A critical need for an electronic particle counter is identified and funds are requested to purchase a Multisizer lle electronic particle counter made by Coulter Corporation. The particle counter will be used (1 ) to study the feeding ecology of larval mosquitoes and the relationship of feeding rates and particle selection to trophic state of larval developmental sites; (2) to study natural selection, population genetics, and plant reproductive ecology by quantifying traits such as pollen production, the amount of pollen removed by pollinators and pollination success, and by examining variation and environmental influences on the male component of plant reproductive success; (3) to determine the selection of different particle types by mosquito larvae and the impact of behavioral changes in feeding ecology (which cause resistance to ingestible toxins) on particle selection. feeding rates and, eventually, on the life histories of resistant vs susceptible strains of Culex mosquitoes; (4) to measure particle size distributions and abundance in mosquito developmental sites; and (5) to quantify and size occluded bacculoviruses. In addition to fulfilling the needs of the major and minor users, a particle counter will foster collaborations with colleagues at University of California - Riverside (UCR) and other institutions, meet the needs of postdoctoral scientists and graduate students working in our laboratories, and enhance the education of undergraduate and graduate students at UCR. The particle counter will be used by investigators applying diverse methodologies to a wide range of particle size. Therefore, funds are requested to purchase four additional aperatures. Funds are also requested to purchase software designed for the Multisizer lle, a free-standing IBM-compatible computer and a printer. As compared to comparably priced electronic particle counters, the advantages of the Multisizer lle system include ease of operation, a greater dynamic range of particle size, features that significantly enhance user safety, flexible and user-friendly software, features that reduce electronic interference from outside sources. and superior user-support services.
