Goutam Saha | University of Calcutta (original) (raw)

Papers by Goutam Saha

PLOS ONE, Mar 14, 2022

Intraguild predation (IGP) is common in the freshwater insect communities, involving a top predat... more Intraguild predation (IGP) is common in the freshwater insect communities, involving a top predator, intraguild prey (IG prey) and a shared prey. Influence of the habitat complexity on the prey-predator interactions is well established through several studies. In the present instance, the IGP involving the heteropteran predators and the dipteran prey were assessed in the background of the habitat complexity. The three predators Diplonychus rusticus, Ranatra filiformis, and Laccotrephes griseus, one intraguild prey Anisops bouvieri and two dipteran prey Culex quinquefasciatus and Chironomus sp. were used in different relative density against the complex habitat conditions to deduce the impact on the mortality on the prey. In comparison to the open conditions, the presence of the macrophytes and pebbles reduced the mortality of the shared prey under intraguild system as well as single predator system. The mortality of the shared prey was however dependent on the density of the predator and prey. Considering the shared prey mortality, predation on mosquito larvae was always higher in single predator system than chironomid larvae irrespective of identity and density of predators. However, for both the shared prey, complexity of habitat reduced the prey vulnerability in comparison to the simple habitat condition. Higher observed prey consumption depicts the higher risk to predation of shared prey, though the values varied with habitat conditions. Mortality of IG prey (A. bouvieri) in IGP system followed the opposite trend of the shared prey. The lower mortality in simple habitat and higher mortality in complex habitat conditions was observed for the IG prey, irrespective of shared prey and predator density. In IGP system, the shared prey mortality was influenced by the habitat conditions, with more complex habitat reducing the vulnerability of the shared prey and increased mortality of the IG prey. This implies that the regulation of the mosquitoes, in the IGP system will be impeded by the habitat conditions, with the heteropteran predators as the top predator.

Journal of entomology and zoology studies, May 1, 2016

The abundance and distribution of the larval odonates (dragonfly and damselfly) depend on the hyd... more The abundance and distribution of the larval odonates (dragonfly and damselfly) depend on the hydrophytes, which was tested in the present study. A total of 19 genera of Odonata were observed in different relative abundance against the hydrophytes. Among the damselflies and dragonflies genera, Ceriagrion and Pantala respectively, remained dominant over others with significant variations in relative abundance in the samples. Hydrophytes like Wolffia and Marsilea were key factors in explaining the relative abundance of larval odonates as explained through the canonical correspondence analysis. The species specific abundance seemed highly dependent on the hydrophytes in the concerned water bodies. In order to enhance the sustenance of the Odonata in wetland habitats, availability of different species of hydrophytes seems to be an essential criterion. Considering the multifunctional role of the larval odonates in the freshwater aquatic communities, conservation effort should include the systematic inclusion of the preferred hydrophytes in the wetlands.

Invertebrate Reproduction & Development, Jul 27, 2022

Limnological Review, Apr 27, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Environmental Science and Pollution Research

Proceedings of the Zoological Society

Prionailurus viverrinus, a wetland-dependent lesser cat with globally declining population, is su... more Prionailurus viverrinus, a wetland-dependent lesser cat with globally declining population, is suffering from increasing destruction/conversion of wetlands for various anthropogenic use, poaching, retaliatory killing etc. In India, they prefer to thrive in dense emergent vegetation adjoining different wetlands along the east coast and Gangetic plains. However, surveys determining their distribution range were carried out long ago and, due to various threats they have been decimated from many areas where they used to thrive earlier. This demands for a reassessment of their present status across its reported distribution range. Here we report the presence of fishing cats (through camera trap evidence) for the first time from a human-dominated wetland habitat of Murshidabad district, West Bengal, India. Out of all camera-trap images in the present study (N = 39), majority are of fishing cats Prionailurus viverrinus (25 pictures, 64.10%) followed by golden jackal Canis aureus (12 pictures, 30.76%), and jungle cat Felis chaus (two pictures, 5.12%). None of these wild fauna were recorded during day time. Fishing cats and golden jackals were mostly recorded between 21:01-3:00 h and 18:00-21:00 h respectively. Two images of jungle cats were also captured, one each during 21:01-00:00 h and 00:01-3:00 h. Similar studies in other wetlands within the distributional range of fishing cats will collectively validate their present distribution, which might be useful for in-situ conservation of this elusive vulnerable species. Keywords Fishing cat Á Camera traps Á First report Á Murshidabad Á Human-dominated area Á Conservation Samrat Chakraborty and Souvik Barik these authors have contributed Equally to this work.

