Institute of Ecology INECOL

Interactions between ants and plants can form complex ecological networks, which may have their structure affected by human-induced habitat modification, such as urbanization. In this study, we investigated if the species diversity and the network topology of ant-plant co-occurrence networks (facultative associations between plants and ants) differs between remnants of Neotropical savannas. We sampled 12 savanna fragments (cerrado sensu stricto) in wild, rural and urban areas of Minas Gerais, Brazil. In total, the 12 ant-plant interaction networks were composed by 65 ant species, 83 plant species and 432 distinct interactions. We observed that in addition to variations in species composition, wild areas exhibited higher richness and abundance of ants compared to urban areas. However, our results show no variation in the specialization, modularity, and nestedness of ant-plant co-occurrence networks among urban, rural, and wild areas. Despite changes in species diversity, ant-plant interactions maintain consistent organization across studied environments, showcasing resilience to anthropogenic disturbances similar to that observed in wild remanants.

Mosquitoes are closely associated with wetlands, as stagnant water in these ecosystems provides an ideal environment for the development of their immature stages. Human activities, such as artificial drainage for mosquito control, impact the ecological integrity of these ecosystems. Therefore, the objective was to compare the species composition of mosquitoes in two types of wetlands (swamp and herbaceous wetland) and a nearby human settlement, and determine the degree of risk, advocating for the conservation of these ecosystems. Collection of mosquito immature stages was conducted throughout on year in the municipality of Jamapa, in Veracruz state, Mexico. The richness and abundance of the collected species were determined, and the species composition of each site was compared through cluster and beta diversity analysis and analysis of similarity. The richness was higher in the two wetlands, and the abundance in human settlements. The species composition was different in all three sites. Mosquito species posing higher health risks were found in human settlements, and those posing lower risks in the swamp. As a result, it was possible to determine a disturbance gradient, with human settlements at the negative end of the gradient, the herbaceous wetland in the middle, and the swamp at the positive end, demonstrating that ecosystems preserving their original flora and fauna do not represent a significant risk for the transmission of mosquito-borne diseases.

Male genitalia morphology in Myrmeleontidae has traditionally been insufficiently studied, although it has received increased attention for its diagnostic value in recent times. A neutral terminology has generally been applied in standard taxonomic practice, yet knowledge of an equivalent and stable terminology across taxa based on comparative morphology has been missing. Herein a detailed comparative morphology study with examples from most tribes within Myrmeleontidae, including owlflies (Ascalaphinae), attempts to relate external and internal genital structures based on a proposed groundplan for Neuroptera and Myrmeleontidae. We contend that a groundplan based on 10 abdominal segments, plus vestigial structures from an 11th segment, coherently depicts structural components across myrmeleontid taxa. A gonarcus, an element of Neuropterida amply referred in Neuroptera, is supported to represent the pair of abdominal appendages of segment X medially fused, with gonocoxite and gonostylus components. In most myrmeleontid taxa, basal (gonocoxites) and distal (gonostyli) components separate, with gonostyli positioned posteriorly with respect to gonocoxites, still united with translucent, lightly sclerotized tissue, forming a more or less conical structure, a proposed synapomor-phy for the family. Ninth gonostyli are generally reduced (pulvini) and have migrated close to the base of gonarcus (10th gonocoxites). A pelta, also a potential synapomorphy for Myrmeleontidae, derives from paired setose surfaces of the 10th gonostyli, medially positioned (still evident in Bubopsis). Three structural types of gonarcus are diagnosed for illustrative purposes, as they may represent convergent constructs.

