RESUMEN
Little is known about the extent to which species use homologous regulatory architectures to achieve phenotypic convergence. By characterizing chromatin accessibility and gene expression in developing wing tissues, we compared the regulatory architecture of convergence between a pair of mimetic butterfly species. Although a handful of color pattern genes are known to be involved in their convergence, our data suggest that different mutational paths underlie the integration of these genes into wing pattern development. This is supported by a large fraction of accessible chromatin being exclusive to each species, including the de novo lineage-specific evolution of a modular optix enhancer. These findings may be explained by a high level of developmental drift and evolutionary contingency that occurs during the independent evolution of mimicry.
Asunto(s)
Evolución Biológica , Mimetismo Biológico , Mariposas Diurnas , Ensamble y Desensamble de Cromatina , Alas de Animales , Animales , Mimetismo Biológico/genética , Mariposas Diurnas/anatomía & histología , Mariposas Diurnas/genética , Mariposas Diurnas/crecimiento & desarrollo , Pigmentación/genética , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Elementos de Facilitación GenéticosRESUMEN
The distribution of Aedes aegypti (L.) (Diptera: Culicidae) is expanding towards colder regions, which could be aided by an adaptation of the immature stages to the local thermal conditions. This study aimed to assess the developmental success at different temperatures in three populations of Ae. aegypti located across a climate gradient in Argentina. Survival to the adult stage, development time, and wing length at 14, 18.5 and 24°C were compared among three populations of Argentina: Resistencia in the subtropical region, and Buenos Aires and San Bernardo in the temperate region. Survival was similar between populations and equal to or higher than 69%, and increased at higher temperatures within the studied range. Development times were similar between populations. A negative effect of temperature was observed and the reduction of development time at increasing temperatures was stronger for males than for females. Wing lengths were negatively affected by increasing temperatures, and the reduction of wing length was stronger for females than for males. Also, the reduction of wing lengths with temperature was stronger for San Bernardo and Resistencia than for Buenos Aires, and differences between sexes were larger for Resistencia than for Buenos Aires or San Bernardo. Although the results do not evidence differences in survival and development time between temperate and tropical populations, the three populations have a higher tolerance to low temperatures than the populations from other regions.
Asunto(s)
Aedes/crecimiento & desarrollo , Animales , Argentina , Clima , Femenino , Masculino , Temperatura , Alas de Animales/crecimiento & desarrolloRESUMEN
Many insects use photoperiod as a signal to anticipate upcoming unfavorable conditions. Photoperiod sensitivity may be a relevant factor in Aedes (Stegomyia) aegypti (L.) populations at the cool margins of the species' range, where winter conditions have a strong effect on population dynamics. In this study, we evaluated the effect of parental photoperiod on preimaginal survival and developmental time, and on wing length for the first generation of Ae. aegypti from a temperate region (Buenos Aires City, Argentina). Our experiment started with eggs from parents exposed to short-day (SD; 10:14 [L:D]) or long-day (LD; 14:10 [L:D]) photoperiods during their entire life span. Eggs were stored under the same photoperiod (SD or LD) as their parents for 91 d, until immersion. After hatching, larvae were reared until adult emergence in thermal baths at one of two constant temperatures (17 or 23°C), at a photoperiod of 12:12 (L:D) h and fed ad libitum. Survival from larva I to adult emergence was not affected either by parental photoperiod or rearing temperature. At a rearing temperature of 23°C, female offspring from the SD parental photoperiod developed faster and had shorter wings compared with those from the LD parental photoperiod. No effect of parental photoperiod was observed on female offspring reared at 17°C. In male offspring, parental photoperiod had no effect on developmental time and wing length, independently of the rearing temperature. Results indicate that the parental photoperiod may affect some offspring traits. This effect may be a characteristic of Ae. aegypti populations in temperate regions to deal with the winter conditions.
