The influence of humidity and temperature on the vertical richness and abundance of blood-sucking flies (Culicidae and Ceratopogonidae) in a montane cloud forest in Mexico

Because the vertical distribution and diversity of blood-sucking flies are poorly known, we determined the diversity, structure, and composition of culicids between vertical vegetation strata. We evaluated the influence of microclimatic variables during different times of the day over a year. We used eight CDC traps baited with CO2 at a height of 1.5 m and 12-15 m. We conducted rank-abundance curves, similarity analysis (ANOSIM and SIMPER), and multivariate clustering with incidence and abundance data. We used GAM models to analyze the influence of strata (understory vs canopy), humidity, and temperature on insect richness and abundance. During the day, the difference between strata was mainly due to higher abundance of Wyeomyia arthrostigma and Wyeomyia ca. adelpha in the understory. During the night, the differences were mainly due to higher abundance of Culex stigmatosoma, Culex salinarius, and Aedes allotecnon in the canopy, and Wyeomyia arthrostigma in the understory. Seasonality played a role in the similarity between the strata. Diversity during the day was positively related to humidity and temperature, and nocturnal diversity increased with temperature but decreased with higher humidity. The effects of environmental factors on the spatiotemporal distribution of fly species are essential for epidemiological surveillance.

Phylogenetic relations among Mexican phlebotomine sand flies (Diptera: Psychodidae) and their divergence time estimation

Phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae) have biological relevance as vectors of several pathogens. To ensure periodic entomological monitoring it is necessary to have efficient and accurate tools for an adequate taxonomic identification. There are only few studies on phylogenetic analyses of phlebotomine sand flies from Neotropics, based mostly on morphological and/or molecular data, which makes the delimitation of intra- and interspecific variability of species challenging. Here we generated new molecular information on sand fly species distributed in endemic areas of leishmaniasis in Mexico, using mitochondrial and ribosomal genes, and incorporating morphological information available. Specifically, we established their phylogenetic relationships, and estimated their divergence time. Our study provides molecular information for 15 phlebotomine sand fly species from different areas of Mexico, contributing to the genetic inventory and phylogenetic relations among Neotropical species of the subfamily Phlebotominae. Mitochondrial genes proved to be suitable markers for the molecular identification of phlebotomine sand flies. However, the incorporation of additional nuclear gene information could increase the significance of phylogenetic inferences. We also provided evidence about a possible divergence time of phlebotomine sand fly species, supporting their presumable origin in the Cretaceous period.

An updated catalogue of biting midges of the genus Culicoides Latreille, 1809 (Diptera, Ceratopogonidae) of Mexico and their known distribution by state

An updated catalogue of Culicoides of Mexico is presented. It includes 86 species with their regional distribution and corresponding record references, known immature stages and associated pathogens. In addition, a taxonomic key for subgenera and species groups for Mexico is presented and an index of species by state is included.

Trichoprosopon mixtli sp. nov., a new sabethine species (Diptera: Culicidae) from a Mexican cloud forest, with an assessment of the genus and keys for the identification of known species

The genus Trichoprosopon Theobald, 1901 includes 13 described species in the Neotropical Region, three of which have been recorded in Mexico. In this work, a new species, Trichoprosopon mixtli sp. nov., is described based on characteristics of the fourth-instar larva, pupa, female and male genitalia, and adults. Larvae and pupae were collected from the flower bracts of Heliconia bourgaeana Petersen at the Instituto de Ecología, A.C. (INECOL), inside the "Santuario del Bosque de Niebla", in Xalapa, Veracruz State, Mexico. This is the first time that the complete larval and pupal chaetotaxy of a species of Trichoprosopon is described. Keys for the identification of known species of Trichoprosopon are provided and the internal classification of the genus is discussed.

Métodos de recolecta y monitoreo de adultos Phlebotominae (Diptera: Psychodidae), vectores de los agentes causales de las leishmaniasis

Los flebotominos son los vectores de diferentes especies de parásitos del género Leishmania, los cuales son los agentes etiológicos de variadas formas clínicas de las leishmaniasis. El principal riesgo de transmisión a humanos es el contacto con los vectores portadores del parásito, por lo que la actividad de incriminación de vectores y el entendimiento de las capacidades vectoriales de las especies son aspectos muy importantes desde el punto de vista epidemiológico. Entonces, es de suma relevancia estimar con precisión la presencia, abundancia, tasa de picadura, tasa de infección, estructura de edades, entre otras. para evaluar los riesgos de transmisión de Leishmania spp. y que la información generada pueda ser analizada y comprendida por los tomadores de decisiones en cuanto a políticas públicas de salud. Sin embargo, para que esta información de campo sea realmente útil al sector salud o para fines de investigación, los estimadores poblacionales deben tener un mínimo de sesgo con relación a las capturas de las especies de importancia médica o bien del ensamble biológico. El principal objetivo de la presente contribución es presentar una revisión descriptiva basada en la literatura publicada sobre los métodos más comúnmente empleados en la captura y monitoreo de flebotominos, haciendo énfasis en los estudios realizados en México y con discusiones acerca de cada método en cuanto ventajas, desventajas e interpretaciones. Así como, los aspectos generales del muestreo e inferencias poblaciones, con mención de las perspectivas futuras de investigación.

