Southern Mexico Research Articles

Impact of climate change on the distribution of insectivorous bats: Implications for small-scale farming in southern Mexico

Bats provide important ecosystem services for agriculture, such as pest control, a function that is particularly relevant for small-scale farmers. However, climate change is causing a decrease in bat populations. To assess the potential impacts of climate change on insectivorous bats and the implications on small-scale farming of indigenous communities in the Chiapas Highlands in southern Mexico we developed a three-step protocol: (1) projecting distribution shifts of insectivorous bats under climate change scenarios using non-dispersal and limited-full dispersal assumptions, (2) using official information to estimate the average economic value of conducting chemical pest control in crops at a state level, (3) surveying small-scale farmers to estimate the local economic value of pest control and determine how bats are perceived by small-scale farmers. Our models project shifts in bat species due to climate change. Given that new suitable climatic areas are also projected, if we assume a limited-full dispersal scenario, bats might not be as at risk by climate change, but shifting their distribution to more suitable habitats will probably affect the dynamic of the ecosystem service they provide. The official estimated value of chemical pest control is $15.15 USD/ha, while the estimated cost resulting from a hybrid survey with small-scale farmers was $47.53 USD/ha. The difference in cost could be related to an overuse of insecticides for pest control or an increase in price due to reduced accessibility. Sixty percent of surveyed farmers perceived a decline in bat populations, 68% were unaware of the benefits that bats provide to their crops, 51% believe that bats are mainly hematophagous, and 10% recognize that people harm or kill bats. A new approach including communicating small-scale farmers in their native languages the benefits that insectivorous bats provide along with a pest management strategy for the efficient use of insecticides needs to be implemented.

A mixed-methods community needs assessment of Santa Maria and Guadalupe, California

Santa Maria and Guadalupe are neighboring cities in northern Santa Barbara County that have a lower socioeconomic profile than the county overall, are >75% Latino, and have up to 32,000 residents who identify as Indigenous, primarily Mixtec-speaking people from southern Mexico. We conducted a mixed-methods community needs assessment to identify unique health challenges and barriers that Latinx and Mixtec individuals faced. From January to April 2021, targeted and general recruitment approaches were used to recruit a convenience sample of 159 participants (74% Latinx, 72% female, mean age 41.3 years) to complete modified long- and short-form versions of a community health concerns survey. Fifty-four completed the 40-item form and 102 completed the 19-item form. Of these, 24 individuals who expressed interest in further participation took part in structured, open-ended interviews. Among the key issues raised in surveys and interviews were housing, healthcare, and access to recreational resources. However, perspectives and priorities differed depending on the form of data collection (closed-ended survey vs. open-ended interview). For example, interviews echoed survey respondents’ dissatisfaction regarding lack of safe and affordable housing but added perspective on housing conditions and vulnerability to landlords’ decisions. In interviews, expanding existing resources and mobilizing as a community were noted as potential solutions; existing policies, language, and lack of interest by those in power were raised as significant barriers. Our assessment suggests that Santa Maria and Guadalupe communities face concerns about housing, healthcare, and access to recreational resources. Government, community, and healthcare sectors should focus on addressing these basic health needs.

Morphological variations in relation to sex and habitat in southern Mexico populations of the longarm river prawn Macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae)

Morphological variations in relation to sex and habitat in southern Mexico populations of the longarm river prawn <i>Macrobrachium tenellum</i> (Smith, 1871) (Decapoda: Caridea: Palaemonidae)

Anatomical-Foliar Diversity of Agave salmiana subsp. salmiana (Asparagaceae) in Three Populations of the Teotihuacán Region (Mexico).

