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Showing 3 results for Sexual Dimorphism
Biological aspectss of the Marsh frog Pelophylax ridibundus population from the Shadegan Wetland, Khuzestan Province, Iran
Ashraf Jazayeri, Fahimeh Saberi, Tayebeh Mohammadi,
Volume 3, Issue 1 (3-2021)
Abstract
The Marsh frog, Pelophylax ridibundus (Pallas) is distributed in Central Europe from northeastern France, north to the southern shorelines of the Baltic Sea (and extreme southern Finland), south to northeastern Spain, northern Italy and the Balkans including eastern Greece, east to approximately 81° E in Asiatic Russia, and south to western Iran and Afghanistan. The present study has been conducted on populations of P. ridibundus in the northern, eastern and southern regions of the Shadegan Wetland of Khuzestan Province, Iran with the aim of examining some aspects of its morphology and karyotype. Frog specimens were collected from different portions of the Shadegan Wetland during spring and autumn 2016 and transferred to the laboratory. According to the morphological results, three color patterns are identified among the samples in terms of the morphology, morphometry and sex - according to the sex independency test. T-test results between males and females indicate a significant difference in all traits and the results of a T2 Hotelling test show that there is sexual dimorphism between males and females. However, the results of multivariate analysis of variance (MANOVA) illustrate a separation between males of the northern region and the two other regions, and no differentiation between females in the eastern and southern regions of the wetland. The karyotype of the species in the wetland included 2n = 26, one pair of which had a sex chromosome.
 

Foraging and nesting behavior of Pallas’s fish eagle, Haliaeetus leucoryphus (Pallas, 1771) in the Himalayan Bhutan
Sherab Jamtsho, Sonam Phuntsho, Tshering Dorji, Lhendup Tharchen,
Volume 5, Issue 2 (6-2023)
Abstract
Pallas’s fish eagle, Haliaeetus leucoryphus (Pallas), is listed as endangered (En) in the IUCN Red List of Threatened Species with a global population of 2,500 to 9,999 individuals. It is one of the least known species in Bhutan and assessing its foraging and nesting behavior will be one of the best conservation measures to monitor its status, ecology and conservation threats. Therefore, the nesting behavior of the eagle was observed for two months and chick feeding activities for sixteen weeks at 21 vantage points along a 75 km highway in the Punatshangchu River Valley, Bhutan. Fifty households residing 500 m from the river were interviewed using structured questionnaires to examine their perception towards the eagle. A total of 92% (n= 46) of respondents were aware of the presence of H. leucoryphus in their locality and 78% felt that it is a rare and endangered fishing eagle. However, 84% (n= 42) of respondents were not aware of nesting within their vicinity. The sexes of H. leucoryphus can be differentiated by their plumage and the fledgling was observed approximately one week after the end of the incubation period. It took 112 days for the fledging to leave the nest. The study revealed that the eagle preferred foraging between 7  and 9 AM in the morning and in the afternoon from 1 to 3 PM. The maximum foraging attempts occurred in a pool habitat 54% (n= 37) with a success rate of 78% (n= 54). The hunting and feeding of the fledgling was done by the male and prey delivery in the first two months consisted of 78.5% fish and 19.5% rodents. However, the feeding of fish declined by 35% in the next two months and its diet mainly consisted of small birds. Attacks on the fledgling were done by the crested serpent eagle (Spilornis cheela Latham) (48%), followed by the black eagle Ictinaetus malaiensis (Temminck) (33%).

Sexual dimorphism in external morphology and pelvis of the lesser bandicoot rat, Bandicota bengalensis (Gray, 1835) (Mammalia: Rodentia: Muridae)
Pritom Roy, Antara Das, Md. Asir Uddin, Jadab Kumar Biswas,
Volume 5, Issue 2 (6-2023)
Abstract
We used linear morphometric measurements to assess secondary sexual dimorphism in the external traits and pelvis of the lesser bandicoot rat, Bandicota bengalensis (Gray). Multivariate analysis of variance revealed significant difference between the sexes in both external (Wilks' lambda = 0.542, F = 3.378, P < 0.05) and pelvis measurements (Wilks' lambda = 0.238, F = 10.05, P < 0.05). Males were larger than females in most of the external traits. In contrast, females were larger in most variables of the pelvis. Separation between the sexes was also demonstrated in the discriminant analysis. Although allometric slopes did not differ between the sexes, means adjusted for allometry were sexually dimorphic in five out of seven variables of the pelvis. In conclusion, our results revealed differential patterns of secondary sexual dimorphism for the external morphology and pelvis in B. bengalensis. These patterns are explained with respect to the accessible evolutionary theories on mammalian sexual dimorphism.

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