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Journal of Insect Physiology 2017
Topics: Animals; Genome, Insect; Rhodnius
PubMed: 28254111
DOI: 10.1016/j.jinsphys.2017.02.005 -
Journal of Medical Entomology Jun 2019Spermatozoa are among the most diverse cell types, and their morphologies often provide data that can be used to reliably evaluate phylogenetic relationships. They can...
Spermatozoa are among the most diverse cell types, and their morphologies often provide data that can be used to reliably evaluate phylogenetic relationships. They can also help to clarify the nature of 'specific complexes', which are common among triatomines. In the present study, we evaluated the copulation behavior of Triatoma rubrovaria Blanchard 1843 (Hemiptera: Reduviidae: Triatominae) and the structural morphology of sperm from T. carcavalloi Jurberg Rocha & Lent, 1998, T. infestans Klug, 1834, T. pintodiasi Jurberg Cunha & Rocha, 2013, and T. rubrovaria. Copulatory behavior was described from the moment males and females genitalia joined until they separated. Insemination was confirmed by the presence of a spermatophore in the female's bursa copulatrix. To measure their sperm, males were dissected and their seminal vesicles were removed, squashed on glass slides, and then spread, fixed, and observed under a photomicroscope. The images obtained were analyzed to measure the sperm. Seminal vesicles were also prepared for transmission electron microscopy. We performed K-means clustering separately for each species to group their sperm based on morphology. The differences in spermatozoa length among species of Triatominae, sperm types, and the interaction between species and sperm type were assessed with a two-way analysis of variance (ANOVA). The copulation time in T. rubrovaria was 3 to 5 min, which was sufficiently long for spermatophore transfer. All taxa showed polymorphic (short and long) sperm, with significant differences in the lengths of sperm among taxa. Using electron microscopy, the sperm cells of the four taxa examined were found to have similar ultrastructural morphology, confirming the hypothesized synapomorphies of sperm within the suborder Heteroptera (Hemiptera).
Topics: Animals; Copulation; Female; Male; Spermatozoa; Triatoma
PubMed: 30801646
DOI: 10.1093/jme/tjz017 -
The Journal of Experimental Biology May 2019Given that hematophagous insects ingest large quantities of blood in a single meal, they must undergo a rapid post-prandial diuresis in order to maintain homeostasis. In...
Given that hematophagous insects ingest large quantities of blood in a single meal, they must undergo a rapid post-prandial diuresis in order to maintain homeostasis. In the kissing bug (Hemiptera: Reduviidae), the coordinated activity of the Malpighian tubules and anterior midgut maintains water and ion balance during the post-prandial diuresis. Three to four hours after the meal, the diuretic process finishes, and the animal enters an antidiuretic state to ensure water conservation until the next blood intake. The diuretic and antidiuretic processes are tightly regulated by serotonin and neuropeptides in this insect. In the present work, we report that the neuropeptide precursor CCHamide2 is involved in the regulation of the post-prandial diuresis in Our results suggest a dual effect of RhoprCCHamide2 peptide, enhancing the serotonin-induced secretion by Malpighian tubules, and inhibiting serotonin-induced absorption across the anterior midgut. To our knowledge, this is the first report of a hormone presenting opposite effects in the two osmoregulatory organs (i.e. midgut and Malpighian tubules) in insects, probably reflecting the importance of a well-tuned diuretic process in hematophagous insects during different moments after the blood meal.
Topics: Animals; Chagas Disease; Diuresis; Insect Proteins; Insect Vectors; Malpighian Tubules; Neuropeptides; Rhodnius
PubMed: 31053646
DOI: 10.1242/jeb.203000 -
Infection, Genetics and Evolution :... Mar 2022Even when an animal has a generalist diet, different food sources can impact its body shape and fluctuating asymmetry (a stress indicator; FA). To test this, we varied...