Agave salmiana Otto ex Salm-Dyck is an endemic Mexican plant distributed from 1230 to 2460 m above sea level, native to the arid zones of central and southern Mexico. It is a traditionally used species, with morphotypes ranging from wild to cultivated, with an ample cultural and management history. The species is important because it generates employment, and its products are used for self-consumption and are marketed as raw materials; however, little is known about its leaf anatomical description or studies that report the variation in its characters in terms of its level of management and its altitudinal gradient. To address this, we collected leaf samples from three localities of the Teotihuacan region in the State of Mexico (Mexico) and obtained anatomical leaf sections; with these, we also obtained thirty-eight parameters to quantitatively describe leaf anatomy. Thus, in this study, the general anatomical description of the leaf of Agave salmiana subsp. salmiana is presented. Unique leaf characters and others shared with the species of the genus were identified for the leaf of A. salmiana subsp. salmiana. In addition, significant variation was observed when comparing the three sampled localities (78.95%). From the analysis of anatomical characters, abaxial outer periclinal wall length, length of adaxial palisade parenchyma cells, fiber length, surface area of abaxial epidermal cells, width of abaxial palisade parenchyma cells, and total length of parenchyma in adaxial palisade were found to distinguish individuals from the three localities analyzed and the differences are related to management and altitude gradients.

Unravelling the diversity of Posthodiplostomum Dubois, 1936 (Trematoda: Diplostomidae) in fish-eating birds from the Neotropical region of Mexico, with the description of a new species.

Adults of the genus Posthodiplostomum, Dubois, 1936 are parasites of fish-eating birds, mainly of the family Ardeidae, and are globally distributed. The genus currently comprises 35 species, although recent molecular evidence has shown that the diversity of the genus is underestimated since several candidate species have been recognized. In the Neotropical region of Mexico, at least 6 Posthodiplostomum lineages have been detected with metacercaria stages recovered from unrelated fish hosts. Here, we obtained adult specimens of Posthodiplostomum from 6 fish-eating birds representing 2 families (Butorides virescens, Ardea herodias, Nycticorax nycticorax, Tigrisoma mexicanum – Ardeidae, and Rynchops niger and Leucophaeus atricilla – Lariidae) from 4 localities in southern Mexico. Specimens were sequenced for 2 nuclear (28S and ITS1–5.8S–ITS2) and 1 mitochondrial (cox1) molecular marker. Phylogenetic analyses allowed us to link metacercariae and adult specimens and recognized a lineage, which was described morphologically. The new species can be distinguished from its congeners by its prosoma morphology and body size; this is the first described species in the Neotropical region of Mexico. Additionally, new host and locality records for P. macrocotyle and P. pricei are presented, expanding their geographical distribution range in the Americas.

Vesicular Stomatitis Virus Transmission Dynamics Within Its Endemic Range in Chiapas, Mexico.

Vesicular stomatitis virus (VSV), comprising vesicular stomatitis New Jersey virus (VSNJV) and vesicular stomatitis Indiana virus (VSIV), emerges from its focus of endemic transmission in Southern Mexico to cause sporadic livestock epizootics in the Western United States. A dearth of information on the role of potential arthropod vectors in the endemic region hampers efforts to identify factors that enable endemicity and predict outbreaks. In a two-year, longitudinal study at five cattle ranches in Chiapas, Mexico, insect taxa implicated as VSV vectors (blackflies, sandflies, biting midges, and mosquitoes) were collected and screened for VSV RNA, livestock vesicular stomatitis (VS) cases were monitored, and serum samples were screened for neutralizing antibodies. VS cases were reported during the rainy (n = 20) and post-rainy (n = 2) seasons. Seroprevalence against VSNJV in adult cattle was very high (75-100% per ranch) compared with VSIV (0.6%, all ranches). All four potential vector taxa were sampled, and VSNJV RNA was detected in each of them (11% VSNJV-positive of 874 total pools), while VSIV RNA was only detected in four pools of mosquitoes. Our findings indicate that VSNJV is the dominant serotype across our sampling sites with a variety of potential insect vectors involved in its transmission throughout the year. Although no livestock cases were reported in Chiapas during the dry season, VSNJV was detected in insects during this period, suggesting that mechanisms other than transmission from livestock support VSV endemicity.

