In this series, we explore the unique experiences of field ecologists conducting research in remote field stations during the holiday season. Through personal stories and reflections, our contributors share what it’s like to conduct scientific work in remote, biodiverse environments, where the challenges of research intersect with the spirit of the holidays. From the solitude of secluded field stations to unexpected festive moments in the wild, this series highlights the resilience and dedication of ecologists and evolutionary biologists working in these remarkable regions of the world. Here, María C. Tocora and colleagues, relay their field experiences in the Galápagos, the Ecuadorian archipelago where Darwin’s observations of finches later inspired his theory of evolution.

Post provided by María C. Tocora, Patricio Picón-Renteria, Henri W. Herrera.

“The natural history of this archipelago is remarkable: it seems to be a little world within itself” —
Charles Darwin.

Galápagos! Tortoises, finches, hammerhead sharks, and iguanas might come to mind, but this story goes beyond size — it’s a hidden tale overlooked by even Darwin’s gaze. Insects are the most diverse group in the Galápagos Islands, and still, we know little about them. There is a preliminary list of 84 species of Hymenoptera for the archipelago, mainly composed of ants (50 species). However, most scientific efforts have studied invasive species (i.e., Wasmannia auropunctata, Solenopsis geminata, Polistes versicolor) leaving endemic bees, ants, and wasps understudied in the archipelago. At the end of 2022 and 2023, our group of entomologists embarked on a journey to the islands with the motivation to study 1) the diversity of the order Hymenoptera, and 2) the evolution of carpenter ants across the Galápagos. These ants, along with their multiple subspecies which are differentially distributed across islands, were last studied over a century ago. New information on the evolution and ecology of these species, first collected by Charles Darwin in 1835, is long overdue. Considering that microbes have spurred the diversification of multiple insect lineages by affecting their nutrition and development, we are also exploring how endosymbionts—microbes living inside hosts—have influenced the evolution of ants across the archipelago.

Eyes on the Ground
Based on previous reports, we decided to sample carpenter ants in littoral, arid, and transition zones during the day. Ant nests have been reported in the roots of trees, shrubs, cacti, under rocks, and in dry branches of endemic plants. Additionally, ant nuptial flights have been reported around November/December, making collecting ant reproductives and finding colonies more likely during these months. However, what initially seemed like a straightforward search quickly turned into a realisation of how unique the Galápagos is. The first and most conspicuous challenge was the volcanic heritage of the islands, which required us to walk over basaltic rock—very sharp, and rubbly a’a lava combined with smoother pahoehoe lava flows. Misstepping could have led to severe injuries and an early end to the expedition. Cautiously, we learned how to walk on volcanic landforms while searching for ants under rocks and over cacti thriving in jagged lava blocks. After one week in the field and several failures in finding ant colonies, we conducted 24-hour surveys to determine the time when foragers were most active. Surprisingly, we confirmed that these ants are nocturnal, with both minor and major workers actively foraging outside the nest at midnight. Moving forward, we adjusted our sampling schedule to include afternoon and night shifts, during which we were accompanied by Darwin’s goliath centipede, Scolopendra galapagoensis.

Park Rangers: Great Experts on the Islands
Insect nets, aspirators, forceps, GPS devices, and hundreds of vials with ethanol and RNALater are, among other items (i.e., malaise traps, pitfall traps, and yellow traps), the equipment used in the field. While most people started getting ready for Christmas, the Galápagos National Park rangers walked alongside us, opening otherwise inaccessible trails for sampling. In the field, we carry equipment and our most valuable loads—water and food. Fresh water is scarce in the Galápagos Islands, so our team must always ensure everyone is hydrated and that we have enough water for days with no access to civilisation.

Our target host plants, with which ants interact the most, are mainly endemic plants. After weeks in the field, we observed that most ant nests were underground. With the help of the rangers, we spent the most time under the roots of Jasminocereus, Opuntia, Bursera graveolens, and thousands of lava rocks. We also found little helpers in insectivorous Darwin’s finches and Galápagos mockingbirds, which alerted us to insects on the vegetation. Fieldwork is definitely a joint effort and an exchange of knowledge among humans and nature.

From the Field to Museums
Museums are essential for uncovering the history of collecting and recreating the evolution of insects on the islands. In the Galápagos, we spent weeks working at the Invertebrate Collection of the Charles Darwin Research Station (ICCDRS) on Santa Cruz Island. In this collection, we identify species, deposit samples, and obtain metadata (i.e., date/locality of sampling, vegetation) for each specimen. This information is included in our Hymenoptera biodiversity inventory. We also combine molecular and museum data to recreate the phylogeography of carpenter ants in the Galápagos. Museum data is also used to identify historically under-sampled localities for future expeditions. On the mainland, we work with other entomological collections at the University of California, the Escuela Superior Politécnica de Chimborazo (ESPOCH), the University of Texas, and the Smithsonian Institution’s National Museum of Natural History.

Our Discovery
Recently, we published an article with a complete list of ant species from 382,000 specimens studied in different entomological collections. We are also working on a comprehensive update about the richness and distribution of the order Hymenoptera for the archipelago. In this work, we found a high and unexplored diversity of parasitoid wasps on the islands, with a new species recently published from the family Azotidae. As for carpenter ants, we recently obtained the first reference genome of a neotropical species—Camponotus planus—and its associated endosymbiont. Preliminary data suggest genetic and geographic variations across ant-bacteria interactions in the islands. We also found unique genomic features in bacteria in the Galápagos compared to their mainland counterparts. More ant and microbe specimens are currently being re-sequenced to be used in different genomic studies.

The Galápagos is not completely uninhabited. Some breaks in Puerto Ayora (Santa Cruz Island) took us back into the Christmas vibes of the season. Music and food at local festivals reminded us of another reality of the islands: the warmth of their people.

We are grateful to all the park rangers who kindly joined these expeditions, especially Wilma Perez, John Macias, and Roberto Ballesteros. We thank ESPOCH, the Galápagos National Park Directorate, the Galápagos Biosecurity Agency, the Galápagos Governing Council, the Charles Darwin Foundation, and the Ministry of Environment of Ecuador for their support for fieldwork, exporting, and sampling permits. Also, we thank Profs. Carlos Sarmiento, Fernando Fernandez, Megan Frederickson, Joseph Manthey, John Herati, and Charlotte Causton; and Jose Aveldano and Gianpiero Fiorentino for their support in these projects.

Practice “Leave-No-Trace”
To guarantee the conservation of the Galápagos as a biodiversity hotspot, we must avoid leaving evidence of our presence at field sites, especially on uninhabited islands. Before every trip to a different island, we must ensure all equipment is first checked and disinfected. Additionally, all specimens are stored in vials to prevent the transportation of live organisms. As a team, we even avoid eating raw fruits and vegetables to prevent the introduction of any species into the habitats where we collect.

Post edited by Sthandiwe Nomthandazo Kanyile