Asunto(s)
Aedes/crecimiento & desarrollo , Tamaño Corporal , Fotoperiodo , Animales , Argentina , Femenino , Masculino , Temperatura , Alas de Animales/crecimiento & desarrolloRESUMEN
Organs mainly attain their size by cell growth and proliferation, but sometimes also grow through recruitment of undifferentiated cells. Here we investigate the participation of cell recruitment in establishing the pattern of Vestigial (Vg), the product of the wing selector gene in Drosophila. We find that the Vg pattern overscales along the dorsal-ventral (DV) axis of the wing imaginal disc, i.e., it expands faster than the DV length of the pouch. The overscaling of the Vg pattern cannot be explained by differential proliferation, apoptosis, or oriented-cell divisions, but can be recapitulated by a mathematical model that explicitly considers cell recruitment. When impairing cell recruitment genetically, we find that the Vg pattern almost perfectly scales and adult wings are approximately 20% smaller. Conversely, impairing cell proliferation results in very small wings, suggesting that cell recruitment and cell proliferation additively contribute to organ growth in this system. Furthermore, using fluorescent reporter tools, we provide direct evidence that cell recruitment is initiated between early and mid third-instar larval development. Altogether, our work quantitatively shows when, how, and by how much cell recruitment shapes the Vg pattern and drives growth of the Drosophila wing.
Asunto(s)
Tipificación del Cuerpo/genética , Proteínas de Drosophila/genética , Proteínas Nucleares/genética , Alas de Animales/crecimiento & desarrollo , Animales , División Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriología , Drosophila melanogaster/genética , Regulación del Desarrollo de la Expresión Génica/genética , Discos Imaginales/crecimiento & desarrollo , Proteínas Nucleares/metabolismo , Transducción de Señal , Factores de Transcripción/metabolismo , Proteína Wnt1/metabolismoRESUMEN
Coordinated intra- and inter-organ growth during animal development is essential to ensure a correctly proportioned individual. The Drosophila wing has been a valuable model system to reveal the existence of a stress response mechanism involved in the coordination of growth between adjacent cell populations and to identify a role of the fly orthologue of p53 (Dmp53) in this process. Here we identify the molecular mechanisms used by Dmp53 to regulate growth and proliferation in a non-autonomous manner. First, Dmp53-mediated transcriptional induction of Eiger, the fly orthologue of TNFα ligand, leads to the cell-autonomous activation of JNK. Second, two distinct signaling events downstream of the Eiger/JNK axis are induced in order to independently regulate tissue size and cell number in adjacent cell populations. Whereas expression of the hormone dILP8 acts systemically to reduce growth rates and tissue size of adjacent cell populations, the production of Reactive Oxygen Species-downstream of Eiger/JNK and as a consequence of apoptosis induction-acts in a non-cell-autonomous manner to reduce proliferation rates. Our results unravel how local and systemic signals act concertedly within a tissue to coordinate growth and proliferation, thereby generating well-proportioned organs and functionally integrated adults.
Asunto(s)
Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulación del Desarrollo de la Expresión Génica , Péptidos y Proteínas de Señalización Intercelular/genética , Proteínas de la Membrana/genética , Especies Reactivas de Oxígeno/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Animales Modificados Genéticamente , Apoptosis/genética , Proliferación Celular/genética , Drosophila melanogaster/fisiología , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Larva/crecimiento & desarrollo , Sistema de Señalización de MAP Quinasas/genética , Proteínas de la Membrana/metabolismo , Modelos Animales , Tamaño de los Órganos/genética , Alas de Animales/crecimiento & desarrolloRESUMEN
Fluctuating asymmetry (FA), a phenotypic marker used as indicator of developmental stress or instability, is sometimes associated with insecticide application and resistance. Here we investigated the occurrence and amount of wing size and wing shape FA in Triatoma infestans females and males collected before and 4â¯months after a community-wide pyrethroid spraying campaign in a well-defined rural area of Pampa del Indio, Argentina. Moderate levels of pyrethroid resistance were previously confirmed for this area, and postspraying house infestation was mainly attributed to this condition. In the absence of insecticide-based selective pressures over the previous 12â¯years, we hypothesized that 1- if postspraying triatomines were mostly survivors to insecticide spraying (pyrethroid resistant), they would have higher levels of FA than prespraying triatomines. 2- if postspraying triatomines have a selective advantage, they would have lower FA levels than their prespraying counterparts, whereas if postspraying infestation was positively associated with immigrants not exposed to the insecticide, prespraying and postspraying triatomines would display similar FA levels. For 243 adult T. infestans collected at identified sites before insecticide spraying and 112 collected 4â¯months postspraying, wing size and wing shape asymmetry was estimated from landmark configurations of left and right sides of each individual. At population level, wing size and shape FA significantly decreased in both females and males after spraying. Males displayed greater wing size and shape FA than females. However, at a single peridomestic site that was persistently infested after spraying, FA declined similarly in females whereas the reverse pattern occurred in males. Our results suggest differential survival of adults with more symmetric wings. This pattern may be related to a selective advantage of survivors to insecticide spraying, which may be mediated or not by their pyrethroid-resistant status or to lower triatomine densities after insecticide spraying and the concomitant increase in feeding success.
