Biology subjects

Rabeling, C.

Publications and source records attributed to Rabeling, C..

6 recordsLinked to original sources

bioRxiv2026

Next-generation insect digitization: combining phenomics and genomics by subsequent synchrotron X-ray imaging and DNA sequencing

Recent technological advances allow for the large-scale acquisition of genetic and morphological data: high-throughput sequencing has transformed the field of genomics while synchrotron X-ray microtomography enables rapid, noninvasive 3D imaging. However, integrating these approaches for the same specimens is challenging because X-rays can fragment DNA, and DNA extraction damages internal morphology, particularly relevant for small bodied organisms, such as insects. We systematically tested multiple extraction protocols and irradiation conditions across three model insect species. We irradiated more than 1,000 specimens under varying conditions and tested DNA quality through DNA barcoding and UCE sequencing. Our results demonstrate that high-quality DNA and high-resolution tomograms can be obtained from the same individuals, provided that the parameters are carefully optimized and rapid SR-CT scanning precedes DNA extraction. In this respect, our findings establish practical guidelines for combining genomics and phenomics, paving the way for comprehensive integrative digitization of biodiversity.

genetics↗

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↗

bioRxiv2024

Phylogenomics resolve the systematics and biogeography of the ant tribe Myrmicini and tribal relationships within the hyperdiverse ant subfamily Myrmicinae

Ants are a globally distributed and highly diverse group of eusocial animals, playing key ecological roles in most of the worlds terrestrial ecosystems. Our understanding of the processes involved in the evolution this diverse family is contingent upon our knowledge of the phylogeny of the ants. While relationships among most subfamilies have come into resolution recently, several of the tribal relationships within the hyperdiverse subfamily Myrmicinae persistently conflict between or within studies, mirroring the controversial relationships of the Leptanillinae and Martialinae to the remaining ant subfamilies. Another persistent issue of debate in ant phylogenetics is the timing of major evolutionary events as inferred via divergence dating. Here, we test the topology of the myrmicine tribes using genome scale data, inspect gene tree-species tree concordance, and use posterior predictive checks and tests of compositional heterogeneity to infer sequence characteristics which potentially introduce systematic bias in myrmicine tribal topology. Furthermore, we test the placement of the fossil {dagger}Manica andrannae by integrating phylogenomic and morphological data from nearly all species within the genus Manica, and a broad sampling of its sister genus Myrmica. Subsequently, we demonstrate the effect of fossil placement on overall divergence times in the Myrmicinae. We then re-evaluate the historical biogeography of the Myrmicini and Pogonomyrmecini considering newly generated genetic data and insights from our phylogenomic results. We find that our current understanding of tribal topology in the Myrmicinae is strongly supported, but this topology is highly sensitive to compositional heterogeneity and gene-tree species-tree conflict. Our fossil placement analyses strongly suggest that {dagger}Manica andrannae is a stem Manica species, and that placement of this fossil in the crown group affects not only divergence dates within the tribe Myrmicini, but also has broad implications for divergence times throughout the formicoid clade. The results of our biogeographic reconstructions indicate a South American origin for the Pogonomyrmecini + Myrmicini, with the MRCA of Myrmica inhabiting the western Nearctic in the early Miocene prior to repeated dispersal across Beringia throughout the Miocene and Pliocene. The MRCA of Manica, on the other hand, was inferred to have a Holarctic range prior to vicariance during the Pliocene. Unexpectedly, we found strong support in the Pogonomyrmecini for three coordinated dispersal events from South to Central America during the early Miocene, which has been previously proposed as an early biotic interchange event prior to the more commonly accepted 3.5 Ma closure of the Isthmus of Panama.

evolutionary biology↗

bioRxiv2023

The discovery of mixed colonies in Temnothorax ants supports the territoriality hypothesis of dulotic social parasite evolution in myrmicine ants

Social parasitism, where one social species parasitically depends on the other for survival and reproduction, is a highly successful life history strategy, especially in the eusocial Hymenoptera. In ants alone, more 400 species of socially parasitic species exist and multiple forms of social parasitism evolved independently and convergently. Yet disentangling the evolutionary history of obligate social parasitism is challenging. Identifying species that inform the transition from eusocial toward socially parasitic behavior is crucial for understanding the underlying co-evolutionary processes. Here, we report the first case of mixed colonies involving four predominantly free-living Temnothorax ant species from the western United States. Three Temnothorax species supplement their worker force with brood from the nests of their four congeners. We suggest, based on these observations and other published evidence, that this facultative dulotic behavior may have resulted from territorial contests due to limited nest sites. Socially parasitic behavior is not present in all populations across the species distribution ranges, however in populations where this behavior was observed, it is also associated with significant increases in interspecific aggression. These four species of Western US Temnothorax ants represent a particularly interesting case of social parasitism, because the presence of between-population behavioral variation provides a powerful system to test hypotheses about the ecological and behavioral conditions underlying the evolutionary transition from eusocial to socially parasitic behavior.

