Orientation of Belminus triatomines to cockroaches and cockroaches’ fecal volatiles: an ethological approach

Most triatomine bugs (Hemiptera: Reduviidae: Triatominae) are hematophagous, though Belminus species can live off of cockroach hemolymph to complete their life cycle. In this work we described the fixed action pattern (FAP) employed by B. ferroae to identify, approach and suck on a living cockroach. The FAP described here is composed of the following stereotyped behaviors: 1) visual and/or olfactory detection of the cockroach, 2) reaching, 3) cautious approach, 4) antennal exploration, 5) extension of the proboscis, 3) piercing to sedate, 5) walking  away and waiting (post sedation behavior), 6) second cautious approach, 7) extension of the proboscis, 8) piercing to suck hemolymph. In order to identify chemicals cues that could elicit such FAP, we examined the behavior of B. corredori, B. ferroae and B. herreri in response to the cockroaches’ odor, fresh cockroach feces and fresh rodent wastes. The last two sources were tested based on the assumption that abundant chemicals near host refuges could serve as cues for host orientation. We found the cockroach odor emanating from a box significantly attracted B. herreri in a still air olfactometer. The three Belminus species approached the captive cockroach after one hour, but avoided to climb the box. Odors emanating from the cockroach feces attracted B. corredori and B. ferroae in a Y-olfactometer. The FAP sequence observed suggests Belminus bugs are not predators like the rest of reduviids (assassin bugs) —but are kleptophagous ectoparasites, since they do not attack and kill a prey but rather steal hemolymph from its invertebrate host. Triatomines and their hosts have intimately shared the same refuge for millions of years. Similar odors occur across invertebrate and vertebrate refuges, and are recurrent in human abodes, thus plausibly explaining how these kleptophagous bugs can readily switch to the domestic habitat

Especies de género Lutzomyia (Psychodidae, Phlebotominae) en áreas de transmisión de leishmaniasis tegumentaria y visceral en el departamento de Santander, en la cordillera oriental de los Andes colombianos

Introduction. Phlebotomine sand flies are the only known vectors of leishmaniasis and show an interesting biodiversity in the Andean mountain range of South America. We update the registry of species prevalent in the municipalities and endemic areas of the department of Santander, in the eastern range of the Colombian Andes.Objective. To present an updated inventory and distribution of the Lutzomyia species in the department of Santander and to discuss some ecological aspects of the principal species of medical importance.Materials and methods. Phlebotomines were collected in 12 municipalities in the years 1998 to 2001 between 19:00-6:00 using CDC miniature light traps, manual aspirators on protected human baits between 18:00 and 20:00, and occasionally by direct aspiration on tree trunks between 8:00-11:00 and resting on walls at different times of the day.Results. 3.972 phlebotomines of 41 species were captured, of which 16 species were new records for this area of the country. In zones of endemic American cutaneous leishmaniasis, L. gomezi, L. trapidoi, L. panamensis, L. ovallesi and L.yuilli were remarkable for their abundance, their presence within dwellings and their epidemiological relevance. In areas of visceral leishmaniasis, the most relevant species was L. longipalpis.Conclusion. The significant presence of vectors within human dwellings and the prevalence of human infection are continuing evidence of household transmission of Leishmania as an important public health problem in this department of Colombia.Introducción. Los flebótomos desde el punto de vista de salud pública son especialmente conocidos como los únicos insectos vectores de las leishmaniasis y demuestran una interesante biodiversidad en algunas zonas como la cordillera de los Andes en Suramérica. Este estudio presenta las especies de flebótomos organizadas por municipios y zonas endémicas que pueden encontrarse en el departamento de Santander, ubicado sobre la cordillera oriental andina en Colombia.Objetivo. Presentar una actualización del inventario de las especies del género Lutzomyia en el departamento de Santander,señalar la distribución y discutir algunos aspectos de la ecología de las especies de mayor importancia en salud pública.Materiales y métodos. Durante 1998 a 2001 en 12 municipios se realizaron capturas de flebótomos utilizando trampas de luz tipo CDC miniatura, entre las 19:00-6:00 horas, también capturas con cebo humano protegido utilizando aspiradores manuales entre las 18:00-20:00 horas, ocasionalmente aspiración directa sobre troncos de árboles entre las 8:00-11:00 horas y capturas de flebótomos en reposo sobre las paredes en horario diurno.Resultados. Se capturaron un total de 3.972 flebótomos distribuidos en 41 especies; de éstas, 16 especies son nuevos registros para esta región del país. En las zonas consideradas endémicas para leishmaniasis tegumentaria americana se destacaron por su abundancia, presencia en el intradomicilio e importancia epidemiológica L. gomezi, L. trapidoi, L. panamensis, L. ovallesi y L. yuilli yuilli. En las zonas de leishmaniasis visceral americana predominó L. longipalpis

