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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #171990
Title: EXTRAFLORAL NECTAR FROM COTTON (GOSSYPIUM HIRSUTUM) AS A FOOD SOURCE FOR PARASITIC WASPS

Author
item ROSE, U - MAX-PLANCK INST/GERMANY
item Lewis, Wallace
item TUMLINSON, J - PSU/UNIVERSITY PARK, PA

Submitted to: Functional Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2005
Publication Date: 3/1/2006
Citation: Rose, U.S.R., Lewis, J., Tumlinson, J.H. 2006. Extrafloral nectar from cotton (Gossypium hirsutum) as a food source for parasitic wasps. Functional Ecology. 20:67-74.

Interpretive Summary: A better understanding and use of natural enemies of agricultural pests is important to developing effective alternatives to the economic costs and environmental hazards of conventional pesticides. ARS scientists at Tifton, GA together with their cooperators, are studying how cotton and other plants provide nectar resources and chemical signals to optimize the host/pest-finding efficiency of parasitic wasps such as Microplitis croceipes, a natural enemy of the bollworm/corn earworm. They demonstrated that extrafloral nectar produced by glands located on leaves and other nonfloral parts of the plant is important to the parasitic wasps. The wasps can quickly locate these nectar sources, and it significantly increases their longevity and reproductive capacities. Also, encounters with these nectaries increases the wasps' preference and retention for those plants that provide the nectar. This knowledge of the role of extrafloral nectar in mediating plant interactions with parasitic wasps is an important step in developing improved strategies for biologically-based pest management of agricultural crops.

Technical Abstract: For many adult nectar-feeding parasitoids food and moisture is essential for survival in the field. Early in the season, when floral nectar is not yet available, extrafloral nectar (EFN) is already present on young plants, such as cotton, which was used in our study. The parasitoid Microplitis croceipes can use EFN of cotton leaves as an only food source. The longevity and reproduction of EFN-fed female wasps was comparable to wasps fed with honey and water provided on nectariless cotton plants, and was significantly higher compared to wasps kept on nectariless plants with no additional food source. Wasps that were given preflight experiences on nectaried cotton plants choose nectaried cotton over nectariless cotton plants in two choice experiments in the flight tunnel. The parasitoids are more willing to search on a nectaried plant at their second and third encounter with a plant previously visited, compared to a nectariless cotton plant. Wasps can locate extrafloral nectar from short distance by its odor alone, and find it almost as fast as honey, but much faster than odorless sucrose that is only found randomly. Experience with extrafloral nectar increased the retention ability of parasitoids on a flower model.