Plant–hummingbird interactions are considered a classic example of coevolution, a process in which mutually dependent species influence each other’s evolution. Plants depend on hummingbirds for pollination, whereas hummingbirds rely on nectar for food. As a step towards understanding coevolution, this review focuses on the macroevolutionary consequencesof plant–hummingbird interactions, a relatively underexplored area in the current literature. We synthesize prior studies,illustrating the origins and dynamics of hummingbird pollination across different angiosperm clades previouslypollinated by insects (mostly bees), bats, and passerine birds. In some cases, the crown age of hummingbirds pre-datesthe plants they pollinate. In other cases, plant groups transitioned to hummingbird pollination early in the establishmentof this bird group in the Americas, with the build-up of both diversities coinciding temporally, and hence suggestingco-diversification. Determining what triggers shifts to and away from hummingbird pollination remains a major openchallenge. The impact of hummingbirds on plant diversification is complex, with many tropical plant lineages experienc-ing increased diversification after acquiringflowers that attract hummingbirds, and others experiencing no change oreven a decrease in diversification rates. This mixed evidence suggests that other extrinsic or intrinsic factors, such as localclimate and isolation, are important covariables driving the diversification of plants adapted to hummingbird pollination.To guide future studies, we discuss the mechanisms and contexts under which hummingbirds, as a clade and as individualspecies (e.g. traits, foraging behaviour, degree of specialization), could influence plant evolution. We conclude bycommenting on how macroevolutionary signals of the mutualism could relate to coevolution, highlighting theunbalanced focus on the plant side of the interaction, and advocating for the use of species-level interaction data inmacroevolutionary studies.

This study assessed the bacterioplankton community and its relationship with environmental variables, including total petroleum hydrocarbon (TPH) concentration, in the Yucatan shelf area of the Southern Gulf of Mexico. Beta diversity analyses based on 16S rRNA sequences indicated variations in the bacterioplankton community structure among sampling sites. PERMANOVA indicated that these variations could be mainly related to changes in depth (5 to 180 m), dissolved oxygen concentration (2.06 to 5.93 mg L⁻¹), and chlorophyll‐a concentration (0.184 to 7.65 mg m³). Moreover, SIMPER and one‐way ANOVA analyses showed that the shifts in the relative abundances of Synechococcus and Prochlorococcus were related to changes in microbial community composition and chlorophyll‐a values. Despite the low TPH content measured in the studied sites (0.01 to 0.86 μL L⁻¹), putative hydrocarbon‐degrading bacteria such as Alteromonas, Acinetobacter, Balneola, Erythrobacter, Oleibacter, Roseibacillus, and the MWH‐UniP1 aquatic group were detected. The relatively high copy number of the alkB gene detected in the water column by qPCR and the enrichment of hydrocarbon‐degrading bacteria obtained during lab crude oil tests exhibited the potential of bacterioplankton communities from the Yucatan shelf to respond to potential hydrocarbon impacts in this important area of the Gulf Mexico.

One of the mechanisms that can lead to the formation of new species occurs through the evolution of reproductive barriers. However, recent research has demonstrated that hybridization has been pervasive across the tree of life even in the presence of strong barriers. Swordtail fishes (genus Xiphophorus) are an emerging model system for studying the interface between these barriers and hybridization. We document overlapping mechanisms that act as barriers between closely related species, X. birchmanni and X. cortezi, by combining genomic sequencing from natural hybrid populations, artificial crosses, behavioral assays, sperm performance, and developmental studies. We show that strong assortative mating plays a key role in maintaining subpopulations with distinct ancestry in natural hybrid populations. Lab experiments demonstrate that artificial F1 crosses experience dysfunction: crosses with X. birchmanni females were largely inviable and crosses with X. cortezi females had a heavily skewed sex ratio. Using F2 hybrids we identify several genomic regions that strongly impact hybrid viability. Strikingly, two of these regions underlie genetic incompatibilities in hybrids between X. birchmanni and its sister species X. malinche. Our results demonstrate that ancient hybridization has played a role in the origin of this shared genetic incompatibility. Moreover, ancestry mismatch at these incompatible regions has remarkably similar consequences for phenotypes and hybrid survival in X. cortezi × X. birchmanni hybrids as in X. malinche × X. birchmanni hybrids. Our findings identify varied reproductive barriers that shape genetic exchange between naturally hybridizing species and highlight the complex evolutionary outcomes of hybridization.

