Role of herbicides in the decline of butterfly population and diversity.

The herbicides not only produce a lethal effect on herbs but also indirectly harm those species which use herbs as host plants during their life cycle. The adverse effect of herbicide is comparatively more than any insecticide found in the agricultural industry. Herbicides act as enzyme inhibitors that block the synthesis of essential biomolecules in herbs. Action mechanisms in which herbicides act on the plant body as well as the classification of the herbicides according to their mode of action have been recorded. Lethal effects of herbicides cause qualitative and quantitative losses of herb-weeds and associated beneficial herbs from crop fields that lead to the decline in diversity of butterfly population. Lack of food sources, alteration of life cycle and morphological anomalies are found as a result of herbicidal interference on enzymatic reactions in butterflies. Beneficial organisms and pollinators are included within the affected ones. We selected the butterfly as it is recognized as a good indicator species. The effects of two graminicide fluazifop-p-butyl and sethoxydim, and a surfactant (like 'Preference' that help to increase penetration) were evaluated on Icaricia icarioides blackmorei and Pieris rapae in the laboratory. Glyphosate and glufosinate ammonium (GLA) kill milkweed plants (Asclepias sp.) by blocking the 5-enolpyruvylshikimate-3 phosphate synthase (EPSPS) enzyme. 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), an herbicide used in forest and nature reserves, is toxic to springtails (Onychiurus quadriocellatus) upon direct contact resulting a disastrous effect on Monarch. Fifth instar caterpillars of skipper butterfly Calpodes ethlius die when they are fed GLA-treated host plants. Atrazine and S-metolachlor are the two other herbicides which are thought to have a role on milkweed plant whose leaves are the food of the larvae. Triclopyr, sethoxydim, and imazapyr are the three herbicides that reduced the adult emergence of Behr's metalmark butterfly. The objective of the study is to provide precise information regarding the relationship between herbicides and butterflies as well as the recommendation of feasible strategies for butterfly conservation with respect to weed management.

Harnessing fertilizer potential of human urine in a mesocosm system: a novel test case for linking the loop between sanitation and aquaculture.

Human urine (HU) is a biogenic fertilizer which has raised immense interest owing to its capacity of combining sanitation and nutrient recovery. In search of an alternative organic fertilizer for fish culture, the nutrient potential of HU was evaluated. Fries of Indian carps and larvae of freshwater prawn were reared for 120 days under six conditions: (a) aerated and (b) non-aerated fresh HU (0.01%), (c) cattle manure (CM; 1.8 kg tank-1), mixed treatment with CM and HU under (d) iso-phosphorus and (e) iso-nitrogenous condition and (f) control. Monitoring of water quality and biological parameters revealed that total fish yield was the highest in CM (621.5 g tank-1) followed by mixed treatments under iso-nitrogenous (428 g tank-1) and iso-phosphorus (333 g tank-1) conditions, aerated HU (321 g tank-1) and HU (319 g tank-1). The gross primary productivity (GPP) in HU was satisfactory (601.8 mg C m-2 h-1) and superior to all but CM treatment. The abundance of heterotrophic bacteria (HB) was highest in CM and lowest in HU. Both GPP and HB population were correlated positively with fish yield per tank. Although pH in all treatments remained high (pH 8.4-8.9), no ammonia toxicity was observed. No E. coli infestation in any fish muscle was encountered. The concentrations of cadmium and lead in fish muscle were within respective safe level. The study established that high fertilizer potential of HU could be exploited as an alternative organic fertilizer or as a candidate to be blended with cattle manure.

Storage induced changes in coliform, heterotrophic groups of bacteria and nutrient levels of human urine for its safe use in biological production.

Human urine is a potential source of various nutrients, minerals and trace elements. Its use as a fertilizer is growing popular among farmers. Here, we examined the pattern of changes in the counts of coliform, heterotrophic bacteria as well as physico-chemical characteristics of human urine during different days of storage under closed conditions at ambient temperature. We observed that after 253 days of storage under closed condition, the coliform counts were reduced significantly and remained within the safe limit to be used as fertilizer. With increase in storage period, the concentration of phosphate showed decline coupled with rise in pH, alkalinity and electrical conductance. Our study revealed that human urine can be used as safe fertilizer after 8 months of storage under closed conditions at ambient temperature ranging 25-35ºC.

Responses of succinate dehydrogenase and non-specific alkaline phosphatases and mortality of tilapia to ambient pH stress in a sewage-fed aquaculture pond.

The fish, tilapia (Oreochromis mossambicus) of 50-60 g body weight was experimentally exposed to effluent gradients of highly alkaline pH in a sewage-fed aquaculture farm for examining the pH stress-induced responses of mortality and the stress marker enzyme succinate dehydrogenase and the non-specific alkaline phosphatases of fish prior to death at different hours of intoxication. A second trial was performed after two months when water quality changed along the sewage effluent gradient. An in situ experiment was also performed for better understanding of the responses of enzymatic activities attributable to different levels of pH conditions. Time required for 100% mortality of fish tended to increase from 30 min in pH 11.6 to 22 hr in pH 10.2. There was no mortality of fish when water quality improved significantly (with pH ranging between 9.6 to 8.0) after two months. The activities of succinate dehydrogenase and intracellular alkaline phosphatases assayed in gills and liver prior to death of fish tended to reduce with increase in survival hour, following a pattern of decay curve. On the other hand, percent of enzymatic inhibition of the exposed fish over the control increased as the survival hour increased following a pattern of exponential curve. It appears that the highest water pH of 11.6. maximum ratio for ammonium to ammonium hydroxide (1: 21) and reduced level of dissolved oxygen (2.62 mg/l) were perhaps responsible for the 100% mortality of fish within 30 min of their exposure and the enzymatic activities in the gills and liver assayed prior to death of fish tended to reduce as the acclimatization period of fish increased and vice-versa.