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| Geographic location of the nests of Nylanderia sp.1, Nylamderia sp. 2, Nylanderia fulva and Paratrechina longicornis infected and uninfected with Wolbachia. Colors in N. fulva correspond to the clades determined in this work (Figure 2).
Source publication
Antagonistic interactions can affect population growth and dispersal of an invasive species. Wolbachia are intracellular endosymbiont bacteria that infect arthropod and nematode hosts and are able to manipulate reproduction, which in some cases leads to cocladogenesis. Moreover, the presence of the strictly maternally transferred Wolbachia in a pop...
Contexts in source publication
Context 1
... of the best-fitting evolutionary model, maximum likelihood (ML) analyses and bootstrapping (1000 replicates) were performed for all datasets with IQ-TREE v. 2 (27,28). Finally, to evaluate the potential of the selected fragment of glyQ gene, we compared the phylogeny of Wolbachia based on MLST loci with one estimated with glyQ ( Figure S1). ...
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... inspection of the presence of the Wolbachia ftsZ gene, we found infections in 41% of the 34 Nylanderia nests, and a high percentage of infected nests within N. fulva (68%) ( Table 1). Distribution of the Wolbachia carrying nests spanned throughout northeastern Argentina ( Figure 1). The sample of P. longicornis (PL150), resulted positive for Wolbachia, as well as Nylanderia sp. 1 with both nests infected. ...
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... Wolbachia phylogeny inferred with the glyQ fragment shows a similar pattern as that of the MLST tree ( Figure S1). Nylanderia fulva clades appear infected by three monophyletic Wolbachia lineages: one infecting N. fulva clade I nests, another infecting clade II nests, and the third infecting nests that belong to clades I, II and III. ...
Context 4
... of the best-fitting evolutionary model, maximum likelihood (ML) analyses and bootstrapping (1000 replicates) were performed for all datasets with IQ-TREE v. 2 (27,28). Finally, to evaluate the potential of the selected fragment of glyQ gene, we compared the phylogeny of Wolbachia based on MLST loci with one estimated with glyQ ( Figure S1). ...
Context 5
... inspection of the presence of the Wolbachia ftsZ gene, we found infections in 41% of the 34 Nylanderia nests, and a high percentage of infected nests within N. fulva (68%) ( Table 1). Distribution of the Wolbachia carrying nests spanned throughout northeastern Argentina ( Figure 1). The sample of P. longicornis (PL150), resulted positive for Wolbachia, as well as Nylanderia sp. 1 with both nests infected. ...
Context 6
... Wolbachia phylogeny inferred with the glyQ fragment shows a similar pattern as that of the MLST tree ( Figure S1). Nylanderia fulva clades appear infected by three monophyletic Wolbachia lineages: one infecting N. fulva clade I nests, another infecting clade II nests, and the third infecting nests that belong to clades I, II and III. ...
Citations
... However, no sampling of N. fulva from its home range (central South America), nor of any subspecies of N. fulva, was included. A single-gene cytochrome c oxidase subunit I (COI) phylogeny, including sampling of N. fulva from its native range, supported 3 distinct N. fulva clades alongside 1 N. pubens clade, with one of the 3 N. fulva lineages exclusively including samples from populations outside the native range (Fernández et al. 2022). This is consistent with the determination that southeastern United States populations of N. fulva constitute a single supercolony (Eyer et al. 2018). ...
... Twenty-three more samples from Tamaulipas, Mexico, collected by Sandoval-Becerra et al. (Universidad Autónoma de Tamaulipas) were donated by Milan Janda (Universidad Nacional Autónoma de México). The remaining 18 samples were selected to represent 3 different COI lineages within the N. fulva complex and were sampled by Fernández et al. (2022). During sample selection, priority was given to samples, including nest series with representations of queens and males alongside workers. ...
... Genital capsules of 38 Nylanderia males representing 4 hypothesized clades (based on COI data) from the N. fulva species complex (N. fulva I, N. fulva II, N. fulva III, and N. pubens clades according to Fernández et al. (2022)) were scanned using 2 nano-CT scanners at the Research Service Centers Nanoscale Research Facility at the University of Florida. See Supplementary Table S4 for a complete summary of taxon sampling and nano-CT scanning specifications for specimens selected for 3DGM analysis. ...