Estado actual del conocimiento de los hábitos hematófagos de los Phlebotominae (Diptera: Psychodidae) de México y sus implicaciones zoonóticas

Las preferencias hematófagas de los insectos determinan la asociación entre parásito, hospedero y vector, siendo indispensable para saber que especie mantiene la infección en los animales silvestres o domésticos y cuál la transfiere al humano, para que la parasitemia se convierta en una zoonosis. Conocer las fuentes de alimentación de sangre de las especies de vectores es un requisito para valorar el papel que juega cada una de ellas en la infección humana. En México se registran 50 especies de Phlebotominae y aunque las hembras de la subfamilia se mencionan como hematófagas de anfibios, reptiles, aves y mamíferos; sus hábitos hematófagos y sus preferencias por hospederos son variados. Se hace una revisión descriptiva de la literatura sobre las preferencias hematófagas de las especies registradas en México, para valorar cuáles tienen especial importancia en la transmisión de Leishmania al humano y cuales mantienen la infección enzoótica en otros vertebrados, al tiempo que se incentiva el estudio de las preferencias hematófagas para aquellas cuyos hábitos alimentarios se desconocen.

Integrated Approaches for the Identification of Mosquitoes (Diptera: Culicidae) from the Volcanoes of Central America Physiographic Subprovince of the State of Chiapas, Mexico

Nowadays, there is a lack of information on the mosquito's fauna and DNA barcoding sequence reference library from many areas in Mexico, including the Volcanoes of Central America physiographic subprovince in the state of Chiapas. Consequently, a survey was undertaken to delineate the mosquito (Diptera: Culicidae) fauna in this region across different seasons using different collecting techniques. All species were identified by morphology and DNA barcoding, and their ecological features were also defined. In total, 62 taxa were morphologically examined, 60 of these were successfully identified based on morphological characteristics, but two were unable to be identified at the species level. The genera Aedes, Anopheles, Culex, and Wyeomyia are the most diverse among mosquito genera collected and include several species of medical and veterinary importance. Ecological characteristics of the immature habitats indicated that they were grouped into four categories namely, (1) large water bodies at ground level, (2) small and shady phytotelmata (e.g., tree holes and bamboo internodes), (3) large phytotelmata (e.g., plant leaves and axis bromeliad), and (4) artificial containers. The cytochrome c oxidase subunit I (COI) DNA barcoding sequences successfully separated the majority of these species, although specific species showed >2% intraspecific genetic divergences.

Landscape Anthropization Affects Mosquito Diversity in a Deciduous Forest in Southeastern Mexico

Mosquitoes (Diptera: Culicidae) are considered the group of insects that most impacts human health. Land use change, conversion of conserved sites into agricultural environments, urbanization, defaunation, and introduction of domestic animals can affect mosquito diversity positively or negatively, increasing the risk of transmission of zoonotic diseases. Here, we describe the diversity of adult mosquitoes in two environments (deciduous forest and anthropized zone) over 2 yr (2014-2016), using eight CDC traps at each site in three climatic seasons (rainy, cold, and dry). We captured 795 individuals belonging to 22 species. We constructed rank-abundance curves to determine spatial and temporal changes in the mosquito communities. We measured alpha diversity using the Shannon index (H'), Shannon exponential (eH) and Simpson dominance (Ds), and beta diversity using Jaccard's coefficient of similarity (Ij). The most abundant species were Culex quinquefasciatus (40.5%), Culex coronator (18.3%), and Anopheles pseudopunctipennis (12.4%). The highest mosquito diversity was in the deciduous forest during the rainy season. Beta diversity analysis showed that species overlap varied among climatic seasons, with the sites sharing 65% species during the rainy season, but only 33% of species during the dry season. We found differences in the diversity of mosquitoes at the two sites, and the mosquito assemblage of the anthropized zone was significantly different from that of the deciduous forest.

First record of larval microhabitats of sandflies in Mexico with the description of the fourth instar larva of Brumptomyia hamata

Despite the medical importance of sandflies as vectors (Diptera: Phlebotominae) of Leishmania spp., immature stages of phlebotomine sandflies have never been found in the wild in Mexico. In the present investigation, we sought to identify specific microhabitats associated with the presence of sandfly immature stages. Field work was conducted in 11 localities of the Yucatan Peninsula and we collected soil samples from each site during two periods (November 2007 to April 2008, November 2008). Soil samples were transported to our base camp and were processed using the Berlese's funnels. We processed a total 242 soil samples with an average weight of 362 ± (SD) 317 gr. From these samples, we were able to recover 51 phlebotomine larvae in five different microhabitats and largest number was obtained from mammal burrows (88%) and from tree-buttresses of Brosimium alicastrum (Berg) (6%). We identified larval microhabitat for Brumptomyia hamata (Fairchild & Hertig) and those specimens provided the material to describe for the first time the fourth instar larva. We also include information of a larval microhabitat of Lutzomyia cruciata (Coquillett). In addition, we recorded a total of 4872 arthropods from 15 taxa in all those soil samples in which sandfly larvae were found, being Collembola (76%) and Acari (10%) the most abundant.