Range extension of the Mexican-endemic killifish Profundulus chimalapensis (Cyprinodontiformes: Profundulidae), with comments on its phylogenetic placement and possible intergeneric hybridization with Tlaloc Álvarez &amp; Carranza 1951

Recent ichthyological surveys in southern Mexico resulted in the unexpected discovery of populations of P. chimalapensis outside its distribution range, broadening its extent of occurrence to a total of three river basins (Coatzacoalcos [original], Grijalva, Ostuta) and two versants (Atlantic [original] and Pacific). The taxonomic nature of these populations was further investigated using comparative genetic data in a phylogenetic framework. Our results include the first assessment of the phylogenetic position of P. chimalapensis with respect to other Profundulus species and imply a sister-group relationship with P. oaxacae. Remarkably, our results also imply a close phylogenetic affinity of some P. chimalapensis samples with the genus Tlaloc, which we interpret as possible evidence of intergeneric hybridization, a phenomenon previously unreported in the family. If our interpretation in this regard is correct, it raises several broader evolutionary and taxonomic questions, such as the role that introgressive hybridization might be playing as a driver of speciation in profundulid fishes. From a historical biogeographic perspective, the proposed expanded geographic range could be explained by inter-basin dispersal enabled by recent or historical events (e.g., paleodrainage connections, headwaters stream capture, floodings) in the same fashion as these have been invoked to explain distribution patterns in other Middle American freshwater fishes.

Shape variability and morphological discrimination of haptoral attachment structures in Urocleidoides spp. Mizelle et Price, 1964 (Monogenea: Dactylogyridae) parasitizing fish from neotropical rivers in southern Mexico

The morphology of attachment organs in Monogenea is an essential source of evidence for taxonomic assessments and understanding of ecology and evolutionary history. It has been demonstrated that geometric morphometry analysis of the haptoral attachment organs provides rich and precise information about monogeneans morphology. In this study, we consider three monogenean species of Urocleidoides, U. simonae, U. vaginoclaustrum, U. vaginoclaustroides, and the incertae sedis species U. strombicirrus that parasitize fish of the Poeciliidae, Profundulidae and Characidae in neotropical rivers in southern Mexico. We aimed to identify new morphological characteristics that can be used to describe these populations with greater certainty and to test whether these characteristics present geographic variation. Anchor shape data (n = 69) were generated using geometric morphometric methods. We discriminated species using principal components and canonical variate analysis of shape data. Our results showed that there was discernible interspecific variation. The four species contributed four new morphological characteristics: anchor point length, short versus long anchor roots, elongated versus wide anchor shape, and the relative length of inner versus outer roots. Intraspecific variation was relatively low compared to interspecific anchor shape variation in Urocleidoides spp. These new morphological characteristics may also be useful for delimiting other similar species in Monogenea.

Una propuesta para el Manejo Basado en Ecosistemas (MBE) del Área Natural Protegida “Reserva de la Biósfera Pantanos de Centla, Tabasco” (Sureste Mexicano) como ecosistema vulnerable

This article represents a review of studies carried out in the Reserva de la Biosfera Pantanos de Centla (RBPC), a Protected Natural Area (ANP for its Spanish acronym) with important ecosystems of which a large amount of representative flora and fauna species of the Tabasco state (southern Mexico) are living. Present revision revealed that the anthropic activities that take place within and outside the Reserve, such as livestock farming, urbanization, pollution by private companies and the overexploitation of natural resources, degrade the habitats found there, altering the ecosystem services it offers. Therefore, here in an Ecosystem-Based Management is proposed (EBM) with strategies aimed at restoring and conserving the natural resources of the RBPC. Keywords: RBPC, pollution, urbanization, over exploitation, EBM, restoration and conservation.

Effects of biological and environmental filtering on the community assembly of two grasslands in southern Mexico

AbstractQuestionsCommunity assembly is envisaged as filters that preclude some species in the regional pool from invading local communities. We tested whether the large floristic differences between adjacent calcicole and calcifuge grasslands are explained by either of five filters: environment (soil) or positive or negative interactions with plants and with soil biota.LocationSouthern Mexico.MethodsWe conducted a reciprocal‐transplant experiment with 20 species that were introduced to both habitats under three conditions: intact local community, without plants, and in sterilized plots. Each of the five filters mentioned above predict unique patterns in the performance (survival and growth) of plants in the six treatments. Thus, we used multimodel inference to determine which filters (patterns) were consistent with the evidence.ResultsWe detected at least one filter operating on all but four species. Survival data showed frequent support for environmental filtering, with interactions (mostly positive) playing a secondary role; however negative interactions became as frequent as environmental filtering when growth was considered.ConclusionsThe large physicochemical differences between the soils of both grasslands explain the high frequency of environmental filtering. Soils differed in nutrient availability, but also had toxic concentrations of different elements. Survival was strongly influenced by early mortality, while size was measured at the end of the experiment. It is thus likely that the differences between analyses based on survival and size reflect an ontogenetic change from positive to negative interactions. Other plants frequently facilitate seedlings, but this interaction often turns competitive over time. Soil mutualists provide nutrients that seedlings cannot access, but antagonists build up in the rhizosphere as plants age. Unlike studies that infer filters from extant plants in communities or from successful invasions, our approach provides direct evidence on which filters cause species to be absent from communities.