Premise Functional traits reflect species’ responses to environmental variation and the breadth of their ecological niches. Fagus grandifolia and Oreomunnea mexicana have restricted distribution in upper montane cloud forests (1700–2000 m a.s.l.) in Mexico. These species were introduced into plantings at lower elevations (1200–1600 m a.s.l.) that have climates predicted for montane forests in 2050 and 2070. The aim was to relate morphological leaf traits to the ecological niche structure of each species. Methods Leaf functional traits (leaf area, specific leaf area [SLA], thickness, and toughness) were analyzed in forests and plantings. Atmospheric circulation models and representative concentration pathways (RCPs: 2.6, 4.5, 8.5) were used to assess future climate conditions. Trait–niche relationships were analyzed by measuring the Mahalanobis distance (MD) from the forests and the plantings to the ecological niche centroid (ENC). Results For both species, leaf area and SLA were higher and toughness lower in plantings at lower elevation relative to those in higher‐elevation forests, and thickness was similar. Leaf traits varied with distance from sites to the ENC. Forests and plantings have different environmental locations regarding the ENC, but forests are closer (MD 0.34–0.58) than plantings (MD 0.50–0.70) for both species. Conclusions Elevation as a proxy for expected future climate conditions influenced the functional traits of both species, and trait patterns related to the structure of their ecological niches were consistent. The use of distances to the ENC is a promising approach to explore variability in species’ functional traits and phenotypic responses in optimal versus marginal environmental conditions.

We tested the hypothesis that bioclimatic conditions affect the species richness, abundance, and diversity of sand flies in neighboring physiographic regions with endemic transmission of cutaneous leishmaniasis. A sampling program was performed in southeastern Mexico in the High Plateau of Chiapas and the Eastern Mountains physiographic regions, between April 2009 and March 2011. CDC light traps were placed in five randomly selected houses, four CDC traps in four transects in the surrounding vegetation zones, and a modified Magoon trap baited with one protected person was installed at the periphery of the villages at each study site. A total of 12,349 sand flies were identified as species, of which 98.2% were collected in the Eastern Mountains and the rest in the High Plateau of Chiapas. The Eastern Mountains region recorded a significantly higher diversity (H’ = 2.04), with a species richness of 27 sand flies species and a higher evenness index (J´ = 0.62) compared to the High Plateau of Chiapas region (H’ = 1.02, S=10, J´ = 0.31). Psychodopygus panamensis (Shannon) (Diptera: Psychodidae) and Pintomyia (Pifanomyia) ovallesi (Ortiz) were the most abundant species in the Eastern Mountains, whereas Lutzomyia (Tricholateralis) cruciata (Coquillett) was most abundant in the High Plateau of Chiapas. We conclude that the differences in species richness, diversity, and abundance of sand flies between these two physiographic regions are due to the bioclimatic effects that in the Eastern Mountains are favorable for the formation of microhabitats due to the warm-warm conditions and the humid-temperate conditions which act as limiting factors in the High Plateau of Chiapas region. In addition, changes in land use due to anthropogenic activities significantly affected the structure of sand fly communities in both regions.

Given the current environmental crisis, biodiversity protection is one of the most urgent socio-environmental priorities. However, the effectiveness of protected areas (PAs), the primary strategy for safeguarding ecosystems, is challenged by global climate change (GCC), with evidence showing that species are shifting their distributions into new areas, causing novel species assemblages. Therefore, there is a need to evaluate PAs' present and future effectiveness for biodiversity under the GCC. Here, we analyzed changes in the spatiotemporal patterns of taxonomic and phylogenetic diversity (PD) of plants associated with the Neotropical seasonally dry forest (NSDF) under GCC scenarios. We modeled the climatic niche of over 1000 plant species in five representative families (in terms of abundance, dominance, and endemism) of the NSDF. We predicted their potential distributions in the present and future years (2040, 2060, and 2080) based on an intermediate scenario of shared socio-economic pathways (SSP 3.70), allowing species to disperse to new sites or constrained to the current distribution. Then, we tested if the current PAs network represents the taxonomic and phylogenetic diversities. Our results suggest that GCC could promote novel species assemblages with local responses (communities' modifications) across the biome. In general, models predicted losses in the taxonomic and phylogenetic diversities of all the five plant families analyzed across the distribution of the NSDF. However, in the northern floristic groups (i.e., Antilles and Mesoamerica) of the NSDF, taxonomic and PD will be stable in GCC projections. In contrast, across the NSDF in South America, some cores will lose diversity while others will gain diversity under GCC scenarios. PAs in some NSDF regions appeared insufficient to protect the NSDF diversity. Thus, there is an urgent need to assess how the PA system could be better reconfigured to warrant the protection of the NSDF.

