Resumen Dada la rica variedad de textos recibidos en Educación Química, así como el intenso desarrollo experimentado en los últimos 50 años en investigación educativa en química, es necesaria una nueva clasificación de publicaciones. Aquí se comparten los acuerdos de los miembros del consejo editorial acerca de los criterios de clasificación de cada una de las modalidades de textos que se publican. Con ello se busca orientar mejor, clarificar y enfocar la aportación desde el envío mismo, invitando a más expertos a publicar en esta revista. De la misma manera, se da a conocer una nueva categoría, Relatos de experiencias, que enriquece el corpus de conocimientos de la educación química.

Abstract Given the rich variety of texts received at the Journal of Educación Química, as well as the development that Educational Research in Chemistry has experienced during the last 50 years, classifications in this area must gradually redefine their criteria. The agreements of the members of the editorial board are shared, to clarify these classification criteria for each of the modalities of texts that are published, in such a way that it guides better, in a clearer and more focused way from the very sending of the contribution, and invite more chemistry and science education experts, teachers, and science outreach professionals to publish. In the same way, a new category is disclosed, Experience reports, which enriches the corpus of knowledge of chemical education.

Triatoma infestans is the main vector of the parasite that causes the Chagas disease in South America. It is known that T. infestans has different reproductive and development patterns depending on whether they feed on birds or mammals. Using the head of adult insects as an estimator of the specimen development, we attempt to determine if there are any differences in the sexual size dimorphism associated with the availability of the food resource in T. infestansof natural habitats in the Llanos Riojanos region (Argentina). The nutritional status resulted higher in chicken coops and, in both habitats, it was higher for females in relation to males. The centroid size was larger in females than in males from chicken coops, but not in the specimens from goat corrals. Centroid sizes revealed smaller medians in goat insects in comparison to those coming from chicken coops. Sexual size dimorphism occurs associated with differences in the nutritional status only for triatomines from chicken coops in natural habitats. The heads shape was not infuenced by the nutritional status. The sexual morphophysiological differences found in T. infestanshelp us understand aspects of the behavior of the species in diverse environments and its implications in the vectorial transmission o f Trypanosoma cruzi.

Triatoma infestanses el principal vector del parásito que causa la enfermedad de Chagas en Sudamérica. Se sabe que T. infestanstiene diferentes patrones reproductivos y de desarrollo dependiendo de si se alimentan de aves o mamíferos. Utilizando la cabeza de insectos adultos como estimador del desarrollo, se intenta determinar si existen diferencias en el dimorfsmo de tamaño sexual asociado con la disponibilidad del recurso alimenticio e n T. infestans de hábitats naturales en la región de Llanos Riojanos (Argentina). El estado nutricional fue mayor en gallineros y, en ambos hábitats, fue mayor para las hembras en relación con los machos. El tamaño centroide fue mayor en las hembras que en los machos de gallineros, pero no en los especímenes de corrales de cabras. Los tamaños centroide revelaron medianas más pequeñas en insectos de cabra en comparación con los procedentes de gallineros. El dimorfsmo sexual del tamaño se asocia con diferencias en el estado nutricional solo para triatominos de gallineros de habitats naturales. La conformación de las cabezas no se vio infuenciada por el estado nutricional. Las diferencias morfofsiológicas encontradas en T. infestans ayudan a comprender aspectos del comportamiento de la especie en diversos ambientes y sus implicaciones en la transmisión vectorial d eTrypanosoma cruzi.

Triatoma infestans is the most important vector of Chagas disease in Argentina. We report for the first time the presence of T. infestans (Klug) (Hemiptera: Reduviidae) associated with burrowing parrot nests Cyanoliseus patagonus (Psittasiformes: Psittacidae) built on abandoned adobe houses. The possible implications of this finding are discussed, for entomological surveillance of the vector.

Triatoma infestans es el vector más importante de la enfermedad de Chagas de la Argentina. Se cita por primera vez la presencia de T. infestans (Klug) (Hemiptera: Reduviidae) asociado a nidos de loro barranquero Cyanoliseus patagonus (Psittasiformes: Psittacidae) construidos en viviendas de adobe abandonadas. Se discuten las posibles implicancias de este hallazgo para la vigilancia entomológica del vector.