Effect of seasonality and microclimate on the variation in bat-fly load (Diptera: Streblidae) in a cave bat assemblage in a dry forest

Seasonality causes fluctuations in the availability of resources, affecting the presence and abundance of animal species. These fluctuations can have an impact on parasite-host relationships, which in turn can be exacerbated by microclimatic changes to which bat-flies are exposed. We characterized the bat-fly load and evaluated the effect of seasonality on five bat species in a dry forest. We evaluated variations in microclimatic conditions inside the cave Cerro Huatulco between seasons and the response of the bat-fly load. We collected 1165 bat-fly specimens belonging to 16 species from 688 bats. The obtained results indicate that the mean abundance and infestation intensity exhibited changes between seasons in Artibeus jamaicensis, Desmodus rotundus, Glossophaga soricina, and Pteronotus parnellii. In the case of the effect of microclimate conditions, we observed that prevalence is negatively correlated with temperature in G. soricina, while mean abundance and mean infestation intensity were negatively related to temperature in A. jamaicensis and G. soricina. The present study provides significant information about host-parasite relationships in a dry forest and discusses the relevance of abiotic and biotic factors that could affect host-parasite interactions, as well as the importance of each parasite load parameter for the understanding of this interaction.

A new species of Bithoracochaeta Stein (Diptera: Muscidae) with comments on Mexican species of the genus and their implication as possible biocontrol agents for greenhouses pests

A new species of Bithoracochaeta Stein, 1911 (Diptera, Muscidae), Bithoracochaeta couriae sp. nov., is described and illustrated. In addition, we present comments on all Mexican species of the genus, a brief description of hunting behavior of B. couriae sp. nov. and its possible use as a biological control agent of greenhouses pests.

DNA barcoding and fauna of phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae) from Los Tuxtlas, Veracruz, Mexico

Mexico has great diversity of phlebotomine sand flies related to cases of leishmaniasis, yet few studies have dressed the molecular taxonomy of these sand fly species. The use of the cytochrome oxidase subunit 1 (COI) gene, as a DNA Barcode has facilitated the molecular identification of sand flies species worldwide. We use the DNA barcode as a useful tool for the identification of phlebotomine sand flies of the natural reserve Los Tuxtlas from Veracruz, México. A fragment of 536 bp of the COI gene was obtained from 36 individuals belonging to eight species of five genera (Dampfomyia, Lutzomyia, Psathyromyia, Psychodopygus and Brumptomyia) with coverage between 92-100%, and found similarities ranging from 93-98% with other New World phlebotomine sand flies. The NJ dendogram grouped sand flies into eight clusters according to identified species, supported by bootstrap of 97%-100%. In conclusion, all phlebotomine sand flies were correctly identified and agree with the morphological identification, also could separate genetics the isomorphic females of the genus Brumptomyia.

Management of ecosystems alters vector dynamics and haemosporidian infections

The presence of insect vectors is a key prerequisite for transmission of vector-borne disease such as avian haemosporidians. In general, the effects of land use change on Diptera vectors are not well studied; the response of vectors to forest management depends on vector species, as has been shown previously for the birds. We tested if abundance of insects from different Diptera families and haemosporidian infection are affected through alteration of habitat structural variables (measured by LiDAR) and forest management intensities. We identified higher large-scale variation of female insect abundance in northeastern than in southwestern Germany. Unmanaged forest stands had higher Diptera insect abundances. We found that abundance of female Diptera increased with the amount of forest gaps but decreased in forest plots with more south facing aspect, higher habitat structural heterogeneity, temperature and humidity. We found that haemosporidian infections in Diptera insects increased with increased management intensity and more canopy structural diversity (e.g., amount of edge habitat), but decreased with a denser shrub layer, deeper leaf litter and higher humidity (characteristics for unmanaged forest stands). Although higher forest management intensity decreased vector abundance, the haemosporidian infections in the vectors increased, indicating a significant effect of forest management on disease dynamics.

Description of the pupa and additional characters of the fourth-instar larva, female, and male genitalia of Uranotaenia (Uranotaenia) coatzacoalcos Dyar amp; Knab, with keys for the identification of Mexican species of Uranotaenia (Diptera: Culicidae)

Eleven species of Uranotaenia, one belonging to the subgenus Pseudoficalbia and ten to the subgenus Uranotaenia, have been recorded in Mexico. In general, two species are commonly recorded in urban areas by the vector surveillance programs, but the other species are rarely collected as they occupy habitats in non-anthropized environments, and for that reason they remain poorly known. Some of the species recorded in Mexico have not been described in the pupal stage and other developmental stages have only been partially described, making their recognition difficult. One of these species is Uranotaenia (Uranotaenia) coatzacoalcos Dyar Knab, as a complete description of its larval chaetotaxy is not available, and the pupa has not been described. In this report, we provide a complete morphological description of the fourth-instar larva, the first description of the pupa, and a review of the female and male diagnostic characteristics useful for recognition of the species. We also provide keys in English and Spanish for the recognition of the larvae, pupae, females, and male genitalia of the species of Uranotaenia recorded in Mexico.

