Transcriptomic Insights into the Molecular Responses of Red Imported Fire Ants (Solenopsis invicta) to Beta-Cypermethrin and Cordyceps cicadae

TL;DR

This study uses transcriptomics to explore how red imported fire ants respond to two different pesticides, revealing key genes and pathways involved in their molecular responses.

Contribution

The study provides novel insights into the molecular responses of S. invicta to beta-cypermethrin and Cordyceps cicadae through transcriptomic analysis.

Findings

Beta-cypermethrin caused significantly more differentially expressed genes than Cordyceps cicadae.

Higher pesticide concentrations increased the number of differentially expressed genes.

Immune-related genes were downregulated with beta-cypermethrin but upregulated with Cordyceps cicadae.

Abstract

Background: Solenopsis invicta, commonly known as the red imported fire ant (RIFA), is an important global invasive pest, and its management is challenging because of insecticide resistance and environmental problems. Methods: In this research, we applied transcriptomics to analyze the molecular responses of S. invicta worker ants exposed to different types of pesticides, beta-cypermethrin (BC) and the entomopathogenic fungus Cordyceps cicadae (CC), as well as to different concentrations of these pesticides. Results: A total of 2727 differentially expressed genes (DEGs) were identified across all samples. The number of DEGs in the BC treatment group was significantly higher than that in the CC treatment group (2520 vs. 433), and higher concentrations resulted in more DEGs (an increase of 47 in the BC group and 229 in the CC group). KEGG pathway analysis revealed that the DEGs were significantly enriched in lipid metabolism, carbohydrate metabolism, amino acid metabolism, signal transduction, and membrane transport. Immune-related gene analysis showed more general down-regulation (average FPKM value in BC 741.37 to 756.06 vs. CK 1914.42) of pathogen recognition genes (PGRP-SC2) under BC stress conditions, while CC treatment resulted in increases in expression of important immune effectors such as various serine proteases. Conclusions: Overall, this study provides useful insights into the molecular basis of responses to different pesticides in S. invicta and offers a basis to develop new approaches to control this pest.

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