Asunto(s)
Resistencia a los Insecticidas , Insecticidas/efectos adversos , Piretrinas/efectos adversos , Triatoma/crecimiento & desarrollo , Animales , Argentina , Femenino , Control de Insectos , Masculino , Tamaño de los Órganos/efectos de los fármacos , Dinámica Poblacional , Triatoma/efectos de los fármacos , Alas de Animales/efectos de los fármacos , Alas de Animales/crecimiento & desarrolloRESUMEN
BACKGROUND: Aedes aegypti is the main vector of the dengue, Zika and several other arboviruses. It is highly adapted to urbanized environments and can be found worldwide. Mosquito population control is considered the best strategy for fighting mosquito-borne diseases, making an understanding of their population dynamics vital for the development of more effective vector control programs. This study therefore sought to investigate how different levels of urbanization affect Aedes aegypti populations and modulate population structure in this species with the aid of wing geometric morphometrics. METHODS: Specimens were collected from eleven locations in three areas with distinct levels of urbanization in the city of São Paulo, Brazil: conserved, intermediate and urbanized. The right wings of female mosquitoes collected were removed, and photographed and digitized. Canonical variate analysis and Mahalanobis distance were used to investigate the degree of wing-shape dissimilarity among populations. Thin-plate splines were calculated by regression analysis of Canonical Variation Analysis scores against wing-shape variation, and a cross-validated reclassification was performed for each individual; a neighbor-joining tree was then constructed. RESULTS: Metapopulation and individual population analysis showed a clear segregation pattern in the Canonical Variation Analysis. Pairwise cross-validated reclassification yielded relatively high scores considering the microgeographical scale of the study and the fact that the study populations belong to the same species. The neighbor-joining tree showed that mosquitoes in the intermediate urban area segregated in the metapopulation and individual population analyses. Our findings show significant population structuring in Aedes aegypti mosquitoes in the areas studied. This is related to the different degrees of urbanization in the areas where the specimens were collected along with their geographical location. CONCLUSIONS: Urbanization processes in the study areas appear to play an important role in microevolutionary processes triggered by man-made modifications in the environment, resulting in a previously unknown population structuring pattern of major epidemiological importance.
Asunto(s)
Aedes/anatomía & histología , Infecciones por Arbovirus/transmisión , Mosquitos Vectores/anatomía & histología , Infección por el Virus Zika/transmisión , Aedes/crecimiento & desarrollo , Aedes/virología , Animales , Infecciones por Arbovirus/epidemiología , Brasil/epidemiología , Dengue , Femenino , Mosquitos Vectores/crecimiento & desarrollo , Mosquitos Vectores/virología , Dinámica Poblacional , Urbanización , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrollo , Infección por el Virus Zika/epidemiologíaRESUMEN
Gene regulatory networks (GRNs) evolve as a result of the coevolutionary processes acting on transcription factors (TFs) and the cis-regulatory modules they bind. The zinc-finger TF zelda (zld) is essential for the maternal-to-zygotic transition (MZT) in Drosophila melanogaster, where it directly binds over thousand cis-regulatory modules to regulate chromatin accessibility. D. melanogaster displays a long germ type of embryonic development, where all segments are simultaneously generated along the whole egg. However, it remains unclear if zld is also involved in the MZT of short-germ insects (including those from basal lineages) or in other biological processes. Here we show that zld is an innovation of the Pancrustacea lineage, being absent in more distant arthropods (e.g. chelicerates) and other organisms. To better understand zld´s ancestral function, we thoroughly investigated its roles in a short-germ beetle, Tribolium castaneum, using molecular biology and computational approaches. Our results demonstrate roles for zld not only during the MZT, but also in posterior segmentation and patterning of imaginal disc derived structures. Further, we also demonstrate that zld is critical for posterior segmentation in the hemipteran Rhodnius prolixus, indicating this function predates the origin of holometabolous insects and was subsequently lost in long-germ insects. Our results unveil new roles of zld in different biological contexts and suggest that changes in expression of zld (and probably other major TFs) are critical in the evolution of insect GRNs.