Biologia, 2021

Urbanization is noticed across the globe often leading to biotic homogenization. Birds that are a... more Urbanization is noticed across the globe often leading to biotic homogenization. Birds that are able to exploit novel urban conditions to their benefit usually flourish (urban exploiters), some species are tolerant to moderate levels of urbanization (urban adapters) while others avoid and gradually decline in urban areas (urban avoiders). However, studies on the influence of habitat features on urban exploiters, adapters and avoiders are still very few. So, we made this comparative assessment of habitat-wise and seasonal patterns of abundance of common myna (urban exploiter), Asian pied starling (urban adapter) and jungle myna (urban avoider) in an urban landscape, and assessed the relationship between habitat features and weather parameters with their respective abundance. Fixed radius (50 m) point count was carried out in five different habitats (i.e. roadside habitat, residential area, market area, open fields and waterbodies) of Kolkata, West Bengal, India. Surveys were carried out twice a month from May 2019 to March 2020, wherein the number of individuals of common myna, pied starling and jungle myna were recorded for 10 min. We found that the abundance of common myna was highest followed by pied starling and jungle myna. Three species of mynas are influenced by different habitat features within an urban area. Our findings might be useful to foster sustainable management plan for many urban areas across the globe where all three species are still thriving. This study might be replicated in many urban areas across the globe for other avian species of urban exploiter, urban adapters and urban avoiders.

Invertebrate Reproduction & Development, 2020

ABSTRACT The effect of larval feeding on the life history traits of the mottled emigrant butterfl... more ABSTRACT The effect of larval feeding on the life history traits of the mottled emigrant butterfly Catopsilia pyranthe (Linnaeus, 1758) (Lepidoptera: Pieridae) was assessed to link life history variations as a function of food availability. The 0-day-old larvae of C. pyranthe were reared with varying quantity of food (100, 200, 400, 800, 1600 and 3200 mg/day) against a control set with ad libitum food availability. Significant differences in instar duration and body weight of the larva and therefore fitness were found in relation to the amount of food available. In urban regions like Kolkata, India, disparity in food availability may induce variations in life history traits and thus fitness and survival in C. pyranthe.

Écoscience, 2020

The fishing cat (Prionailurus viverrinus) is a medium-sized felid, which uses various habitats in... more The fishing cat (Prionailurus viverrinus) is a medium-sized felid, which uses various habitats including areas adjoining wetlands. This species is listed as 'vulnerable' in the IUCN Red List 2016, Appendix 2 of CITES and under Schedule 1 of the Wildlife (Protection) Act. In spite of being mired with several threats, studies on fishing cats outside protected areas are scarce in West Bengal, and their confirmed presence has so far been reported only from the Howrah and Hooghly districts. This is the first published account of the presence of fishing cats in human-dominated landscapes of East Medinipur (West Bengal, India) through camera-trap evidence. We have observed that habitat alterations and disturbances associated with the construction of a brick kiln have possibly led to the displacement of fishing cats and other associated wildlife species from the study area. Similar surveys in yet unexplored areas of fishing cat distribution range are needed to identify remaining populations, threats to their survival and to initiate appropriate conservation initiatives. Our findings indicate that current anthropocentric land-use policies need to be reviewed to reduce anthropogenic disturbances and destruction of habitats sustaining fishing cats and other wildlife in human-dominated landscapes.

