Original paper
Facultative symbiont provides fitness benefits to the grain aphid, but not to parasitoid offspring
Zhu, Huimin; Li, Delu; Desneux, Nicolas; Gatti, Jean-Luc; Hu, Zuqing; Luo, Chen
Entomologia Generalis Volume 44 Number 1 (2024), p. 163 - 170
published: Mar 6, 2024
published online: Jan 16, 2024
manuscript accepted: Dec 6, 2023
manuscript revision received: Nov 21, 2023
manuscript revision requested: Aug 15, 2023
manuscript received: Jun 6, 2023
DOI: 10.1127/entomologia/2023/2146
ArtNo. ESP146004401013, Price: 29.00 €
Abstract
Symbiotic microbes have evolved to become an important source of phenotypic plasticity in host insects. In aphids, facultative endosymbionts have been found capable of influencing host phenotypes, such as against natural enemies and host fitness. However, the related evidence has been mainly gathered from a few model organisms, such as the pea aphid. Here, we explored the roles of a common facultative symbiont of the genus Rickettsia in the grain aphid pest Sitobion avenae. We first observed that Rickettsia-infected aphids (either natural or artificial status) benefit of a higher population increase rate (nearly 1.23-fold) than the Rickettsia-free aphids from the same genetic background. While Rickettsia presence did not confer resistance against the aphid parasitoid Aphidius gifuensis, emerged wasps from Rickettsia-infected aphids had a significantly reduced weight and their sex ratio was biased toward more female wasps. These results suggest that the presence of the symbiont ameliorates the fitness of its aphid host, but impacts the growth of parasitoid offspring and the parasitoid sex-ratio in a way that could be detrimental for the aphid. This demonstrates that the presence of a facultative symbiont may lead to both positive and negative trade-offs, which may ultimately not affect the fitness of the host population as they are compensatory.
Keywords
secondary symbiont •
parasitic wasps •
trade-off •
population dynamic •
sex bias •
Sitobion miscanthi