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Title: PATTERNS OF HOST UTILIZATION BY CATOLACCUS GRANDIS, AN EXOTIC PARASITE OF BOLL WEEVIL: EFFECTS OF HOST STAGE

Author
item Summy, Kenneth
item GREENBERG, SHOIL - TX A&M EXPER STATION
item MORALES-RAMOS, JUAN - TX A&M EXPER STATION

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Studies were conducted under laboratory conditions to determine host preferences by the boll weevil parasite Catolaccus grandis. The parasite exhibited a strong preference for third-stage boll weevil larvae and pupae, and deposited eggs to only a limited extent on remaining life stages. Immature parasites developed readily on third-stage host larvae and pupae, to a lesser extent on second-stage host larvae, and failed to develop on the remaining life stages of the host. Results of these studies demonstrated that attacks by C. grandis tend to be concentrated among third-stage boll weevil larvae and pupae, both of which are suitable for development of immature parasites. These ovipositional preferences provide an explanation for trends in parasitism that are commonly observed in field release sites.

Technical Abstract: Oviposition experiments were conducted under laboratory conditions to clarify patterns of host utilization by Catolaccus grandis (Burks), an exotic parasite of boll weevil, Anthonomus grandis Boheman. In both choice and no-choice situations, female C. grandis concentrated attacks among third-instar host larvae and pupae, most of which were superparasitized to a considerable extent. Parasitism of younger and older host stages was either nonexistent (eggs and first-instar larvae) or occurred at extremely low levels (second-instar larvae and unemerged teneral adults). Immature C. grandis developed with equal facility on third-instar boll weevil larvae and pupae, to a lesser extent on second-instar host larvae, but failed to develop on the remaining life stages of the host. The relationship between ovipositional preferences of C. grandis and its potential efficacy under field conditions is discussed.