Abstract: INTRODUCTION : Insects of the subfamily Triatominae are vectors of Trypanosoma cruzi , the Chagas disease parasite, and their flying behavior has epidemiological importance. The flying capacity is strikingly different across and within Triatominae species, as well as between sexes or individuals. Many Triatoma infestans individuals have wings but no flying muscles. In other Triatominae species, no clear relationships were found between wing length and flying behavior. If wing presence or size is not reflective of the flying behavior, which other parts of the body could be considered as reliable markers of this important function? METHODS : The genus Mepraia has exceptional characteristics with invariably wingless females and wingless or winged males. We calculated the porous surface exposed to odorant molecules to estimate the olfactory capacity of Mepraia spinolai . The head shape and thorax size were estimated using the geometric morphometric approach and traditional morphometric techniques, respectively. RESULTS : Alary polymorphism in M. spinolai was significantly associated with consistent modification of the thorax size, head shape, and notable change in the estimated olfactory capacity. The macropterous individuals had a larger olfactory surface and thorax size and significantly different head shape compared to those of the micropterous individuals. CONCLUSIONS: We concluded that these structural changes could be associated with the flying potential of Triatominae. Thus, morphological attributes not found on wings could help determine the likely flying potential of the bugs.

The goal of this work was to explore the thermal relationship between foraging Triatoma brasiliensis and its natural habitat during the hottest season in the state of Ceará, Brazil. The thermal profiles were determined using infrared analysis. Although the daily temperature of rock surfaces varied in a wide range, T. brasiliensisselected to walk through areas with temperatures between 31.7-40.5ºC. The temperature of T. brasiliensisbody surface ranged from 32.8-34.4ºC, being higher in legs than the abdomen. A strong relationship was found between the temperature of the insect and the temperature of rock crevices where they were hidden (r: 0.96, p < 0.05). The species was active at full sunlight being a clear example of how the light-dark rhythm may be altered, even under predation risk. Our results strongly suggest a thermal borderline for T. brasiliensisforaging activity near 40ºC. The simultaneous determination of insect body and rock temperatures here presented are the only obtained in natural habitats for this or other triatomines.

Introduction In Triatominae, reproductive efficiency is an important factor influencing population dynamics, and a useful parameter in measuring a species' epidemiological significance as a vector of Trypanosoma cruzi (Chagas, 1909). The reproductive efficiency of triatomines is affected by food availability; hence, we measured and compared the effects of feeding frequency on the reproductive parameters of Triatoma patagonica (Del Ponte, 1929) and Triatoma infestans (Klug, 1934), and the effects of starvation on T. patagonica. Methods Couples from both species were fed weekly, or every 3 weeks; in addition, females in couples of T. patagonica were not fed. Each couple was observed weekly and reproductive efficiency was assessed on the following parameters: fecundity (eggs/female), fertility (eggs hatched/eggs laid), initiation and end of oviposition, initiation of mating, number of matings/week, and number of reproductive weeks. Relative meal size index (RMS), blood consumption index (CI), and E values (eggs/mg blood) were also calculated. Results Changes in feeding frequency affected the reproductive parameters of T. patagonica only, with a decrease in fecundity and number of reproductive weeks for those fed every 3 weeks, or not fed. The reproductive period, RMS index, and CI were lower for T. patagonica than T. infestans. However, despite the lower fecundity of T. patagonica, this species required less blood to produce eggs, with an E values of 2 compared to 2.94 for T. infestans. Conclusions Our results suggest that the differences in fecundity observed between species reflect the availability of food in their natural ecotopes.

