Biology subjects

Montoya-Lerma, J.

Publications and source records attributed to Montoya-Lerma, J..

4 recordsLinked to original sources

bioRxiv2026

Atta Leafcutter Ants are Fine-Scale Bioindicators of Geographic and Seasonal Climate Changes Across the Americas

AimWe develop Atta leafcutter-ants as bioindicators that respond at fine scales to geographic and seasonal climate changes in the Americas, thereby addressing the paucity of versatile insect bioindicator systems capable of monitoring climate in both Southern and Northern Hemispheres. LocationAmerican tropics and sub-tropics from latitudes S33.6{degrees} to N33.2{degrees}, with case studies from Colombia, Mexico, and southern USA. Time Period2012-2024. Taxon StudiedAtta leafcutter-ants. MethodsWe elucidate biogeographic patterns of mating-flight phenology of Atta leafcutter-ants across the entire Atta range from Uruguay/Argentina to the USA, using 2335 records of Atta reproductives from the community database iNaturalist, then ground-truth these patterns by comparison with (i) mating-flight records (n=806) from the Atta literature; and (ii) mating-flight observations (n=836) accumulated by a consortium of experts who have researched Atta for a combined 1000+ work-years. Onset of mating flights can be timed with great precision in Atta populations because mass-mating flights are synchronized and triggered by the first major rainfall of a rainy season. ResultsBiogeographic patterns in climate-dependent mating-flight phenologies recorded at iNaturalist are corroborated by observations accumulated in the literature and by Atta experts. Analyses reveal so-far unknown gradients in mating-flight phenology (e.g., Colombia to USA) that are correlated to geographic climate gradients, and season switches of mating flights from early to late in the year between proximate Atta populations (e.g., 200 kilometers apart), for example in the climatically complex Andean regions of Colombia. Regional differences in Atta mating-flight phenology correspond to temporal differences in rainfall between ecoregions of Colombia. Main ConclusionsAtta ants are tractable insect bioindicators to monitor climate impacts with detailed spatial and temporal resolution across a 9200-kilometer trans-equatorial transect in the Americas. We outline future research directions to explore climate-dependent biology using the continuously growing, and now ground-truthed, information at iNaturalist on Atta mating behavior.

ecology↗

bioRxiv2021

Landscape genetics across the Andes Mountains: Environmental variation drives genetic divergence in the leaf-cutting ant Atta cephalotes

Disentangling the mechanisms underlying spatial distribution of genetic variation into those due to environment or physical barriers from mere geographic distance is challenging in complex landscapes. The Andean uplift represents one of the most heterogeneous habitats where these questions remain unexplored as multiple mechanisms might interact, confounding their relative roles. We explore this broad question in the leaf-cutting ant Atta cephalotes, a species distributed across the Andes Mountains using nuclear microsatellite markers and mtCOI gene sequences. We investigate spatial genetic divergence across the Western range of Northern Andes in Colombia by testing the relative role of alternative scenarios of population divergence, including geographic distance (IBD), climatic conditions (IBE), and physical barriers due to the Andes Mountains (IBB). Our results reveal substantial genetic differentiation among A. cephalotes populations for both types of markers, but only nuclear divergence followed a hierarchical pattern with multiple models of genetic divergence imposed by the Western range. Model selection showed that IBD, IBE (temperature and precipitation), and IBB (Andes mountains) models, often proposed as individual drivers of genetic divergence, interact, and explain up to 33% of genetic divergence in A. cephalotes. IBE models remained significant after accounting for IBD, suggesting that environmental factors play a more prominent role when compared to IBB. These factors in combination with idiosyncratic dispersal patterns of ants appear to determine hierarchical patterns of gene flow. This study enriches our understanding of the forces shaping population divergence in complex habitat landscapes.

genetics↗

bioRxiv2021

The role of the Andean uplift as an asymmetrical barrier to gene flow in the Neotropical leaf-cutting ant Atta cephalotes

Neotropical diversification by the Andean uplift is typically addressed on a large evolutionary scale (e.g. speciation), even though many species are still distributed in both sides of the mountains. The three parallel mountain ranges in the northern Andes (Colombia) impose a major geographical barrier to species migration from South to Central America. How important these barriers are for conspecific diversification of cross-Andean species such as the leaf-cutting ants remains largely unknown. To answer this question, we studied the mtCOI gene of Atta cephalotes, the most widely distributed leaf-cutting ant species. Our hierarchical analyzes evidenced substantial genetic structure among regions and populations, suggesting a more complex biogeographical history of Andean populations than previously thought. These mountains seem to isolate Central American and Western Colombian populations from the rest of A. cephalotes in South America. Population and migration modelling are consistent with the origin of this species in South America and a major role of the Eastern cordillera as a geographical barrier to historical gene flow, restricting dispersion from north to south. These findings provide insights into the role of the Andean uplift as barrier to gene flow and, eventually, implications for monitoring and designing management strategies for leaf-cutting ants.

genetics↗

bioRxiv2018

Degree of urbanization and predation pressure on artificial lepidopteran caterpillars in Cali, Colombia

Growing urban expansion results in the alteration of ecological processes (i.e. predation) within trophic networks. Predation on herbivores is known to vary with the size of the area covered in vegetation, successional stage, altitude, and the structure of the predator community, but there are gaps in information regarding how this occurs in urban and suburban environments. The purpose of this study was to determine whether the predation pressure on artificial models of lepidopteran larvae varied with degree of urbanization, type of substrate, and group of predators (birds or arthropods) in Cali, Colombia. Five hundred and eighteen artificial larvae were placed in two areas of the city (urban vs. suburban) and in two types of substrate (leaf vs. stem) for 30 continuous days and with two replications over time. Total predation was measured as the number of models with evidence of attack by predators. The overall incidence of predation was 24.13%, and was significantly higher in the urban area (63.20%) when compared to the suburban area (36.80%). The leaf substrate was attacked significantly more than the stem (60% vs. 40%). The proportion of attacks carried out by birds was significantly higher (74.40%) than that carried out by arthropods (24.80%). Together, these results suggest that the incidence of predation varies with the disturbance caused by urbanization and by the type of substrate in which prey organisms are found. In addition, the study confirms that birds are the main controllers of herbivorous insects in urban environments.

animal behavior and cognition↗