Acta Oecologica, 2018

Butterflies (Insecta: Lepidoptera) contribute to the ecosystem services and thereby qualify as a ... more Butterflies (Insecta: Lepidoptera) contribute to the ecosystem services and thereby qualify as a group deserving conservation effort. Information on the butterfly-plant links is used as a foundation to sustain population and enhance conservation and management. Thus, in the present study, the structure of a butterfly-plant network in an urban landscape like Kolkata, India, was deciphered highlighting metrics like degree distribution, nestedness, and interaction strength and specialization index. A total of forty eight butterfly species associated with thirty different angiosperm plant species were observed during the study period of one year. While Lantana camara was observed to be the dominant plant species with 37 links to different butterflies, the Catopsilia pyranthe butterfly species was dominant in terms of the generalist pattern of links (21 links) with the plants. Differential ability of the shrubs and herbs in the sustenance of the butterflies was reflected in the network indices using the herbs and the shrubs, separately. In urban landscapes with restricted variety of flowering plants, an estimate of relative strength of interactions enables identification and further use of the concerned species in sustaining butterfly populations. In accordance with these propositions, the butterfly-plant network illustrated in the present instance may prove useful in selection of plant species required for the enhancement of population of desired butterfly species in urban areas like Kolkata, India.

Acta Ornithologica, 2019

Abstract. Facultative scavengers often forage on organic wastes from urban dumps. Despite being a... more Abstract. Facultative scavengers often forage on organic wastes from urban dumps. Despite being a major scavenging raptor in many urban areas, studies on Indian subspecies of Black Kites Milvus migrans govinda are very few. We studied the pattern of offal preference by Black Kites foraging in the dumping sites adjoining two major markets of Kolkata, India through cafeteria experiments, where successful foraging events and abundance of foraging Black Kites were recorded. We also carried out questionnaire surveys among 156 meat and fish sellers of 32 markets of this area to assess their offal disposal practice and understand their attitude towards Black Kites. During questionnaire surveys majority of the respondents (77.92%), indicated that Black Kites consume various kinds of offal, particularly chicken offal from garbage dumps of Kolkata. 51.92% respondents opined that Black Kite population has declined in Kolkata, and 41.03% of them believe such decline is due to food scarcity. Still many respondents (64.74%) sell their offal, which reflect their indifferent attitude towards this scavenging raptor. During ‘cafeteria experiments, we noticed that foraging kites pick up small pieces of offal from the garbage dumps, particularly chicken, mutton and fish offal (in 15.45 ± 7.749, 9.7 ± 4.542 and 9.95 ± 4.951 successful foraging events/h respectively). Energy content (cal/g) of sun-dried samples of each type of offal substances revealed that the energy (calorie) of swine offal was highest followed by beef offal, mutton offal, chicken offal and fish offal. In spite of being energetically rich, beef and swine offal were less selected by Black Kites possibly because they are visibly larger than other offal, thus requires greater handling time and invites higher risk of kleptoparasitism. Successful foraging events were significantly influenced by offal type, but not by months, study sites or by the relative abundance of foraging Black Kites.