New Geographical Records of Bat Flies (Diptera: Streblidae) Associated With Phyllostomid Bats (Chiroptera: Phyllostomidae) in the West Highlands of Mexico

Streblidae are ectoparasites exclusive to bats and feed only on their blood. Studies on ectoparasite fauna have increased our ecological knowledge of the parasitic relationship between streblids and their bat hosts. We evaluate assemblages of phyllostomid bats and their ectoparasitic flies in three scenarios with different types of anthropogenic use: pine-oak forest, avocado orchards, and an urban park during an annual cycle in the highlands of Michoacan, Mexico. We recorded a total of 325 bats belonging to nine species in three subfamilies: Glossophaginae, Desmodontinae, and Stenodermatinae, and obtained 225 bat flies belonging to seven species. The nectivorous bat Anoura geoffroyi Gray, 1838, had the highest prevalence of infestation and the hematophagous bat Desmodus rotundus (É. Geoffroy, 1810) was the host with the highest mean parasite abundance and mean intensity. Aspidoptera delatorrei Wenzel, 1966, Megistopoda proxima (Séguy, 1926), Paratrichobius longicrus (Miranda Ribeiro, 1907), Trichobius brennani Wenzel, 1966, and T. parasiticus Gervais, 1844, are new records for the state of Michoacan reported in this study.

The mosquitoes (Diptera: Culicidae) of Hidalgo state, Mexico

In order to document the species richness of mosquitoes (Diptera: Culicidae) and their distributions in the Mexican state of Hidalgo, collecting trips were conducted to all physiographic regions (Coastal Plain of North Gulf, Sierra Madre Oriental, and Neo-volcanic Axis) and subregions of the state. Additionally, mosquito specimens from Hidalgo deposited in the Collection of Arthropods of Medical Importance (CAIM) were reexamined. A total of 3225 specimens were collected and studied and an additional 69 pinned mosquitoes and 15 microscope slides in CAIM were examined. The two Culicidae subfamilies Anophelinae and Culicinae, 8 tribes, 12 genera, 24 subgenera, and 56 species were documented. Of these, 4 tribes, 7 genera, 13 subgenera, and 26 species are new records for the mosquito fauna of Hidalgo. Nine species previously recorded were not found in the collections made during this study. Taxonomic notes, new distribution records, and comments about the medical importance of the species found are included.

Comprehensive inventory of true flies (Diptera) at a tropical site

Estimations of tropical insect diversity generally suffer from lack of known groups or faunas against which extrapolations can be made, and have seriously underestimated the diversity of some taxa. Here we report the intensive inventory of a four-hectare tropical cloud forest in Costa Rica for one year, which yielded 4332 species of Diptera, providing the first verifiable basis for diversity of a major group of insects at a single site in the tropics. In total 73 families were present, all of which were studied to the species level, providing potentially complete coverage of all families of the order likely to be present at the site. Even so, extrapolations based on our data indicate that with further sampling, the actual total for the site could be closer to 8000 species. Efforts to completely sample a site, although resource-intensive and time-consuming, are needed to better ground estimations of world biodiversity based on limited sampling.

Descriptions of the Immature Stages of Lutzomyia (Tricholateralis) cruciata (Coquillett) (Diptera: Psychodidae, Phlebotominae)

The present study presents morphological and chaetotaxic descriptions of the immature stages of Lutzomyia (Tricholateralis) cruciata (Coquillett), a probable vector of leishmaniasis in Mexico. The egg exochorion is consistent with the species already known as Lu. (Tricholaterialis), but different from the Lu. cruciata egg of Chiapas, Mexico. The fourth instar larva of Lu. (Tricholateralis) cruciata possesses a novel antenna, combining morphological characteristics of categories 2 and 3 for neotropical sandflies. Differences between the chaetotaxy of first and fourth instar larvae of Lu. cruciata with those of Lu. (Lutzomyia) and Lu. (Tricholaterlis) are compared and discussed. This is the first time in which the chaetotaxy and morphology of pupa of a species belonging to Lutzomyia (Tricholateralis) sensu Galati have been described, and we recorded for the first time the anterior prothorax setae, which was previously only considered for Old World species.

Establishment of Aedes aegypti (L.) in mountainous regions in Mexico: Increasing number of population at risk of mosquito-borne disease and future climate conditions

The study was conducted in the central region of Veracruz Mexico, in the metropolitan area of Xalapa. It is a mountainous area where Aedes aegypti (L.) is not currently endemic. An entomological survey was done along an elevation gradient using the Ae. aegypti occurrences at different life cycle stages. Seven sites were sampled and a total of 24 mosquito species were recorded: 9 species were found in urban areas, 18 in non-urban areas with remnant vegetation, and 3 occurred in both environments. Ae. aegypti was found only in the urban areas, usually below 1200m a.s.l., but in this study was recorded for the first time at 1420m a.s.l. These occurrences, together with additional distribution data in the state of Veracruz were used to developed species distribution models using Maxlike software in R to identify the current projected suitable areas for the establishment of this vector and the human populations that might be affected by dengue transmission at higher elevations. Its emergence in previously unsuitable places appears to be driven by both habitat destruction and biodiversity loss associated with biotic homogenization. A border study using data from the edges of the vector's distribution might allow sensitive monitoring to detect any changes in this mosquito's distribution pattern, and any changes in the anthropic drivers or climate that could increase transmission risk.