The presence of Triatoma infestans in habitats treated with insecticides constitutes a frequent problem in endemic areas. Basing our study on the hypothesis that descendants of a residual population should be more similar to the pre-treatment population than to any other, we compared the indications of two quantitative morphological approaches. This study seeks to find the origin of 247 T. infestans from three populations found in two chicken coops and a goat corral after treatment with insecticides. The results obtained by quantitative morphology suggest that the T. infestans found between three-34 months after the application of insecticides formed mixed populations with insects derived from residual foci and neighbouring habitats. Our analyses also showed the presence of a phenotype which does not resemble neither the pre-treatment phenotype nor the one from neighbouring populations, suggesting the presence of a particular post-treatment phenotype. The heads size showed some variations in males from different populations and remained unchanged in females, which reinforces the hypothesis of an intraspecific competition for food with priority for females. This article presents, for the first time, the combined analysis of geometric morphometry of heads and antennal phenotypes to identify the composition of reinfesting populations.

Triatoma infestans is the main vector of Trypanosoma cruzi, the aetiological agent of Chagas disease in the Gran Chaco region of South America. As a frequent blood meal source for triatomine bugs, domestic goats play a key role in the eco-epidemiology of Chagas disease. The aim of this study was to evaluate the mortality and blood intake of T. infestans fed on goats that had been treated with different doses of pour-on insecticide. Third-instar nymphs were fed on goats that had been treated with 0 cc, 5 cc, 10 cc or 15 cc of a pour-on formulation of cypermethrin. The exposure of T. infestans to animals treated at different post-application intervals revealed a residual activity of the insecticide. The mortality rate in the treated groups was higher than in the control groups until 30 days post-insecticide application (p = 0.03), except in the group treated with 5 cc, in which no mortality was detected after seven days of insecticide application. Rainfall affected the triatomicide effect, reducing the time of residual activity. The cypermethrin pour-on treatment decreased the blood intake of T. infestans. Thirty days after the cypermethrin application, nymph mortality was 16% (± 13) with both doses (10 cc and 15 cc). The 15 cc dose did not result in higher insect mortality or increased persistence compared to the 10 cc dose.

The association between land use and land cover changes between 1979-2004 in a 2.26-million-hectare area south of the Gran Chaco region and Trypanosoma cruzi infection in rural communities was analysed. The extent of cultural land, open and closed forests and shrubland up to 3,000 m around rural communities in the north, northwest and west of the province of Córdoba was estimated using Landsat satellite imagery. The T. cruzi prevalence was estimated with a cross-sectional serological survey conducted in the rural communities. The land cover showed the same patterns in the 1979, 1999 and 2004 satellite imagery in both the northwest and west regions, with shrinking regions of cultured land and expanding closed forests away from the community. The closed forests and agricultural land coverage in the north region showed the same trend as in the northwest and west regions in 1979 but not in 1999 or 2004. In the latter two years, the coverage remote from the communities was either constant or changed in opposite ways from that of the northwest and west regions. The changes in closed forests and cultured vegetation alone did not have a significant, direct relationship with the occurrence of rural communities with at least one person infected by T. cruzi. This study suggests that the overall decrease in the prevalence of T. cruzi is a consequence of a combined effect of vector control activities and changes in land use and land cover.

The aim of this paper was to analyse the active dispersal of Triatoma infestans and the role of chickens as passive carriers of this insect in peridomestic areas of La Rioja, Argentina. To measure active dispersal, monthly catches were made on six consecutive nights for five months (in the warm season) using light traps (for flying insects) and sticky dispersal barriers (for walking insects). The nutritional and reproductive states of adults were evaluated. Over the course of the sampling period, a total of eight flying adults, six walking nymphs and 10 walking adults of the species T. infestans were captured, as well as specimens of Triatoma guasayana, Triatoma eratyrusiformis and Triatoma platensis. Our data demonstrate for the first time that females of T. infestans can disperse by walking. This may be an adaptive strategy because it allows them to move with eggs and/or with good blood reserves, which are not possible when flying. All flying and walking individuals of both genders were of an appropriate physiological state that would allow for colonisation of the target habitat. However, manual inspection of 122 chickens suggests that it is unlikely that these animals passively transport T. infestans. Finally, the dispersal activity of T. infestans was compared with other triatomines using a dispersion index.

