The effect of bacterially-dense environments on the development and immune defences of the blowfly Lucilia sericata Item Type Article The effect of bacterially-dense environments on the development and immune defences of the blowfly, Lucilia sericata

. Abstract Competitive interactions between insects and microbes and the associated cost of development in bacterially-dense environments are investigated using the blowfly Lucilia sericata (Meigen) as a model. The effects of developing in a bacterially-dense environment are measured by assessing the fitness consequences of competition using the pathogen Staphylococcus aureus. Fitness is quantified in terms of larval survival, puparial development and adult emergence. The influence of bacteria on larval immune defences is investigated using optical density to assess whether antibacterial potency of the larval excretion/secretion changes in response to the degree of contamination of the larval environment. The results demonstrate that bacterial presence has no detrimental effect on survival of L. sericata from egg to adult eclosion, or on puparial size. Additionally, the level of microbial contamination of larvae has no effect on the antibacterial potency of the larval excretion/secretion. These findings confirm that larval antibacterial activity is not induced by the presence of environmental bacteria but is produced constitutively

An assessment of the antibacterial activity in larval excretion/secretion of four species of insects recorded in association with corpses, using Lucilia sericata Meigen as the marker species

The relative antibacterial activities of excretion/secretion (ES) from two carrion-feedinginsects, Calliphora vicina Robineau-Desvoidy and Dermestes maculatusDeGeer, and a detritivore, Tenebrio molitor Linnaeus, were compared to that ofLucilia sericata Meigen, a species with ES of known antibacterial capacity, in orderto explore the antimicrobial potential of other carrion and detritivore species.Viable counts were used to assess time-kill of ES against five bacterial species,Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa andProteus mirabilis. Antibacterial activity was recorded in all four insect speciesalthough T. molitor and D. maculatus were the most effective in controlling growthof P. mirabilis. The blowflies were more effective in controlling a wider range ofboth Gram-positive and Gram-negative bacteria. The larval ES from all species wasshown to reduce bacterial growth rate although differences in antibacterialspectrum were noted and the degree of potency varied between the four species.These differences may be explained ecologically by the different colonisation timesof each insect species on the corpse. Overall, this study demonstrates that researchinto other carrion-feeding insect species has potential to provide an increasedsource of antimicrobial chemicals to broaden the range of bacterial species beyondthat currently controlled using L. sericata.</p

Investigation into the antibacterial activity in excretion/secretions (ES) from four insects associated with a corpse

Poster presentation</p

Investigation into the antibacterial activity in excretion/secretions (ES) from four insects associated with a corpse

Poster presentation</p

An assessment of the antibacterial activity in larval excretion/secretion of four species of insects recorded in association with corpses, using Lucilia sericata Meigen as the marker species

The relative antibacterial activities of excretion/secretion (ES) from two carrion-feedinginsects, Calliphora vicina Robineau-Desvoidy and Dermestes maculatusDeGeer, and a detritivore, Tenebrio molitor Linnaeus, were compared to that ofLucilia sericata Meigen, a species with ES of known antibacterial capacity, in orderto explore the antimicrobial potential of other carrion and detritivore species.Viable counts were used to assess time-kill of ES against five bacterial species,Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa andProteus mirabilis. Antibacterial activity was recorded in all four insect speciesalthough T. molitor and D. maculatus were the most effective in controlling growthof P. mirabilis. The blowflies were more effective in controlling a wider range ofboth Gram-positive and Gram-negative bacteria. The larval ES from all species wasshown to reduce bacterial growth rate although differences in antibacterialspectrum were noted and the degree of potency varied between the four species.These differences may be explained ecologically by the different colonisation timesof each insect species on the corpse. Overall, this study demonstrates that researchinto other carrion-feeding insect species has potential to provide an increasedsource of antimicrobial chemicals to broaden the range of bacterial species beyondthat currently controlled using L. sericata.</p