Ehrlichia chaffeensis is a bacterium belonging to the Anaplasmataceae family. In Mexico, only 2 species have been recorded in association with tick species and humans. The objective of the present study was to detect the presence of bacteria of the genus Ehrlichia in ticks collected from the Chamela-Cuixmala Biosphere Reserve, Jalisco, Mexico. The collected ticks were identified and analyzed individually by polymerase chain reaction to amplify a fragment of the Anaplasmataceae 16S rRNA gene and the Ehrlichia-specific dsb gene. A total of 204 ticks, corresponding to 5 species of Ixodidae and 1 of Argasidae, were collected from 147 mammals of 6 species and 4 orders; 57 ticks collected from vegetation were also included. Among the total ticks collected, 1.47% (3/204) was positive for Ehrlichia sp. DNA was obtained using the primers EHR 16SD and EHR 16SR for 16S rRNA and DSB-330 and DSB-728 for dsb. The positive samples corresponded to a larva (Amblyomma sp.) associated with Didelphis virginiana and 2 nymphs (Amblyomma cf. oblongoguttatum) infesting Nasua narica. None of the ticks collected from the vegetation tested positive for Ehrlichia sp. DNA on the basis of the 16S rRNA and dsb genes. The sequences from the larvae of Amblyomma sp. and the nymphs of A. cf. oblongoguttatum were similar to those of E. chaffeensis. The phylogenetic analysis inferred with maximum likelihood corroborated the identity as E. chaffeensis. Although the role of these tick species as vectors of E. chaffeensis is still undetermined, the presence of infected ticks in the area indicates a potential zoonotic risk.

Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown. Here we evaluated the relative importance of grazing pressure and herbivore type, climate and plant functional traits on 24 soil physical and chemical attributes that represent proxies of key ecosystem services related to decomposition, soil fertility, and soil and water conservation. To do this, we conducted a standardized global survey of 288 plots at 88 sites in 25 countries worldwide. We show that aridity and plant traits are the major factors associated with the magnitude of plant effects on fertile islands in grazed drylands worldwide. Grazing pressure had little influence on the capacity of plants to support fertile islands. Taller and wider shrubs and grasses supported stronger island effects. Stable and functional soils tended to be linked to species-rich sites with taller plants. Together, our findings dispel the notion that grazing pressure or herbivore type are linked to the formation or intensification of fertile islands in drylands. Rather, our study suggests that changes in aridity, and processes that alter island identity and therefore plant traits, will have marked effects on how perennial plants support and maintain the functioning of drylands in a more arid and grazed world.

Biochar materials have garnered attention as potential catalysts for peroxymonosulfate (PMS) activation due to their cost-effectiveness, notable specific surface area, and advantageous structural properties. In this study, a suite of plantain-derived biochar (MBB-400, MBB-600, and MBB-800), possessing a well-defined pore structure and a substantial number of uniformly distributed active sites (oxygen vacancy, OVs), was synthesized through a facile calcination process at varying temperatures (400, 600, and 800 °C). These materials were designed for the activation of PMS in the degradation of sulfamethoxazole (SMX). Experimental investigations revealed that OVs not only functioned as enriched sites for pollutants, enhancing the opportunities for free radicals (•OH/SO4•−) and surface-bound radicals (SBRs) to attack pollutants, but also served as channels for intramolecular charge transfer leaps. This role contributed to a reduction in interfacial charge transfer resistance, expediting electron transfer rates with PMS, thereby accelerating the decomposition of pollutants. Capitalizing on these merits, the MBB-800/PMS system displayed a 61-fold enhancement in the conversion rate for SMX degradation compared to inactivated MBB/PMS system. Furthermore, the MBB-800 exhibited less cytotoxicity towards rat pheochromocytoma (PC12) cells. Hence, the straightforward calcination synthesis of MBB-800 emerges as a promising biochar catalyst with vast potential for sustainable and efficient wastewater treatment and environmental remediation.