Linepithema humile (Mayr, 1868), es una de las especies invasoras más dañinas a escala global. En este estudio analizamos su distribución en México mediante un enfoque areográfico y temporal y modelamos su distribución potencial a partir de la literatura científica, colecciones biológicas y plataformas de ciencia ciudadana. Asimismo, evaluamos el grado de expansión urbana y la presencia de supercolonias en la Ciudad de México. La especie se registró en 14 estados y 15 ecorregiones, con una alta concentración en la Ciudad de México y áreas del centro del país y presencias dispersas en otros entornos urbanos. Encontramos un aumento pronunciado de registros desde 2015, impulsado por las plataformas de ciencia ciudadana. Los modelos de distribución potencial predicen una alta idoneidad ambiental en Baja California y en la Faja Volcánica Transmexicana, especialmente en zonas urbanizadas. En la Ciudad de México, L. humile ocupó 13 alcaldías y los ensayos de agresividad indicaron la existencia de una única supercolonia. Los resultados destacan el papel de la urbanización en la dinámica de invasiones, la necesidad de abordar los sesgos asociados a la procedencia de los datos y el valor de la ciencia ciudadana para el monitoreo de esta especie.
Accurate inventories of species living at isolated islands are essential for understanding the biogeographic and functional composition of insular faunas, habitat area vs. faunal-size relations and levels of endemism, as well as for purposes of conservation and management. Constructing such inventories involves new field research and rigorous winnowing of existing records that have errors in specimen identification and metadata or are unsubstantiable due to a lack of reliable source information. This paper provides a curated, photographically illustrated inventory of reef- associated fishes found at the 4 islands in the Revillagigedo National Park (RNP), 400 km southwest of Baja California. We assessed the quality of data about records relating to 364 species and added new data (specimens of 132 species and images of 182 species) that confirm species occurrences at each island in the park. The resultant inventory includes 234 accepted species occurrences, with 121 unaccepted occurrences (33.2% of the assessed species). Among the confirmed species, 166-189 (70.9-80.8%) evidently are park residents. New information indicates that the RNP fauna includes 23 named and probable species of endemics, representing 9.8% of the accepted species and 12.2-13.9% of the residents, highlighting the uniqueness of the RNP and its importance for conservation.
We explored habitat use and foraging effort in 2 migratory species, the Golden-cheeked warbler and the Townsend’s warbler (Parulidae) to identify wintering habitats and foraging costs associated to group behavior. We compared densities, sex/age ratios and use of foraging substrates within and between species as a function of habitat conditions in 2 landscapes of varying forest cover. Then, we estimated home range and proxies of foraging effort to identify potential fitness costs of group behavior. Densities along with sex and age ratios of the 2 focal species differed between higher and lower quality sites, with adult males of both species being more abundant in flocks. Higher frequency in use of inner branches and trunks and lower stratums such as the understory at the micro-site level was observed in the Townsend’s warbler, whereas use of outermost leaves, twigs and upper stratums such as canopy were observed in the Golden-heeked warbler. Home ranges of individual Townsend’s warblers overlapped areas used by flocks suggesting potential benefits of retaining a territory in areas where flocks occur. Traveled distances, daily used areas and searching times were higher in lower-quality sites for both species with increased group size as an underlying variable influencing cumulative searching times.
En México, Pinus hartwegii Lindl. define el límite altitudinal de la distribución arbórea cuyos bosques están amenazados por disturbios naturales y antropogénicos, principalmente, debido al cambio climático. Los objetivos del estudio fueron: a) analizar la estructura poblacional de P. hartwegii en el monte Tláloc, Estado de México y su variabilidad en 3 niveles altitudinales, y b) examinar las fuentes y los riesgos de mortalidad. Se establecieron 12 parcelas circulares de 19.95 m de radio, en 3 altitudes. Se censaron y midieron todos los árboles de P. hartwegii con diámetro a la altura del pecho ≥ 1 cm y el diámetro del cuello de rebrotes e individuos ≤ 1.4 m de altura. Además, se censaron los rebrotes, árboles reproductivos dañados y muertos y las posibles causas de daño y muerte. La estructura del bosque reveló una regeneración continua, similar a una J-invertida. La densidad de plántulas fue baja, pero la de rebrotes fue alta, lo que alude al nicho de persistencia como estrategia de regeneración vegetativa complementaria, al nicho de regeneración vía semillas. Ambos nichos son funcionalmente complementarios y aseguran que la regeneración natural y las tasas de reemplazo ocurran temporalmente a distintas tasas.