The Bolivian Chaco is part of the endemic region of Chagas disease and an area where pyrethroid resistant Triatoma infestans (Hemiptera: Reduviidae) populations has been reported. The World Health Organization identified these resistant populations as an important focus for research. The objective of this study was to evaluate the residual effect of a micro-encapsulated formulation containing organophosphate active ingredients and a juvenile hormone analogue (Inesfly 5A IGR) on the mortality of T. infestans. Studies took place in rural houses of the Bolivian Chaco that were treated up to 34 months before and evaluated the susceptibility to pyrethroids of the offspring of field collected insects. Thirty houses were randomly selected within three communities to carry out wall bio-assays with T. infestans nymphs. Mortality was recorded 24, 48 and 72 h after wall contact. Eggs laid by females collected in the area were used to obtain first-instar nymphs and carry out pyrethroid susceptibility tests. The wall bio-assays showed that the micro-encapsulated insecticide eliminates T. infestans populations and produces detectable mortality of insects exposed to walls treated 34 months prior to the tests. The discriminant dose of deltamethrin (0.01 mg/mL) showed 65% nymph survival, whereas at the highest tested dose (1.0 mg/mL) 14% of the nymphs survived. These results show that Inesfly 5A IGR is an appropriate tool for the elimination of intradomestic and peridomestic populations of T. infestans resistant to pyrethroids.

INTRODUCTION: the antennal phenotype has proven to be a useful tool for the taxonomic comparison between Triatominae species. OBJECTIVE: to study the antennal phenotype in adults of T. flavida and T. bruneri adults to clarify the taxonomic status of these species as well as to learn about the specific adaptation of each of them to its habitat. METHODS: four types of sensilla were counted and analyzed: Bristles (BR), thin walled trichoidea (TH), thick walled trichoidea (TK) and basiconic (BA). RESULTS: the pedicel of T. flavida showed only two different types of receptors whereas T. bruneri males had a greater number of chemoreceptors of three different types. Among T. flavida and T. bruneri females, there were differences in BR and BA; differences in males were found in the receptors TH, TK and BA on the pedicel and BR, TK and BA in the flagellum 1. Discriminatory analysis allowed the separation of the two species; however, the analysis by sex did not show any difference. CONCLUSIONS: as a consequence of the adaptation of each species to its habitat, morphological changes of the antennal phenotype occurred. So, further studies at ecological, morphometric and molecular levels are needed to make their present taxonomic status clear.

INTRODUCCIÓN: el fenotipo antenal ha mostrado ser una herramienta útil para la comparación taxonómica entre especies de Triatominae. OBJETIVO: estudiar el fenotipo antenal en adultos de T. flavida y T. bruneri para clarificar el estado taxonómico de estas especies así como conocer la adaptación específica de cada una a su hábitat. Métodos: fueron contadas y analizadas 4 tipos de sensilla: bristles (BR), tricoide de pared fina (TPF), tricoide de pared gruesa (TPG) y basicónica (BA). RESULTADOS: el pedicelo de T. flavida mostró solamente 2 tipos de receptores mientras que T. bruneri tuvo un mayor número de quimiorreceptores de 3 tipos diferentes. Entre las hembras de T. flavida y T. bruneri fueron observadas diferencias en los BR y BA, para los machos las diferencias fueron observadas en los receptores TPF, TPG y BA sobre el pedicelo y en los BR, TPG y BA en el flagelo 1. El análisis discriminante permitió la separación de las 2 especies, sin embargo, en el análisis de acuerdo con el sexo no se observaron diferencias. CONCLUSIONES: como consecuencia de la adaptación de cada especie a su hábitat se observaron modificaciones morfológicas en el fenotipo antenal. Futuros estudios a los niveles ecológico, morfométrico y molecular son necesarios para clarificar el estado taxonómico de estas especies.

This article reports the effects of a pour-on formulation of cypermethrin (6% active ingredient) applied to chickens exposed to Triatoma infestans, the main vector of Chagas disease in rural houses of the Gran Chaco Region of South America. This study was designed as a completely random experiment with three experimental groups and five replicates. Third instar nymphs were fed on chickens treated with 0, 1 and 2 cc of the formulation. Nymphs were allowed to feed on the chickens at different time intervals after the insecticide application. Third-instar nymphs fed on treated chickens showed a higher mortality, took less blood during feeding and had a lower moulting rate. The mortality rate was highest seven days after the insecticide solution application and blood intake was affected until 30 days after the application of the solution.