animal behavior and cognition↗

bioRxiv2020

The evolution of social parasitism in Formica ants revealed by a global phylogeny

Studying the behavioral and life history transitions from a cooperative, eusocial life history to exploitative social parasitism allows for deciphering the conditions under which changes in behavior and social organization lead to diversification. The Holarctic ant genus Formica is ideally suited for studying the evolution of social parasitism because half of its 176 species are confirmed or suspected social parasites, which includes all three major classes of social parasitism known in ants. However, the life-history transitions associated with the evolution of social parasitism in this genus are largely unexplored. To test competing hypotheses regarding the origins and evolution of social parasitism, we reconstructed the first global phylogeny of Formica ants and representative formicine outgroups. The genus Formica originated in the Old World during the Oligocene ([~]30 Ma ago) and dispersed multiple times to the New World. Within Formica, the capacity for dependent colony foundation and temporary social parasitism arose once from a facultatively polygynous, independently colony founding ancestor. Within this parasitic clade, dulotic social parasitism evolved once from a facultatively temporary parasitic ancestor that likely practiced colony budding frequently. Permanent social parasitism evolved twice from temporary social parasitic ancestors that rarely practiced colony budding, demonstrating that obligate social parasitism can originate from different facultative parasitic backgrounds in socially polymorphic organisms. In contrast to inquiline ant species in other genera, the high social parasite diversity in Formica likely originated via allopatric speciation, highlighting the diversity of convergent evolutionary trajectories resulting in nearly identical parasitic life history syndromes.

evolutionary biology↗

bioRxiv2017

Compositional heterogeneity and outgroup choice influence the internal phylogeny of the ants

Knowledge of the internal phylogeny and evolutionary history of ants (Formicidae), the worlds most species-rich clade of eusocial organisms, has dramatically improved since the advent of molecular phylogenetics. A number of relationships at the subfamily level, however, remain uncertain. Key unresolved issues include placement of the root of the ant tree of life and the relationships among the so-called poneroid subfamilies. Here we assemble a new data set to attempt a resolution of these two problems and carry out divergence dating, focusing on the age of the root node of crown Formicidae. For the phylogenetic analyses we included data from 110 ant species, including the key species Martialis heureka. We focused taxon sampling on non-formicoid lineages of ants to gain insight about deep nodes in the ant phylogeny. For divergence dating we retained a subset of 62 extant taxa and 42 fossils in order to approximate diversified sampling in the context of the fossilized birth-death process. We sequenced 11 nuclear gene fragments for a total of ~7.5 kb and investigated the DNA sequence data for the presence of among-taxon compositional heterogeneity, a property known to mislead phylogenetic inference, and for its potential to affect the rooting of the ant phylogeny. We found sequences of the Leptanillinae and several outgroup taxa to be rich in adenine and thymine (51% average AT content) compared to the remaining ants (45% average). To investigate whether this heterogeneity could bias phylogenetic inference we performed outgroup removal experiments, analysis of compositionally homogeneous sites, and a simulation study. We found that compositional heterogeneity indeed appears to affect the placement of the root of the ant tree but has limited impact on more recent nodes. We put forward a novel hypothesis regarding the rooting of the ant phylogeny, in which Martialis and the Leptanillinae together constitute a clade that is sister to all other ants. After correcting for compositional heterogeneity this emerges as the best-supported hypothesis of relationships at deep nodes in the ant tree. The results of our divergence dating under the fossilized birth-death process and diversified sampling suggest that the crown Formicidae originated during the Albian or Aptian ages of the Lower Cretaceous (103-124 Ma). In addition, we found support for monophyletic poneroids comprising the subfamilies Agroecomyrmecinae, Amblyoponinae, Apomyrminae, Paraponerinae, Ponerinae, and Proceratiinae, and well-supported relationships among these subfamilies except for the placement of Proceratiinae and (Amblyoponinae + Apomyrminae). Our phylogeny also highlights the non-monophyly of several ant genera, including Protanilla and Leptanilla in the Leptanillinae, Proceratium in the Proceratiinae, and Cryptopone, Euponera, and Mesoponera within the Ponerinae.

evolutionary biology↗