Complete chromosome-level genome assembly data from the tawny crazy ant, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae)

The tawny crazy ant, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae) has a native range that extends from northern Argentina to southern Brazil. In the U.S.A. this species has often been misidentified as Nylanderia (Paratrechina) pubens or N. cf. pubens and has likely been present in Florida and Texas for several decades [1]. In the early 2000's explosive population growth in Texas and neighboring states drew renewed taxonomic focus. Genetic analyses [2,3] aided in identifying the pest species as N. fulva. This species poses an invasive threat to native flora and fauna and human structures. In its invasive range it has been reported to displace another invasive species, the red imported fire ant. The specimens used for genome sequencing were obtained from the coastal region of Mississippi. DNA was extracted from pupae. The genome data set was deposited to the National Center for Biotechnology Information as submission ID: SUB10775679, Project ID: PRJNA796544, Accession IDs: SAMN24895442 and JAKFQQ000000000. The organism taxid is 613905, locus tag prefixes are L1K79. The assembly, USDA_Nfulva_1.0, was generated in collaboration with Dovetail Genomics (now Cantata Bio) to yield a chromosome-level assembly of 375 Mb with a 15.67 Mb N50 and 78X coverage and revealing 16 putative chromosomes. This high-quality chromosome-level genome assembly was released prior to publication as a public service to the research community.

First Report of the Tramp ant Technomyrmex vitiensis Mann, 1921 (Formicidae: Dolichoderinae) in Brazil with Cytogenetic and Sperm Structure Data and an Updated Key to Brazilian Dolichoderinae Genera

Invasive ants are usually harmful taxa and are considered a potential problem to biodiversity due to their negative ecological impacts, as they can outcompete native ant species. Ten such species are reported in Brazil. In this study, we report for the first time the Asian tramp ant Technomyrmex vitiensis Mann, 1921 at the municipality of Oiapoque, in the Brazilian Amazon. The colony studied contained workers, intercastes, males and larvae, which provided sperm structure and cytogenetic data. Considering the unprecedented report of the genus Technomyrmex as well as the recent finding of the primarily Australian genus Leptomyrmex in Brazil, we present a revised key for the workers of Brazilian Dolichoderinae genera. Technomyrmex vitiensis presented 2n = 16 chromosomes; all metacentrics and comparative cytogenetics on the genus is provided. A single rDNA 18S site located in intrachromosomal region was observed in this species, which is a common trait in ants. The spermatozoa of T. vitiensis had a filiform shape, with 78.13 (± 1.96) μm of total length and 11.43 (± 0.51) μm of nucleus length. Total and nucleus sperm size length fit with the known variation observed in other ant species. The occurrence of T. vitiensis in Brazil is probably a result of traffic between French Guiana and the Amapá state. Cytogenetics and sperm structures of T. vitiensis enhance the biological knowledge of this tramp species. We highlight the scarce knowledge of ant diversity in the state of Amapá and the consequences that the presence of this species may have in this region.

North American Invasion of the Tawny Crazy Ant (Nylanderia fulva) Is Enabled by Pheromonal Synergism from Two Separate Glands

A new invader, the "tawny crazy ant", Nylanderia fulva (Hymenoptera: Formicidae; Formicinae), is displacing the red imported fire ant, Solenopsis invicta (Formicidae: Myrmicinae), in the southern U.S., likely through its superior chemical arsenal and communication. Alone, formic acid is unattractive, but this venom (= poison) acid powerfully synergizes attraction of tawny crazy ants to volatiles from the Dufour's gland secretion of N. fulva workers, including the two major components, undecane and 2-tridecanone. The unexpected pheromonal synergism between the Dufour's gland and the venom gland appears to be another key factor, in addition to previously known defensive and detoxification semiochemical features, for the successful invasion and domination of N. fulva in the southern U.S. This synergism is an efficient mechanism enabling N. fulva workers to outcompete Solenopsis and other ant species for food and territory. From a practical standpoint, judicious point-source release formulation of tawny crazy ant volatiles may be pivotal for enhanced attract-and-kill management of this pest.

Fatty Amines from Little Black Ants, Monomorium minimum, and Their Biological Activities Against Red Imported Fire Ants, Solenopsis invicta

Red imported fire ants, Solenopsis invicta, are significant invasive pests. Certain native ant species can compete with S. invicta, such as the little black ant, Monomorium minimum. Defensive secretions may contribute to the competition capacity of native ants. The chemistry of ant defensive secretions in the genus Monomorium has been subjected to extensive research. The insecticidal alkaloids, 2,5-dialkyl-pyrrolidines and 2,5-dialkyl-pyrrolines have been reported to dominate the venom of M. minimum. In this study, analysis of defensive secretions of workers and queens of M. minimum revealed two primary amines, decylamine and dodecylamine. Neither amine has been reported previously from natural sources. Toxicity and digging suppression by these two amines against S. invicta were examined. Decylamine had higher toxicity to S. invicta workers than dodecylamine, a quicker knockdown effect, and suppressed the digging behavior of S. invicta workers at lower concentration. However, the amount of fatty amines in an individual ant was not enough to knockdown a fire ant or suppress its digging behavior. These amines most likely work in concert with other components in the chemical defense of M. minimum.