Introducción. Triatoma dimidiata es uno de los triatominos más ampliamente distribuidos en Colombia, la caracterización fenotípica antenal de poblaciones de diferentes hábitats proporcionaran conocimientos sobre su biología y comportamiento que podrán ser utilizados en nuevas propuestas metodológicas para su control. Objetivo. Estudiar el comportamiento de poblaciones de Triatoma dimidiata en diferentes hábitats utilizando el fenotipo antenal. Materiales y métodos. Se analizaron un mecanorreceptor y tres quimiorreceptores antenales de 60 individuos de Triatoma dimidiata provenientes de diferentes hábitats en Santander utilizando análisis univariados y multivariados. Resultados. Los análisis multivariados diferenciaron significativamente las poblaciones de las hembras, estas diferencias estuvieron asociadas a variaciones en el número de tricoides de pared gruesa, con aumento de los tricoides de pared fina en hábitats cercanos al domicilio humano. Los machos con mayor número de sensilla y de tricoides de pared fina, no se diferenciaron, sin embargo tendencias similares fueron apreciadas. Se observó dimorfismo sexual entre todas las poblaciones y fue menor en el del domicilio. Conclusiones. El fenotipo de sensilla antenal fue útil en la diferenciación intraespecífica de Triatoma dimidiata en diferentes hábitats. Las diferencias en hembras ponen de manifiesto nuevos arreglos sensoriales para la explotación del hábitat a diferencia de los machos, que por su mayor capacidad de dispersión, no se diferenciaron entre los ecotopos. La similitud entre hembras de zona urbana, con hembras de peridomicilio rural permite proponer al fenotipo antenal como un sencillo y eficiente indicador para la determinación del origen de triatominos que intentan colonizar nuevos hábitats.

Introduction. Triatoma dimidiata is one of the widely distributed triatomines in Colombia. The phenotype of the antenna is a characteristic of populations that can differ among habitats and can give information concerning its biology and behavior. This information in turn can be used in the development of new methodological proposals for its control. Objective. The behavior of populations of Triatoma dimidiate was studied in several different habitats, using the antennal phenotype. Materials and methods. A mechanoreceptor and three chemoreceptors were compared in the antennae of 60 Triatoma dimidiata adults from several defined habitats in Santander, using unvariate and multivariate analyses. Results. The multivariate analysis differentiated the female populations significantly. These differences were associated with variations in the number of thick-walled trichoids and with the numerical increase of the thin walled trichoids in habitats close to human housing. The males, with a larger number of sensilla and thin walled trichoids, were not differentiated significantly, although, similar tendencies were observed. Sexual dimorphism was clear in these characters in the total population, but less pronounced in the domestic populations. Conclusions. The antennal sensilla patterns were useful in the intraspecific differentiation of Triatoma dimidiata in different habitats. The differences in the female population shed light on new sensorial arrangements for the exploration of the habitat, in contrast with the male populations that, because of their great capacity for dispersion, were not differentiated in the distinct habitats. The differences in sensilla patterns between females from urban areas and those from rural surroundings may be a simple and efficient marker of the origin of individual Triatominae attempting to colonize new habitats.

Antennal sensilla patterns were used to analyze population variation of domestic Rhodnius prolixus from six departments and states representing three biogeographical regions of Colombia and Venezuela. Discriminant analysis of the patterns of mechanoreceptors and of three types of chemoreceptors on the pedicel and flagellar segments showed clear differentiation between R. prolixus populations east and west of the Andean Cordillera. The distribution of thick and thin-walled trichoids on the second flagellar segment also showed correlation with latitude, but this was not seen in the patterns of other sensilla. The results of the sensilla patterns appear to be reflecting biogeographic features or population isolation rather than characters associated with different habitats and lend support to the idea that domestic R. prolixus originated in the eastern region of the Andes.