RESUMEN
Wolbachia pipientis (Hertig, 1936), also referred as Wolbachia, is a bacterium present across insect taxa, certain strains of which have been demonstrated to impact the fitness and capacity to transmit viruses in mosquitoes, particularly Aedes aegypti (Linnaeus, 1762). Most studies examine these impacts in limited sets of environmental regimes. Here we seek to understand the impacts of environmentally relevant conditions such as larval density, temperature, and their interaction on wAlbB-infected A. aegypti. Using a factorial design, we measured wAlbB stability (relative density, post-emergence in females, and in progeny), the ability for wAlbB to induce cytoplasmic incompatibility, and bacterial effects on mosquito fitness (fecundity, fertility, and body mass) and performance (adult survival and time to pupation) across 2 temperature regimes (fluctuating and constant) and 2 initial larval densities (low and high). Fluctuating daily regimes of temperature (27 to 40 °C) led to decreased post-emergence wAlbB density and increased wAlbB density in eggs compared to constant temperature (27 °C). An increased fecundity was found in wAlbB-carrying females reared at fluctuating temperatures compared to uninfected wild-type females. wAlbB-carrying adult females showed significantly increased survival than wild-type females. Contrarily, wAlbB-carrying adult males exhibited a significantly lower survival than wild-type males. We found differential effects of assessed treatments (Wolbachia infection status, temperature, and larval density) across mosquito sexes and life stages. Taken together, our results indicate that realistic conditions may not impact dramatically the stability of wAlbB infection in A. aegypti. Nonetheless, understanding the ecological consequence of A. aegypti-wAlbB interaction is complex due to life history tradeoffs under conditions faced by natural populations.
RESUMEN
Recent declines of insect populations at high rates have resulted in the need to develop a quick method to determine their diversity and to process massive data for the identification of species of highly diverse groups. A short sequence of DNA from COI is widely used for insect identification by comparing it against sequences of known species. Repositories of sequences are available online with tools that facilitate matching of the sequences of interest to a known individual. However, the performance of these tools can differ. Here we aim to assess the accuracy in identification of insect taxonomic categories from two repositories, BOLD Systems and GenBank. This was done by comparing the sequence matches between the taxonomist identification and the suggested identification from the platforms. We used 1,160 COI sequences representing eight orders of insects from Colombia. After the comparison, we reanalyzed the results from a representative subset of the data from the subfamily Scarabaeinae (Coleoptera). Overall, BOLD systems outperformed GenBank, and the performance of both engines differed by orders and other taxonomic categories (species, genus and family). Higher rates of accurate identification were obtained at family and genus levels. The accuracy was higher in BOLD for the order Coleoptera at family level, for Coleoptera and Lepidoptera at genus and species level. Other orders performed similarly in both repositories. Moreover, the Scarabaeinae subset showed that species were correctly identified only when BOLD match percentage was above 93.4% and a total of 85% of the samples were correctly assigned to a taxonomic category. These results accentuate the great potential of the identification engines to place insects accurately into their respective taxonomic categories based on DNA barcodes and highlight the reliability of BOLD Systems for insect identification in the absence of a large reference database for a highly diverse country.
Asunto(s)
Escarabajos , Bases de Datos de Ácidos Nucleicos , Animales , Código de Barras del ADN Taxonómico/métodos , Reproducibilidad de los Resultados , Colombia , Insectos , ADN/genética , Escarabajos/genética , FilogeniaRESUMEN
Information about mosquito ecology in the high mountain ecosystems of the Neotropical region is sparse. In general, few genera and species have been reported in these ecosystems and there is no information available on habitats and the mosquitoes occupying them. In the present study, specimens collected from NW Colombia in HME were grouped using larval habitat data via an Operational Taxonomic Unit (OTU) determination. A total of 719 mosquitoes was analyzed belonging to 44 OTUs. The analysis considered habitat features and clustered the specimens into six groups from A-F. Five of these included species from different genera, suggesting common habitat requirements. Group E with four genera, seven subgenera, and six species occupied the highest areas (above 3,000 m), whereas three groups (B, D, F) were detected at lower altitudes (1,960-2,002 m). Bromeliads were the most common larval habitat, with 47% (335/719) of the specimens; five genera, six subgenera, and eight species were identified and classified into 66% (29/44) of the OTUs. This work showed some similarities to the habitat requirements and provides a grouping system that constitutes an important baseline for the classification of mosquito fauna from high mountain ecosystems according to altitude and larval habitat.
Asunto(s)
Culicidae/clasificación , Culicidae/fisiología , Larva/clasificación , Larva/fisiología , Animales , Colombia , Ecología , EcosistemaRESUMEN
Accurate taxonomic identification of highland mosquito species may be complicated because of the lack of comprehensive regional morphological keys and taxonomic specialists, particularly for mosquitoes of medical or ecological importance. We applied a multi-locus approach to explore the diversity of genera/species collected, to define the Molecular Operational Taxonomic Units (MOTUs) and to perform phylogenetic clustering. Twenty MOTUs and three single sequences were revealed from 78 concatenated cox1 + ITS2 sequences, and the species name was allocated for five of these. This study provides molecular taxonomic information of culicid fauna present in high Andean mountain ecosystems in Antioquia, Colombia. However, future morphological and integrative taxonomic studies should be conducted to achieve the specific identity of all detected MOTUs.
Asunto(s)
Culicidae , Filogenia , Animales , Colombia , Ecología , EcosistemaRESUMEN
Although phlebotomine sand flies breeding sites have been identified and recorded by several studies, the microhabitats exploited by these insects remain little-known and hard to find. In this context, the difficulty of finding immature stages, and the limited number of taxonomic studies to identify immature stages of phlebotomine sand flies, are considered the major obstacles when attempting a complete inventory of Lutzomyia species. The objective of this study is to validate Cytochrome Oxidase I (Barcode region) as a marker for the identification of immature stages of Lutzomyia species recovered from natural breeding sites in Colombia. Among 142 collected sand flies, 18 immature individuals that did not complete their life cycle were identified to species level through sequencing of the COI gene. Values of K2P genetic distance between 0.002-0.031 allowed the identification of larvae at species level. The bootstrap support values (96%) in the Neighbor-Joining dendrogram were consistent for the majority of the established MOTUS of Lutzomyia atroclavata, Lutzomyia micropyga, Lutzomyia serrana, Lutzomyia cayennensis, Lutzomyia rangeliana, Lutzomyia shannoni and some species of the genus Brumptomyia. The COI gene is validated as a marker for the identification of immature stages of the genus Lutzomyia.