Larval Transport Pathways for Lutjanus peru and Lutjanus argentiventris in the Northwestern Mexico and Tropical Eastern Pacific

Understanding how ocean currents influence larval dispersal and measuring its magnitude is critical for conservation and sustainable exploitation, especially in the Tropical Eastern Pacific (TEP), where the larval transport of rocky reef fish remains untested. For this reason, a lagrangian simulation model was implemented to estimate larval transport pathways in Northwestern Mexico and TEP. Particle trajectories were simulated with data from the Hybrid Ocean Coordinate Model, focusing on three simulation scenarios: (1) using the occurrence records of Lutjanus peru and L. argentiventris as release sites; (2) considering a continuous distribution along the study area, and (3) taking the reproduction seasonality into account in both species. It was found that the continuous distribution scenario largely explained the genetic structure previously found in both species (genetic brakes between central and southern Mexico and Central America), confirming that the ocean currents play a significant role as predictors of genetic differentiation and gene flow in Northwestern Mexico and the TEP. Due to the oceanography of the area, the southern localities supply larvae from the northern localities; therefore, disturbances in any southern localities could affect the surrounding areas and have impacts that spread beyond their political boundaries.

Rove beetle species diversity and the patterns of interactions with their host plants in primary and secondary tropical forests

In tropical disturbed forests, it is relatively unknown the extent insect communities are experiencing shifts in species diversity and the consequences for ecosystem functions and services. In southern Mexico, we used the rove beetle community associated to Heliconia wagneriana bracts, as a model system, to investigate differences in community attributes and feeding habits between old-growth and human induced secondary forests. We tested if the beta diversity components of rove beetle communities were influenced by forest type and bract traits. Furthermore, we described the topology of individual-based heliconia-rove beetle ecological networks. Overall, we recorded 26 rove beetle species with significantly greater abundance in secondary forests. High compositional dissimilarity between forest types was observed with saprophagous species being more likely detected in old-growth forests; whereas predatory species in secondary forests. Heliconia-rove beetle networks showed a significant nested pattern with incidence data for old-growth forests and incidence and abundance data for secondary forests. Compared to old-growth forests, the rove beetle community in secondary forests showed strong shifts in species composition, diversity and differences in the detection probability of feeding habits, with consequences for ecosystem functioning. We further discuss these findings according to the forest disturbance and phytotelm systems. Implications for insect conservation: Individuals of H. wagneriana represent biodiversity reservoirs for invertebrates, especially in human-modified landscapes.

Long-lived topography of the Oaxacan Complex (southern Mexico) after the assembly of Pangea: Evidence from apatite fission-track dating

