@article {33476, title = {Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host}, journal = {Proceedings of the Royal Society B: Biological Sciences}, volume = {282}, year = {2015}, month = {Oct-01-2016}, pages = {20141976 - 20141976}, abstract = {

The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant\ Lasius neglectus\ and its fungal ectosymbiontLaboulbenia formicarum\ for potential costs and benefits. We tested ants with different\ Laboulbenia\ levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen\ Metarhizium brunneum. While survival of\ L. neglectus\ workers under starvation was significantly decreased with increasing\ Laboulbenia\ levels, host survival underMetarhizium\ exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high\ Laboulbenia\ levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (\β-1,3-glucan binding protein,Prophenoloxidase), compared with ants carrying low\ Laboulbenia\ levels. This suggests that the ectosymbiont\ Laboulbenia formicarum\ weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens.

}, keywords = {grooming behaviour, host{\textendash}parasite interactions, immune gene expression, Laboulbenia formicarum, Metarhizium brunneum, symbiosis}, issn = {0962-8452}, doi = {10.1098/rspb.2014.1976}, url = {http://rspb.royalsocietypublishing.org/cgi/doi/10.1098/rspb.2014.1976}, author = {Konrad, M. and Grasse, A. V. and Tragust, S. and Cremer, S.} }