Effects of Garden Attributes on Ant (Formicidae) Species Richness and Potential for Pest Control

Abstract

Urban vegetable gardens serve as sources of social, economic, and biodiversity conservation opportunities. Determining how gardens can be developed to enhance biodiversity and ecosystem services is important for organic food production. This study investigated the diversity of ant (Formicidae) species in relation to various garden attributes in three distinct gardening sites in Ann Arbor, MI. Further, predation experiments were conducted to explore the potential bio‐control services of commonly encountered ant species on Cabbage Looper moths (Trichoplusia ni) and Squash Bugs (Anasa tristis). Results indicated that community gardens have the capacity to support a multitude of ant species; 19 species from 12 genera were sampled. However, soil texture, intense tilling, and distance from less disturbed areas significantly reduces species richness. Less intensively tilled garden plots averaged nearly double the number of ant species collected in tractor‐tilled plots. Plots bordered by grass lawns and closer to wooded areas had significantly more ant species than plots surrounded by other garden plots. Predation experiments indicated that ants consume Cabbage Looper moth eggs and larvae, although predation on Squash Bugs was less common. Some of the species that demonstrated levels of predation are rare in gardens due to sensitivity to disturbance. Thus, reducing disturbance within and around gardens can promote ant biodiversity and beneficial predators leading to increased predation on garden pests.