Showing papers by "Martha S. Hunter published in 2010"
TL;DR: The differences between fungal and bacterial endosymbiotic insect mutualists are explored and predictions about why a bacterium or fungus might be found associated with an insect host given particular ecological, physiological, or evolutionary conditions are made.
Abstract: Endosymbiosis is a pervasive, powerful force in arthropod evolution. In the recent literature, bacterial symbionts of insects have been shown to function as reproductive manipulators, nutritional mutualists and as defenders of their hosts. Fungi, like bacteria, are also frequently associated with insects. Initial estimates suggest that insect-fungal endosymbionts are hyperdiverse, yet there has been comparatively little research investigating the roles that fungi play in their insect hosts. In many systems in which the bacterial symbionts are well-characterized, the possible presence of fungi has been routinely ignored. Why has there been so little research on this important group of symbionts? Here, we explore the differences between fungal and bacterial endosymbiotic insect mutualists. We make predictions about why a bacterium or fungus might be found associated with an insect host given particular ecological, physiological, or evolutionary conditions. We also touch on the various hurdles for studying fungal vs. bacterial endosymbionts and potential future research directions.
178 citations
TL;DR: Cardinium was found to spread rapidly in all populations, even in cases where the initial infection frequency was well below the predicted invasion threshold frequency, which is best explained by weaker CI than measured in the lab and a cryptic fitness benefit to the infection.
Abstract: Cytoplasmic incompatibility (CI) is a common phenotype of maternally inherited bacterial symbionts of arthropods; in its simplest expression, uninfected females produce few or no viable progeny when mated to infected males. Infected females thus experience a reproductive advantage relative to that of uninfected females, with the potential for the symbiont to spread rapidly. CI population dynamics are predicted to depend primarily on the strength of incompatibility, the fitness cost of the infection and how faithfully symbionts are inherited. Although the bacterial symbiont lineage Wolbachia has been most identified with the CI phenotype, an unrelated bacterium, Cardinium may also cause CI. In the first examination of population dynamics of CI-inducing Cardinium, we used population cages of the parasitic wasp Encarsia pergandiella (Hymenoptera: Aphelinidae) with varying initial infection frequencies to test a model of invasion. Cardinium was found to spread rapidly in all populations, even in cases where the initial infection frequency was well below the predicted invasion threshold frequency. The discrepancy between the modeled and actual results is best explained by weaker CI than measured in the lab and a cryptic fitness benefit to the infection. Heredity (2010) 104, 239‐246; doi:10.1038/hdy.2009.130; published online 7 October 2009
18 citations