Environmental stressors can be key drivers of phenotypes, including reproductive strategies and morphological traits. The response to stress may be altered by the presence of microbial associates. For example, in aphids, facultative (secondary) bacterial symbionts can provide protection against natural enemies and stress induced by elevated temperatures. Furthermore, aphids exhibit phenotypic plasticity, producing winged (rather than wingless) progeny that may be better able to escape danger, and the combination of these factors improves the response to stress. How symbionts and phenotypic plasticity, both of which shape aphids’ stress response, influence one another, and together influence host fitness, remains unclear. In this study, we investigate how environmental stressors drive shifts in fecundity and winged/wingless offspring production, and how secondary symbionts influence the process. We induced production of winged offspring through distinct environmental stressors, including exposure to aphid alarm pheromone and crowding, and, in one experiment, we assessed whether the aphid response is influenced by host plant. In the winged morph, energy needed for wing maintenance may lead to trade‐offs with other traits, such as reproduction or symbiont maintenance. Potential trade‐offs between symbiont maintenance and fitness have been proposed but have not been tested. Thus, beyond studying the production of offspring of alternative morphs, we also explore the influence of symbionts across wing/wingless polyphenism as well as symbiont interaction with cross‐generational impacts of environmental stress on reproductive output. All environmental stressors resulted in increased production of winged offspring and shifts in fecundity rates. Additionally, in some cases, aphid host‐by‐symbiont interactions influenced fecundity. Stress on first‐generation aphids had cross‐generational impacts on second‐generation adults, and the impact on fecundity was further influenced by the presence of secondary symbionts and presence/absence of wings. Our study suggests a complex interaction between beneficial symbionts and environmental stressors. Winged aphids have the advantage of being able to migrate out of danger with more ease, but energy needed for wing production and maintenance may come with reproductive costs for their mothers and for themselves, where in certain cases, these costs are altered by secondary symbionts.
Aphids are hosts to diverse viruses and are important vectors of plant pathogens. The spread of viruses is heavily influenced by aphid movement and behaviour. Consequently, wing plasticity (where individuals can be winged or wingless depending on environmental conditions) is an important factor in the spread of aphid‐associated viruses. We review several fascinating systems where aphid‐vectored plant viruses interact with aphid wing plasticity, both indirectly by manipulating plant physiology and directly through molecular interactions with plasticity pathways. We also cover recent examples where aphid‐specific viruses and endogenous viral elements within aphid genomes influence wing formation. We discuss why unrelated viruses with different transmission modes have convergently evolved to manipulate wing formation in aphids and whether this is advantageous for both host and virus. We argue that interactions with viruses are likely shaping the evolution of wing plasticity within and across aphid species, and we discuss the potential importance of these findings for aphid biocontrol.
more » « less- Award ID(s):
- 2152954
- NSF-PAR ID:
- 10416335
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Insect Molecular Biology
- Volume:
- 32
- Issue:
- 6
- ISSN:
- 0962-1075
- Format(s):
- Medium: X Size: p. 575-582
- Size(s):
- p. 575-582
- Sponsoring Org:
- National Science Foundation
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