Data documenting the potential distribution of Aedes aegypti in the center of Veracruz, Mexico

The data presented in this article are related to the research article entitled “Establishment of Aedes aegypti (L.) in mountainous regions in Mexico: Increasing number of population at risk of mosquito-borne disease and future climate conditions” (M. Equihua, S. Ibáñez-Bernal, G. Benítez, I. Estrada-Contreras, C.A. Sandoval-Ruiz, F.S. Mendoza-Palmero, 2016) [1]. This article provides presence records in shapefile format used to generate maps of potential distribution of Aedes aegypti with different climate change scenarios as well as each of the maps obtained in raster format. In addition, tables with values of potential distribution of the vector as well as the average values of probability of presence including data of the mosquito incidence along the altitudinal range.

Datziinae as a new subfamily name for the unavailable name Protopsychodinae Stebner et al., 2015, (Diptera: Psychodidae)

In a recent paper a new subfamily of Psychodidae was inadequately named Protopsychodinae. This nomenclatural act cannot be considered as a valid name under ICZN regulations because the subfamily name is not based on the type genusDatziaStebner et al., 2015, and furthermore the fossil genusProtopsychodaAzar et al., 1999 was originally described under the subfamily Psychodinae. Therefore, the new family-group name Datziinae is herein proposed.

Spatiotemporal variation of mosquito diversity (Diptera: Culicidae) at places with different land-use types within a neotropical montane cloud forest matrix

Background

Land-use change has led to a dramatic decrease in total forest cover, contributing to biodiversity loss and changes of ecosystems’ functions. Insect communities of medical importance can be favored by anthropogenic alterations, increasing the risk of novel zoonotic diseases. The response of mosquito (Diptera: Culicidae) abundance and richness to five land-use types (shade coffee plantation, cattle field, urban forest, peri-urban forest, well-preserved montane cloud forest) and three seasons (“dry”, “rainy” and “cold”) embedded in a neotropical montane cloud forest landscape was evaluated.

Methods

Standardized collections were performed using 8 CDC miniature black-light traps, baited with CO2 throughout the year. Generalized additive mixed models were used to describe the seasonal and spatial trends of both species richness and abundance. Rank abundance curves and ANCOVAs were used to detect changes in the spatial and temporal structure of the mosquito assemblage. Two cluster analyses were conducted, using 1-βsim and the Morisita-Horn index to evaluate species composition shifts based on incidences and abundances.

Results

A total of 2536 adult mosquitoes were collected, belonging to 9 genera and 10 species; the dominant species in the study were: Aedes quadrivittatus, Wyeomyia adelpha, Wy. arthrostigma, and Culex restuans. Highest richness was recorded in the dry season, whereas higher abundance was detected during the rainy season. The urban forest had the highest species richness (n = 7) when compared to all other sites. Species composition cluster analyses show that there is a high degree of similarity in species numbers across sites and seasons throughout the year. However, when considering the abundance of such species, the well-preserved montane cloud forest showed significantly higher abundance. Moreover, the urban forest is only 30 % similar to other sites in terms of species abundances, indicating a possible isolating role of the urban environment.

Conclusion

Mosquito assemblage was differentially influenced by land-use change and seasonality, but at the same time the assemblage is rather homogeneous across the studied landscape, suggesting a high degree of spatial connectivity. Information generated in this study is potentially useful in the development of urban planning and surveillance programs focused mainly on mosquito species of medical and veterinary importance.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-1086-9) contains supplementary material, which is available to authorized users.

Moth flies and sand flies (Diptera: Psychodidae) in Cretaceous Burmese amber

One new subfamily, four new genera and 10 new species of Psychodidae are described from Burmese amber which significantly increases our knowledge about this group in the Cretaceous. Protopsychodinae n. subfam. probably represents the oldest known ancestor of modern Psychodinae and includes three species within two genera: Datzia setosa gen. et sp. n., Datzia bispina gen. et sp. n., and Mandalayia beumersorum gen. et sp. n. Sycoracinae and Phlebotominae are represented by two genera each in the studied material, Palaeoparasycorax globosus gen. et sp. n., Palaeoparasycorax suppus gen. et sp. n., Parasycorax simplex sp. n., and Phlebotomites aphoe sp. n. and Phlebotomus vetus sp. n., respectively. Bruchomyiinae is represented by Nemopalpus quadrispiculatus sp. n. Furthermore, one genus of an incertae sedis subfamily, Bamara groehni gen. et sp. n., is described. The systematic positions of the new taxa are discussed.

Change of name for the Oriental robber fly Nyssomyia Hull, 1962 (Diptera: Asilidae, Asilinae), nec Nyssomyia Barretto, 1962 (Diptera: Psychodidae, Phlebotominae)

A new name for the Oriental genus Nyssomyia Hull, 1962 (Diptera: Asilidae) is proposed. Homonymy exists between this Oriental robber fly genus and the more senior Neotropical phlebotomine sand fly genus Nyssomyia Barretto, 1962 (sensu Galati 2003) (Diptera: Psychodidae), and the following replacement name is proposed: Ekkentronomyia nom. nov. for Nyssomyia Hull (nec Barretto 1962). Accordingly, a new combination is herein proposed for the only species currently included in this genus: Ekkentronomyia ochracea (Hull, 1962) comb. nov.