Aún falta digitalizar los datos de las etiquetas de un alto porcentaje de especímenes de plantas vasculares en los herbarios. Existen experiencias del uso de la técnica OCR para apoyar el proceso de digitalización de especímenes; sin embargo, aún es necesario explorar y describir con mayor detalle sus limitaciones y fortalezas. La digitalización de algunos de los datos de las etiquetas de ejemplares de herbario se puede realizar de forma masiva y automática mediante la aplicación de técnicas de reconocimiento óptico de caracteres (OCR). Se seleccionaron 5 campos objetivo (campos superprimarios geográficos y taxonómicos) para obtener su información mediante OCR aplicado a 8,451 imágenes de especímenes de herbario, guiado por una arquitectura de la información de las etiquetas y con intervención humana. La información contenida en los 5 campos objetivo se identificó en 70.6% de las etiquetas, en 23.7% en 1-4 de los campos objetivo y solo en 5.7% no se pudo identificar ninguna. Los errores variaron de 0.8 a 3.3% según el campo. El OCR no puede identificar automáticamente todos los campos de información de las etiquetas de organismos de herbario, sin embargo, es posible obtener la información en un alto porcentaje de los campos más consultados.
Approximately 24.9% of the national territory is classified as mountainous, characterized by high floristic diversity and by the challenges in its biogeographic regionalization. The objective of this study was to determine whether the mountain ranges of central Mexico constitute a single phytogeographic province or comprise independent provinces. To resolve this enigma, a quantitative floristic analysis was conducted. Floristic composition was determined in 51 grid cells, each measuring 1° in latitude and longitude; subsequently, a floristic similarity analysis was performed using the β-Simpson index, followed by a cluster analysis to regionalize the study area. A total of 10,431 native species were documented in the mountains, representing 44.5% of Mexico’s entire flora. Of these, 3,723 species are exclusive to temperate regions, while 5,562 are also distributed in lowland tropical zones. Furthermore, 7,024 species endemic to the mountains were recorded. In resolving the enigma, 5 floristic provinces were identified, each supported by a significant number of endemic species, thereby demonstrating their distinct identity as biogeographic regions. The analysis presented here lends quantitative rigor to the traditionally qualitative debate regarding the regionalization of central Mexico’s mountains, thereby enabling an explicit comparison with previous proposals.
The presence of toxins in the Zamiaceae family suggests limited interaction with vertebrates, despite records of predation and seed dispersal. The male strobilus has received little attention in studies of these interactions, but it could represent a valuable wildlife resource. The Dioon edule Lindl. and Dioon angustifolium Miq. species constitute an endemic Mexican cycad complex at risk of extinction; therefore, exploring their ecological relationships is essential, as their visitors may be able to transfer pollen from one strobilus to another. We monitored the male and female strobili of these species in the Sierra Madre Oriental using cameras. Our aim was to analyze visitor diversity and its relevance to pollination potential. We recorded a high diversity of native fauna that interacts with the strobili in various ways, which are almost entirely distinct for each species in the complex. We identified birds as the group with the greatest potential for pollen transfer. Vertebrates that visit both strobili could potentially pollinate the Zamiaceae family. However, visitors that interact only with the male strobilus at high frequency may also be stealing pollen.
Composting earthworms play a key role in the decomposition of organic matter. Epigeic species of the genus Eisenia are widely used both in vermicomposting and as bioindicators in toxicological studies. However, accurate taxonomic identification of these species remains challenging due to their high morphological similarity, which affects the efficiency and function of vermicomposting processes. In this study, the earthworm species present in 5 vermicomposting facilities located in Veracruz and Quintana Roo, M & eacute;xico, were identified through molecular analyses of the mitochondrial COI gene. The results revealed the presence of 2 species: Eisenia andrei and Perionyx excavatus, ruling out Eisenia fetida, which had previously been assumed by facility operators. Genetic distances between the identified specimens were below 1.3%, while divergences from E. fetida exceeded 16%, supporting clear species delimitation. Our results highlight the need to integrate molecular methods into earthworm identification for their use in toxicological studies and to strengthen the sustainable management of organic waste.
