CHARACTERISTICS OF FARM PONDS THAT PROMOTE DRAGONFLIES AS BIOLOGICAL CONTROL AGENTS IN PASTURE SYSTEMS

Abstract

Dragonflies (Insecta: Odonata) are voracious insects that have dynamic relationships within their ecosystems due to their predatory lifestyle as aquatic nymphs and terrestrial adults. They are well documented bioindicators, as nymphs and adults. However, limited research has been conducted on their role as biological control agents in agricultural systems. Many species are dependent on lentic water systems for reproduction and in an altered landscape such as agricultural systems this could pose a problem. Farm ponds may support dragonfly nymphs that emerge as adults and subsequently provide biological control services in agricultural systems such as pastures. To better understand how farm ponds can support dragonflies as biological control agents, I investigated farm pond characteristics that promote dragonfly reproduction, identified species of dragonflies that forage within or above agricultural fields and ponds and investigated dragonfly species that overlap the two habitats. I found that farm ponds supported 19 different species across 16 genera despite variation in water quality, vegetation cover, fish presence and macroinvertebrate community structure. There was an overlap of 14 dragonfly species that were able to successfully utilize farm ponds for reproduction and active cattle pastures as foraging sites. The dominant behavior over ponds was territorial displays and mating while the most common behavior over cattle was foraging. The results give a glimpse into how farm ponds of various features and under different management strategies can provide habitat for dragonfly species that act as biological control agents in livestock pastures.