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20211
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Subject: Zoology × Author: Harpreet Kaur × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Effect of imidacloprid on reproductive performance of Eudrilus eugeniae and Metaphire posthuma
    (Punjab Agricultural University, Ludhiana, 2021) Harpreet Kaur; Hundal, S.S.
    The current study investigated the effect of neonicotinoid insecticide imidacloprid on the reproductive performance of exotic earthworm Eudrilus eugeniae and indigenous earthworm Metaphire posthuma. The experiments were conducted in the Department of Zoology, Punjab Agricultural University, Ludhiana. The earthworm species were exposed to different concentrations of imidacloprid (1.00, 2.50, 4.00, 5.50 and 7.00 mg/kg dry soil) to calculate the LC50 value. Dosages were selected based upon the studies performed by earlier workers. The LC50value calculated was 3.19 mg/kg (2.65 mg/kg ~3.74 mg/kg) and 2.23 mg/kg (1.87 mg/kg ~2.59 mg/kg) for earthworm Eudrilus eugeniae and Metaphire posthuma respectively. In artificial test soil Eudrilus eugeniae and Metaphire posthumawere exposed to different doses (0.3, 0.6 and 1.0 mg/kg) to evaluate reproductive potential along with biochemical and genotoxicity studies as per OECD guidelines. Upon exposure to doses (0.3, 0.6 and 1.0 mg/kg) a significant (p<0.05) decrease in body weight was observed in both the earthworm species. Subsequently cocoon production and hatching success in dose 0.3 mg/kg decreased significantly (p<0.05) tending towards nil in doses 0.6 and 1.0 mg/kg. Mortality due to morphological alterations was 0.33% and 10% for Eudrilus eugeniae and Metaphire posthuma respectively in 1.0 mg/kg dose. The activity of AchE and GST are potential biomarker to assess toxicity levels. The inhibited activity of these enzymes in the applied doses followed an increasing pattern 0.3< 0.6< 1.0 mg/kg. Comet assay revealed a high DNA damage in both the earthworm species. These laboratory studies have revealed that effect of imidacloprid is species specific as well as dose and duration dependent leading to toxicity in earthworm physiology. Metaphire posthuma the indigenous species is more susceptible as compared to Eudrilus eugeniae leading to loss of soil fauna.