Descripción de setas cuticulares externas de cabeza, tórax, patas, abdomen y genitales en cuatro especies de Triatominae

Introduction: The classification of the cuticular extensions of insects has been proposed as a taxonomic tool; however, the internal and external processes of the cuticular extensions of the Triatominae subfamily have not been fully analyzed and categorized. Objective: To describe the setae from different regions of the outer cuticle of several triatomine species by scanning electron microscopy. Materials and methods: Triatomines were washed and dried, after which different regions of the body from Eratyrus mucronatus, Triatoma maculata, Panstrongylus geniculatus and Belminus ferroae specimens were dissected, mounted on graphite double-sided adhesive tape over metal supports, metalized with gold and micrographed for further analysis. Results: We described nine types of cuticular setae. We found five types of setae in B. ferroae and T. maculata, four in P. geniculatus and only one in E. mucronatus. According to the proposed typology, type 3 seta was the most common in T. maculata, P. geniculatus and E. mucronatus, whereas type 1a predominated in B. ferroae. Conclusion: Type 3 seta was the most common in the Triatomini tribe (T. maculata, E mucronatus and P. geniculatus), whereas type 1a seta was specific to B. ferroae (tribe Bolboderini), suggesting that the surface morphology of the setae may have taxonomic value at tribe taxonomic level.Introducción. Se han propuesto clasificaciones de las extensiones cuticulares de los insectos para utilizarlas como herramienta taxonómica. A pesar de los diversos estudios morfológicos adelantados en triatominos, el conocimiento que se tiene sobre la distribución y los tipos morfológicos de estas estructuras en la subfamilia aún es escaso y fragmentario. Objetivo. Describir las setas de diferentes regiones de la cutícula externa de varias especies de triatominos mediante microscopía electrónica de barrido. Materiales y métodos. Se lavaron y se secaron especímenes de Eratyrus mucronatus, Triatoma maculata, Panstrongylus geniculatus y Belminus ferroae, y a continuación se disecaron diferentes regiones de sus cuerpos y se montaron sobre cinta adhesiva de grafito de doble faz en soportes metálicos. Se metalizaron con oro y se tomaron las micrografías para su posterior análisis. Resultados. Se describieron nueve tipos de setas cuticulares. En B. ferroae y T. maculata se encontraron cinco tipos de setas, en P. geniculatus, cuatro, y en E. mucronatus, un solo tipo. Según la tipología propuesta, la seta de tipo 3 fue la más común en cada especie, excepto en B. ferroae, en la cual predominó la seta de tipo 1a. Conclusión. La seta más común en las especies de la tribu Triatomini (T. maculata, E. mucronatus y P. geniculatus) fue la de tipo 3; la seta de tipo 1a fue específica para la especie B. ferroae, taxón de la tribu Bolboderini, lo cual permite suponer que la morfología superficial de las setas podría tener valor taxonómico a nivel de tribu

The sandfly fauna, anthropophily and the seasonal activities of Pintomyia spinicrassa (Diptera: Psychodidae: Phlebotominae) in a focus of cutaneous leishmaniasis in northeastern Colombia

This study was conducted to identify the sandfly fauna and the anthropophilic species in a coffee-growing area of Villanueva, Norte de Santander, Colombia, a focus of American cutaneous leishmaniasis, and to analyse the relationship between the most frequent species and rainfall, relative humidity and temperature, with the aim of contributing to epidemiological surveillance in the area. Sandfly collections were performed fortnightly between February 2006-September 2007 using automatic light traps, Shannon traps, protected human bait and aspiration in resting places. A total of 7,051 sandflies belonging to 12 species were captured. Pintomyia spinicrassa (95.7%) predominated. Pintomyia oresbia and Lutzomyia sp. of Pichinde were found in the state of Norte de Santander for the first time. Pi. spinicrassa, Pintomyia nuneztovari, Micropygomyia venezuelensis, Lutzomyia (Helcocyrtomyia) scorzai and Lu. (Helcocyrtomyia) sp. were captured on the protected human bait. A significant association between Pi. spinicrassa abundance and the total rainfall and the average temperature and humidity 10 days before the collection was observed. The dominance of Pi. spinicrassa, a recognised vector of Leishmania braziliensis, especially during the dry periods, indicates that the risk of parasite transmission may increase.Instituto de Física de Líquidos y Sistemas Biológico