Asunto(s)
Proteínas de Drosophila/genética , Desarrollo Embrionario/genética , Evolución Molecular , Redes Reguladoras de Genes/genética , Factores de Transcripción/genética , Animales , Tipificación del Cuerpo/genética , Escarabajos/genética , Proteínas de Drosophila/biosíntesis , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Proteínas Nucleares , Regiones Promotoras Genéticas , Interferencia de ARN , Factores de Transcripción/biosíntesis , Activación Transcripcional/genética , Alas de Animales/crecimiento & desarrolloRESUMEN
The aim of this study was to evaluate the genotoxicity of the herbicide diuron in the wing-spot test and a novel wing imaginal disk comet assay in Drosophila melanogaster. The wing-spot test was performed with standard (ST) and high-bioactivation (HB) crosses after providing chronic 48 h treatment to third instar larvae. A positive dose-response effect was observed in both crosses, but statistically reduced spot frequencies were registered for the HB cross compared with the ST. This latter finding suggests that metabolism differences play an important role in the genotoxic effect of diuron. To verify diuron's ability to produce DNA damage, a wing imaginal disk comet assay was performed after providing 24 h diuron treatment to ST and HB third instar larvae. DNA damage induced by the herbicide had a significantly positive dose-response effect even at very low concentrations in both strains. However, as noted for the wing-spot test, a significant difference between strains was not observed that could be related to the duration of exposure between both assays. A positive correlation between the comet assay and the wing-spot test was found with regard to diuron genotoxicity.
Asunto(s)
Daño del ADN/efectos de los fármacos , Diurona/toxicidad , Drosophila melanogaster , Herbicidas/toxicidad , Animales , Ensayo Cometa , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/genética , Femenino , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Masculino , Pruebas de Mutagenicidad , Alas de Animales/efectos de los fármacos , Alas de Animales/crecimiento & desarrollo , Alas de Animales/patologíaRESUMEN
Bursicon is a heterodimeric neurohormone that acts through a G protein-coupled receptor named rickets (rk), thus inducing an increase in cAMP and the activation of tyrosine hydroxylase, the rate-limiting enzyme in the cuticular tanning pathway. In insects, the role of bursicon in the post-ecdysial tanning of the adult cuticle and wing expansion is well characterized. Here we investigated the roles of the genes encoding the bursicon subunits during the adult cuticle development in the honeybee, Apis mellifera. RNAi-mediated knockdown of AmBurs α and AmBurs ß bursicon genes prevented the complete formation and tanning (melanization/sclerotization) of the adult cuticle. A thinner, much less tanned cuticle was produced, and ecdysis toward adult stage was impaired. Consistent with these results, the knockdown of bursicon transcripts also interfered in the expression of genes encoding its receptor, AmRk, structural cuticular proteins, and enzymes in the melanization/sclerotization pathway, thus evidencing roles for bursicon in adult cuticle formation and tanning. Moreover, the expression of AmBurs α, AmBurs ß and AmRk is contingent on the declining ecdysteroid titer that triggers the onset of adult cuticle synthesis and deposition. The search for transcripts of AmBurs α, AmBurs ß and candidate targets in RNA-seq libraries prepared with brains and integuments strengthened our data on transcript quantification through RT-qPCR. Together, our results support our premise that bursicon has roles in adult cuticle formation and tanning, and are in agreement with other recent studies pointing for roles during the pharate-adult stage, in addition to the classical post-ecdysial ones.