Even when an animal has a generalist diet, different food sources can impact its body shape and fluctuating asymmetry (a stress indicator; FA). To test this, we varied the food source (mammalian, avian or defibrinated mammalian blood; and control animals - ad libitum feeding) and the time of feeding (every 8 days, 45 days and ad libitum) having the Chagas triatomine vector, Triatoma pallidipennis (Stål, 1892), as a study animal which has presumable generalist feeding habits. This factorial design was applied since first instar animals until adulthood. As response variables, we measured body shape and FA in adults of both sexes, using a two-dimensional geometric morphometrics protocol. The highest variance in body shape was explained by diet (17%), followed by sex nested within diet (12%). Males had less morphological differentiation than females: females with defibrinated blood provided every 45 days differentiated more, while those that fed on mammalian blood every 8 days differed less. Distances among the averages of the FA component related to shape indicated greater distances between avian blood provided every 45 days and mammalian blood provided every 8 days, as well as between the two groups fed on avian blood (feeding every 8 and 45 days), followed by avian and defibrinated blood, both fed every 8 days. These results indicate that blood source and feeding time have significant effects on the body shape, and FA in females and both sexes. Thus, despite general feeding habits, avian blood showed a greater impact on shape and FA in triatomines. This may select for triatomines to use mammal blood rather than avian blood if they have the chance to do so.
Topics: Animals; Diet; Feeding Behavior; Female; Male; Nymph; Somatotypes; Time Factors; Triatoma
PubMed: 34974200
DOI: 10.1016/j.meegid.2021.105199 -
Medical and Veterinary Entomology Dec 2022Exposure to sublethal doses of insecticide may affect biological traits in triatomines. We investigated the effects of toxicological phenotype (pyrethroid resistance...
Exposure to sublethal doses of insecticide may affect biological traits in triatomines. We investigated the effects of toxicological phenotype (pyrethroid resistance status) and exposure to sublethal doses of deltamethrin on two traits of Triatoma infestans Klug (Heteroptera: Reduviidae) using a phenotypic plasticity experimental design. First-instar nymphs from 14 and 10 full-sib families from pyrethroid-susceptible and pyrethroid-resistant populations, respectively, were used. For the susceptible population, we treated first instars topically with acetone (control) or deltamethrin (treatment) once. For the resistant population, instars were treated once, twice and three times as first, third or fifth-instar nymphs, respectively. We measured cuticle thickness, wing size and wing shape of 484 emerging adults, and tested for treatment effects using mixed ANOVA and MANOVA models. Toxicological phenotype, exposure to deltamethrin and full-sib family exerted significant effects on cuticle thickness, wing size and wing shape. Adult triatomines previously treated with deltamethrin developed significantly thicker cuticles than control triatomines only in the resistant population and significantly bigger wings in both populations. Mean cuticle thickness and wing size increased with increasing exposures to deltamethrin. Exposure to sublethal doses of deltamethrin generated morphological modifications that may affect insect survival and flight dispersal, and hence may have evolutionary and epidemiological consequences.
Topics: Animals; Triatoma; Insecticides; Insecticide Resistance; Pyrethrins; Nitriles; Nymph; Insect Vectors
PubMed: 35946595
DOI: 10.1111/mve.12600 -
Journal of Vector Ecology : Journal of... Dec 2023Triatominae are associated with various Brazilian habitats, including bird nests, animal burrows, and peridomestic structures. Despite extensive studies on triatomines...
Triatominae are associated with various Brazilian habitats, including bird nests, animal burrows, and peridomestic structures. Despite extensive studies on triatomines in domiciliary environments in Ceará, Brazil, there has been limited research on their presence in the wild. This study focuses on the municipality of Morrinhos in Ceará, which is characterized by a Caatinga biome and riparian forests along the Acaraú River. During the study, a total of 185 nests of were analyzed in rural locations and triatomines were collected in 26 nests from 12 different locations. A total of 117 triatomines was collected, belonging to three species: , , and . was the only species found in a nest inhabited by . Nests of serve as shelters for various animals, providing an ideal environment for triatomines to establish colonies due to their proximity to food sources and their generalist feeding habits. The incorporation of anthropogenic materials by birds in nest construction can indirectly affect the presence of other animals that may serve as food sources for triatomines. Understanding the interactions between triatomines, birds, and their habitats is essential for assessing the risks associated with triatomine infestation in wild ecosystems.
