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Thesis Abstract – Sutor (1995)

Title:

Efficacy of Bacillus thuringiensis var. israelensis in the Presence of the Fairy Shrimp Branchinecta lindahli

Author and college:

Julie Sutor, Harvey Mudd College

Date:

May 7, 1995

Degree:

Bachelor of Science in Biology

Advisor:

Catherine McFadden, Harvey Mudd College

Abstract:

In the interest of controlling mosquito-vectored diseases such as malaria and encephalitis, it is important to understand the factors which might compromise the efficacy of mosquito control agents. One commonly used method of control is application of the bacterial larvicide Bacillus thuringiensis var. israelensis (Bti) to larval habitats. A previous study showed that Bti-induced larval mortality of the mosquito, Aedes aegypti, declined in the presence of the anostracan (fairy shrimp), Branchipus schaefferi (Blaustein and Margalit 1991). In the laboratory, I studied the efficacy of Bti on larvae of the mosquito, Culex quinquefasciatus, in the presence of the fairy shrimp, Branchinecta lindahli. I compared the Bti-induced mortality of C. quinquefasciatus larvae when B. lindahli were present to mortality in their absence. Larval mortality in the presence of B. lindahli was reduced from 77% to 31%. Also, when the anostracans were present in water for six hours and then removed immediately prior to the introduction of Bti and Aedes aegypti, larval mortality was reduced from 84% to 49%. These results suggest that this phenomenon may occur among a broad range of mosquito and anostracan species. As a consequence, those involved in mosquito control should consider taking into account the presence of anostracans during application of Bti.

For more information:

Contact Catherine McFadden – mailto:catherine_mcfadden@hmc.edu