Tuesday, December 12, 2006 - 2:47 PM
0877

Innate and conditioned response of a cursorial spider (Hibana futilis) to nectar odor

Joseph Patt, jpatt@weslaco.ars.usda.gov and Robert Pfannenstiel, rpfannenstiel@weslaco.ars.usda.gov. USDA-ARS, Beneficial Insects Research Unit, Subtropical Agricultural Research Center, 2413 E. Highway 83, Weslaco, TX

Hibana futulis is one of several cursorial spiders that consume significant numbers of moth eggs in row crop foliage. Recent work has shown that ingestion of extra-floral nectar enhances these spiders' survival, development, and activity levels. However, nothing is known about the responses of cursorial spiders to stimuli associated with extra-floral nectar. A novel laboratory assay constructed from a glass petri dish was used to measure the response of H. futilis to nectar odor following ingestion of sucrose. Non-induced H. futilis tend to crawl linearly and remain along the dish edge; the assay measured the amount of time it took induced and non-induced spiders to move from the edge and locate scented or unscented nectar droplets positioned in the dish center. Following ingestion of sucrose, spiders displayed movements stereotypical of localized searching behavior (i.e., continuous circular motions and repeated forays into the dish center.). Induced spiders located droplets of scented nectar (diluted honey) placed in the dish center more quickly than droplets of unscented nectar (sugar-water solution). Non-induced spiders displayed no difference in their location time of scented or unscented nectar droplets. In a second set of experiments, spiders that ingested vanilla-scented sucrose droplets during pre-tests located vanilla-scented droplets in the dish center more quickly than did controls that ingested unflavored sucrose droplets during pre-tests. These results indicate that: 1) Ingestion of sucrose induces localized searching behavior in H. futilis; 2) Nectar volatiles are important stimuli in close-range (2.5- 7.5 cm) recognition and location of extra-floral nectar; and, 3) Cursorial spiders can learn to recognize volatile compounds associated with the presence of extra-floral nectar.


Species 1: Araneae Anyphaenidae Hibana futilis