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Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/15/2009 Publication Date: 10/1/2009 Citation: Tillman, P.G. 2009. Beneficial insects and insect pollinators on milkweed in south Georgia. J. Entomol. Sci. 44(4):402-409. Interpretive Summary: Insect pollinators are essential for the reproduction of more than two-thirds of the world’s crop species, and beneficial insects play an important role in reducing or controlling populations of pest insects in agricultural farmscapes. These insects depend on nectar for their survival in these farmscapes. Because the flowers of milkweed provide a rich supply of nectar, establishing a habitat of tropical milkweed could possibly enhance beneficial insects and pollinators in south Georgia farmscapes. Therefore, the purpose of this study was to monitor feeding activity of these insects on tropical milkweed in a corn farmscape in south Georgia. Eight flowering potted plants of tropical milkweed were placed next to a corn field, and then insects feeding on nectar of these milkweed plants were observed and recorded throughout the day on weekly basis for the growing season in 2008. It was determined that many species of beneficial insects and insect pollinators fed on the nectar of topical milkweed, and for the first time scelionids and other small parasitoids were observed feeding on nectar of a milkweed species. Corn plants do not produce nectar, and so an addition of a habitat of nectar-producing milkweed plants in this environment could possibly enhance beneficial insects and insect pollinators. Technical Abstract: Insect pollinators are essential for the reproduction of more than two-thirds of the world’s crops, and beneficial insects play an important role in managing pest insects in agricultural farmscapes. These insects depend on nectar for their survival in these farmscapes. The flowers of tropical milkweed provide a rich supply of nectar so establishing a habitat of this milkweed could possibly enhance beneficial insects and pollinators in south Georgia farmscapes. Therefore, the purpose of this study was to monitor feeding activity of these insects on tropical milkweed near a corn field in Mystic, GA. Eight flowering potted plants of this milkweed species were placed adjacent to the outer row corn. Insects visiting these milkweed plants were observed weekly throughout the corn growing season in 2008. Each plant was observed for 2 min. on an hourly basis from 9 AM to 5 PM. Every insect that fed on nectar of these plants during this observation period was recorded. Many species of beneficial insects and insect pollinators fed on the nectar of topical milkweed. The predators, including 4 lady beetle species, were the most abundant insects visiting milkweed flowers in May and early June. Stink bug egg parasitoids were observed feeding on milkweed nectar early in the season. This is the first record of scelionids and other small parasitoids feeding on nectar of any milkweed species. Free-living flies feeding on milkweed nectar began to build up the end of May and increase through the middle of June. Free-living wasps and bees fed on milkweed throughout the season, but they began increasing in mid-to-late June and were the most abundant insects visiting milkweed flowers the later half of the season. Stink bug adult parasitoids fed on nectar from early June through the rest of the season. Nectar-feeding activity of these insects was relatively higher from 10 AM to 2 PM. Corn plants do not produce nectar, and so an addition of a habitat of nectar-producing milkweed plants in this environment could possibly enhance beneficial insects and insect pollinators. |