Understanding the exhumation history of ancient orogens is crucial for unraveling the tectonic and climatic forces that shape Earth's landscapes. Relict topography from ancient orogenic belts can persist on the surface for tens of millions of years, providing detritus to surrounding areas even without significant uplift events. This study examines the exhumation history of the Oaxacan Complex in southern Mexico, a Proterozoic peri-Gondwanan continental block located at the periphery of western equatorial Pangea during the l ate Paleozoic. This complex supplied detritus to extensional basins in southern Mexico throughout the Mesozoic and Cenozoic. We reinterpret existing apatite fission track (AFT) data from in situ samples of the Oaxacan Complex and add a set of detrital AFT data from modern sediments of the Peñoles River, which drains the northern Oaxacan Complex. The detrital AFT age distribution is continuous, ranging from ∼180 Ma to ∼50 Ma, without a predominant component age and showing a positive age-elevation correlation, suggesting a slow cooling history of the basement exposed in the drained area. QTQt thermal history modeling of the detrital AFT ages corroborates this slow cooling. Moreover, reinterpretation of in-situ AFT data from the literature confirms that the cooling history of the crustal block exposed in the northern Oaxacan Complex is characterized by a prolonged residence time in the Partial Annealing Zone of the apatite fission-track thermochronometer, spanning at least from the Triassic to the Paleogene. These results suggest that the Oaxacan Complex did not undergo any significant exhumation events after the Late Paleozoic assembly of Pangea, neither during the Triassic–Early Cretaceous rifting associated with Pangea breakup nor during development of the Late Cretaceous–Eocene Mexican Orogen. According to this scenario, we suggest that the post-collision relict topography of the Oaxacan Complex was likely sustained by isostatic rebound and lithological resistance, supplying sediment for tens of millions of years to the Mesozoic and Cenozoic basins of southern Mexico.

First Detection of Pseudocerradoa paullula Causing Aroid Leaf Rust on Swiss Cheese Plant (Monstera deliciosa) in Virginia.

Monstera deliciosa Liebm. (Araceae) is a monocotyledonous plant that is native to tropical forests of southern Mexico to Panama. It is widely grown as an ornamental in the United States because of its easy maintenance and attractive, fenestrate leaves. On May 10th, 2024, at a nursery and garden center in Henrico County, Virginia, four M. deliciosa plants in 3.8 L containers were observed with necrotic spots surrounded by a yellow halo on the leaves (Fig. 1A). Uredinia were present in the center of the lesions with dense, reddish-brown sporulation mostly on the abaxial surface of the leaves (Fig. 1B). Urediniospores with pedicels were golden brown in color, globose, echinulate, with two opposite germ pores, averaging (28) 25.2 x 25 (23) µm (n = 40) in size and a wall thickness of 1.5 to 2 µm (n = 40) (Fig. 1F - K). Telia were not present. The host, symptoms, and urediniospore size was comparable to reports of Pseudocerradoa paullula (Syd. & P. Syd.) M. Ebinghaus & Dianese from South Carolina (22.9 to 27.9 μm), Florida (24 to 31 μm), and Japan (24.8 to 29.3 μm) (Ebinghaus et al. 2022; Sakamoto et al. 2023; Urbina et al. 2023; Yang et al. 2023). Urediniospores from the infected plants were collected with a sterile needle and DNA was extracted using a Qiagen DNeasy PowerLyzer Microbial Kit (Germantown, MD) according to the manufacturer's instructions. PCR and sequencing of the small ribosomal subunit (SSU) and large ribosomal subunit (LSU) gene regions was performed with primer sets NS1/Rust18SR and LRust1R/LR3 (Beenken et al. 2012; Vilgalys and Hester 1990). The resulting 1,630bp and 638 bp sequence fragments of the SSU and LSU loci from strain GS24-AE50 were deposited into the NCBI Genbank database under accessions PQ059898 and PQ059897, respectively. A pairwise alignment of the SSU gene shared 1,363/1,366 (99%) nucleotides with the P. paullula voucher (ON887197) from Florida. A Genbank nBLAST analysis of the LSU gene shared 636/638 (99%), 636/638 (99%), and 592/600 (99%) nucleotides with vouchers from M. deliciosa from South Carolina (OQ746460), Florida (ON887197) and Japan (OK509070) (Sakamoto et al. 20222; Urbina et al. 2023; Yang et al. 2023). Koch's postulates were fulfilled by spraying four, healthy, non-wounded M. deliciosa plants to run-off with a urediniospore suspension (1 x 106 spores/ml distilled water, 20 ml per plant) that was collected from the original infected plants. An additional four, healthy control plants were sprayed with distilled water only. After 6 weeks in a greenhouse at 22 ± 2°C with ≥85% relative humidity under an 8-h photoperiod, uredinia in the center of lesions identical to those on the original symptomatic plants developed on 12 out of 20 leaves from the inoculated plants, while all the leaves from the control plants remained asymptomatic (Fig.1C - E). Urediniospores collected from the inoculated plants were morphologically identical to the urediniospores from the original infected plants with 100% LSU sequence homology to accession PQ059897. Globally, P. paullula has been reported from Australia, China, Japan, Malaysia, the Philippines, and the United States, where the pathogen was detected at the port of Los Angeles in 2014, Florida in 2019, and South Carolina in 2023 (Sakamoto et al. 2023; Shaw et al. 1991; Urbina et al. 2023; Yang et al. 2023). Although the pathogen is not known to be established in Virginia, the recent surge of reports suggests that the pathogen's distribution is expanding. The impact of aroid leaf rust on M. deliciosa production is unclear, but it has the potential to reduce the aesthetic and commercial value of plants under favorable conditions.

