterns were correlated with the numbers of feathers growing at different stages in each tract. The primary tract accumulated dry matter at the highest relative rate, while the rectricial, secondary, tertiary and alula tracts did so at successively lower rates. The maximum relative rate of increase in dry weight in any given tract of flight feathers was fairly similar in all five species, but was possibly related inversely to body weight. Maximum absolute rates of increase in dry tract weight were also calculated.During the springtime period when non‐moulting and moulting birds were present simultaneously in the population, no difference could be detected between these groups in any species in body and fat weights; in individuals obtained together with evidence of reproductive activity, few had begun primary moult, but in post‐second‐year C. frugilegus with branchers, males began before females; in C. corone and C. frugilegus testes weight was lower in moulting than in non‐moulting birds.In conclusion, some aspects of moult for further research are suggested.