Asunto(s)
Abejas/genética , Ecdisteroides/genética , Hormonas de Invertebrados/genética , Metamorfosis Biológica/genética , Animales , Abejas/crecimiento & desarrollo , AMP Cíclico/genética , Ecdisteroides/biosíntesis , Regulación del Desarrollo de la Expresión Génica , Técnicas de Silenciamiento del Gen , Hormonas de Invertebrados/antagonistas & inhibidores , Muda/genética , Interferencia de ARN , Receptores Acoplados a Proteínas G/genética , Alas de Animales/crecimiento & desarrollo , Alas de Animales/metabolismoRESUMEN
Two new species of Ulmeritoides Traver, 1959 are described from Southeastern Brazil based on male and female imagos. Ulmeritoides angelus sp. nov. (Holotype male deposited in DZRJ: Minas Gerais State) differs from all other species of the genus by the following combination of characters: forewings hyaline, base dark brown and purplish; veins R1 light brown; dark brown spots on bullae of veins Sc and R2; apex of penis lobes somewhat rounded, each with one central spine. Ulmeritoides tamoio sp. nov. (Holotype male deposited in DZRJ: São Paulo State) differs from all other species of the genus by the following combination of characters: wings hyaline; veins C, Sc and R1 brownish; brownish spots on bullae of veins Sc and R2; apex of penis lobes straight, ending in rather acute apical and mesal projections. An updated key to the genera Ulmeritoides Traver, 1956 and Ulmeritus Traver, 1956 is also given.
Asunto(s)
Ephemeroptera/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Brasil , Ecosistema , Ephemeroptera/anatomía & histología , Ephemeroptera/crecimiento & desarrollo , Femenino , Masculino , Tamaño de los Órganos , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrolloRESUMEN
Brasineura serranortensis sp. n. is here described and illustrated. This is the third known species of Brasineura and differs from the other species in the genus in phallosome, hypandrium and paraproct structure. Comments on variation in fore wing venation, and new records for B. troglophilica are included. A revised generic diagnosis is also presented.
Asunto(s)
Insectos/anatomía & histología , Insectos/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Brasil , Ecosistema , Insectos/crecimiento & desarrollo , Masculino , Tamaño de los Órganos , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrolloRESUMEN
Two new genera and species of Megaloptera are described from the Lower Cretaceous Crato Formation of Brazil. Cratocorydalopsis brasiliensis gen. et sp. nov. and Lithocorydalus fuscata gen. et sp. nov. are both placed within the family Corydalidae. The specimens represent the first Cretaceous examples of adult megalopteran body fossils not preserved in amber, and are the first megalopterans to be formally described from the Crato Formation.
Asunto(s)
Fósiles/anatomía & histología , Insectos/clasificación , Distribución Animal , Animales , Tamaño Corporal , Brasil , Ecosistema , Femenino , Insectos/anatomía & histología , Insectos/crecimiento & desarrollo , Masculino , Tamaño de los Órganos , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrolloRESUMEN
Probiotic effects on growth performance, carcass traits, blood parameters, cecal microbiota, and immune response of broilers were studied. Two hundred one-day-old male chickens were allocated to one of five treatments (four replicates of 10 birds per treatment): control, and the same control diet supplemented with 0.005%, 0.01%, 0.015% and 0.02% probiotics. Probiotics in feed at 0.01% or higher levels of supplementation improved body weight gain (+12%) and feed conversion rate (-5%) compared with the control. There were no effects on carcass traits, but the relative weights of drumsticks and wings showed increasing and decreasing linear responses, respectively, to probiotic supplementation level. Blood plasma glucose and albumin contents linearly increased (from 167.1 to 200.5 mg dl-1, and from 1.70 to 3.25 g dl-1) with increasing probiotic supplementation. Triglycerides and cholesterol contents were lower in probiotic supplemented treatments (average contents 71.3 and 125.3 mg dl-1 vs. 92.6 and 149.9 mg dl-1 in the control). Probiotics decreased cecal Escherichia coli counts, but had no effects on immunity related organs or immune response. The linear trends, either positive or negative, observed in many of the parameters studied, suggest that more studies are needed to establish the optimal concentration of probiotics in broiler feed.
