Comparative study on composition of insect in close and open nursery of Federal College of Forestry Jos, Plateau State, Nigeria

Abstract

Nursery being an area where young plants are raised before sowing or transplanting in gardens or field contains rich insect assemblages whose composition and abundance is under researched even in research institutes. Thus, the comparative study on the composition of insect in close and open nursery of Federal College of Forestry Jos, Plateau State, Nigeria was carried out in May 2015 in relation to the abundance and diversity of insect using pitfall trap and hand-picking sampling techniques. A total of 2,052 individuals distributed into 13 orders, 39 families, 50 genera and 55 species were collected. 1,557 (75.9%) individuals were collected from the open nursery (with: 13 orders, 39 families, 41 genera and 46 species) while, 495 (24.1%) individuals were found in the close nursery (with: 11 orders, 27 families, 38 genera and 47 species). Five individuals could not be identified beyond class and order levels. The distribution of insect taxa in descending order showed that Hymenoptera (62.8%), Coleoptera (11.1%) and Orthoptera (10.1%) are the most dominant, with Hymenoptera occurring the most in both sites. There was no significant difference (P > 0.05) in the pooled abundance of insect from both sampling techniques between the two nursery types. Although, insect abundance from pitfall trap collection between the two nursery types showed a significant difference (t= -2.494, df = 8, P = 0.03729) while, no significant difference (t= 1.0263, df = 8, P= 0.3348) for hand-picked insect between the two nursery types. To this end, this study shows that the nursery of Federal College of Forestry Jos is healthy due to the abundant and diverse insect species recorded in which the phytophagus individuals are the most dominant group, but are kept under check by the predaceous ones. The pitfall trap was a more efficient collection technique and should be used by insect collectors.

Keywords: Close and open nursery, insect, pitfall trap, hand-picking