Paratrechina

Genus of ants

Paratrechina is one of seven ant genera (alongside Euprenolepis, Nylanderia, Paraparatrechina, Prenolepis, Pseudolasius, and Zatania) in the Prenolepis genus group from the subfamily Formicinae (tribe Lasiini). Six species are included in Paratrechina; one of which, the longhorn crazy ant (Paratrechina longicornis), is a widespread, pantropical pest.

Most Paratrechina species are native to sub Saharan Africa and Madagascar, but one species, Paratrechina umbra, has only been found in southern China and is native to Southeast Asia. The only species found outside of these regions is Paratrechina longicornis, which has been introduced by humans to tropical areas across the globe. The native range of Paratrechina longicornis is currently unknown, but it is thought to be of either African or Asian origin. Although Paratrechina longicornis has been found in undisturbed habitats in Southeast Asia, This taxonomic change resulted in Paratrechina becoming monotypic with Paratrechina longicornis as its sole species. A taxonomic review of Paratrechina in 2013 resulted in the description of another species from Africa, called Paratrechina zanjensis, and in 2014 the central African species Paratrechina kohli was transferred from Prenolepis and two more new species from Madagascar were described: Paratrechina ankarana and Paratrechina antsingy.

Paratrechina queens and males are known only from Paratrechina longicornis and have not been described for any other species within the genus. The males of Paratrechina longicornis are quite distinct from those of closely related genera. Compared to those of Prenolepis and Zatania, males of Paratrechina longicornis have much shorter, more robust parameres. The parameres also have a more dorsal orientation and curvature, making them especially unique among Prenolepis genus group males.

While most ant species exhibit arrhenotokous parthenogenesis in which diploid, fertilized eggs become females (workers or queens), and haploid, unfertilized eggs become males, Paratrechina longicornis is one of several ant species also known to be thelytokous, and queens can additionally produce female offspring asexually. As a result, sibling mating allows recombination of alleles without increasing deleterious homozygosity and bypasses the downsides of inbreeding because the genomes of the queens and males within a colony are not linked.

Some species of Paratrechina have been reported to engage in mutualistic association with caterpillars of Eurybia elvina, a metalmark butterfly. The ants are attracted to the tentacle nectary organ of the caterpillars, which produces exudates rich in sugar and amino acids. The ants are thought to provide protection to the caterpillars against natural enemies in return for this source of nutrition. However, it is important to note that this observation was made in 1987, long before major taxonomic changes to the genus in 2010. The publication that describes this mutualistic behavior does not specify which Paratrechina species engaged in this behavior, and the only Paratrechina species currently known from Mexico, where this behavior was documented, is the exotic pest, the longhorn crazy ant (Paratrechina longicornis.). All other species in Mexico that were thought to be Paratrechina at the time of this publication (1987) are now classified as Nylanderia species.

Myrmecophilous, kleptoparasitic ant crickets of the species Myrmecophilus americanus are closely associated with Paratrechina longicornis nests from localities in tropics all around the world. Ant crickets live inside of ant nests and steal food resources, presumably through trophallaxis with worker ants. All known cases of ants in association with this ant cricket except one involve Paratrechina longicornis as the host ant species. The body of Myrmecophilus americanus is similar in overall size and shape to the gaster of Paratrechina longicornis queens, indicating that this may be a form of mimicry that reduces the chances that the cricket will be detected within the colony.

The longhorn crazy ant (Paratrechina longicornis) made an appearance as one of the companion species to the eponymous superhero in the Marvel movie, Ant Man (2015). Although the film refers to the species as Paratrechina longicornis, the CGI rendered ants and their behaviors in the movie arguably hold more resemblance to the Rasberry/tawny crazy ant. (Nylanderia fulva).