Patterns of Insect Abundance and Distribution in Urban Domestic Gardens in Bangalore, India

Abstract

Domestic gardens may play a vital role in supporting urban insect biodiversity, despite their small size. This paper assesses the abundance, diversity and distribution of insects in urban domestic gardens in the tropics, through a study in the rapidly expanding Indian city of Bangalore. Fifty domestic gardens were studied using a combination of light traps and pitfall traps. We recorded a large number of insects, 2,185 insects from 10 orders, of which ants, bugs, beetles and flies were the most common. We found 25 species of trees (from 160 individuals) and 117 species of herbs and shrubs in the 50 sampled domestic gardens. The number of insect orders encountered was significantly related to the number of tree and herb/shrub species. Garden management practices also influenced the abundance and richness of insect orders. Thus, greater numbers of insects were observed in gardens with a greater proportion of bare soil relative to grass area and with less intensive weeding practices. More insect orders were encountered in gardens with a composting pit. Insect numbers were significantly reduced in gardens subjected to pesticide application. Most residents avoided application of pesticides and herbicides, citing health concerns.

Validation of 走肖爲王: Can insects write letters on leaves?

“…Although we could not replicate the writing of letters on leaves by insects, it does not directly mean that the 走肖爲王 incident was not a historical event. Present‐day usage of pesticides can significantly reduce insect abundance (Jaganmohan et al ), and failure to replicate the 走肖爲王 incident could be due to differences in insect abundance. Insect abundance may have been greater during the Joseon dynasty due to an absence of pesticide use in that era.…”

Diversity of Ants (Hymenoptera: Formicidae) in a Sub-Montane and Sub-Tropical Cityscape of Northeastern Mexico

“…Ideal organisms for biodiversity analysis in urban environments should perform various functions in the community, have a relatively short generation time (in order to assess sensitivity to environmental changes), and be abundant and relatively easy to collect (Monteiro-Júnior et al, 2015). Based on these criteria, insects are good indicators of the impact of urbanization on biodiversity (Jaganmohan et al, 2013). Among the vast insect groups, ants (Hymenoptera: Formicidae) represent a suitable group for studying the effects of urbanization because of their important ecological role in ecosystems.…”

Providing Habitats for Urban Insects

“…In Bangalore, India, for example, many species are planted for their culinary, medicinal or sacred properties (Jaganmohan et al 2013 ). Although their samples of insects from pitfall and light trap catches in 50 domestic gardens were interpreted only to order level, numbers appeared to increase as fl oristic diversity increased, but decreasing garden space from other human pressures in Bangalore city was a concern for insect wellbeing.…”