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Ciego/microbiología , Pollos/crecimiento & desarrollo , Suplementos Dietéticos , Microbioma Gastrointestinal , Probióticos/administración & dosificación , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Glucemia/metabolismo , Pollos/sangre , Masculino , Aumento de Peso , Alas de Animales/crecimiento & desarrolloRESUMEN
The new micro-dolichopodid genus Haromyia gen. nov. and the type species H. iviei sp. nov. are described from the island of Dominica in the Lesser Antilles. Males and females of Haromyia are distinguished by the large setae on a bulging clypeus, minute size, and wing veins that are nearly straight and evenly diverging from wing base. Haromyia does not fit readily into any contemporary dolichopodid subfamily, although it superficially resembles the Enliniinae and Achalcinae. Haromyia should be regarded as incertae sedis until the dolichopodid subfamilies can be refined, particularly to better incorporate the tropical diversity of this large family.
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Braquiuros/clasificación , Dípteros/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Braquiuros/anatomía & histología , Braquiuros/crecimiento & desarrollo , Dípteros/anatomía & histología , Dípteros/crecimiento & desarrollo , Dominica , Femenino , Masculino , Tamaño de los Órganos , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrolloRESUMEN
Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds.
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Tamaño de la Nidada , Pájaros Cantores/crecimiento & desarrollo , Pájaros Cantores/fisiología , Clima Tropical , Alas de Animales/crecimiento & desarrollo , Animales , Arizona , Malasia , Mortalidad , Comportamiento de Nidificación , Conducta Predatoria , VenezuelaRESUMEN
The stochastic nature of biochemical processes is a source of variability that influences developmental stability. Developmental instability (DI) is often estimated through fluctuating asymmetry (FA), a parameter that deals with within-individual variation in bilateral structures. A relevant goal is to shed light on how environment, physiology and genotype relate to DI, thus providing a more comprehensive view of organismal development. Using Drosophila melanogaster isogenic lines, we investigated the effect of parental age, parental diet and offspring heterozygosity on DI. In this work, we have uncovered a clear relationship between parental age and offspring asymmetry. We show that asymmetry of the progeny increases concomitantly with parental age. Moreover, we demonstrate that enriching the diet of parents mitigates the effect of age on offspring symmetry. We show as well that increasing the heterozygosity of the progeny eliminates the effect of parental age on offspring symmetry. Taken together, our results suggest that diet, genotype and age of the parents interact to determine offspring DI in wild populations. These findings provide us with an avenue to understand the mechanisms underlying DI.
Asunto(s)
Drosophila melanogaster/crecimiento & desarrollo , Factores de Edad , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Drosophila melanogaster/genética , Extremidades/anatomía & histología , Extremidades/crecimiento & desarrollo , Femenino , Heterocigoto , Masculino , Fenotipo , Fenómenos Fisiológicos Reproductivos , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrolloRESUMEN
BACKGROUND: In Brazil, the autochthonous transmission of extra-Amazonian malaria occurs mainly in areas of the southeastern coastal Atlantic Forest, where Anopheles cruzii is the primary vector. In these locations, the population density of the mosquito varies with altitude (5-263 m above sea level), prompting us to hypothesise that gene flow is also unevenly distributed. Describing the micro-geographical and temporal biological variability of this species may be a key to understanding the dispersion of malaria in the region. We explored the homogeneity of the An. cruzii population across its altitudinal range of distribution using wing shape and mtDNA gene analysis. We also assessed the stability of wing geometry over time. METHODS: Larvae were sampled from lowland (5-20 m) and hilltop (81-263 m) areas in a primary Atlantic Forest region, in the municipality of Cananéia (State of São Paulo, Brazil). The right wings of males and females were analysed by standard geometric morphometrics. Eighteen landmarks were digitised for each individual and a discriminant analysis was used to compare samples from the hilltop and lowland. A 400-bp DNA fragment of the mitochondrial cytochrome oxidase gene subunit I (CO-I) was PCR-amplified and sequenced. RESULTS: Wing shapes were distinct between lowland and hilltop population samples. Results of cross-validated tests based on Mahalanobis distances showed that the individuals from both micro-environments were correctly reclassified in a range of 54-96%. The wings of hilltop individuals were larger. The CO-I gene was highly polymorphic (haplotypic diversity = 0.98) and altitudinally structured (Фst = 0.085 and Jaccard = 0.033). We found 60 different haplotypes but only two were shared by the lowland and hilltop populations. Wing shape changed over the brief study period (2009-2013). CONCLUSIONS: Wing geometry and CO-I gene analysis indicated that An. cruzii is vertically structured. Wing shape varied rapidly, but altitude structure was maintained. Future investigations should identify the biotic/abiotic causes of these patterns and their implications in the local epidemiology of malaria.
