Piperideine Alkaloids from the Poison Gland of the Red Imported Fire Ant (Hymenoptera: Formicidae)

AbstractThe red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae), is a serious invasive alien ant around the world and has expanded its invasive range to the Pacific Rim since the early 2000s. It was first reported in Japan in 2017, and its entry through cargo has been reported numerous times in many ports. Colonies have been found in Tokyo Port since 2019, and now it is an urgent issue to prevent further invasion and establishment. Chemical control is the best tested method of insect control, but we have little information on the efficacy of insecticides against S. invicta in Japan. Here, we conducted acute toxicity assays of six quick-acting pyrethroids (transfluthrin, prallethrin, phenothrin, permethrin, metofluthrin, and pyrethrin) for killing adults and five new-type insecticides (fipronil, thiamethoxam, indoxacarb, imidacloprid, and hydramethylnon) for controlling colonies with toxic baits. We found that the LD50 from six pyrethroids were comparable to each other. The ED50 causing abnormal behaviors were smaller than LD50, but some ants recovered from paralysis within 12 h. Fipronil showed the lowest LD50 suggesting this chemical is the most promising agent for controlling S. invicta. Our results promise to develop a method for the chemical control of S. invicta.

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Comparison of gene expression in the red imported fire ant (Solenopsis invicta) under different temperature conditions

Scientific Reports ◽

10.1038/s41598-021-95779-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mohammad Vatanparast ◽

Robert T. Puckett ◽

Deuk-Soo Choi ◽

Youngjin Park

Keyword(s):

Gene Expression ◽

Gene Ontology ◽

High Temperature ◽

Temperature Stress ◽

Solenopsis Invicta ◽

Expression Profiles ◽

Fire Ant ◽

Molecular Response ◽

Red Imported Fire Ant ◽

Imported Fire Ant

AbstractThe red imported fire ant (RIFA), Solenopsis invicta Buren is native to South America and is known as a global problematic invasive species. This study focused on the molecular response of RIFA by comparing gene expression profiles after exposing ants to low (10 °C) and high (40 °C) temperature stress and comparing them to untreated controls (30 °C). A total of 99,085 unigenes (the clustered non-redundant transcripts that are filtered from the longest assembled contigs) were obtained, of which 19,154 were annotated with gene descriptions, gene ontology terms, and metabolic pathways. 86 gene ontology (GO) functional sub-groups and 23 EggNOG terms resulted. Differentially expressed genes (DEGs) with log2FC ≥ 10 were screened and were compared at different temperatures. We found 203, 48, and 66 specific DEGs co-regulated at 10, 20, and 40 °C. Comparing transcriptome profiles for differential gene expression resulted in various DE genes, including cytochrome P450, NADH dehydrogenase subunit 1, cuticle protein and heat shock protein (HSP), which have previously been reported to be involved in cold and high temperature resistance. GO analysis revealed that antioxidant activity is up-regulated under high temperature stress. We verified the RNA-seq data by qPCR on 20 up- and down-regulated DEGs. These findings provide a basis for future understanding of the adaptation mechanisms of RIFA and the molecular mechanisms underlying the response to low and high temperatures.

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