Topics: Animals; Triatominae; Brazil; Ecosystem; Insect Vectors; Triatoma; Rhodnius; Birds; Chagas Disease; Trypanosoma cruzi
PubMed: 37843454
DOI: 10.52707/1081-1710-48.2.124 -
Memorias Do Instituto Oswaldo Cruz 2022Panstrongylus rufotuberculatus (Hemiptera-Reduviidae) is a triatomine species with a wide geographic distribution and a broad phenotypic variability. In some countries,...
BACKGROUND
Panstrongylus rufotuberculatus (Hemiptera-Reduviidae) is a triatomine species with a wide geographic distribution and a broad phenotypic variability. In some countries, this species is found infesting and colonising domiciliary ecotopes representing an epidemiological risk factor as a vector of Trypanosoma cruzi, etiological agent of Chagas disease. In spite of this, little is known about P. rufotuberculatus genetic diversity.
METHODS
Cytogenetic studies and DNA sequence analyses of one nuclear (ITS-2) and two mitochondrial DNA sequences (cyt b and coI) were carried out in P. rufotuberculatus individuals collected in Bolivia, Colombia, Ecuador and Mexico. Moreover, a geometric morphometrics study was applied to Bolivian, Colombian, Ecuadorian and French Guiana samples.
OBJECTIVES
To explore the genetic and phenetic diversity of P. rufotuberculatus from different countries, combining chromosomal studies, DNA sequence analyses and geometric morphometric comparisons.
FINDINGS
We found two chromosomal groups differentiated by the number of X chromosomes and the chromosomal position of the ribosomal DNA clusters. In concordance, two main morphometric profiles were detected, clearly separating the Bolivian sample from the other ones. Phylogenetic DNA analyses showed that both chromosomal groups were closely related to each other and clearly separated from the remaining Panstrongylus species. High nucleotide divergence of cyt b and coI fragments were observed among P. rufotuberculatus samples from Bolivia, Colombia, Ecuador and Mexico (Kimura 2-parameter distances higher than 9%).
MAIN CONCLUSIONS
Chromosomal and molecular analyses supported that the two chromosomal groups could represent different closely related species. We propose that Bolivian individuals constitute a new Panstrongylus species, being necessary a detailed morphological study for its formal description. The clear morphometric discrimination based on the wing venation pattern suggests such morphological description might be conclusive.
Topics: Animals; Chagas Disease; Heteroptera; Humans; Insect Vectors; Panstrongylus; Phylogeny; Triatoma
PubMed: 35137904
DOI: 10.1590/0074-02760210259 -
PloS One 2020Triatomines (Hemiptera: Reduviidae) are the insect vectors of Trypanosoma cruzi, the causative agent of Chagas disease. The gut bacterial communities affect the...
Triatomines (Hemiptera: Reduviidae) are the insect vectors of Trypanosoma cruzi, the causative agent of Chagas disease. The gut bacterial communities affect the development of T. cruzi inside the vector, making the characterization of its composition important in the understanding of infection development. We collected 54 triatomine bugs corresponding to four genera in different departments of Colombia. DNA extraction and PCR were performed to evaluate T. cruzi presence and to determine the discrete typing unit (DTU) of the parasite. PCR products of the bacterial 16S rRNA gene were pooled and sequenced. Resulting reads were denoised and QIIME 2 was used for the identification of amplicon sequence variants (ASVs). Diversity (alpha and beta diversity) and richness analyses, Circos plots, and principal component analysis (PCA) were also performed. The overall T. cruzi infection frequency was 75.9%, with TcI being the predominant DTU. Approximately 500,000 sequences were analyzed and 27 bacterial phyla were identified. The most abundant phyla were Proteobacteria (33.9%), Actinobacteria (32.4%), Firmicutes (19.6%), and Bacteroidetes (7.6%), which together accounted for over 90% of the gut communities identified in this study. Genera were identified for these main bacterial phyla, revealing the presence of important bacteria such as Rhodococcus, Serratia, and Wolbachia. The composition of bacterial phyla in the gut of the insects was significantly different between triatomine species, whereas no significant difference was seen between the state of T. cruzi infection. We suggest further investigation with the evaluation of additional variables and a larger sample size. To our knowledge, this study is the first characterization of the gut bacterial structure of the main triatomine genera in Colombia.
