Defensive insect symbiont leads to cascading extinctions and community collapse
van Veen, FF
Wiley / Centre National de la Recherche Scientifique (CNRS)
Open access under a Creative Commons licence: https://creativecommons.org/licenses/by/4.0/
Animals often engage in mutualistic associations with microorganisms that protect them from predation, parasitism or pathogen infection. Studies of these interactions in insects have mostly focussed on the direct effects of symbiont infection on natural enemies without studying community-wide effects. Here, we explore the effect of a defensive symbiont on population dynamics and species extinctions in an experimental community composed of three aphid species and their associated specialist parasitoids. We found that introducing a bacterial symbiont with a protective (but not a non-protective) phenotype into one aphid species led to it being able to escape from its natural enemy and increase in density. This changed the relative density of the three aphid species which resulted in the extinction of the two other parasitoid species. Our results show that defensive symbionts can cause extinction cascades in experimental communities and so may play a significant role in the stability of consumer-herbivore communities in the field.
The authors thank two anonymous reviewers for their helpful comments. This project was funded by the British Ecological Society (BES research grant #4682/5720 to EF), and by the Natural Environment Research Council (NERC grant #NE/K005650/1 to FJFvV). EF was funded by Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme, FP7-PEOPLE-2012-IEF #329648.
This is the final version of the article. Available from Wiley via the DOI in this record.
Vol. 19 (7), pp. 789 - 799
Place of publication