Some viruses which infect plants, animals and man are transmitted by an intermediary arthropod vector. The viruses for which this is true are termed arboviruses (Arthropod-borne-viruses). In many instances the virus delivered to the new host results in the establishment of a disease state and/or the death of the infected host. In all instances, however, the arthropod (invertebrate) vector is apparently unaffected by the virus it is carrying. One family of viruses which are transmitted to their vertebrate host via an arthropod vector is the virus family Bunyaviridae, in this dissertation specifically the viruses Inkoo and Uukuneimi are described. The characteristics of Inkoo and Uukuneimi growth in both vertebrate baby hamster kidney (BHK-21, WI2) and invertebrate Aedes albopictus (mosquito) cell cultures has been examined. Vertebrate cells supported, to a high titer, the growth of both Inkoo and Uukuneimi virus while Aedes albopictus cell cultures supported high titer growth of Inkoo but not Uukuneimi. In both cases, however, the vertebrate cells were killed as a cosequence of infection where as, the invertebrate infection did not result in cell death or in detectable cytopathic effect. The invertebrate cells infected with either Inkoo or Uukuneimi continue to grow and also continue to express virus specific (actinomycin D resistent) RNA synthesis. The virus infected invertebrate cells are characterized as being persistently infected because of their resistence to homologous virus superinfection and by detectable virus specific RNA synthesis. Virus released from the Inkoo persistently infected cells displays a heterogeneous plaque morphology as well as temperature sensitive virus plaque mutants. Virus particles released from the Inkoo persistently infected Aedes albopictus cells are considered defective interfering-like. The RNA profile both intracellularly and of released virus particles from the persistently infected cell cultures is different from that observed during vertebrate cell culture infections. Cell death resulted from infection of BHK-21 WI2 cells with virus from Inkoo persistently infected Aedes albopictus cell cultures. The virus plaque morphology and RNA profile is similar to standard virus infection of BHK-21 WI2 cells. The experiments with tissue culture virus-cell systems aids in understanding the natural transmission of arboviruses between the vertebrate-invertebrate portions of the arbovirus natural life-cycle.

Components of host plant affiliation for two, small, blue butterflies were examined and compared. The two butterflies, Glaucopsyche lygdamus and Plebijus icariodes (Lycaenidae), are superficially quite similar but differ in host range. Oviposition preferences were determined for each butterfly species by following individual butterflies in the field and recording butterfly behavior, host plant availability and host plant characteristics. Where preferences for one host species or one plant part over another were found, potential explanations were pursued by assessing and comparing larval performance on those plant species and parts in question. Larval performances were measured in terms of survival, growth, and ant attendance in the field, and survival, growth, and pupal mass in the laboratory. All foods were also analyzed for alkaloid content, and larvae were raised on plants known to differ in alkaloid content. Individuals of both butterfly species preferred to oviposit on those host species with which they had had recent experience; nevertheless, individual butterflies of both species frequently oviposited on multiple host species during the course of a single follow bout. For G. lygdamus the availability of flower buds was critical for ovipositing adults and feeding larvae. Flower buds of any one host species were unpredictable, however, and G. lygdamus consequently utilized different host species at different times. This observation predicted a positive relationship between butterfly population density and host species diversity. This prediction was tested and supported by two large-scale surveys of hostplant patches. P. icariodes differed from G. lygdamus in that both ovipositing adults and feeding larvae preferred old leaves to flower buds. The two species also differed in diapause stage, growth rates and reaction to alkaloids. Results predicted a relationship between diapause stage, oviposition site on the plant, and host range. The prediction was tested and upheld by a general survey of temperate lycaenid butterflies. The relationship was significant even when phylogenetic relationships were included in the analysis, and diapause stage was suggested as the characteristic evolutionarily most constrained.

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