Metaciclogénesis de Trypanosoma cruzi en Belminus ferroae (Reduviidae: Triatominae) y capacidad infectiva de las heces en condiciones de laboratorio

Introduction: Belminus ferroae is a triatominae with entomophagous behavior. However, it may occasionally feed on vertebrates. Currently, there is no evidence of natural infection with Trypanosoma cruzi or the occurrence of metacyclogenesis in this species.Objective: To test T. cruzi metacyclogenesis in B. ferroae and the infectivity of their feces or intestinal contents in rodents under laboratory conditions.Materials and methods: Twenty nymphs of B. ferroae were infected with an autochthonous strain of T. cruzi (M/HOM/VE/09/P6). Fecal and urine samples were collected from spontaneous droppings or by compressing the bugs’ abdomens and, eventually, by removing their gut contents, and then examined at 10, 20, 30, 40, 50, and 60 days. We quantified T. cruzi parasitic load, as well as the evolutionary forms in feces, urine, and intestinal contents by Giemsa staining. Similarly, we evaluated the infectivity of T. cruzi metacyclic trypomastigotes in albino mice.Results: The parasitological analysis showed three insects (15%) infected with T. cruzi at 30 (n=1), 40 (n=1), and 50 (n=1) days post-infection. We observed parasitic loads of up to 1.62 x 105 trypanosomes/mm3 and metacyclogenesis percentages between 3.5% and 6.78%.Conclusions: This is the first time that T. cruzi metacyclogenesis is reported in a species of the genus Belminus under laboratory conditions and the infectivity of Belminus’ feces is demonstrated on a vertebrate host.Introducción. Belminus ferroae es un triatomino de comportamiento entomófago, sin embargo, puede alimentarse de vertebrados ocasionalmente. No se ha demostrado infección natural por Trypanosoma cruzi en esta especie, como tampoco la metaciclogénesis del parásito.Objetivo. Examinar la metaciclogénesis de T. cruzi en B. ferroae y la capacidad infectiva de las heces o sus contenidos intestinales en roedores.Materiales y métodos. Se analizaron las heces y la orina expulsadas espontáneamente por los insectos o mediante compresión abdominal o extracción del contenido intestinal a los 10, 20, 30, 40, 50 y 60 días. Se cuantificó la carga parasitaria de T. cruzi y sus formas evolutivas se identificaron con tinción de Giemsa. Asimismo, se evaluó en ratones albinos la apacidad infectiva de los tripomastigotes metacíclicos de T. cruzi obtenidos de las heces o contenidos intestinales de los especímenes infectados.Resultados. El análisis parasitológico reveló tres (15 %) insectos infectados con T. cruzi a los 30 (n=1), 40 (n=1) y 50 (n=1) días después de la infección con cargas parasitarias de hasta 1,62 x 105 tripanosomas/mm3 y porcentajes de metaciclogénesis entre el 3,5 y el 6,78 %. Conclusiones. Se demuestra por primera vez, en una especie del género Belminus, la metaciclogenésis de T. cruzi en condiciones de laboratorio y la capacidad infectiva de las heces para un huésped vertebrado

