We conducted a systematic review to evaluate the knowledge base for amphibian chytrid Batrachochytrium dendrobatidis (Bd) infection in the continent of Asia. Despite an indication of geographic bias in terms of studying chytrid fungus distribution in Asia, 167 amphibian species (145 spp. native to Asia) from 16 countries have been reported as infected with Bd. Our meta-analysis shows that overall prevalence is 8.19 % (out of 28,433 samples), and Bd-positive rate in amphibia significantly varies among sampling sources (χ2= 380.57, DF= 6, P< 0.001) and age categories (χ2= 22.09, DF= 2, P< 0.001). We used Kernel Density analysis to produce a hotspot map for chytrid infection, and Digital Elevation Model to understand the distribution of chytrid positive locations across different elevations. In our meta-analysis, most of the Bd-positive sites range between 4.45–27.49 °C, 167–4,353 mm rainfall, 10–40°N, and at lower elevations (<500 m). Using land cover analysis, we did not find a statistically significant difference among six different land cover categories in relation to the prevalence of Bd across Asia. Although no mass die-off events have been reported so far, Maximum Entropy modelling shows that Bd distribution and infection may potentially occur across a vast region of south-east Asia. In conclusion, we call for more systematic research and monitoring strategies in place for countries with little to no information, but have a moderately higher risk of chytrid distribution and infection.
The Northern Plains sacred langurs are characterized by their ability to adapt to a variety of habitats. We compared activity budgets of two langur groups, one living in the rural area and the other in the center of Keshabpur town. Data was collected from September, 2012 to August, 2013 through continuous focal animal sampling. Types of different food items and its availability in two habitats were mainly responsible for the variations in activity budgets. We found time spent feeding and resting were significantly higher in the urban group whereas, langurs of the rural group spent more time in moving. There were no significant differences in time spent on grooming and other social interactions. Seasonal variations in all major behaviors were significantly affected by groups. Langurs of both groups spent greater time on feeding and resting in the winter than other seasons while moving was at its peak in the summer. Females spent more time in grooming than males while males spent more time in vigilance and interaction than females. The langurs showed a considerable behavioral plasticity in response to variation of habitat and resources, and the knowledge of these differences is important for the conservation and management of this species.
An extensive study was conducted on food consumption and feeding behavior of saltwater crocodile (Crocodylus porosus) in the Reptiles Farm Ltd. (RFL) located at Hatiber village, Bhaluka, Mymensingh. The study was mainly based on direct observation and previous data collected by the technicians of the RFL. Average temperature (0C) in the farm area was significantly correlated with average food consumption (g) of the hatchlings (r = 0.714, p<0.05, n = 12). The average temperature and the average food consumption were highest in August and it was 30.5 ±5.5 0C and 45.02 ±13.05 g, respectively. Monthly feeding of hatchlings was different in three individual tubs. The highest food consumption was in August although; hatcherys temperature was constant (320C). Crocodilians can increase their level of consumption during warmer months of the year while decreasing it in the cooler months. The highest quantity of food was given in October, probably for accumulation of fat in their body which would provide energy in the whole winter season. A total of 93.1 kg provisioned food was supplied to an adult crocodiles per year. Food consumption of crocodile is temperature dependent and the potentiality of crocodile farming is embedded in it, by considering this factor it may gain prosperity of crocodile farming in our country.Bangladesh J. Zool. 41(2): 173-179, 2013
Social interactions of Hanuman langurs (Semnopithecus entellus)were studied from August, 2013 to July, 2014 at Keshabpur and Manirampur Upazila, Jessore, Bangladesh. The study was mainly based on direct field observations from dawn to dusk and data was collected through focal animal sampling in 10-minutes duration. During the study period seven groups of Hanuman langurs were found in urban and rural habitats. Eight behavioral activities like resting, feeding, grooming, moving, parental care, playing, submission and aggression were recorded. They interacted with each other through grooming, parental care, playing, submission and aggression. Social interactions varied in urban and rural habitats. Aggression was mostly observed in rural habitat and generally showed by the males. Adults were engaged in playing to encourage infants, juveniles and sub-adults. Significant seasonal variation of grooming was observed between age classes. Females were engaged more in grooming and parental care than males. Allomothering was also observed within a group. More submission was received by dominant males within a group. Langurs of focal groups spent 41.04% of their total activity budget in resting which was the highest activity followed by 33.75% in feeding, 11.73% in grooming, 4.87% in moving and 8.61% time for other activities.
Global amphibian populations are facing a novel threat, chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), which is responsible for the severe decline of a number of species across several continents. Chytridiomycosis in Asia is a relatively recent discovery yet there have been no reports on Bd-presence in Bangladeshi amphibians. We conducted a preliminary study on 133 wild frogs from seven sites in Bangladesh between April and July 2018. Nested PCR analysis showed 20 samples (15.04%) and 50% of the tested taxa (9 species from 6 genera and 4 families) as Bd-positive. Eight of the nine species are discovered as newly infected hosts. Analysis of Bd-positive samples shows prevalence does not significantly vary among different land cover categories, although the occurrence is higher in forested areas.The prevalence rate is similar in high and low disturbed areas but the range of occurrence is statistically higher in low disturbance areas. Maximum entropy distribution modelling indicates high probabilities of Bd occurrence in hilly and forested areas in south-east and central-north Bangladesh. The Bd-specific ITS1-5.8S-ITS2 ribosomal gene sequence from the Bd-positive samples tested is completely identical. A neighbor-joining phylogenetic tree reveals that the identified strain shares a common ancestry with strains previously discovered in different Asian regions. Our results provide the first evidence of Bd-presence in Bangladeshi amphibians, inferring that diversity is at risk. The effects of environmental and climatic factors along with quantitative PCR analysis are required to determine the infection intensity and susceptibility of amphibians in the country.
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