A Comparative Study Of The Butterfly Fauna In Natural Forest And Pinus Plantation At North Nandi District, Kenya

Abstract

The studies were conducted in two 10 ha plots in the North Nandi Forest, one in natural forest and one in planted. forest with exotic. Pinus sp. Using Malaise traps, Visual counts and Capture-mark-release recapture techniques, records were made of the butterfly species occurring in each habitat for comparative analysis. A total of seven butterfly families comprising of 128 species were found in the two habitats. This number forms about 14% of the total Kenya butterfly fauna. The natural forest had a Shannon - Weiner index of 3.96 while the Pinus forest had an index of 2.61. Sixty four species were recorded exclusively in the natural forest as against seven from the soft-wood Pinus forest. The Pinus forest had the highest number of species in March contrasting with the natural forest, in which the highest diversity occurred in 'January. Some congeners were temporally separated. Two new records of larval food plants for Mylothris poppea were determined. Estimation of survival rate of Amauris sp. were made for the Pinus plantation, where the insects were abundant. The changes in the survival reflected the onset of the-dry period during which the survival rate increased. The rate was 0.68 per week during the wet period and 0.76 in dry period indicating an expectation of life of 2.59 weeks and 3.64 weeks for ·the wet and dry period, respectively. This finding is about 2 - 21/2 times that of most of the temperate Lepidoptera