Monday, 18 November 2002

This presentation is part of : Student Competition Display Presentations, Section D. Medical and Veterinary Entomology

Differences in the responses of Aedes albopictus and Ochlerotatus triseriatus larvae to water-borne cues from Toxorhynchites rutilus predation

Banugopan Kesavaraju, Katie Costanzo, and Steven A. Juliano. Illinois State University, Biological Sciences, Campus box 4120, Normal, IL

Aquatic prey often detect predators via chemical cues, and react by reducing activity. Toxorhynchites rutilus preys upon other container dwelling insects, including larvae of Ochlerotatus triseriatus and Aedes albopictus, an introduced species native to Asia. Previous work has established that Oc. triseriatus adopts low-risk behaviors in response to water-borne cues from Tx. rutilus predation. It is unknown whether Ae. albopictus shows a similar behavioral response. Behavior of 4th instar Ae. albopictus or Oc. triseriatus was recorded in water that had held either Ae. albopictus or Oc. triseriatus larvae, respectively, alone (control), and in water that had held Tx. rutilus larvae feeding on either Ae. albopictus or Oc. triseriatus, respectively (predation). Activity and position of larvae were recorded in 30 minute instantaneous scan censuses, and analyzed by Principal Components Analysis and MANOVA. Behavior of the two species was similar in control water. In response to water-borne cues to predation, Oc. triseriatus adopted significantly more low-risk behaviors (more resting, less feeding and movement), but Ae. albopictus showed no significant change in behavior. We also observed 1st instar larvae of both species and found that Oc. triseriatus moved less than Ae. albopictus, even in the absence of water-borne cues to predation. This suggests a lower risk of predation for young larvae of Oc. triseriatus compared to Ae. albopictus. Our data suggest that Ae. albopictus is generally more vulnerable to Tx. rutilus predation than Oc. triseriatus.

Species 1: Diptera Culicidae Aedes albopictus (Asian tiger mosquito)
Species 2: Diptera Culicidae Ochlerotatus triseriatus (eastern tree hole mosquito)
Species 3: Diptera Culicidae Toxorhynchites rutilus
Keywords: prey

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