Parimalendu Haldar

Acridids as indicators of disturbance in dry deciduous forest of West Bengal in India

Acridid communities are sensitive to anthropogenic disturbance and the community structure of acridids plays vital role in functioning the forest ecosystem. They are potentially useful bioindicators for conservation planning and habitat disturbances. Acridid assemblages of three different habitat types based on degree of disturbance as follows five natural sites, five moderately disturbed sites and five highly disturbed sites in Chaupahari forest, West Bengal, India were studied. Diversity, abundance, equitability and species richness of acridid were observed in respect to undisturbed and disturbed habitats. The species richness and diversity of the sites tracked the intensity of disturbance, the greatest value being associated with the natural site followed by the moderately disturbed site and highly disturbed site. The highest species richness and diversity index indicate the suitable habitat for acridid population. Statistical analysis infers that different species show different behavior and the sites are also different in relation to different habitat types.

A Preliminary Study on Oxya fuscovittata (Marschall) as an Alternative Nutrient Supplement in the Diets of Poecillia sphenops (Valenciennes)

Growth of the ornamental fish industry is being hindered by the scarcity of low cost feed; hence alternative protein supplements should be explored. In this context the present study aims to evaluate whether the grasshopper Oxya fuscovittata could be used as a supplement for fish meal in the diets of Poecillia sphenops, which is one of the most common ornamental fishes worldwide. The present work is divided into three phases: In the first phase proximate composition of the grasshopper is obtained and five diets are prepared where fish meal is gradually replaced by Oxya meal and named as control, D1, D2, D3 and D4. All the diets are formulated on iso-nitrogenous basis where the protein percentage is fixed at 400 g/kg. The second phase deals with feeding trial and in the third phase all the data of the feeding trial are subjected to a linear model. The feeding trial shows that the control, D1 and D2 fed fishes have almost similar results. The linear model proves that the variation in the indices are mainly due to replacement of fish meal by Oxya meal, not due to the variations of rice husk and mustard oil cake that are also used to formulate the diets of the present study. From the results two Oxya supplemented diets, i.e. D1 and D2 are proved to be almost equivalent to the control diet. Hence it is concluded that Oxya meal is able to replace 25% to 50% of fish meal from the diets of P. sphenops.

Scanning electron microscopy of egg-surface sculpturing of two common Indian short-horn grasshoppers (Orthoptera, Acrididae)

Abstract Surfaces of the eggs of acridids show chorionic sculpturing — distinct features that can be used to identify species. With a scanning electron microscope, we document dimensions and surface detail for eggs of two common Indian acridids: Hieroglyphus banian and Acrida exaltata. Their eggs are characterized by distinguishing features: A. exaltata by many small tubercles scattered almost uniformly, H. banian by thick-ridged hexagonal polygons. The similarities and dissimilarities of their egg-surfaces to those of other acridid species are not consistent with subfamilial classification.

Acridid grasshoppers: An imperative unconventional protein source in poultry diets

This study was conducted to estimate the longevity of thermostable Newcastle disease (ND) vaccine (strain I-2) in village chickens of Nepal. A total of 56 (27 day old) chicks were allocated randomly into 2 groups (treatment and control) with 28 birds in each group. On day 28, thermostable ND vaccine (strain I-2) was administered to the treatment group only. Blood samples were collected from experimental birds at 1 day prior to vaccination and 14, 21, 30, 60, 90, 105 and 120 days after vaccination. The serum obtained was titrated for NDV antibody using haemagglutination inhibition (HI) test. The log2 HI antibody titre level in vaccinated birds at 14, 21, 30, 60 and 90 days after vaccination were higher (P 0.05) in the antibody titre level in vaccinated birds at 1 day before vaccination and 105 days after vaccination suggesting that booster dose is required after 90 days of primary vaccination. Thus, thermostable ND vaccine (strain I-2) produced specific immunity against ND for at least 90 days after vaccination in village chickens of Nepal and may be considered suitable in Nepalese condition where cold chain maintenance is a huge challenge especially in rural area.

Assessment of consumption, utilisation and growth of Oedaleus abruptus (Thunberg) and Spathosternum prasiniferum prasiniferum (Walker) (Orthoptera: Acrididae) fed with various food plants in laboratory conditions

Summary. Grasshoppers are serious pests of crops worldwide. In the present era of changing agricultural practices and uncertainty regarding the impacts of global climate change, the need to understand the nutritional ecology of grasshoppers is urgent. In the present study newly hatched nymphs of two multivoltine acridids, Spathosternum prasiniferum prasiniferum and Oedaleus abruptus, were fed with four food plants of the family Poaceae: Cynodon dactylon, Triticum aestivum, Sorghum halepense and Oryza sativa. Then their growth, adult life span, food consumption and utilisation were recorded. Sorghum halepense was found to be the most suitable food plant for S. pr. prasiniferum whereas for O. abruptus it was Triticum aestivum followed by Sorghum halepense in most cases. The results from the present study may help forecasting modellers to simulate a predictive model that may speculate future outbreaks, forage loss and its possible effects on the economy more efficiently.

Effects of Mercury on Development of Oxya fuscovittata (Marschall) (Orthoptera: Acrididae)

Abstract Grasshoppers are ecologically significant because many animals consume them as a major protein source and thus any change in their population dynamics may have detrimental effects on an ecosystem. This study evaluates effects of mercury (Hg2+) on the developmental periods of different instars of a common short-horned grasshopper, Oxya fuscovittata (Marschall). Newly hatched nymphs were fed foods treated with three sublethal concentrations of HgCl2 i.e., dose 1 (d1): 20 mg HgCl2/ kg dry weight in oats, dose 2 (d2): 40 mg HgCl2/ kg dry weight in oats, and dose 3 (d3): 80 mg HgCl2/ kg dry weight in oats, until they reached the adult stage. The experiment was conducted for two consecutive generations (F1 and F2), tested in the same way for the same variables, in order to observe if there is any additional adversity in the latter generation. As HgCl2 concentrations in food increased, the Total Rearing Time (TRT) for each instar significantly increased, whereas survival, adult body weight and adult life span significantly decreased. The results for the F2 generation almost always showed more severe effects than those of the F1 generation.