Abundance, Activity, Diversity, and Species Interactions of Ground-Dwelling Ants (Hymenoptera: Formicidae) in Open Versus Canopied Habitats in Central Georgia (USA)

2020 ◽  
Vol 55 (4) ◽  
pp. 469-486
Author(s):  
Reid M. Ipser ◽  
Wayne A. Gardner

Abstract The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), and ground-dwelling ant species native to Georgia were observed and studied in tree-canopied and open uncanopied habitats in two state parks in central Georgia. Population density, native species diversity, and interactions of native species with each other and with the invasive S. invicta were determined and compared in the two habitats. Sampling methods included pitfall traps, baits, collection of leaf litter, and visual searches. In comparison to the open uncanopied habitats, red imported fire ant population density was lower in tree-canopied habitats, and native ant species diversity was greater in the canopied habitats. We also observed native species competing with red imported fire ants more intensely in canopied than in open habitats primarily by foraging activity and by predation of S. invicta reproductives. Our results suggest that native ant species can suppress S. invicta population numbers and density and that competition by native ant species should be considered in approaches of managing red imported fire ant.

2020 ◽  
Vol 49 (2) ◽  
pp. 304-311 ◽  
Author(s):  
Karl A Roeder ◽  
Rebecca M Prather ◽  
Anna W Paraskevopoulos ◽  
Diane V Roeder

Abstract For social organisms, foraging is often a complicated behavior where tasks are divided among numerous individuals. Here, we ask how one species, the red imported fire ant (Solenopsis invicta Buren) (Hymenoptera: Formicidae), collectively manages this behavior. We tested the Diminishing Returns Hypothesis, which posits that for social insects 1) foraging investment levels increase until diminishing gains result in a decelerating slope of return and 2) the level of investment is a function of the size of the collective group. We compared how different metrics of foraging (e.g., number of foragers, mass of foragers, and body size of foragers) are correlated and how these metrics change over time. We then tested the prediction that as fire ant colonies increase in size, both discovery time and the inflection point (i.e., the time point where colonial investment toward resources slows) should decrease while a colony’s maximum foraging mass should increase. In congruence with our predictions, we found that fire ants recruited en masse toward baits, allocating 486 workers and 148 mg of biomass, on average, after 60 min: amounts that were not different 30 min prior. There was incredible variation across colonies with discovery time, the inflection point, and the maximum biomass of foragers all being significantly correlated with colony size. We suggest that biomass is a solid indicator of how social taxa invest their workforce toward resources and hypothesize ways that invasive fire ants are able to leverage their enormous workforce to dominate novel ecosystems by comparing their foraging and colony mass with co-occurring native species.


1996 ◽  
Vol 21 (1) ◽  
pp. 389-390
Author(s):  
Bill Summerlin ◽  
Roger Gold ◽  
Harry Howell ◽  
Jerry Cook

2021 ◽  
Vol 56 (2) ◽  
pp. 217-224
Author(s):  
Hironori Sakamoto ◽  
Koichi Goka

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Vatanparast ◽  
Robert T. Puckett ◽  
Deuk-Soo Choi ◽  
Youngjin Park

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.


2011 ◽  
Vol 67 (11) ◽  
pp. 1434-1438 ◽  
Author(s):  
Lekhnath Kafle ◽  
Wen-Jer Wu ◽  
Suey-Sheng Kao ◽  
Cheng-Jen Shih

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