The ants of the Galápagos Islands (Hymenoptera, Formicidae): a historical overview, checklist, and identification key

Abstract

The Galápagos ant fauna has long been understudied, with the last taxonomic summary being published almost a century ago. Here, a comprehensive and updated overview of the known ant species of the Galápagos Islands is provided with updated species distributions. The list is based on an extensive review of literature, the identification of more than 382,000 specimens deposited in different entomological collections, and recent expeditions to the islands. The ant fauna is composed of five subfamilies (Dolichoderinae, Dorylinae, Formicinae, Myrmicinae, and Ponerinae), 22 genera, 50 species, and 25 subspecies, although three species (Crematogaster crinosa Mayr, 1862, Camponotus senex (Smith, 1858), and Solenopsis saevissima (Smith, 1855)) are considered dubious records. Finally, an illustrated identification key of the species found in the archipelago is presented.

Aliens on the Menu: High Prevalence of Introduced Ants in the Diet of Galápagos Lava Lizards, Microlophus spp.

“…This study provides the first documentation of a high prevalence of ants, mainly introduced, in the diet of Galápagos lava lizards. Since the early stomach content analyses of Galápagos lava lizards by Denburgh and Slevin (1913) The increase in the introduction of exotic ant species during the mid and late-20th century (Herrera et al 2020;Herrera et al 2024) might have fueled such a dietary shift towards a high proportion of introduced ants, as a response to altered food availability. In the Galápagos, while there are some species whose status is not clear, non-native ant species vastly outnumber native taxa in the order of 3:1 (Herrera et al 2020;Herrera et al 2024).…”

“…These heads were point-mounted and identified to subfamily and genus level, using taxonomic keys available at AntWiki (2022) (Fernández and Palacio 2003;Baccaro et al 2015) and at species-level using keys available in AntWeb (AntWeb 2024). We further classified ant species as introduced, nonintroduced, or uncertain status following the recent review of the Galápagos ant fauna by Herrera et al (2024).…”

“…roads) have resulted in significant fatalities (Tanner and Perry 2007;Medrano-Vizcaíno et al 2023) and, increased tourism-related activities and urbanization have impacted their behavior and activity patterns, particularly on highly populated islands (Boada-Viteri 2021). Additionally, the introduction of exotic species has escalated over the last decades (Quiroga, D. 2018), particularly regarding small invertebrates (Toral-Granda et al 2017), including ants (Herrera 2014;Herrera et al 2020;Herrera et al 2024) another potential threat to the unique species that inhabit the Archipelago. However, the ecological consequences of introduced species, particularly insects, on lava lizard populations remain unexplored.…”