Dengue virus in bats from southeastern Mexico

To identify the relationship between landscape use and dengue virus (DENV) occurrence in bats, we investigated the presence of DENV from anthropogenically changed and unaltered landscapes in two Biosphere Reserves: Calakmul (Campeche) and Montes Azules (Chiapas) in southern Mexico. Spleen samples of 146 bats, belonging to 16 species, were tested for four DENV serotypes with standard reverse transcriptase polymerase chain reaction (RT-PCR) protocols. Six bats (4.1%) tested positive for DENV-2: four bats in Calakmul (two Glossophaga soricina, one Artibeus jamaicensis, and one A. lituratus) and two bats in Montes Azules (both A. lituratus). No effect of anthropogenic disturbance on the occurrence of DENV was detected; however, all three RT-PCR-positive bat species are considered abundant species in the Neotropics and well-adapted to disturbed habitats. To our knowledge, this study is the first study conducted in southeastern Mexico to identify DENV-2 in bats by a widely accepted RT-PCR protocol. The role that bats play on DENV's ecology remains undetermined.

Household risk factors associated to infestation of Triatoma dimidiata, the Chagas disease vector in Central Region of Veracruz, Mexico

 Objective. To evaluate risk factors facilitating the coloniza­tion of dwellings by Triatoma dimidiata in the central region of the state of Veracruz. Materials and methods. We applied socioeconomic questionnaires and entomologic surveys in three localities (Chavarrillo, Soyacuautla and Arroyo Agrio) in central Veracruz involving 115 households. Results. We found that the main risk factors were the predominance of unplastered walls and particularly those made of light weight aggregate concrete blocks and wood. At Chavarrillo, houses usually have unplastered walls, whereas in Soyocuautla walls are commonly manufactured with wood. In Arroyo Agrio, the phenomenon was seasonal, and bugs were commonly found in the dry season, particularly in relatively new houses, less than 20 years old. Conclusions. These results help to improve the surveillance capacity for this vector and the control strategies to reduce the transmission of Chagas disease in the state of Veracruz and other sites where this species is present.

Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems

The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp.

Current and future niche of North and Central American sand flies (Diptera: psychodidae) in climate change scenarios

Ecological niche models are useful tools to infer potential spatial and temporal distributions in vector species and to measure epidemiological risk for infectious diseases such as the Leishmaniases. The ecological niche of 28 North and Central American sand fly species, including those with epidemiological relevance, can be used to analyze the vector's ecology and its association with transmission risk, and plan integrated regional vector surveillance and control programs. In this study, we model the environmental requirements of the principal North and Central American phlebotomine species and analyze three niche characteristics over future climate change scenarios: i) potential change in niche breadth, ii) direction and magnitude of niche centroid shifts, iii) shifts in elevation range. Niche identity between confirmed or incriminated Leishmania vector sand flies in Mexico, and human cases were analyzed. Niche models were constructed using sand fly occurrence datapoints from Canada, USA, Mexico, Guatemala and Belize. Nine non-correlated bioclimatic and four topographic data layers were used as niche components using GARP in OpenModeller. Both B2 and A2 climate change scenarios were used with two general circulation models for each scenario (CSIRO and HadCM3), for 2020, 2050 and 2080. There was an increase in niche breadth to 2080 in both scenarios for all species with the exception of Lutzomyia vexator. The principal direction of niche centroid displacement was to the northwest (64%), while the elevation range decreased greatest for tropical, and least for broad-range species. Lutzomyia cruciata is the only epidemiologically important species with high niche identity with that of Leishmania spp. in Mexico. Continued landscape modification in future climate change will provide an increased opportunity for the geographic expansion of NCA sand flys' ENM and human exposure to vectors of Leishmaniases.

Genetic structure and divergence in populations of Lutzomyia cruciata, a phlebotomine sand fly (Diptera: Psychodidae) vector of Leishmania mexicana in southeastern Mexico

The low dispersal capacity of sand flies could lead to population isolation due to geographic barriers, climate variation, or to population fragmentation associated with specific local habitats due to landscape modification. The phlebotomine sand fly Lutzomyia cruciata has a wide distribution throughout Mexico and is a vector of Leishmania mexicana in the southeast. The aim of this study was to evaluate the genetic diversity, structure, and divergence within and among populations of Lu. cruciata in the state of Chiapas, and to infer the intra-specific phylogeny using the 3' end of the mitochondrial cytochrome b gene. We analyzed 62 sequences from four Lu. cruciata populations and found 26 haplotypes, high genetic differentiation and restricted gene flow among populations (Fst=0.416, Nm=0.701, p<0.001). The highest diversity values were recorded in populations from Loma Bonita and Guadalupe Miramar. Three lineages (100% bootstrap and 7% overall divergence) were identified using a maximum likelihood phylogenetic analysis which showed high genetic divergence (17.2-22.7%). A minimum spanning haplotype network also supported separation into three lineages. Genetic structure and divergence within and among Lu. cruciata populations are hence affected by geographic heterogeneity and evolutionary background. Data obtained in the present study suggest that Lu. cruciata in the state of Chiapas consists of at least three lineages. Such findings may have implications for vector capacity and hence for vector control strategies.

