Data from: A facultative endosymbiont in aphids can provide diverse ecological benefits

Ecologically important traits of insects are often affected by facultative
bacterial endosymbionts. This is best studied in the pea aphid
Acyrthosiphon pisum, which is frequently infected by one or more of eight
facultative symbiont species. Many of these symbiont species have been
shown to provide one ecological benefit, but we have little understanding
of the range of effects that a single strain can have. Here, we describe
the phenotypes conferred by three strains of the recently discovered
bacterium known as X-type (Enterobacteriaceae), each in their original
aphid genotype which also carries a Spiroplasma symbiont. All comparisons
are made between aphids at that are coinfected with Spiroplasma and X-type
and aphids of the same genotype that harbor only Spiroplasma. We show that
in all cases, infection with X-type protects aphids from the lethal fungal
pathogen Pandora neoaphidis, and in two cases resistance to the parasitoid
Aphidius ervi also increases. X-type can additionally affect aphid stress
responses – the presence of X-type increased reproduction after the aphids
were heat stressed. Two of the three strains of X-type are able to provide
all of these benefits. Under benign conditions the aphids tended to suffer
from reduced fecundity when harboring X-type, a mechanism that might
maintain intermediate frequencies in field populations. These findings
highlight that a single strain of a facultative endosymbiont has the
potential to provide diverse benefits to its aphid host.