RESEARCH ARTICLE Effect of natural gas flaring upon the butterfly, Eurema hecabe (Lepidoptera: Pieridae) and its host plant, Cassia tora (Fabales: Fabaceae) in two group gathering stations of Assam, India: an approach of environmental monitoring Bitopan Sarma 1,2 & Pranab Ram Bhattacharyya 2 & Mantu Bhuyan 2 Received: 18 April 2017 /Accepted: 13 February 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Apart from other pollutants, flaring of natural gas adds carbon dioxide into the environment and changes the atmospheric composition, including temperature and humidity. As a major gaseous product, carbon dioxide changes plant structural compo- nents as well as herbivores, i.e., insect by dilution of nitrogen under such circumstances. Present analysis demonstrated the impact of gas flaring upon adjoining biota especially Eurema hecabe butterfly and its host plant, Cassia tora in some wells (group gathering stations) of Assam, India. Analysis, pertaining from the current investigation, documented higher carbon dioxide as well as temperature in the studied flaring sites. Apart from this, reduction of leaf nitrogen, SLA, and chlorophyll with increasing in LDMC, thickness, and carbon in the studied plant as well as poor developmental rate, RGR, ECD with high RCR in insect indicated severe impact of flaring in those areas. Simulation studies with different concentration of CO 2 in open top chamber on the plant and butterfly also revealed similar trend of results. Keywords Gas flaring . Carbon dioxide . Nitrogen . Eurema hecabe . Cassia tora Introduction Natural gas flaring associated with oil exploration emits gas- eous pollutants to the atmosphere, such as addition of carbon dioxide and significantly contributes to global warming. Elevation of atmospheric carbon dioxide can directly and in- directly effect on plant and animals, including oviposition and foraging behavior of insects (Abrell et al. 2005). Persistent escalation of carbon dioxide induces physiological changes of insects and alters leaf chemistry of host plant (Stiling et al. 1999, 2003). The impact may lead to fluctuations be- tween herbivore and its hosts via altering phenology of herbi- vore and its host plants in a seasonal environment (Singer and Parmesan 2010). For insects, acquisition of nitrogen during larval stages is supposed to be vital for their growth as well as development. Dilution effect of nitrogen adversely affects her- bivore performance (Brooks and Whittaker 1998; Mattson 1980; Scriber and Feeny 1979; Scriber and Slansky 1981; Vogelweith et al. 2011) and is ominous in respect to plant herbivore interaction. In general, plants are capable to adapt themselves by changing chemistry of their tissue under this stress environment (Robinson et al. 2012). However, insects need to consume more for proper growth and development in such situation. Variety of environmental factors, including concentration of atmospheric gases such as carbon dioxide, air temperatures, humidity, and their variations reflect the per- formance of insect herbivore. Therefore, adaptive response of plants, their interaction with enriched carbon dioxide, and its allied studies are gaining importance (Sage 2002). Assam is the part of two important hotspots, i.e., Indo- Burma and Himalaya hotspot. Eastern Assam is enriched in oil and natural gases with numbers of oil exploration units including the century old Digboi oil refinery. Natural gas flar- ing is a common phenomenon of these oil exploration units, which contributed significant amount of carbon dioxide to the Responsible editor: Philippe Garrigues * Mantu Bhuyan mantubhuyan155@gmail.com 1 Academy of Scientific and Innovative Research, CSIR-NEIST Campus, Jorhat, India 2 Medicinal Aromatic and Economic Plant Group, CSIR-North East Institute of Science and Technology, Jorhat, Assam, India Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-1543-z