Richness and abundance of ticks associated with domestic animals at different altitudes in Southern Mexico

The objective of this study was to determine the richness, abundance, and altitudinal distribution of ticks collected from domestic animals in five municipalities and sixteen distinct communities along the Pacific coast of southern Mexico in Chiapas. Ticks were sampled from dogs, horses, and cows in each range. A total of 311 hosts were sampled, of which 264 (85 %) were dogs, 26 (8 %) were horses, and 21 (7 %) were cows. Of these, 83 (26 %), 17 (5 %), and 7 (2 %) hosts were infested, respectively. A total of 583 ticks were collected, representing four genera and six species. The most prevalent species was Rhipicephalus linnaei (68.61 %, n = 400), followed by Rhipicephalus microplus (0.51 %, n = 3), Amblyomma ovale (1.71 %, n = 10), Amblyomma mixtum (1.71 %, n = 10), Ixodes ci. boliviensis (2.22 %, n = 13), and Dermacentor dissimilis (25.21 %, n = 147). Of the identified ticks, A. mixtum, A. ovale, R. microplus, and R. linnaei were distributed at elevations between 0 and 1000 m, while at elevations between 1000 and 2000 m, only the species I. ci. boliviensis and D. dissimilis were found. The characteristics of each locality are discussed in order to explain the abundance of ticks and to assess their potential risk as vectors of public health pathogens.

Life history of Mexican species of the genus &lt;i&gt;Tlaloc&lt;/i&gt; (Cyprinodontiformes, Profundulidae)

Fish of the genus Tlaloc are distributed from southern Mexico to Central America and are a distinctive example of the endemic fauna of the Mesoamerican highlands, which has been scarcely studied in Mexico. The present study provides basic life-history data for the species Tlaloc hildebrandi, T. candalarius, and T. labialis, which are native to the headwaters of the Grijalva-Usumacinta basin in southeastern Mexico. We collected 918 specimens to determine their Length-Weight Relationship (LWR), Relative Condition Factor (Kr), sex ratio, Gonadosomatic Index (GSI), fecundity, and size at first sexual maturity. Both sexes of all species had positive allometric growth, except for T. candalarius females (isometric). Mean Kr and sex ratio values differed significantly among species. Females’ GSI values differed significantly among species but were highest during the dry season in all three species. Absolute fecundity was positively correlated with standard length and weight. Sexual maturity was reached at different lengths among species. Based on these results, we suggest that all three species present an opportunistic life strategy, which is very common in fish of the order Cyprinodontiformes. These results represent a first contribution on the life-history of this group of fish and provide basic information that is fundamental to ensuring their conservation.

The Field Assessment of Quiescent Egg Populations of Aedes aegypti and Aedes albopictus during the Dry Season in Tapachula, Chiapas, Mexico, and Its Potential Impact on Vector Control Strategies.

Although integrated management and control programs implement intense control measures for adult, pupal, larval, and breeding sites during outbreaks, there is a lack of studies to understand the role of the vector egg stage in disease dynamics. This study aimed to assess the dry season quiescent Aedes aegypti and Aedes albopictus egg populations in houses and backyards in Tapachula, southern Mexico. Two hundred and fifty ovitraps were placed in 125 homes in the Las Americas neighborhood. A total of 7290 eggs were collected from 211 (84.4%) ovitraps. Only 5667 (77.7%) hatched under insectary water immersion and food supply conditions, with 4031 (71.1%) identified as Ae. aegypti, and 1636 (28.8%) as Ae. albopictus, respectively. The remaining 1623 (22.3%) did not hatch due to Delayed Hatching and/or quiescence tropical stage. Eighty-three larval containers were sampled with desiccated eggs during the dry season; most of them were described as trash waste because larvicides are only used for larger containers of 5-10 L. Evolutionary characteristics for the two species including partial egg hatching, ambient-regulated quiescence, the ability of the embryo to survive for a more extended period intra-seasonally, the egg sticking to inner container walls, demands urgent operational research to achieve successful egg-proof larval container methods.

