Entomologica Romanica Vol. 21 / 2017


Entomologica romanica 21: 5-8, 2017 ISSN 1224-2594 / doi: 10.24193/entomolrom.21.1 Notes on Biston betularia industrial melanism in the Copșa Mică area Sergiu Török & László Rákosy Summary: The aim of our study is to evaluate the abundance of melanic forms of Biston betularia in the year 2012 from the Copșa Mică area. This locality is well known for the high pollution level caused by the synergic action of SO2, soot black and heavy metals. The two industrial units, which were the pollution sources were closed and the now the pollution level decreased. We captured moths monthly from all eleven sampling points situated in woodland habitats. Results show that the proportion of black form carbonaria has drastically declined since 1987-1988. In the vicinity of the pollution source carbonaria form was 96 % in 1987-1988 and in 2012 the proportion is only 60 %. Overall the abundance of carbonaria also decreases with the increase of distance from the pollution source. In these sites carbonaria has only less than half it was recorded at the end of the 80’s. Key words: Industrial melanism, Biston betularia, atmospheric pollution, Copșa Mică, renaturation Introduction The Copșa Mică area was one of the most polluted sites in the world (lanculescu et al. 2009), the non­ferrous metallurgy factory SC SOMETRA SA based here emitting extremely high concentrations of atmospheric emissions (Lăcătușu and Lăcătușu 2010). The negative effects of this unit were amplified by another industrial unit, the carbon black smoke factory SC CARBOSIM SA which emitted other types of pollutants. The most damaging to vegetation was the sulphur compounds emitted by the metallurgy factory, the black smoke from the second industrial unit only enhanced the effects of the sulphur compounds (lanculescu et al. 2009). Soil, litter, vegetation and fauna were all affected by these pollutants. Based on the level of pollutants found in litter and vegetation, Barbu (2006) and lanculescu et al. (2009) recognized three levels of degradation due to pollution, the forest stands closest to the pollution source being the most affected. On insect populations, one effect was the overall decrease of diversity and another was the occurrence of melanic forms (Sanda et al. 1976, Rákosy and Rákosy 1997). Biston betularia is world renowned for its three forms: carbonaria, insularia and typica. In Britain, the carbonaria form was strongly associated with high levels of atmospheric coal pollution (Kettlewell 1961, Clarke and Sheppard 1966, Less 1981). A similar association was recorded in the Copșa Mică area in the year 1987-1988; the proportions of carbonaria form in close proximity to Copșa Mică reached 92.6 up to 100% revealing an extremely polluted site (Rákosy and Rákosy 1997). In the two other cities (Mediaș and Blaj) the percentages of this form decreased, and the proportion of the insularia form increased (Rákosy and Rákosy 1997). The SC CARBOSIM SA was closed the 1993 and in 2009 the main pollution source SC SOMETRA SA suspended its activity (Szanto et al. 2011). The aim of this research is to highlight the changes that have occurred in B. betularia melanic form frequencies, revealing the health of forest stands from Copșa Mică area in the year 2012. Material and methods Eleven sampling sites were selected closely matching the sampling localities used in the first study from 1987-1988. The collection points were set in forest habitats. Sampling was done during April and September 2012 using two 8 W black light traps powered by 12 V batteries for each site. In order to increase trap efficiency warm nights, with clear sky and without full moon were chosen. The sampling was done twice a month. Results and Discussions The results of our research recorded significant frequency differences in melanic forms between the two periods 1987 and 2012 (Tabel 1). In the intensely polluted area the carbonaria form was absolutly