Climate change demands the identification of provenances-progenies that are drought-resistant for forest plantations. The objective was to evaluate the genetic control of growth and drought resistance in 9-month-old seedlings from 20 families of 5 provenances of Pinus patula. Before the water stress event, height, diameter, dry biomass were measured, as well as water potential and survival after 10 days without irrigation and subsequent rehydration in the nursery. Phenotypic and genetic correlations were determined between morphological and bioclimatic variables of origin. There were significant differences between provenances and families, except for root biomass. Height, diameter, and aerial biomass were positively correlated with minimum temperature and negatively correlated with altitude. Families from humid sites had higher mortality, while those from dry environments showed greater resilience. Heritability was high for height (0.74) and moderate for the other variables (0.20-0.58). Genetic control in the stress response was confirmed. Phenotypic correlations were low; moderate negative genetic correlations were detected between size and survival, indicating a functional trade-off between growth and drought resistance. The origin of the germplasm is important to produce plants adapted to restrictive environments and to anticipate their field performance.
Cactaceae is a diverse group in the arid and semi-arid regions of Mexico. Taxonomy of Cactaceae has been reconfigured in recent years. This work aims to update the list of Cactaceae for Jalisco and analyze their geographical distribution. A database with 1,894 records was built. Taxonomic richness and phylogenetic diversity were analyzed using different geographical criteria. The study recognized 98 native species and 25 genera. The most diverse genera were Mammillaria and Opuntia. Six zones with high richness were identified. The most diverse cells are located in the northeast of the state, at the limits of the municipalities of Lagos de Moreno and Ojuelos in the Chihuahuan Desert province. Those cells in northeastern Jalisco concentrated the highest richness, where arid conditions are ideal for the establishment and diversification of the family. The southern region of the state, with a marked dry season, showed significant diversity. The Pacific Lowlands and the Chihuahuan Desert presented 59 and 56 species, respectively. Meanwhile, the tropical deciduous forest included 86 species. Those results ranked Jalisco in the eighth position in cactus richness. The results highlight the need for complementary conservation efforts across different regions to protect this plant group.
Las lombrices de tierra composteras desempeñan un papel clave en la descomposición de la materia orgánica, las especies epigeas del género Eisenia son utilizadas ampliamente para efectuar el proceso de lombricompostaje y como bioindicadores en los estudios toxicológicos. Sin embargo, la identidad taxonómica precisa de las especies (semejanza morfológica) representa un desafío y puede afectar la eficacia y función del proceso de lombricompostaje. En este estudio se determinó la identidad de lombrices presentes en 5 instalaciones de vermicompostaje de Veracruz y Quintana Roo, México, empleando análisis molecular basado en la secuenciación del gen mitocondrial COI. El análisis reveló la presencia de 2 especies, Eisenia andrei y Perionyx excavatus, descartando la presencia de Eisenia fetida, la especie asumida previamente por encargados de las plantas de lombricompostaje. Las distancias génicas fueron < 1.3%, mientras que las divergencias con E. fetida superaron 16%, lo que valida la delimitación específica. Nuestros resultados destacan la necesidad de integrar métodos moleculares en la identificación de lombrices de tierra para su uso en los estudios toxicológicos y fortalecer el manejo sostenible de residuos orgánicos.
El cambio climático exige identificar procedencias-progenies resistentes al déficit hídrico para plantaciones forestales. El objetivo fue evaluar el control genético del crecimiento y la resistencia a la sequía en plántulas de 9 meses de 20 familias de 5 procedencias de Pinus patula. Antes del déficit hídrico, se midieron altura, diámetro y biomasa seca, además del potencial hídrico y supervivencia después de 10 días sin riego y posterior rehidratación en vivero. Se determinaron correlaciones fenotípicas y genéticas entre variables morfológicas y bioclimáticas de origen. Hubo diferencias significativas entre procedencias y familias, excepto en biomasa de raíz. La altura, diámetro y biomasa aérea se correlacionaron positivamente con la temperatura mínima y negativamente con la altitud. Las familias de sitios húmedos presentaron mayor mortalidad y las de ambientes secos mostraron mayor resiliencia. La heredabilidad fue alta para la altura (0.74) y moderada para las demás variables (0.20-0.58). Se confirmó control genético en la respuesta al estrés. Las correlaciones fenotípicas fueron bajas; se detectaron correlaciones genéticas negativas moderadas entre tamaño y supervivencia, lo que indicó una compensación funcional entre crecimiento y resistencia a la sequía. El origen del germoplasma es importante para producir plantas adaptadas a ambientes restrictivos y anticipar su desempeño en campo.
