Premium
A defensive endosymbiont fails to protect aphids against the parasitoid community present in the field
Author(s) -
LENHART PAUL A.,
WHITE JENNIFER A.
Publication year - 2017
Publication title -
ecological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.865
H-Index - 81
eISSN - 1365-2311
pISSN - 0307-6946
DOI - 10.1111/een.12419
Subject(s) - parasitoid , biology , mutualism (biology) , parasitism , aphid , ecology , population , community , aphis craccivora , biological pest control , host (biology) , habitat , homoptera , botany , pest analysis , aphididae , demography , sociology
1. The value of protective mutualisms provided by some facultative endosymbionts has been well demonstrated in the laboratory, yet only recently has their effectiveness in the field been studied. ‘ C andidatus H amiltonella defensa’ is known to defend aphids from parasitoid wasps in laboratory trials. However, the efficacy of this defence varies among parasitoids, suggesting that protection will vary spatially and temporally depending on parasitoid community composition. 2. This demonstrated specificity and a dearth of studies on H amiltonella in the field prompted the authors to quantify parasitism rates of H amiltonella‐ infected and ‐uninfected A phis craccivora K och aphid colonies in a manipulative field study. 3. It was found that A . craccivora in central K entucky alfalfa were parasitised by L ysiphlebus testaceipes ( C resson) and A phelinus sp. S urprisingly, H amiltonella infection did not lower successful parasitism by the naturally occurring parasitoid wasps. Whether H amiltonella was effective against L . testaceipes was subsequently tested in a controlled laboratory assay, and no effect on parasitism rate was found. 4. This study emphasises the fact that defensive symbionts sometimes provide no tangible defensive benefits under field conditions, depending on parasitoid community composition. It is hypothesised that the protective mutualism may be beneficial in geographically localised areas. When the symbiosis is effective against a local parasitoid community, aphid clones may experience eruptive population growth and rapidly disperse across a large area, allowing spread to habitats with different parasitoid communities where the mutualism is an ineffective defence.