Seasonal and Diurnal Activity ofLarra bicolor(Hymenoptera: Crabronidae) and Potential Ornamental Plants as Nectar Sources

Abstract

Larra bicolor was introduced to Florida for biological control of mole crickets (Scapteriscus spp.) and has spread to adjacent states. The objectives of this study were to determine the seasonal and diurnal activity of L. bicolor in its expanded range and to compare ornamental plants as nectar sources. Experiments with colored, pan-type traps and sugar solutions to monitor for L. bicolor were unsuccessful and direct observations of wasps feeding on flowers or hunting in turfgrass were used to monitor activity. Seasonal activity of L. bicolor was monitored on four sites in coastal Mississippi from 2006-2008. Wasps are active from June to October and were active later in the season on flowering plants. Diurnal activity on flowering plants was monitored during August and October. Activity began at 0700 h in August and 0900 h in October and continued to near dusk. Populations on flowers were typically male-biased with numbers of females on flowers being greatest in the afternoon (about 1300 h). Sixteen plant taxa representing nine genera and seven families were evaluated in common garden experiments during 2007 and 2008. Of these, wasps only fed on Pentas lanceolata and Spermacoce verticillata. However, pentas, a popular ornamental, may be a more aesthetic and less problematic alternative to S. verticillata, a weed in turfgrass, as a nectar source for L. bicolor in urban landscapes.