Genital morphology, a cornerstone in taxonomy that predates Linnaeus’s Systema Naturae, is vital for species delimitation. However, the widely accepted paradigm that genitalia are taxonomically informative lacks robust testing between closely related species, and supporting evidence is often limited to taxonomic literature in which genitalia are assumed a priori to be species-specific. The cosmopolitan ant genus Nylanderia Emery includes 123 described species, with most in the Neotropics still undescribed. Workers are often morphologically cryptic, and males are rare in collections but required for morphological delimitation. Using Ultraconserved Elements (UCEs) from 236 samples, including 53 Neotropical Nylanderia species, we reconstructed a phylogenetic framework to compare the genitalia (gonopods) of males collected alongside workers. We used geometric morphometrics on images of slide-mounted genitalia from 16 species and nano-CT scans of Nylanderia fulva (Mayr) and Nylanderia pubens (Forel) genital capsules and interpreted results considering phylogeny under maximum likelihood and the multispecies coalescent. We found strong morphological and molecular support for 2 distantly related American clades, identifiable by gonopod shape, with significant differences observed among most species. Three previously reported COI clades of N. fulva were not supported as monophyletic, nor were their gonopods significantly different. However, N. pubens was supported as distinct by all phylogenetic and 3DGM results. Our findings emphasize the importance of male genitalia for delimiting species boundaries and revising Neotropical Nylanderia. Given their importance, particularly in morphologically cryptic taxa, we recommend a greater focus on linking male and worker phenotypes, which can be facilitated through comprehensive nest series collection.
Background
The tawny crazy ant (Nylanderia fulva (Mayr)) is native to South America and was first reported in the continental United States (US) in 1938. It was not until the 1990s in Florida and 2000s in Texas that this ant was considered a serious pest in the US. Tawny crazy ant (TCA) is currently considered an invasive pest in six US states. A limited number of low-density molecular markers have previously shown little genetic differentiation among Nylanderia fulva across their geographic distribution in the US.
Results
Using high-throughput sequencing we obtained high-density molecular markers, a total of 4,557 single nucleotide polymorphisms (SNPs), that provided increased resolution for detecting population genetic differences. There was genetic variation among tawny crazy ants in the US and Argentina. Additionally, there was substructure among some geographic locations in the US (i.e., Texas, Louisiana, Alabama, Mississippi, Georgia, and Florida). Samples from Colombia and Perú were genetically very distant from N. fulva in Argentina and US, and thus they are likely potential cryptic species or belong to another cryptic species complex.
Conclusion
There is genetic differentiation observed between and within tawny crazy ants in Argentina and the US as well as among tawny crazy ants in the US. Locations associated with port cities in the US are most closely related to ants from Buenos Aires, Argentina. The higher levels of differentiation among other locations and Buenos Aires may be the result of the introduction of an unidentified genotype, admixture, a sample size artifact, or a combination of these factors. Although these tawny crazy ants may act as a supercolony across wide geographic scales, our results support that N. fulva is structured into genetically differentiated populations.
Background
The tawny crazy ant (Nylanderia fulva Mayr) is native to South America and was first reported in the continental United States (US) in 1938. It was not until the 1990s in Florida and 2000s in Texas that this ant was considered a serious pest in the US. Tawny crazy ant (TCA) is currently considered an invasive pest in six US states and this ant’s invasion success is attributed in part to a unicolonial nature, multiple queens per nest, natural enemies release in the invasive range, and ability to detoxify venom from other competitor ant species. A limited number of low-density molecular markers have previously shown little genetic differentiation among TCA populations across their geographic distribution in the US.
Results
Using High Throughput Sequencing (HTS) we obtained high-density molecular markers (i.e., SNPs) for TCA samples. With 26,657 SNPs we identified genetic variation among TCA populations in different states across the US (i.e., Texas, Louisiana, Alabama, Mississippi, Georgia, and Florida) and in South America (i.e., Argentina, Colombia, and Peru).
Conclusion
Our results underscore that for recently introduced invasive species, increasing the number of molecular markers used in population genetic studies can provide greater resolution. High-resolution information on regional genetic differences can help inform pest management strategies.
