Heavy Metals Accumulation in Dragonflies (Insecta: Odonata) and Their Microhabitats in District Mardan, Khyber Pakhtunkhwa, Pakistan

Abstract

Dragonflies (Odonata: Insecta) are bio-physical environmental indicators and limited information of this important insect group are reported from Khyber Pakhtunkhwa, province of Pakistan. Therefore, the present study was attempted to find out the bionomics of dragonflies and heavy metals concentration in their habitats in District Mardan, Khyber Pakhtunkhwa, Pakistan. During the present study total of 1400 adult dragonflies’ specimens were collected from May to October, 2018 in three tehsils of District Mardan. Orthetrum anceps (N = 209, 14.93%) was the most abundant species followed by O. pruinusum neglectum (N = 177, 12.64%) and Trithemis festiva (N = 141, 10.07%). Diversity was highest for Katlang as compared to other tehsils. Dragonflies’ peak aggregation was observed in July and August. O. pruinusum neglectum positively correlated (p < 0.05) with monthly total rainfall. Dragonfly species were sampled in abundance from all surveyed elevation (< 361 to 953m), on agriculture land and q of lithological unit. Significant difference in heavy metals (Mg, Zn, Fe, Cu, Cr and Pb) accumulation in water bodies and sediments was observed among studied tehsils. Metals accumulation significantly varied among body parts of different species of dragonflies. One of the first studies to report species composition, spatial distribution and effects of heavy metals contamination on dragonflies in district Mardan.