Proceedings of the Zoological Society, 2016

All birds construct nests to lay eggs and/or to raise offspring. Scientific description on the ne... more All birds construct nests to lay eggs and/or to raise offspring. Scientific description on the nest materials of Black Kite Milvus migrans govinda is very few and is particularly lacking in urban landscape. Therefore, the present study was carried out on three nests of Black Kites collected from different regions of Kolkata metropolis, India to generate quantitative data on the nest parameters and materials used by the Black Kites to construct nest in this urban metropolis of the country. All these nests of Black Kites were large oval shaped platform nests, which mostly comprised of dry twigs of various plants (1.265 ± 0.094 kg, range 1.147–1.452, n = 3), followed by fair amount of human derived (artificial) objects (0.507 ± 0.049 kg, range 0.42–0.59, n = 3) and clay (0.347 ± 0.038 kg, range 0.29–0.42 kg, n = 3). Dimensions of three nests did not vary significantly (Kruskal–Wallis test: H = 0.195, df = 2, P > 0.05), but the weight of ‘plant materials’, ‘human derived materials’ and ‘clay’ present in all three nests varied significantly (Kruskal–Wallis test: H = 6.88, df = 2, P < 0.05). Present study thus adds to the existing knowledge of nest materials used by Milvus migrans govinda and is the first scientific report on nest materials used by these diurnal raptors in Kolkata metropolis.

2014 IEEE 11th International Conference on e-Business Engineering, 2014

The aim of this paper is to solve the problems related to integrity, security, authenticity and n... more The aim of this paper is to solve the problems related to integrity, security, authenticity and non-repudiation of prevalent ERP based e-business application solution in Indian perspective. Traditional approaches and methodologies for implementing e-business solution have rarely achieved the requisite solution to the above problems even with the role based access control system. We have explored a methodology which emphasizes authentication in e-business with design of intelligent system. It ambitiously replaces the present day written signature authentication process with digital signatures having full compliance to integrity, security, authenticity and non-repudiation. The design also models in-depth functionalities, audit trail and keeps track of evidences of document tampering from any sources after the digital signature is placed in the system. The model is implemented successfully and is found to be at par with the prevalent written signature authentication system. We outline the plausible future work to model it for e-Governance system in Indian perspective.

Proceedings of the Zoological Society, 2014

The Golden jackal is known to have a wide distribution range and has been put under “Least Concer... more The Golden jackal is known to have a wide distribution range and has been put under “Least Concern” category in the IUCN (ver 3.1) Red Data Book. However, the species once quite common along with the Bengal Fox in the eighteenth and nineteenth century of Kolkata has faced serious challenge due to land use and land cover changes in their urban habitats. As such, the Golden jackal has become “locally endangered” in the city of Kolkata, India. Kolkata, one of the largest cities in India, with population density of 14,112,536 is one such example where the land use change is profound. The Tollygunge Club, Kolkata is a social club with restricted entry at the heart of the city of Kolkata and harbours a healthy breeding population of the Golden jackal (Canis aureus Linn.). The present study focuses on the adaptability of the jackals to human proximity and its capacity to switch to natural food (fruits and leaves of available plants in the club, molluscs etc.) present in the club when the club refuse is not available. Their diurnal activity has been studied. These animals show diurnal activity in the open terrains of the club as they are least threatened by the humans. Only few intraspecific and interspecific (with the stray dogs in the club premises) conflicts have been noticed. In is interesting to note that at the heart of a city, in an urban area, such social clubs with restricted entry can provide suitable habitat to sustain a healthy breeding populations of the animals which are showing constant decline in their population due to change in land use pattern.

Limnological Review, Dec 1, 2020

The indirect interactions among multiple prey sharing a common predator characterize apparent com... more The indirect interactions among multiple prey sharing a common predator characterize apparent competition. In conservation biological control involving mosquitoes and controphic prey against generalist insect predators, apparent competition may be a crucial factor determining the extent of success. The possible influence of apparent competition on mosquito prey consumption by three water bugs (Heteroptera: Nepidae): Ranatra elongata, Ranatra filiformis, and Laccotrephes griseus was assessed under laboratory conditions. Tadpoles (Duttaphrynus melanostictus), chironomid larvae, snails (Racesina luteola) and fish fingerlings (Labeo rohita) were considered as alternative prey under two prey or multi prey conditions against instar IV larvae of Culex quinquefasciatus as target prey. Under two prey conditions all the predators exhibited a preference (significant Manly's α) for mosquito larvae, against fish fingerlings by R. filiformis. In the presence of multiple prey, mosquito larvae were selected by the predators. Using the ratio of mosquito selectivity in two prey and multi-prey conditions as a measure of apparent competition, chironomid larvae had greatest effect in suppressing mosquito selectivity for R. elongata, and fish fingerlings for R. filiformis and L. griseus. It seems that the prey preference of R. elongata, R. filiformis and L. griseus may differentially evoke apparent competition among the prey. In the aquatic community where these predators and prey coexist, mosquito larvae may benefit from apparent competition that reduces their vulnerability to predators. The identity of the alternative prey appears to be an important factor for shielding the vulnerability of mosquito prey to the generalist insect predators.