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Anopheles/crecimiento & desarrollo , Insectos Vectores/crecimiento & desarrollo , Altitud , Animales , Anopheles/genética , Anopheles/metabolismo , Evolución Biológica , Brasil , Complejo IV de Transporte de Electrones/genética , Femenino , Proteínas de Insectos/genética , Insectos Vectores/genética , Insectos Vectores/metabolismo , Masculino , Densidad de Población , Dinámica Poblacional , Alas de Animales/crecimiento & desarrollo , Alas de Animales/metabolismoRESUMEN
Host shifts cause drastic consequences on fitness in cactophilic species of Drosophila. It has been argued that changes in the nutritional values accompanying host shifts may elicit these fitness responses, but they may also reflect the presence of potentially toxic secondary compounds that affect resource quality. Recent studies reported that alkaloids extracted from the columnar cactus Trichocereus terscheckii are toxic for the developing larvae of Drosophila buzzatii. In this study, we tested the effect of artificial diets including increasing doses of host alkaloids on developmental stability and wing morphology in D. buzzatii. We found that alkaloids disrupt normal wing venation patterning and affect viability, wing size and fluctuating asymmetry, suggesting the involvement of stress-response mechanisms. Theoretical implications are discussed in the context of developmental stability, stress, fitness and their relationship with robustness, canalization and phenotypic plasticity.
Asunto(s)
Alcaloides/toxicidad , Cactaceae/química , Drosophila/crecimiento & desarrollo , Modelos Biológicos , Alas de Animales/crecimiento & desarrollo , Análisis de Varianza , Animales , Relación Dosis-Respuesta a Droga , Drosophila/efectos de los fármacos , Alas de Animales/efectos de los fármacosRESUMEN
Phlebotominae, a group of insects with great medical importance especially in Brazil, are responsible for transmitting causal agents of cutaneous and visceral leishmaniasis. In Brazil, the most important species of Leishmania Ross, 1903 are L. (Viannia) braziliensis Vianna, 1911, whose main vectors are Nyssomyia intermedia Lutz & Neiva, 1912, Ny. neivai Pin-to, 1926, Ny. whitmani Antunes & Coutinho, 1939 and Migonemyia migonei França, 1920; and L. (Leishmania) amazon-ensis Lainson & Shaw, 1972, for which Bichromomyia flaviscutellata Mangabeira, 1942 is the main vector. The present study sought to investigate the morphological as well as geometrical and linear morphometric characteristics of these five sand flies in an attempt to cluster these species. Our aim was to reveal some of the characters that might help identify these phlebotomine species and also be useful in future phylogenetic studies. Comparative analyses by linear and geometric morphometric characters allowed us to distinguish the genera of these sand flies and assess the taxonomic position of Ny. intermedia and Ny. neivai, the so-called "cryptic species". Significant differences were observed in several of the analyzed structures, including the centroid size of the wings and the ratio between the ejaculatory filament and its tip. Based on the linear morphometric analytical results, the size of the centroids of the wings and their shapes indicated that these three species of Nyssomyia are phenetically more similar to Mg. migonei (all vectors of L. (V.) braziliensis) than to Bi. flavis-cutellata (vector of L. (L.) amazonensis). These results are in agreement with the division of the genera Nyssomyia and Bichromomyia.