Author
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BLACKMER, JACQUELYN |
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CROSS, D. - DEPT OF ENT UOA TUCSON AZ |
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Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/28/2001 Publication Date: 6/1/2001 Citation: N/A Interpretive Summary: In the southwestern United States, Eretmocerus eremicus (Hymenoptera: Aphelinidae) is a native parasitoid of the Bemisia complex (Homoptera: Aleyrodidae); however, little information currently exists on its potential as a biological control agent of whiteflies or of the factors that influence its tendencies to disperse. In this study, we examined the flight behavior of male and female E. eremicus in response to skylight (here simulated by a mercury-vapor lamp) and plant cues (a 550-nm filtered light) in a vertical flight chamber. Approximately 90% of the parasitoids took off in response to the skylight cue. Both sexes were capable of sustained flights in excess of 60 min; however, males had higher rates of climb than females (3.31 +/- 0.17 and 2.63 +/- 0.19 cm/s, respectively). When a plant cue was presented during the parasitoid's phototactic flight, four relatively distinct responses were observed. Fifty-one percent of the eindividuals responded to the plant cue throughout their flight by either flying toward or by landing on the cue. The majority of these parasitoids were females. Approximately 12% of the wasps exhibited an intermittent, positive response to the plant cue. Twenty percent exhibited a "migratory" response. These parasitoids, which were predominantly males, failed to respond to the plant cue until they had flown for a considerable period of time. Finally, 17% failed to respond to the target during their flight. Approximately 37% of the individuals that showed a positive response to the plant cue actually landed on it and the majority of these were female. The differential response to the plant cue by male and female parasitoids could, in part, be due to the fact that females are driven to locate host in which to oviposit, and males are driven to find mates. Technical Abstract: In the southwestern United States, Eretmocerus eremicus (Hymenoptera: Aphelinidae) is a native parasitoid of the Bemisia complex (Homoptera: Aleyrodidae); however, little information currently exists on its potential as a biological control agent of whiteflies or of the factors that influence its tendencies to disperse. In this study, we examined the flight behavior of male and female E. eremicus in response to skylight (here simulated by a mercury-vapor lamp) and plant cues (a 550-nm filtered light) in a vertical flight chamber. Approximately 90% of the parasitoids took off in response to the skylight cue. Both sexes were capable of sustained flights in excess of 60 min; however, males had higher rates of climb than females (3.31 +/- 0.17 and 2.63 +/- 0.19 cm/s, respectively). When a plant cue was presented during the parasitoid's phototactic flight, four relatively distinct responses were observed. Fifty-one percent of the eindividuals responded to the plant cue throughout their flight by either flying toward or by landing on the cue. The majority of these parasitoids were females. Approximately 12% of the wasps exhibited an intermittent, positive response to the plant cue. Twenty percent exhibited a "migratory" response. These parasitoids, which were predominantly males, failed to respond to the plant cue until they had flown for a considerable period of time. Finally, 17% failed to respond to the target during their flight. Approximately 37% of the individuals that showed a positive response to the plant cue actually landed on it and the majority of these were female. The differential response to the plant cue by male and female parasitoids could, in part, be due to the fact that females are driven to locate host in which to oviposit, and males are driven to find mates. |
