Journal of Environment and Sociobiology

Rahul Podder ¹, Chinmoy Ghosh ¹, Debkumar Datta ¹

Affiliations
1 RKMVC College, Rahara, Kolkata-700 118, IN

Abstract

Dragonflies depend on water and/or aquatic plants for their larval life, while adults show interesting territorial behaviour on aquatic weeds. In the present communication, observations on the territoriality of a dozen of dragonflies habitating in temporary small pond at Barakashipur Forest of Dakshin Dinajpur District, West Bengal (JL No. 53, Area 31.7644 ha, External boundary 4.400 km, under Raiganj WLS, Uttar Dinajpur Dist.) and a 300 meter away rain water fed canal from river Atrai (distributary of river Teesta) were made for an year only. Ditch Jewels are noticed to chase and dislocate Ruddy Meadow Skimmers from aquatic vegetation. Common Club Tails do not allow Ruddy Marsh Skimmer and Green Marsh Hawk on the highest tip of aquatic twigs, though the latter accommodate in the lower tiers of the same twig. Yellow Tail Ashy Skimmer roams about all along the territory with other dragonflies and preferably rest on stick like vegetation on marshy bodies. Trumpet Tails and Little Blue Marsh Hawk occupy the central and/or peripheral part of the canal after the Ditch Jewels vacate it, owing to higher fuviatility of the water. Greater Crimson Gliders inhabited the periphery of the canal water but prefers to work on the long grasses and leaf lamina of large foliage in the aquatic body. Common Picture Wing is low fier, peace preferring dragonfly living on non-central of this aquatic body. Fulvous Forest Skimmer and Yellow Tail Ashy Skimmer are friendly in roaming, while the former work on dried benthic vegetation and rest on twig tip. Rufous Marsh Gliders are active in degraded water bodies. These carnivorous (sometimes cannibalistic) insects survive by avoiding competition through territoriality.

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Rita Kundu ¹, Sandeep Chakraborty ¹, Soumya Chatterjee ¹, Debkumar Datta ²

Affiliations
1 Dept. of Botany, University of Calcutta, IN
2 RKMVC College, Rahara, Kolkata, IN

Abstract

Local lowland rice varieties are susceptible to cadmium stress. To address the impact of such stress, surface sterilized germinated lowland rice seedlings (Oryza sativa cv. Hazardus) were maintained in pots with autoclaved sand having Hoagland's solution in controls and 10 μM CdCl₂ solution (a moderate concentration) only in treated pots for 21 days in the laboratory net house of Calcutta University for the purpose of observing impact of exposure during October and December, 2013. Physiological parameters like biomass and length of ischolar_main and shoot are found to be decreased significantly in the treated plants. Cd-induced activation of antioxidant enzymes (ascorbate peroxidase, APX), increase of lipid peroxidation (malonaldehyde level, MDA) and increase in biosynthesis of free proline take place in the process. Phytochelatin synthase (PCS) plays a vital role in intracellular sequestration and compartmentation of divalent cations, e.g., Cd²⁺ within the vacuoles, as assessed by PCR, showing amplification in the shoot sample, in contrast to that in ischolar_main, which is a transcript expression. The active uptake of Cd²⁺ by the ischolar_main was found by overexpression of divalent cation transporter gene, OsNramp³. Reduced Rubisco gene expression and chlorophyll pigments showed that Cd²⁺ is actively translocated from ischolar_main to shoot, leaves and in the grains. This local cultivar of West Bengal is a highly susceptible variety resulting in the accumulation of Cd in its grain making it unsuitable for direct human consumption or as feed for cattle.

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Rahul Podder ¹, Chinmoy Ghosh ¹, Debkumar Datta ¹

Affiliations
1 Department of Zoology, RKMVC College, Rahara, Kolkata–700 118, IN

Abstract

Observations with twelve species of dragonflies habitating a temporary small pond at Barakashipur Forest of Dakshin Dinajpur district, West Bengal (JL No. 53, area 31.7644 ha, external boundary 4.400 km, under Raiganj WLS, Dinajpur N dist.) and a 300 meter away canal, rain water fed from river Atrai (distributary of river Teesta) were continued for an year only. During this observation, Ditch Jewels were noticed to chase and dislocate Ruddy Meadow Skimmers from aquatic vegetation. Common Club Tails do not allow Ruddy Marsh Skimmers and Green Marsh Hawks on the highest tip of aquatic twigs, though the latter accommodate in the lower tiers of the same twig. Yellow Tailed Ashy Skimmers roam about all along the territory with other dragonflies and preferably rest on stick like vegetation on marshy bodies. Trumpet Tails and Little Blue Marsh Hawks occupy the central and/or peripheral part of the canal after the Ditch Jewels vacate it, owing to higher fluviatility of the water. Greater Crimson Gliders inhabited the periphery of the canal water but they prefer to work on the long grasses and leaf lamina of large foliage in the aquatic body. Common Picture Wing is a low flier, peace preferring dragonfly living on non-central of this aquatic body. Fulvous Forest Skimmers and Yellow Tailed Ashy Skimmers are friendly in roaming, while the former work on dried benthic vegetation and rest on twig tip. Rufous Marsh Gliders are active in degraded water bodies. These carnivorous (sometimes cannibalistic) insects survive by avoiding competition through territoriality.

Keywords

Barakashipur Forest, Dakshin Dinajpur District, Dragonflies, Resource Sharing, Partitioning, Dual Flight.

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Partha Ganguly ¹, Debkumar Datta ¹

Affiliations
1 Department of Zoology, Ramakrishna Mission, Vivekananda Centenary College, Rahara, Kolkata 700 118, IN

Abstract

On the occasion of a field study on dragonflies, near and around Rahara, Kolkata, we came across a peculiar plant species, commonly known as Ceylon leadwort, doctorbush or wild leadwort ( Plumbago zeylanica ) which was found to be responsible for the death of numerous dragonflies.

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Debkumar Datta ¹

Affiliations
1 Ramakrishna Mission Vivekananda Centenary College Rahara (Khardah), Kolkata 700118, IN

Abstract

The present study primarily limits to toxicity studies on some animal models. One of the well referred pioneer work dates back to that of Duodroff et al. (1951), in which acute toxicity impacts of industrial wastes on fishes were accounted. For designing experiments, principles to be based on are accounted in the book of Frederick Sperling (1984). Log-probit analysis (Sprague 1971 and Finney 1971 vide Datta, 1996), applied for bioassay studies like LC₅₀ or LD₅₀ assessment, can be programmed in computer (Datta and Sinha 1987 and Datta 1996). Toxicity studies in aquatic systems can be arranged as static bioassay or flow-.system bioassay. Comparative studies of acute and chronic toxicity are in reports per se. Quantal effects are recorded simultaneously. Behavioural changes due to toxic exposure are also recorded.

Depending on the doses toxicity thresholds are designed as slightly toxic, moderately toxic, etc. Impacts of toxicity are recorded at histopathological, biochemical and genetic levels. Genotoxic studies were earlier recorded by chromosomal changes at different stages of cell cycle, depending on the specimen. Such studies at DNA level are nowa- days conducted by Comet assay. Biomonitoring studies can also be another measure.

Keywords

Biomonitoring, LC₅₀ Toxicants, Entry, Tolerance, Storage and Translocation, Effect and Response, Dose Response Relationship, Synergism, Behavioural Change, Bioassay, Comet.

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