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Molecular Ecology Feb 2023Kissing bugs (Hempitera: Reduviidae) are obligately and exclusively blood feeding insects. Vertebrate blood is thought to provide insufficient B vitamins to insects,...
Using axenic and gnotobiotic insects to examine the role of different microbes on the development and reproduction of the kissing bug Rhodnius prolixus (Hemiptera: Reduviidae).
Kissing bugs (Hempitera: Reduviidae) are obligately and exclusively blood feeding insects. Vertebrate blood is thought to provide insufficient B vitamins to insects, which rely on symbiotic relationships with bacteria that provision these nutrients. Kissing bugs harbour environmentally acquired bacteria in their gut lumen, without which they are unable to develop to adulthood. Rhodococcus rhodnii was initially identified as the sole symbiont of Rhodnius prolixus, but modern studies of the kissing bug microbiome suggest that R. rhodnii is not always present or abundant in wild-caught individuals. We asked whether R. rhodnii or other bacteria alone could function as symbionts of R. prolixus. We produced insects with no bacteria (axenic) or with known microbiomes (gnotobiotic). Gnotobiotic insects harbouring R. rhodnii alone developed faster, had higher survival, and laid more eggs than those harbouring other bacterial monocultures, including other described symbionts of kissing bugs. R. rhodnii grew to high titre in the guts of R. prolixus while other tested species were found at much lower abundance. Rhodococcus species tested had nearly identical B vitamin biosynthesis genes, and dietary supplementation of B vitamins had a relatively minor effect on development and survival of gnotobiotic R. prolixus. Our results indicate that R. prolixus have a higher fitness when harbouring R. rhodnii than other bacteria tested, that this may be due to R. rhodnii existing at higher titres and providing more B vitamins to the host, and that symbiont B vitamin synthesis is probably a necessary but not sufficient function of gut bacteria in kissing bugs.
Topics: Humans; Animals; Rhodnius; Vitamin B Complex; Reproduction
PubMed: 36464913
DOI: 10.1111/mec.16800 -
Medical and Veterinary Entomology Mar 2018The behavioural and electrophysiological (electroantennography) responses of the first two instars of Triatoma dimidiata (Hemiptera: Reduviidae) Latreille to fresh and...
The behavioural and electrophysiological (electroantennography) responses of the first two instars of Triatoma dimidiata (Hemiptera: Reduviidae) Latreille to fresh and dry faecal headspace volatile extracts from fifth instar conspecific nymphs and synthetic compounds were analysed in this study. Recently emerged nymphs (3-5 days) aggregated around filter paper impregnated with dry faeces and around filter paper impregnated with extracts from both fresh and dry faeces. Older first instars (10-15 days) and second instars aggregated around filter paper impregnated with fresh and dry faeces, and their respective headspace extracts. Dry faecal volatile extracts elicited the strongest antennal responses, followed by fresh faecal extracts. Gas chromatography-mass spectrometry analysis of dried faecal headspace volatiles demonstrated the presence of 12 compounds: 2-ethyl-1-hexanol, 1,2,4-trimethylbenzene, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-tricosane, n-pentaeicosane, n-hexaeicosane, n-octaeicosane, nonanal, and 4-methyl quinazoline. In fresh faecal headspace extracts, only nonanal was clearly detected, although there were other trace compounds, including several unidentified sesquiterpenes. Four of the 11 compounds tested individually elicited aggregation behaviour at concentrations of 100 ng/µL and 1 µg/µL. A blend containing these four components also mediated the aggregation of nymphs. These volatiles may be valuable for developing monitoring methods and designing sensitive strategies to detect and measure T. dimidiata infestation.
Topics: Animals; Arthropod Antennae; Chemotaxis; Electrophysiological Phenomena; Feces; Nymph; Social Behavior; Triatoma; Volatile Organic Compounds
PubMed: 28892179
DOI: 10.1111/mve.12271 -
Journal of Medical Entomology Jan 2022In recent years, concerns about Chagas disease in the United States have increased. Triatomine bug (Hemiptera: Reduviidae) populations are the vectors of the parasite...
In recent years, concerns about Chagas disease in the United States have increased. Triatomine bug (Hemiptera: Reduviidae) populations are the vectors of the parasite Trypanosoma cruzi Chagas (Trypanosomatida: Trypanosomatidae), which causes Chagas disease, although the route of transmission is considered inefficient in United States. However, more studies on triatomine feeding and defecation behavior are needed. In this study, six related biological parameters from two populations of Triatoma protracta protracta (Uhler) and T. p. woodi (Uhler) from Mexican locations near the U.S. border were evaluated. The four population life cycles were less than 6 mo (161-171 d), with 9-10 blood meals needed to molt. Mortality rates were similar (31-38%) among the four populations. Triatoma p. woodi from Hidalgo, Coahuila was the most aggressive one. Feeding times were over 10 min, increasing with instar in all populations. Defecation behaviors varied among populations. High percentages of male and female fourth- and fifth-instar nymphs of T. p. protracta from Imuris and both populations of T. p. woodi defecated immediately after or <1 min of feeding. Lower percentages were observed for T. p. protracta from Jacumé. Because most parameters were similar among the four populations, independent of their subspecies and their geographic origin, we considered that T. p. protracta and T. p. woodi are efficient vectors of T. cruzi. In contrast, defecation patterns were noticeably different among some of the four triatomine populations studied. Our results highlight the importance of studying the biological parameters of local triatomine populations. They also contribute to increasing the knowledge of North American triatomine behavior and defecation patterns.