Taxonomía y distribución de los anofelinos en el estado de Veracruz, México (Diptera: Culicidae, Anophelinae)

La malaria o paludismo es una enfermedad humana causada por protozoarios del género Plasmodium y es transmitida por hembras de mosquito de ciertas especies de Anopheles. Se estima queen México el 33.1% de la población vive en áreas donde puede ocurrir la transmisión de la malaria. Veracruz es un estado donde la enfermedad es endémica debido a diversos factores que lo hacen una zona de riesgo para la transmisión, entre ellos las condiciones climáticas y la migración humana. Por lo anterior, en este trabajo se presentan las bases para la reactivación de la vigilancia entomológica del paludismo en el estado de Veracruz, para lo cual se provee la diagnosis ilustrada de la larva, la pupa y los adultos de ambos sexos de las especies de anofelinos del estado, así como las claves taxonómicas que permiten su reconocimiento, con base en el examen de ejemplares recolectados o depositados en coleccionesentomológicas de referencia. También se obtuvieron mapas de distribución conocida y potencial de las especies por medio de GARP. Se mencionan además algunos datos bionómicos y la importanciamédica de cada especie. Se conocen en Veracruz 18 especies de anofelinos, agrupadas en dos géneros, Chagasia con una especie y Anopheles con 17 pertenecientes a los subgéneros An. (Anopheles), An. (Kerteszia) y An. (Nyssorhynchus). Se reconocen cuatro grupos de especies de acuerdo a su capacidad de transmisión de plasmodios y por su amplitud de distribución: el grupo de alto riesgo constituido por 2 especies; el grupo de riesgo moderado o regional, con 8 especies; el de escaso riesgo, con 3 especies y el de riesgo nulo con 5 especies. Prácticamente todo el estado posee vectores potenciales por lo que debe reestablecerse la vigilancia permanente de sus poblaciones. Este trabajo aporta elementos de juicio para que el estado pueda ser, en un futuro cercano, certificado como área libre de paludismo.

Current knowledge of Leishmania vectors in Mexico: how geographic distributions of species relate to transmission areas

Leishmaniases are a group of vector-borne diseases with different clinical manifestations caused by parasites transmitted by sand fly vectors. In Mexico, the sand fly Lutzomyia olmeca olmeca is the only vector proven to transmit the parasite Leishmania mexicana to humans, which causes leishmaniasis. Other vector species with potential medical importance have been obtained, but their geographic distributions and relation to transmission areas have never been assessed. We modeled the ecological niches of nine sand fly species and projected niches to estimate potential distributions by using known occurrences, environmental coverages, and the algorithms GARP and Maxent. All vector species were distributed in areas with known recurrent transmission, except for Lu. diabolica, which appeared to be related only to areas of occasional transmission in northern Mexico. The distribution of Lu. o. olmeca does not overlap with all reported cutaneous leishmaniasis cases, suggesting that Lu. cruciata and Lu. shannoni are likely also involved as primary vectors in those areas. Our study provides useful information of potential risk areas of leishmaniasis transmission in Mexico.

Description of the female of the Peruvian sand fly Lutzomyia reclusa (Diptera: Psychodidae: Phlebotominae)

The female of the phlebotomine sand fly Lutzomyia reclusa Fernández & Rogers 1991 [= Pintomyia (Pifanomyia) reclusa (Fernández & Rogers) sensu Galati], is described for the first time, based on specimens collected in the Department of Cajamarca, in northern Peru. The female can be recognized from other species of the series pia, species group Verrucarum, by wing venation with beta shorter than half of alpha, labrum just shorter than head width but longer than flagellomere 1, palpomere 5 much longer than palpomere 3, arrangement of cibarial armature, and form of spermathecae and relative size of spermathecal ducts. Diagnostic characters and measurements of the male of Lu. reclusa are provided as well.

A standardized sampling method to estimate mosquito richness and abundance for research and public health surveillance programmes

Programmes involving mosquito research and surveillance are normally focused on the study of aquatic larval stages, but sampling methods are varied and not systematized, which hinders the comparative analysis of ecological data. A standardized method for assessing the richness and abundance of mosquito larval populations of value for the analysis of mosquito diversity is presented. Based on the study of all the aquatic sites in a one hectare sample area with a proportional number of dips according to the size of the aquatic habitat, comparative data can be obtained on species richness and relative abundance of species found between pairs of sites or in the same area at different times. This technique provides information on the total mosquito fauna at each site, helps recognize species of medical importance and estimates the abundance of each species; parameters that are not estimated by the current entomological indexes used in surveillance programmes. The quality of the inventory is obtained by estimation of the efficiency effort. Procedures for calculating alpha, beta and gamma diversity are presented. The technique was validated in a natural and an urban zone at La Mancha, Veracruz, Mexico, over two years of sampling made during different climatic seasons.