This study evaluated the survival, growth, and reproductive performance of Cardisoma guanhumi maintained for 12 months under semi-controlled conditions. A total of 341 adult crabs were collected from mangrove habitats and housed in a naturalized enclosure equipped with buried PVC shelters, freshwater and saltwater basins, and automated sprinklers to maintain humidity. Crabs were fed a plant-based diet supplemented with tilapia muscle and monitored monthly. Final survival reached 76%, and 68.6% of females became ovigerous, supporting the species’ reproductive viability under captive conditions. Morphometric growth was recorded in 170 intact individuals. Notably, carapace width increased by approximately 1 mm/month despite the near absence of visible molting, particularly among smaller crabs (< 100 g), which gained over 150% in total weight. Seasonal patterns were detected, with greater somatic gains in warmer months. No significant differences were observed between sexes overall, although some interactions were noted in specific morphometric traits. These findings suggest the potential occurrence of hypertrophic tissue expansion or mineral recycling in the absence of ecdysis, which merits further investigation. This study provides the first long-term physiological baseline for C. guanhumi under ex-situ conditions and supports its potential use in conservation and aquaculture programs.
La presencia de toxinas en Zamiaceae sugiere interacciones limitadas con vertebrados, aunque existe registro de depredación y dispersión de semillas. El estróbilo masculino, poco considerado para el análisis de interacciones, podría representar un recurso para la fauna. Las especies Dioon edule Lindl. y Dioon angustifolium Miq. constituyen un complejo de cícadas endémicas de México con riesgo de extinción, por lo que es esencial explorar sus relaciones ecológicas ya que sus visitantes podrían tener la capacidad de acercar el polen de un estróbilo a otro. Monitoreamos estróbilos masculinos y femeninos de las especies del complejo con cámaras en la sierra Madre Oriental. El objetivo fue analizar la diversidad de visitantes y su relevancia respecto de su potencial polinizador. Concluimos el registro de una elevada diversidad de fauna nativa que interactúa con los estróbilos de diversas formas y es casi totalmente distinta para cada especie del complejo. Identificamos a las aves como un posible grupo con mayor potencial de transferencia de polen. Los vertebrados que visitan ambos estróbilos son agentes con potencial polinizador de Zamiaceae. Sin embargo, los visitantes de alta frecuencia que interactúan solo con el estróbilo masculino también podrían estar robando el polen.
The conservation of crop wild relatives is particularly worrisome under global warming scenarios given their potential as sources of diversity for cultivars. Here we evaluate the potential effect of climate change through ecological niche modeling for wild chia (Salvia hispanica) populations as the closest crop wild relative. Current and future (2040, 2060, 2080) climatic conditions were modeled using 4 global climate models (ACCESS-CM2, BCC-CSM2-MR, MIROC6, and CanESM5) and 2 shared socioeconomic pathways (SSP2-4.5 and SSP5-8.5), accounting for both limited and long-distance dispersal scenarios. Current potential wild S. hispanica distribution is 192,789 km2, 16.72% in climatically stable areas and coinciding with 184 Nature Conservancy Areas in Mexico and Guatemala. Unfortunately, by 2040, 2060, and 2080 wild chia’s potential distribution would reduce by 60.81 to 83.07%, respectively under optimistic scenarios with potential of dispersion as well as pessimistic and nondispersal scenarios. Furthermore, the most sensitive areas are in the Trans-Mexican Volcanic Belt, Pacific Coast, and Guatemala, which also are reportedly the most genetically diverse populations. We urge conservation efforts to increase wild germplasm collections and embark on in situ conservation with local communities to preserve the genetic reservoir of the species for future crop breeding.
