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Impact of Symbiotic Bacteria on Insect Reproduction Revealed
Many insect species host symbiotic bacteria that are typically passed from mother to offspring; however, these bacteria are often not transmitted between individuals. Investigating the role of these microorganisms is crucial for managing insect pests, as they can alter several biological processes in their host, including reproduction.
A significant contributor to biological pest control is the predatory mirid bug, Nesidiocoris tenuis, which naturally preys on agricultural pests such as whiteflies and thrips. This insect’s association with the symbiotic bacterium Rickettsia has been noted, yet its influence on the bug’s reproductive biology had not been thoroughly explored.
Recent research conducted by the National Agriculture and Food Research Organization (NARO) in collaboration with the University of Miyazaki has shed light on the effects of Rickettsia in N. tenuis. The findings, published in the journal Proceedings of the Royal Society B: Biological Sciences, revealed that Rickettsia induces a strong form of cytoplasmic incompatibility (CI) in these insects.
Cytoplasmic incompatibility is a reproductive barrier where the offspring of uninfected females fail to hatch when mated with infected males. In the study, mating experiments involving infected N. tenuis and antibiotic-treated uninfected specimens demonstrated that eggs produced in the CI context did not hatch, effectively adding Rickettsia to the list of symbiotic bacteria that cause CI.
Genomic analysis indicated that the Rickettsia strain present in N. tenuis is closely related to those in the Bellii group, a category of symbiotic Rickettsia frequently identified in various insects. Moreover, researchers found that the plasmids associated with this strain contained homologs of a gene responsible for celestial compatibility (cif gene), a feature also seen in Wolbachia, another symbiotic bacterium known for inducing CI.
This finding suggests a potential horizontal gene transfer between Wolbachia and Rickettsia, enriching our understanding of how symbiotic relationships might evolve to manipulate reproductive mechanisms in insects.
Research Implications for Biological Control
The implications of this discovery are profound for biological control strategies, particularly those focused on using predatory insects for pest management. If reproductive failures in these insects are linked to symbiotic infections, managing the status of these bacteria could improve pest control efforts.
The research team emphasized the need to evaluate the prevalence of CI in natural populations of N. tenuis. They noted that the widespread distribution of N. tenuis and similar species across Europe, Asia, and beyond provides a rich opportunity for leveraging these predatory insects in agricultural practices while exploring the evolutionary roots of CI.
Future studies will delve deeper into the mechanisms by which Rickettsia induces CI, which could be crucial for optimizing the use of N. tenuis as a biological control agent and enhancing our insights into how symbiotic bacteria manipulate their hosts.
More information: Yuta Owashi et al, Rickettsia induces strong cytoplasmic incompatibility in a predatory insect, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2024.0680
Citation: Symbiotic bacterium affects reproduction of pest-controlling insect, study reveals (2024, October 9) retrieved 10 October 2024 from https://phys.org/news/2024-10-symbiotic-bacterium-affects-reproduction-pest.html
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