Abstract

An experiment was conducted at the Zoology Laboratory of the Olabisi Onabanjo University, Nigeria to evaluate the suitability of different light colours. Being generated from 15-watt, low-heat, or frequency-generated flourescent tubes as stimulants to enhance, major cast productivity of the earthworm species Hyperiodrilus africanus. The aim was to determine if exposure to the different light colours would improve the cast productivity of the worms and show whether H. africanus would show preference for any particular light colour, in terms of mass of cast produced and rates of emigration. The earthworms were kept in cylindrical plastic containers and put in different cubicles on a wooden shelf, where they are subjected to different light colours that is, white, dark (control), green, blue, and red. Results indicated that the red light colour was the most suitable in terms of cast productivity, as casting was highest (11.96 g/worm), followed by blue (10.66 g/worm), green (9.49 g/worm), dark (7.2 g/worm) and white (4.86 g/worm), respectively. Least emigration was recorded under the control (dark) , followed by red, white, blue and green respectively, which indicated that the worms were probably more ‘comfortable’ in the dark and the red light than  the other light colours tested. Results suggest that if red light is introduced to a farm, casting activities can be increased and therefore, soil fertility can be improved.

Key words: Cast productivity, different light colour, earthworm, Hyperiodrilusafricanus