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Subterranean rodents of the genus Ctenomys (tuco-tucos) are endemic to South America and have experienced relatively recent radiation. There are about 67 recognized species that originated in approximately 1-2 MY. They stand out for their species richness, extraordinary chromosomal diversity, and wide range of habitat they occupy in the continent. Phylogenetic relationships among species of tuco-tucos have been challenging to resolve. Groups of closely-related species have been suggested, but their relationships must be resolved. This study estimates the phylogeny of the genus using massive sequencing, generating thousands of independent molecular markers obtained by RADseq, with a taxonomic sampling that includes 66% of the recognized species. The sequences obtained were mapped against the C. sociabilis genome, recovering up to 1,215 widely shared RAD loci with more than 19,000 polymorphic sites. Our new phylogenetic hypothesis corroborated the species groups previously proposed with cytochrome b gene sequences and provided a much greater resolution of the relationships among species groups. The frater group is sister to all other tuco-tucos, whereas some of the earlierliest proposals placed the sociabilis group as sister to all other tuco-tucos. Ctenomys leucodon, previously proposed as an independent lineage, is associated with the frater group with moderate statistical support. The magellanicus and mendocinus are sister groups in a major clade formed by the boliviensis, talarum, tucumanus, torquatus, and opimus groups. Ctenomys viperinus, included in the phylogeny for the first time, belongs to the tucumanus group. This multi-locus phylogenetic hypothesis provides insights into the historical biogeography of understanding this highly diverse genus., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Factors that increase reproductive variance among individuals act to reduce effective population size (Ne), which accelerates the loss of genetic diversity and decreases the efficacy of purifying selection. These factors include sexual cannibalism, offspring investment and mating system. Pre-copulatory sexual cannibalism, where the female consumes the male prior to mating, exacerbates this effect. We performed comparative transcriptomics in two spider species, the cannibalistic Trechaleoides biocellata and the non-cannibalistic T. keyserlingi , to generate genomic evidence to support these predictions. First, we estimated heterozygosity and found that genetic diversity is relatively lower in the cannibalistic species. Second, we calculated dN/dS ratios as a measure of purifying selection; a higher dN/dS ratio indicated relaxed purifying selection in the cannibalistic species. These results are consistent with the hypothesis that sexual cannibalism impacts operational sex ratio and demographic processes, which interact with evolutionary forces to shape the genetic structure of populations. However, other factors such as the mating system and life-history traits contribute to shaping Ne. Comparative analyses across multiple contrasting species pairs would be required to disentangle these effects. Our study highlights that extreme behaviours such as pre-copulatory cannibalism may have profound eco-evolutionary effects.

The convergent evolution of subterranean rodents is an excellent model to study how natural selection operates and the genetic bases of these adaptations, but the study on the different taxa has been very uneven and still insufficient. In the octodontoid caviomorph rodent superfamily there are two independent lineages where they have recently evolved into totally underground lifestyles: the genera Ctenomys (tuco-tucos) and Spalacopus (coruro). The underground habitat is characterized by an hypoxic and hypercapnic atmosphere, thus gas exchange is one of the most important challenges for these animals. The invasion of the underground niche could have modified the selective regimes of proteins involved in the respiration and transport of O 2 of these rodents, positively selecting mutations of higher affinity for O 2 . Here we examine the sequence variation in the beta globin gene in these two lineages, within a robust phylogenetic context. Using different approaches (classical and Bayesian maximum likelihood (PAML/Datamonkey) and alternatives methods (TreeSAAP)) we found at least three sites with evidence of positive selection in underground lineages, especially the basal branch that leads to the Octodontidae family and the branch that leads to the coruro, suggesting some adaptive changes to the underground life. We also found a convergence with another underground rodent, which cannot be identified by the above methods., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The ectoparasite Varroa destructor is the greatest biotic threat of honey bees Apis mellifera in vast regions of the world. Recently, the study of natural mite-resistant populations has gained much interest to understand the action of natural selection on the mechanisms that limit the mite population. In this study, the components of the A. mellifera - V. destructor relationship were thoroughly examined and compared in resistant and susceptible honey bee populations from two regions of Uruguay. Mite-resistant honey bees have greater behavioral resistance (hygienic and grooming behaviors) than susceptible honey bees. At the end of the summer, resistant honey bees had fewer mites and a lower deformed wing virus (DWV) viral load than susceptible honey bees. DWV variant A was the only detected variant in honey bees and mites. Molecular analysis by Short Tandem Repeat showed that resistant honey bees were Africanized ( A. m. scutellata hybrids), whereas susceptible honey bees were closer to European subspecies. Furthermore, significant genetic differentiation was also found between the mite populations. The obtained results show that the natural resistance of honey bees to V. destructor in Uruguay depends on several factors and that the genetic variants of both organisms can play a relevant role.

A new rove beetle species, Edrabius uruguayensis Martínez-Villar, González-Vainer Tomasco, sp. nov., associated with the subterranean rodent Ctenomys rionegrensis in Uruguay, is described and illustrated. Photographs, scanning electron micrographs and drawings of the diagnostic character states are provided. The new species is compared with other species of the genus. Nucleotide sequence of the cytochrome oxidase subunit I was reported for the first time for the genus and phylogenetic reconstruction confirms their close relationship with the other genus used from the tribe Amblyopinini (Heterothops).

[This corrects the article DOI: 10.1016/j.dib.2017.09.017.].