Outbreak of Chikungunya Fever in the Central Valley of Chiapas, Mexico.

The first ever recorded outbreak of Chikungunya virus (CHIKV) in the highlands (central valley of Chiapas) Mexico took place in 2015. Clinical data from 80 infected patients together with information provided from virus isolates offered a vision of the diseased and their response linked to different variables such as age, gender, association with pre-existing diseases of some patients, including CHIKF-DENF co-infection. The origins of the Tuxtla Gutierrez CHIKV viruses isolated in the study, including other Mexican isolates, were traced to viruses circulating in regions of Asia in Micronesia and Philippines. Also, we call the attention of the influx of migrants coming from countries having current explosive outbreaks of CHIKV and DENV in the Americas and into southern Mexico. Further we discuss vulnerabilities and point out specially to the geographic location of Chiapas State and its strategic position for attracting the human migrant population.

Talking to children in Tsotsil Mayan: Interactional formats in child-directed communication across multigenerational caregivers

Research on the acquisition of Mayan languages has shown child-directed communication (CDC) to be low in frequency. Nevertheless, long-term linguistic-anthropological research with the Tsotsil Mayan in Southern Mexico has documented episodes in family life when children engage in interactional routines or interactional formats (IFs) with their multigenerational caregivers. These interactions are sequentially organized communicative acts (verbal and nonverbal) that call forth specific responses from the child in turn-taking episodes (e.g. muts’o la sate ‘close your eyes’, chibat, uto ‘say, good-bye’). This study analyzes IFs in four communicative events involving four children (11–17 months; M = 15) each from multigenerational families with a household average of 7.75 members. Three research questions are addressed: What types and functions of IFs characterize CDC experienced by Tsotsil children? How do IF types distribute across specific communicative events? How do IF types distribute across multigenerational caregivers? The study used both qualitative and quantitative methods. IFs were classified on the basis of their pragmatic function: directive, prompting, teasing, referential, regulatory, and evaluation. The six IF types and their relative frequencies reveal core language socialization practices among the Tsotsil Mayan of the study. Quantitative analysis makes clear a significant association between IFs and event, and IFs and caregivers’ CDC. A central finding is that non-parental input from multigenerational caregivers (i.e. grandmothers and sisters) is a more significant source of CDC than parental input.

Detection of Filariid Infections in Mexican Primate Populations Through qPCR.

Filariae are parasitic nematodes of high veterinary and medical importance, responsible for some acute tropical diseases. They are transmitted through the bite of hematophagous vectors such as biting midges and blackflies. Filariae are among the most prevalent vector-borne parasitoses in Neotropical primates in which severe infections can cause inflammatory reactions and tissue damage. Given the location inside the host (peritoneal cavity, bloodstream, and lymphatics), the detection of filariid nematodes is challenging and is mostly postmortem; hence the scarcity of studies on the prevalence of filariae in wild primate populations. Here, we report the prevalence of filariid infections in free-ranging populations of Geoffroy's spider (Ateles geoffroyi) and black howler (Alouatta pigra) monkeys across southern Mexico, using a combination of noninvasive sampling and molecular diagnostic techniques. Fecal samples were screened for filariid DNA by qPCR protocols. A total of 88 samples were examined with an overall prevalence of 26%. Filariae were slightly more common in spider monkeys compared to howler monkeys. This study constitutes the first report of the prevalence of infection of filariid nematodes in populations of wild spider monkey across southern Mexico, and the first reporting of filariae in black howler monkeys, as part of a new era of primate parasitology and the diagnostics of parasite infections in light of the everyday more affordable molecular tools.