First record of Lutzomyia evansi (Nuñez-Tovar 1924) in Mexico (Diptera: Psychodidae, Phlebotominae)

The phlebotomine sand fly Lutzomyia evansi is recorded in Mexico for the first time. This species is a suspected vector of Leishmania infantum in other parts of its geographical range and was captured in a focus of American visceral leishmaniasis where the principal vector, Lu. longipalpis sensu lato, was also found. The relative public health importance of the two species in the study area (Chiapas state, Southern Mexico) is discussed.

[Natural Trypanosoma cruzi infection of Triatominae bugs associated with human habitations in Mexico ]

OBJECTIVE

To estimate the prevalence of infection with Trypanosoma cruzi in Triatominae species frequently found in and around Mexican dwellings, and to assess the frequency of Triatominae in towns by state.

MATERIAL AND METHODS

Between January 1993 and December 1999, 5,399 Triatominae bugs from 14 states of Mexico, were received in the Department of Entomology of the Institute for Epidemiologic Diagnosis and Referral (InDRE), for taxonomic determination and parasitoscopical search of Trypanosoma cruzi. Results obtained between 1993 and 1999 were analyzed globally.

RESULTS

From 13 bug species associated with human dwellings, nine were naturally infected with T. cruzi. The highest percentage of infection occurred in Triatoma pallidipennis, T. picturata, Rhodnius prolixus and T. longipennis. Nayarit, Morelos, and Michoacán were the states with the highest percentage of infected bugs. The species T. dimidiata, T. gerstaeckeri, T. longipennis, T. mexicana and T. pallidipennis were first state records and Pastrongylus rufotuberculatus was a first local record.

CONCLUSIONS

These findings stress the importance of studying the biology of Triatominae and the need for permanent surveillance, to allow for up-to-date distribution records of Triatominae species in and around human dwellings, those adapting to human dwellings, and frequencies of those naturally infected by T. cruzi.

Mesocyclops longisetus effects on survivorship of Aedes aegypti immature stages in car tyres

The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F.C.B. strain) on the survival of Aedes aegypti immature stages in car tyres was evaluated under semi-natural conditions in the municipality of Merida, Yucatan, Mexico. Life tables were constructed for the immature stages of the mosquito in the presence and absence of M. longisetus, and the survival data were compared using log-linear models. The data set was adjusted using the GLIM statistical package and the quality of adjustment was evaluated with a chi-squared test. Survivorship curves were constructed for each treatment. In the absence of M. longisetus, the survivorship of Ae. aegypti immature stages averaged 9%. The highest mortality rate was observed during the fourth larval instar (54%) and the resulting survival pattern corresponded to a type II survivorship curve. The mortality rate of Ae. aegypti first-instar larvae (fifty per tyre) increased more than 200-fold in the presence of M. longisetus (twenty per tyre) and the highest mortality was during the first two larval instars, where it reached 98.9%, with a resulting survivorship of 0.2%. Overall mortality was sixfold greater in the presence of the copepod than in its absence. The survival pattern of immature stages of Ae. aegypti in the presence of the copepod corresponded to a type III survivorship curve. As M. longisetus was so effective against Ae. aegypti immature stages in tyres under seminatural conditions, its long-term effectiveness should be evaluated under socially and ecologically realistic field conditions in Mexico.

First record in America of Aedes albopictus naturally infected with dengue virus during the 1995 outbreak at Reynosa, Mexico

Mosquito collections were conducted during a dengue outbreak in Reynosa, Tamaulipas, Mexico, July-December 1995. A total of 6694 adult mosquitoes (four genera and nine species) were captured, of which 2986 (78.3% females and 21.7% males) were Aedes albopictus and 2339 (39.7% females and 60.3% males) were Ae.aegypti. These two species comprised 84.2% of the total collection. Specimens were grouped into pools, nearly 50% of them processed for detection of virus by cythopathic effect in C6-36 and VERO cell cultures and by haemagglutination test. Five pools gave positive haemagglutination reactions and were examined by immunofluorescence using monoclonal antibodies to flavivirus and to dengue virus. One pool of ten Ae.albopictus males was positive for dengue virus: serotypes 2 and 3 were identified by serotype-specific monoclonal antibodies and confirmed by RT-PCR. This is the first report of Ae.albopictus naturally infected with dengue virus in America. Also, it is the very first time Ae.albopictus males have been found infected with dengue virus in the wild.

New records of human tungiasis in Mexico (Siphonaptera:Tungidae)

Human cases of tungiasis were recorded in Mexico until 1948. Here we report 3 new cases of infection by chigoe, Tunga penetrans (L.), with 2 from Hidalgo State and the 3rd, although acquired in Mexico City, was associated with the other 2 cases. This is the 1st record of this species in Hidalgo State and indicates a reappearance of this parasite in Mexico.

Aedes albopictus in Mexico

Data relating to the discovery and identification of the Asian tiger mosquito, Aedes albopictus, in Coahuila State, Mexico, are presented. Infestations are reported for Piedras Negras and Ciudad Acuña. Samples from a third community were negative for Ae. albopictus.