Topics: Animals; Chagas Disease; Female; Insect Vectors; Life History Traits; Male; Mexico; Nymph; Triatoma
PubMed: 34608490
DOI: 10.1093/jme/tjab158 -
Acta Tropica Nov 2015Chagas disease, the American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi (Kinetoplastida,...
Chagas disease, the American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi (Kinetoplastida, Trypanosomatidae) and transmitted by insects of the subfamily Triatominae (Hemiptera: Reduviidae). Here we provide an overview on the current knowledge about Triatominae ecology, its association with human, T. cruzi infection and the immediate consequences of habitat fragmentation. We also discuss the geographic distribution of the species and the importance of predicting their distributions to control programs.
Topics: Animal Distribution; Animals; Chagas Disease; Ecology; Ecosystem; Geography; Humans; Insect Vectors; North America; South America; Triatominae; Trypanosoma cruzi
PubMed: 26086951
DOI: 10.1016/j.actatropica.2015.06.006 -
Zootaxa Aug 2021Based on a re-examination of the type materials of all described species and additional non-type specimens, the genus Sphaeridops Amyot Serville, 1843 (Hemiptera:...
Based on a re-examination of the type materials of all described species and additional non-type specimens, the genus Sphaeridops Amyot Serville, 1843 (Hemiptera: Heteroptera: Reduviidae: Sphaeridopinae) is revised. Sphaeridops eulus Maldonado Santiago-Blay, 1992 is downgraded to a new synonym of S. amoenus (Lepeletier Serville, 1825); S. pallescens (Walker, 1873), erroneously treated as a junior synonym of S. amoenus by previous authors, is revalidated. A revised diagnosis and a redescription of the genus and its included species are given, all species are illustrated, and an updated key to the species of Sphaeridops is presented.
Topics: Animal Distribution; Animals; Hemiptera; Heteroptera; Reduviidae
PubMed: 34810989
DOI: 10.11646/zootaxa.5020.3.5 -
Infection, Genetics and Evolution :... Dec 2018The chemical control of Triatoma infestans, the major Chagas disease vector in southern South America, has been threatened in the last years by the emergence of... (Review)
Review
The chemical control of Triatoma infestans, the major Chagas disease vector in southern South America, has been threatened in the last years by the emergence of pyrethroid-resistant bug populations. As an alternative approach, the efficacy of the entomopathogenic fungus Beauveria bassiana to control T. infestans populations (regardless their pyrethroid susceptibility) has been demonstrated. Growing research efforts on the interaction between T. infestans and B. bassiana by molecular, ecological, biochemical and behavioral traits has allowed framing such interaction as an evolutionary arms race. This review will focus on the relationships established in this particular host-pathogen system, compiling available data on the relevance of fungal pathogenesis, insect behavior, population dynamics and human intervention to favor fungal dissemination in bug populations. The current snapshot shows the fungus ahead in the evolutionary arms race and predicts a promissory landscape for the biological control of Chagas disease vectors.
Topics: Animals; Beauveria; Biological Control Agents; Biological Evolution; Chagas Disease; Host-Pathogen Interactions; Humans; Insect Vectors; Insecticide Resistance; Insecticides; Quantitative Trait, Heritable; Triatoma
PubMed: 29496575
DOI: 10.1016/j.meegid.2018.02.032 -
Revista Da Sociedade Brasileira de... 2022After decentralizing the actions of the Chagas Disease Control Program (CDCP) in Brazil, municipalities were now responsible for control measures against this endemic,...
BACKGROUND
After decentralizing the actions of the Chagas Disease Control Program (CDCP) in Brazil, municipalities were now responsible for control measures against this endemic, supervised by the Regional Health Superintendencies (RHS). We aimed to evaluate the recent entomological surveillance of Chagas disease in the Regional Health Superintendence of Governador Valadares (RHS/GV) from 2014 to 2019.
METHODS
Triatomines captured by residents during entomological surveillance were sent to the reference laboratory, where the species and evolutionary stages were identified, place of capture, and presence of Trypanosoma cruzi. A database was created, and the following were calculated: the rate of infection by T. cruzi (overall rate and rate by species), monthly seasonality, spatial distribution of species, number of captures, and infected triatomines/health microregions.