Spiders of the family Thomisidae are scarcely studied in Mexico, and ecological data for this family are practically nonexistent. To fill this gap, we carried out an ecological study of crab spiders in a deciduous tropical forest in San Andrés de la Cal, Tepoztlán, Morelos, central Mexico, evaluating seasonal variation in community structure over the annual cycle. Fieldwork consisted of systematized monthly diurnal collections by 5 people, implementing 3 sampling techniques: beating sheets, sweeping nets, and looking down. In total, we collected 839 spiders representing 9 genera and 16 species, of which 5 genera and 7 species are new state records. The highest richness, abundance, and diversity were recorded in the rainy season; however, unique species were found during each season. According to richness estimators, between 12 and 22% of the estimated species remain to be found in the study area. Evenness factors indicated that the community is composed primarily of rare species, with only a few dominant species. While this study reports a reliable inventory for the region, the species accumulation curve did not reach the asymptote, suggesting that additional ecological studies employing diverse protocols are needed to complement our knowledge of these spiders.
A new species of pycnogonid belonging to the genus Nymphon is described and illustrated from specimens collected at Bahía de La Paz (Gulf of California), where it is part of the dock fouling community. The new species is morphologically similar to Nymphon littus, both species can be separated based on the dentition of the oviger terminal claw, strigilis formula, the relative size of palp segments and chela ornamentation. An identification key for the species reported from the Eastern Pacific is included.
The genus Stagmomantis Saussure, 1869 comprises a group of New World mantids whose taxonomic delimitation and composition have been challenging due to complex morphological variation. Stagmomantis hebardi Rehn, 1935, a species distributed in the Neotropical region and the Mexican Transition Zone, was originally described based on both a female and a male specimen. However, the female was subsequently recognized as belonging to a different species within the subgenus Auromantis. In this study, we provide the redescription of the male and the description of the female of S. hebardi. Descriptions are based on external morphology and both sexes internal genitalia characters. The conspecificity of the male and female is supported by molecular evidence provided in previous studies and further validated by biological observations from captive rearing. The corkscrew-like pda (posterior process of the ventral phallomere) in the male genitalia and the lobe-like structure between the fifth and sixth tergites in the female abdomen are diagnostic characters that distinguish this species from others of the genus Stagmomantis.
The Sierra de Cacoma, Jalisco is a region of high floristic diversity and endemism located in a biogeographic transition zone (2,119 m asl), where temperate and tropical elements converge. We analyzed the relationship between the taxonomic composition of modern and fossil pollen and environmental changes in aPinus-Quercus-Abies forest at La Cumbre de Guadalupe (Talpa de Allende, Jalisco, Mexico). We analyzed 22 modern pollen samples, 62 fossil pollen samples, and vegetation structure in 14 plots (500 m(2) each). We applied Davis palynological association indices, Hill diversity, and a dissimilarity analysis based on chord distance. The past similar to 1,580 years show an interval of greater similarity (similar to 850-400 cal yr BP) interspersed with episodes of change (similar to 1,500, 1,000, and 300 cal yr BP), consistent with Late Holocene climatic transitions. In the recent period, fires and deforestation have promoted vegetation homogenization. Overall, these results document the response of temperate forests to climatic and anthropogenic forcing at centennial scales and highlight the value of integrating modern pollen rain, fossil records, and diversity metrics to interpret vegetation and environmental history.
The order Boletales is one of the most diverse and widespread groups of macromycetes globally, with the genus Scleroderma being a significant representative. Despite the ecological, medical, and biocultural importance of this genus, studies on its systematics and genetic diversity in Mexico are scarce. Here, we studied the diversity and distribution of Scleroderma in Mexico using all available information (voucher registers, voucher DNA, and environmental DNA). A total of 120 nrITS DNA sequences from different species were analyzed, including 27 from environmental samples, while the remaining sequences were obtained from public databases. In Mexico, 15 Scleroderma species have been cited by morphological taxonomy, while molecular evidence suggest around 24 taxa. Phylogenetic analyses divided the genus into 4 main clades. Clade A corresponds to section Scleroderma and includes S. albidum s.l., S. areolatum, and S. cepa/laeve; clade B includes species of section Sclerangium and S. anomalosporum; clade C includes only S. dictyosporum; and clade D corresponds to section Reticulatae and includes S. bovista, S. citrinum s.l., and S. meridionale. The presence of S. capeverdeanum s.l. and S. venenatum is reported for the first time in Mexico.
