Distinct Larva and Adult Food Preferences Drive the Spatial Distribution of Agriotes fuscicollis Miwa (Coleoptera: Elateridae) in the Crop Land, northeast, China

Abstract

We studied food preferences of the wireworm to understand which factors contributed to spatial distribution of insect in cropland landsacpe. The larva of click beetles (Agriotes fuscicollis Miwa) known as the wireworm is a serious underground pest in farmlands. The distribution of adults and larvae alternated between flower and corn growth stages in the field because food resources and foraging behaviors stimulated and restrained the acquisition of supplemental nutrients as a strategy for reproduction. To evaluate their food choices, wireworm were exposed to different types of plants associated with their farmland habitat, as follows: mixed pollen and nectar of flowers (Erigeron annuus, Trifolium repens, Heteropappus hispidus, Potentilla chinensis, Hibiscus trionum), or leaves of grasses (Poa annua, Echinochloa crusgalli), or maize leaves (Songyu 419, a hybrid variety) as food sources to feed the adult of A. fuscicollis. The larvae were reared on roots of the same grasses and germinated maize seedlings. Additionally, potato tuber the common food used to grew the beetles that was selected as a reference to demonstrate that blooming wildflowers through their pollen and nectar can control the A. fuscicollis population and distribution around the field. The greatest number of eggs were deposited by mated couples when the pollen, or nectar mixture was offered compared to the other foods. Each of the five food sources provided a high hatching rate, but particularly the pollen, nectar and potato. Maize seedlings were a better food for larvae than were grass roots, and larvae also consumed more maize in the field. Wild flowers were the most important factor which determined the abundance of A. fuscicollis. Maize, grasses and the wild flowers could explain the alternating distribution of A. fuscicollis between the maize field and the field margins in the farmland.