Topics: Animals; Biodiversity; Chagas Disease; Colombia; DNA, Bacterial; DNA, Protozoan; Gastrointestinal Microbiome; Genotype; Host Specificity; Humans; Insect Vectors; RNA, Ribosomal, 16S; Triatominae; Trypanosoma cruzi
PubMed: 33180772
DOI: 10.1371/journal.pone.0240916 -
Journal of Medical Entomology Jan 2022Chagas disease is caused by the infection of the parasite Trypanosoma cruzi (Chagas, 1909). Mexico is estimated to be among the countries with the highest rates of human...
Chagas disease is caused by the infection of the parasite Trypanosoma cruzi (Chagas, 1909). Mexico is estimated to be among the countries with the highest rates of human infections. The southernmost region of the Baja California peninsula is home to the endemic, highly aggressive, and largest Triatominae vector, thus far described: Dipetalogaster maxima (Uhler 1894). Previous single-year studies have attempted to estimate the natural infection rate of T. cruzi in this species, none encompassing a multiyear sampling design nor a species-specific diagnostic tool. We report the infection rate based on more than 717 individuals examined via a PCR species-specific diagnosis. The infection rate of T. cruzi was of 4.4% (n = 5/112), 0.9% (n = 4/411), and 4.6% (n = 9/194) for 2016, 2017, and 2018, respectively, resulting in an infection rate of 2% across all sites and years (n = 18/717).
Topics: Animals; Chagas Disease; Humans; Insect Vectors; Mexico; Prevalence; Reduviidae; Triatoma; Trypanosoma cruzi; Vector Borne Diseases
PubMed: 34448006
DOI: 10.1093/jme/tjab147 -
Revista Do Instituto de Medicina... 2023Triatoma rubrovaria has been captured in some areas of Rio Grande do Sul State (RS), Brazil, as this species can be found in the Pampa biome. Its distribution across...
Triatoma rubrovaria has been captured in some areas of Rio Grande do Sul State (RS), Brazil, as this species can be found in the Pampa biome. Its distribution across this biome should be described in detail to verify the potential of this vector to transmit Trypanosoma cruzi. This study aimed to investigate the occurrence of T. rubrovaria in the Pampa biome and transitional areas of RS. The collected information resulted from the analysis of secondary data provided by the Centro Estadual de Vigilancia em Saude (CEVS - State's Center of Health Surveillance). The following aspects were taken into consideration: the year in which the insect was captured, the city, the number of specimens captured, invasion or domiciliation, the notification in the household, surroundings or both, and T. cruzi infection. The data comprised the period from 2009 to 2020, in 109 cities located in the Pampa biome and 98 located in transitional areas. The Pampa biome exhibited 85% of the occurrences of T. rubrovaria, while 1.2% of specimens were T. cruzi-like positive. Both the first and second biennia concentrated 64.6% of captures. Alegrete city, Cangucu city and Piratini city were the locations in the Pampa where the largest numbers of specimens were found. Regarding the transitional areas, Roque Gonzales city, Santiago city and Santana da Boa Vista city exhibited the largest numbers. Most insects were adults, which were found in households. Even though positivity for T. cruzi-like was low, the species still has epidemiological importance in the region.
Topics: Animals; Triatoma; Triatominae; Retrospective Studies; Brazil; Insect Vectors; Chagas Disease; Trypanosoma cruzi; Ecosystem
PubMed: 37283413
DOI: 10.1590/S1678-9946202365038