Phototactic Insects: Seasonal Abundance and Diversity in Built Environments in Awka, Anambra State, Nigeria

Abstract

Phototaxis is exhibited by phototrophic organisms such as insects. They move toward the light source to take advantage of the energy necessary for photosynthesis. This paper aims to investigate phototactic insects: seasonal abundance and diversity in built environments in Awka, Anambra State, Nigeria using appropriate standard techniques. The result showed that a total of 1,587 insects belonging to sixteen insect orders were found to be phototactic in built environments. The highest number of insects was collected in site B (44.87%). The result shows that Diptera (42.66%), Hemiptera (24.26%), and Coleoptera (13.11%) had the highest relative abundance. The order Coleoptera was the most diverse group with 12 families and 19 species. The highest mean number of insects was recorded in the wet season (27.87±14.425%) compared to the dry season (6.02±3.226). Most notably, the abundance of phototactic insects collected in built environments Awka was higher during the wet season across all three sites. The correlation analysis revealed that there was no significant positive relationship between ambient temperature, relative humidity, and the abundance of phototactic insects during both the wet (ambient temperature, (r = 0.29, P> 0.05; r = 0.586, P> 0.05) and dry seasons (r = 0.557, P> 0.05; r = 0.612, P> 0.05)). The study revealed a significant difference in the abundance of phototactic insect species among the three sites in Awka. The wet season recorded a higher abundance of insects compared to the dry season. Despite seasonal fluctuations in mean temperature and relative humidity, these environmental variables do not appear to have a deterministic influence on the abundance of phototactic insects in the studied locations.

Keywords

• Phototaxis; Insect abundance; Insect diversity; Light traps; Seasonal variation; Relative humidity