Invasión urbana de flebotomineo transmisores de Leishmania en Mérida, Venezuela

Urban development together with uncontrolled construction in endemic areas of leishmaniasis has resulted in a series of environmental transformations that have promoted the spread of cutaneous leishmaniasis, with the adaptation sandflies transmitters to these urban environments. This study aims to determine the presence of sandflies and the epidemiological factors associated with the transmission of leishmaniasis in an urban area of Zea, Venezuela. Five methods of catching sandflies were used indoors in two urbanizations in Zea, Venezuela. Through a survey-type instrument, the epidemiological variables associated with the transmission of leishmaniasis in the housing estates were determined. The presence in the urban dwellings of Lutzomyia youngi, Lutzomyia spinicrassa, Lutzomyia migonei, Lutzomyia ovallesi, Lutzomyia walkeri, Lutzomyia venezuelensis, Lutzomyia atroclavata and Lutzomyia lichyi were demonstrated. 62.5% of the species caught in urbanized areas have antropohematophagy habits. A 67% and 80% of infestation was determined in the dwellings of the studied urbanizations. It was evidenced a low level of knowledge in the inhabitants mainly on the sandflies, which increases the risk of domiciliation and transmission of leishmaniasis, the control entities are warned to implement preventive and educational measures. El desarrollo urbano ha causado una serie de transformaciones ambientales, que ha promovido la propagación de la leishmaniasis con la adaptación de los flebotomíneos transmisores. Este estudio tiene como objetivo determinar la presencia de flebotomíneos y evaluar factores epidemiológicos asociados a la transmisión de leishmaniasis en una zona urbana de Zea, Venezuela.  Se emplearon cinco métodos  de captura de  flebotomíneo en el interior de las viviendas en dos urbanizaciones en Zea, Venezuela. A través de un instrumento tipo encuestas, se determinaron las variables epidemiológicas asociadas a la transmisión de la leishmaniasis. Se demostró la presencia en el interior de la viviendas urbanas de Lutzomyia youngi, Lutzomyia spinicrassa, Lutzomyia migonei, Lutzomyia ovallesi, Lutzomyia walkeri, Lutzomyia venezuelensis,  Lutzomyia atroclavata  y Lutzomyia lichyi. El 62,5% de las especies capturadas en las áreas urbanizadas poseen hábitos de antropohematofagia. Se determinó un 67 % y 80% de infestación en las viviendas de las  urbanizaciones estudiadas. Se evidenció un bajo nivel de conocimiento en los pobladores principalmente sobre los flebotomíneos, lo cual incrementa el riesgo de domiciliación y  transmisión de la leishmaniasis. Se alerta a los entes encargados del control de dicha enfermedad a implementar las medidas preventivas y de educación necesaria

The sandfly fauna, anthropophily and the seasonal activities of Pintomyia spinicrassa (Diptera: Psychodidae: Phlebotominae) in a focus of cutaneous leishmaniasis in northeastern Colombia

This study was conducted to identify the sandfly fauna and the anthropophilic species in a coffee-growing area of Villanueva, Norte de Santander, Colombia, a focus of American cutaneous leishmaniasis, and to analyse the relationship between the most frequent species and rainfall, relative humidity and temperature, with the aim of contributing to epidemiological surveillance in the area. Sandfly collections were performed fortnightly between February 2006-September 2007 using automatic light traps, Shannon traps, protected human bait and aspiration in resting places. A total of 7,051 sandflies belonging to 12 species were captured. Pintomyia spinicrassa (95.7%) predominated. Pintomyia oresbia and Lutzomyia sp. of Pichinde were found in the state of Norte de Santander for the first time. Pi. spinicrassa, Pintomyia nuneztovari, Micropygomyia venezuelensis, Lutzomyia (Helcocyrtomyia) scorzai and Lu. (Helcocyrtomyia) sp. were captured on the protected human bait. A significant association between Pi. spinicrassa abundance and the total rainfall and the average temperature and humidity 10 days before the collection was observed. The dominance of Pi. spinicrassa, a recognised vector of Leishmania braziliensis, especially during the dry periods, indicates that the risk of parasite transmission may increase.Instituto de Física de Líquidos y Sistemas Biológico

Morphometric Analysis of the Host Effect on Phenotypical Variation of Belminus ferroae

The Triatominae subfamily includes hematophagous insects, well known for their role as vectors for the Trypanosoma cruzi parasite, etiologic agent of Chagas’ disease. Belminus ferroae is a triatomine that showed an increased demographic fitness when cockroaches were used as hosts. Here we compare the centroid size (CS) and wing shape between B. ferroae parents and three successive generations (O1, O2, and O3) of their offspring fed on cockroaches or mice under laboratory conditions. Morphometric analysis of the wings bugs fed on cockroaches showed a significant reduction in CS in both sexes among all generations. Sexual size dimorphism (SSD) was observed in the insects fed on cockroaches (O2 and O3), as well as those bugs fed on mice (O2). Differences in the shape of wings were observed between parental and offspring wings when fed on mice, but not in males (O1, O2, and O3) or females (O1 and O2) fed on cockroaches. There was a greater wing shape similarity between the cockroach-fed offspring and their parents according to the Mahalanobis distances. Our results support the idea of higher adaptation of this Triatominae with arthropod hosts

Comprensión lectora 2 : cuaderno de trabajo para estudiantes de segundo grado de Secundaria 2018

Cuaderno de trabajo sobre comprensión lectora para estudiantes de segundo grado de Secundaria. Texto para el año escolar 2018