Ants from the tropical dry forest in the Cauca River geographic valley, Colombia: new records and expansion of distributions.

Background: Tropical dry forests (TDF) are amongst the most important tropical biomes globally, recognised for their remarkable biodiversity. This biome features a favourable climate and high soil fertility, which has facilitated the development and expansion of human societies. However, continuous and extensive human intervention has led to habitat loss and fragmentation, disrupting the assemblages of biological communities. Within these communities, ants (Hymenoptera, Formicidae) represent one of the predominant groups and their high sensitivity to habitat transformation makes them a useful model for monitoring the effects of land-use changes and assessing ecosystem quality. The objective of this research was to compare ant diversity between two habitat types, tropical dry forest fragments and the surrounding matrices in the Cauca River Valley region. Ants were collected from 2021 to 2022 using six collection methods: arboreal baiting, epigeal baiting, hypogeal baiting, pitfall traps, mini-Winkler extractors and manual capture. A substantial portion of the data generated from this research is available in two datasets associated with two Colombian entomological collections. The first dataset (1574 ant records) is housed at the Centro de Colecciones Biológicas de la Universidad de Magdalena (CBUMAG) and the second (546 records) at the Museo de Entomología de la Universidad del Valle (MUSENUV).

New information: Five ant species were registered for the first time in Colombia: Leptogenysmontuosa Lattke, 2011, Neoponerarugosula Emery, 1902, Neoponerazuparkoi Mackay & Mackay, 2010, Pheidoletraini Wilson, 2003 and Wasmanniasulcaticeps Emery, 1894. Additionally, the distributions of 45 ant species native to two Departments in the Cauca River Valley geographic region (VGRC) have been expanded. Of these, 31 species extended their distribution into the Valle del Cauca Department: Aztecaalfari Emery, 1893, Foreliusdamiani Guerrero & Fernández, 2008, Ecitonmexicanum Roger, 1863, Neivamyrmexemersoni (Wheeler, 1921), Holcoponeramoelleri Forel, 1912, Brachymyrmexmusculus Forel, 1899, Cephalotesporrasi (Wheeler, 1942), Cephalotestargionii (Emery, 1894), Cephalotesumbraculatus (Fabricius, 1804), Crematogastermontezumia Smith, 1858, Crematogasterobscurata Emery, 1895, Nesomyrmexpittieri (Forel, 1899), Octostrumabatesi (Emery, 1894), Octostrumaexcertirugis Longino, 2013, Octostrumaobtusidens Longino, 2013, Pheidolebilimeki Mayr, 1870, Pheidoleboliviana Wilson, 2003, Pheidolecolobopsis Mann, 1916, Pheidolegauthieri Forel, 1901, Pheidolehasticeps Wilson, 2003, Pheidolesimonsi Wilson, 2003, Pheidolesubarmata Mayr, 1884, Pheidolevallifica Forel, 1901, Solenopsisazteca Forel, 1893, Solenopsisbrevicornis Emery, 1888, Strumigenysgrytava (Bolton, 2000), Strumigenysmarginiventris Santschi, 1931, Strumigenyswheeleriana Baroni Urbani, 2007, Temnothoraxsubditivus (Wheeler, 1903), Hypoponeraopacior (Forel, 1893), Leptogenyspubiceps Emery, 1890 and Pseudomyrmexlongior (Forel, 1904). Ten species extended their distribution into the Cauca Department: Aztecavelox Forel, 1899, Brachymyrmexminutus Forel, 1893, Crematogasterevallans Forel, 1907, Megalomyrmexdrifti Kempf, 1961, Pheidolefimbriata Roger, 1863, Pheidolelongiscapa Forel, 1901, Pheidoleradoszkowskii Mayr, 1884 and Rogeriascandens (Mann, 1922); and four species extended their distribution into both Departments: Brachymyrmexcordemoyi Forel, 1895, Pheidolesculptior Forel, 1893, Hypoponerafiebrigiantoniensis (Forel, 1912) and Hypoponeraparva (Forel, 1909). Finally, three exotic species were registered for the first time in the VGRC, extending their distributions within Colombia: Strumigenysemmae (Emery, 1890) in the Valle del Cauca Department and Cardiocondylaemeryi Forel, 1881 and Cardiocondylawroughtonii (Forel, 1890) in the Cauca Department.