We assessed the distribution patterns and relative abundance of mountain ungulates in Prek Chu ca... more We assessed the distribution patterns and relative abundance of mountain ungulates in Prek Chu catchment of Khangchendzonga Biosphere Reserve (BR) during 2008-2009 by sampling trails/transects, vantage points and using camera traps. Presence of goral (Naemorhaedus goral), barking deer (Muntiacus muntjac), serow (Naemorhaedus sumatraensis), musk deer (Moschus sp.) and blue sheep (Pseudois nayaur) was confirmed through direct and indirect evidence. Presence of Himalayan tahr (Hemitragus jemlahicus) was confirmed only through camera traps. Blue sheep herds were readily detectable (n= 31) with the highest detection probability. Photo capture rate of goral (n= 156) was the highest. Differential use of elevation categories along with vegetation categories depicted blue sheep and musk deer as specialists for areas at (Krummholtz zone) and above treeline (>4000 m); and barking deer as specialist for lower elevation (>2500 m) wet temperate forested habitats. Goral and serow were generalists as they used all the forested areas of low altitude (<2000 m) subtropical forest, medium altitude (2000-3000 m) wet temperate forest and subalpine forests (3000-4000 m). Livestock grazing and pack animal presence in the study area along with garbage accumulation due to tourism are the main concerns for degradation of mountain ungulate habitats in Prek Chu catchment.

Zoology and Ecology

Life table features of dengue vectors are significant for the evaluation of the disease transmiss... more Life table features of dengue vectors are significant for the evaluation of the disease transmission potential. Using information on the larval stages thriving in different larval habitats in Kolkata, India, we evaluated life table features of Aedes aegypti (Linnaeus, 1762) and A. albopictus (Skuse, 1894) (Diptera: Culicidae). Daily monitoring of the larval habitats inhabited exclusively by either A. aegypti or A. albopictus was accomplished in order to estimate the instar-wise abundance and, based on it, the larval life table was constructed. Out of 90 positive larval habitats, ~34.4% was exclusively for A. aegypti and ~35.6% for A. albopictus. The life expectancy (ex) of the instar I larva of A. aegypti and A. albopictus was 5 and 4 days, respectively. There was no significant difference found in survival of immature (t(2),14 = 1.144; p = 0.272) and adult (t(2),6 = 0.536; p = 0.611) individuals of the two species. Mortality of the immature stages of A. aegypti and A. albopictus wa...

Acarological Studies

House dust mites play an important role in causing various allergic disorders. Many factors like ... more House dust mites play an important role in causing various allergic disorders. Many factors like temperature, humidity as well as different microclimatic conditions may influence mite growth. The aim of this study was to analyse the mite fauna of Kolkata, West Bengal, India. House dust was collected from 20 selected houses located in and around Kolkata from January 2017 to December 2017. House dust samples were processed following the flotation technique and house dust mites were isolated from all the samples surveyed. A total of 51 species belonging to 34 genera and 17 families were isolated from positive samples. Dermatophagoides pteronyssinus, Blomia tropicalis and Cheyletus malaccensis were present in all positive samples. Most abundant mite in house dust was Dermatophagoides pteronyssinus, constitute 47% of the mites collected from dust samples. Amblyseius longispinosus was first time reported from Indian house dust.

Records of the Zoological Survey of India