RESULTS
We identified 1,708 insects; 1,506 (88.2%) were triatomines, most were adult instars (n=1,469), and few were nymphs (n=37). The identified species were Triatoma vitticeps, Panstrongylus megistus, Panstrongylus diasi, Rhodnius neglectus, and Panstrongylus geniculatus. The first three were most frequently captured and distributed throughout the study area. Most bugs were captured intradomicile (72.5%), mainly in the second semester, between September and November, with an average infection rate of 41.5% (predominantly T. vitticeps, 49.2%). All municipalities sent triatomines, especially in the microregions of Governador Valadares.
CONCLUSIONS
These data reinforce the need and importance of improving Chagas disease control measures in the region to establish active and participatory entomological surveillance.
Topics: Animals; Brazil; Chagas Disease; Humans; Insect Vectors; Panstrongylus; Triatoma; Trypanosoma cruzi
PubMed: 36134858
DOI: 10.1590/0037-8682-0065-2022 -
Medical and Veterinary Entomology Mar 2023Triatomines display most of their activities during the night. Before sunrise, they search, select and occupy adequate shelters to stay during the photophase, avoiding...
Triatomines display most of their activities during the night. Before sunrise, they search, select and occupy adequate shelters to stay during the photophase, avoiding exposure to diurnal predators. In this work, we first explored the interactions between individuals of the same or different species in the shelter selection process of Triatoma infestans (Klug 1834) and Rhodnius prolixus (Stål 1859). When two groups of insects (either of different nutritional status, nymphal instar or species) were released together over an experimental arena containing two identical shelters, all nymphs were distributed randomly, suggesting the absence of intra- and inters-pecific interactions. Secondly, we analysed their preferences for particular features of shelters by releasing one group of insects (either T. infestans or R. prolixus) over an arena containing two different refuges. Nymphs exhibited preferences for darker shelters with a vertical orientation of its substrate and elevated from the ground, highlighting the importance of such features in a shelter selection context. We conclude that these species disregard the presence of other individuals but evaluate certain characteristics of the shelters to choose them. This information may contribute to understanding the colonization/recolonization dynamic processes of these Chagas disease vectors.
Topics: Animals; Triatoma; Rhodnius; Chagas Disease; Nymph
PubMed: 36082811
DOI: 10.1111/mve.12610 -
Zootaxa May 2017Six heteropteran species are reported for the first time from Illinois based on recently caught specimens from various bioinventories: the flat bug Neuroctenus...
Six heteropteran species are reported for the first time from Illinois based on recently caught specimens from various bioinventories: the flat bug Neuroctenus pseudonymus Bergroth (Aradidae: Mezirinae), the stilt bug Metacanthus multispinus (Ashmead) (Berytidae: Metacanthinae), the leaf-footed bugs Anasa repetita Heidemann and Chelinidea vittiger Uhler (Coreidae: Coreinae), the ambush bug Phymata fasciata fasciata (Gray) (Reduviidae: Phymatinae), and the scentless plant bug Arhyssus nigristernum (Signoret) (Rhopalidae: Rhopalinae). Additionally, three more records for the flat bug Nannium pusio Heidemann (Aradidae) and the scentless plant bugs Aufeius impressicollis Stål and Niesthrea louisianica Sailer (Rhopalidae) are newly-reported for the state based on material in the Illinois Natural History Insect Collection (INHS). Supplementing these notes are dichotomous keys to the species of Mezirinae, Berytidae, Coreidae, Phymatinae, and Rhopalidae of Illinois.
Topics: Animals; Heteroptera; Illinois; Reduviidae
PubMed: 28610319
DOI: 10.11646/zootaxa.4269.4.10 -
Journal of Vector Ecology : Journal of... Jun 2019Chagas disease is one of the main vector-borne diseases in Latin America, including Mexico. Understanding the biological parameters of the triatomine species is a...
Chagas disease is one of the main vector-borne diseases in Latin America, including Mexico. Understanding the biological parameters of the triatomine species is a crucial first step in estimating the epidemiologic importance of each group. The aim of this study was to compare the biological fitness of Meccus pallidipennis (Stål), M. bassolsae (Alejandre, Nogueda, Cortez, Jurberg, Galvão, Carcavallo) (Hemiptera: Reduviidae: Triatominae) and their laboratory hybrids, by estimating six biological parameters in order to increase the knowledge of the potential role of triatomine hybrids in the transmission of Trypanosoma cruzi to reservoir hosts. Biological parameters related to lifespan, number of blood meals to molt, mortality for each instar, percentage of females at the end of the cycle, number of eggs laid, and hatching of eggs in four cohorts of 100 specimens of M. pallidipennis, M. bassolsae, and their laboratory hybrids were evaluated and compared. In four of the six studied parameters (accumulative mortality, the percentage of females, mean number of laid eggs, and egg hatching), the hybrid cohorts had better fitness results than the parental cohorts. The increase in hybrid fitness found in our study could lead to an increase in the epidemiologic risks caused by transmission of T. cruzi to humans.
Topics: Animals; Female; Genetic Fitness; Hybridization, Genetic; Male; Triatominae
PubMed: 31124236
DOI: 10.1111/jvec.12341