The data presented in this article are related to the research article entitled "Molecular adaptive convergence in the α-globin gene in subterranean octodontid rodents" (Tomasco et al., 2017) [1]. This article shows the nucleotide sequences of α-globin subunit gene of hemoglobin of several South American caviomorph rodents, including subterranean and fossorial species. These sequences are deposited in Genbank, with accession numbers ranging from MF169881 to MF169898. Of a total of 429 nucleotides analyzed (143 codons), 100 variable sites and 43 amino acid replacements were reported. In this article we also show the results of TreeSaap (Woolley et al., 2003) [2] and MEME (Murrell et al., 2012) [3], that identified some replacement changes as interesting for future studies of adaptive evolution in this large rodent radiation.

Tuco-tucos (Ctenomys) and related coruros (Spalacopus) are South American subterranean rodents. An energetically demanding lifestyle within the hypoxic/hypercapnic underground atmosphere may change the selective regime on genes involved in O 2 transport in blood. In addition, some species of tuco-tucos may be found at high altitude, thus facing additional reductions in changes O 2 availabily. We examined sequence variation in the alpha globin subunit gene of hemoglobine in these lineages, within a robust phylogenetic context. Using different approaches (classical and Bayesian maximum likelihood (PAML/Datamonkey) and alternatives methods (TreeSAAP)) we found at least 2 sites with evidence of positive selection in the basal branch of Octodontidae, but not in tuco-tucos. These results suggest some adaptive changes associated to fossoriality, but not strictly to life underground., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Tuco-tucos (Ctenomys) and related coruros (Spalacopus) are South American subterranean rodents. An energetically demanding lifestyle within the hypoxic, underground atmosphere may change the selective regime on oxidative phosphorylation. We examined whether weak and/or episodic positive directional selection affected the evolution of two mitochondrial genes (COX2, CytB), in a background of purifying selection in these lineages. We estimated rates of synonymous (dS) and non-synonymous (dN) substitutions and found: 1) significantly higher dN/dS ratio in subterranean groups relative to non-subterranean related species, and 2) two codons in each gene under episodic selection: 94 and 277 of COX2 and 269 and 307 of CytB., (© 2013 Elsevier B.V. All rights reserved.)

South American tuco-tucos (Ctenomys) and the related coruro (Spalacopus) are two rodent lineages that have independently colonised the subterranean niche. The energetically demanding lifestyles of these species, coupled with the hypoxic atmospheres characteristic of subterranean environments, may have altered the selective regimes on genes encoding proteins related to cellular respiration. Here, we examined the molecular evolution of 13 protein-coding genes in the mitochondrial genome of seven caviomorph rodents, including these two subterranean genera and their above-ground relatives. Using maximum-likelihood and Bayesian approaches, we estimated rates of synonymous (dS) and nonsynonymous (dN) substitutions. We found a significantly higher ω ratio (dN/dS) in subterranean groups as compared to their non-subterranean counterparts in 11 of 13 genes, although no ω ratio was larger than 1. Additionally, we applied a method based on quantitative physicochemical properties to test for positive selection. Amino acid changes implicated in radical structural or functional shifts in the protein property were found to be ubiquitous across the phylogeny, but concentrated in the subterranean lineages. Convergent changes were also found between the subterranean genera used in this study and other mammals adapted to hypoxia. The results of this study suggest a link between niche shifts and weak directional (or episodic) selection at the molecular level against a background of purifying selection., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Subterranean rodents construct large and complex burrows and spend most of their lives underground, while fossorial species construct simpler burrows and are more active above ground. An important constraint faced by subterranean mammals is the chronic hypoxia and hypercapnia of the burrow atmosphere. The traits, regarded as "adaptations of rodents to hypoxia and hypercapnia", have been evaluated in only a few subterranean species. In addition, well-studied subterranean taxa are very divergent to their sister groups, making it difficult to assess the adaptive path leading to subterranean life. The closely related sister genera Octodon and Spalacopus of Neotropical rodents offer a unique opportunity to trace the evolution of physiological mechanisms. We studied the ventilatory responses of selected octodontid rodents to selective pressures imposed by the subterranean niche under the working hypothesis that life underground, in hypoxic and hypercapnic conditions, promotes convergent physiological changes. To perform this study we used the following species: Spalacopus cyanus (the subterranean coruros) and Octodon degus (the fossorial degus) from central Chile. Ventilatory tidal volume and respiratory frequency were measured in non-anaesthetized spontaneously breathing animals. Acute hypoxic challenges (O(2) 1-15%) and hypercapnia (CO(2) 10%) were induced to study respiratory strategies using non-invasive whole body pletismography techniques. Our results show that coruros have a larger ventilatory response to acute hypoxia as than degus. On the other hand, hypercapnic respiratory responses in coruros seem to be attenuated when compared to those in degus. Our results suggest that coruros and degus have different respiratory strategies to survive in the hypoxic and hypercapnic atmospheres present in their burrows.

The microsporidium Nosema ceranae is an emergent pathogen of European honeybees Apis mellifera. Using a PCR-RFLP diagnosis, 29 samples of infected honeybees obtained in 2007-2008 (N=26), 2004 (N=2) and before 1990 (N=1) were analyzed for the presence of Nosema apis and N. ceranae. Only N. ceranae was found in all samples, indicating that this species dispersed to Uruguay (and likely the region) at some time before 1990. The presence of N. ceranae in Uruguay is not associated with an increase of Nosemosis, and its role in colony loss seems to be irrelevant.