Climatic Variables as Factors Affecting Diversity and Abundance of Butterflies in Okomu National Park, Edo State, Nigeria

Abstract

The effect of climatic variables on butterflies diversity and abundance in Okomu National Park, Edo State was investigated from July-November, 2012 using baited traps and butterfly nets. A total of 76 species involving 5 families (Papilionidae, Pieridae, Nymphalidae, Lycaenidae, Hesperidae) were captured and identified. Diversity of butterflies in the three ranges was calculated using Shannon-wiener diversity index and the highest diversity was found in Arakhuan (H=3.618) and the lowest in Igwuowan range (H=2.997). The relationship between physical factors and individuals, total species and number of butterflies’ per family was determined. Temperature was positively significantly correlated with the total number of individuals (r_s0.418, p=0.05) and species (r_s=0.444, p=0.0001) while Rainfall was negatively correlated with the total number of individuals (r_s=-0.561, p=0.0044) and species (r_s=-0.001, p=0.01), (p<0.05). The total abundance of Hesperidae(r_s=0.229, p=0.0010) and Papilionidae(r_s=0.498, p=0.02) increased with humidity, Pieridae(r_s=-0.465, p=0.02) abundance decreased with rainfall while that of the Nymphalidae(r_s=0.384, p=0.04) increased with temperature.