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The development of fluorescent dyes that emit and absorb light at wavelengths greater than 700 nm and that respond to biochemical and biophysical events in living systems remains an outstanding challenge for noninvasive optical imaging. Here, we report the design, synthesis, and application of near-infrared (NIR)-absorbing and -emitting optical voltmeter based on a sulfonated, phosphine-oxide (po) rhodamine for voltage imaging in intact retinas. We find that po-rhodamine based voltage reporters, or poRhoVRs, display NIR excitation and emission profiles at greater than 700 nm, show a range of voltage sensitivities (13 to 43% ΔF/F per 100 mV in HEK cells), and can be combined with existing optical sensors, like Ca2+-sensitive fluorescent proteins (GCaMP), and actuators, like light-activated opsins ChannelRhodopsin-2 (ChR2). Simultaneous voltage and Ca2+ imaging reveals differences in activity dynamics in rat hippocampal neurons, and pairing poRhoVR with blue-light based ChR2 affords all-optical electrophysiology. In ex vivo retinas isolated from a mouse model of retinal degeneration, poRhoVR, together with GCaMP-based Ca2+ imaging and traditional multielectrode array (MEA) recording, can provide a comprehensive physiological activity profile of neuronal activity, revealing differences in voltage and Ca2+ dynamics within hyperactive networks of the mouse retina. Taken together, these experiments establish that poRhoVR will open new horizons in optical interrogation of cellular and neuronal physiology in intact systems.

Rhodnius prolixusis able to cool down the ingested blood during feeding on a warm-blooded host. This is possible because of a counter-current heat exchanger located in its head, which transfers heat from the warm blood to the insect haemolymph and can dissipate through the head cuticle. Given the key role haemolymph circulation in thermoregulation, we investigated the modulation of the activity of the heart during the warmed meal intake. We evaluated the impact of meal temperature on the heart rate and found that feeding led to an increase in the frequency of heart contractions, which increases with increasing food temperature. We also found that females have a higher heart rate during feeding compare to males.HIGHLIGHTSFeeding increases the heart rate ofRhodnius prolixusThe higher the meal temperature, the higher the heart rate becomesFemales have a higher heart rate than males

All cells maintain ionic gradients across their plasma membranes, producing transmembrane potentials (Vmem). Mounting evidence suggests a relationship between resting Vmem and the physiology of non-excitable cells with implications in diverse areas, including cancer, cellular differentiation, and body patterning. A lack of non-invasive methods to record absolute Vmem limits our understanding of this fundamental signal. To address this need, we developed a fluorescence lifetime-based approach (VF-FLIM) to visualize and optically quantify Vmem with single-cell resolution. Using VF-FLIM, we report Vmem distributions over thousands of cells, a 100-fold improvement relative to electrophysiological approaches. In human carcinoma cells, we visualize the voltage response to epidermal growth factor stimulation, stably recording a 10-15 mV hyperpolarization over minutes. Using pharmacological inhibitors, we identify the source of the hyperpolarization as the Ca2+-activated K+channel Kca3.1. The ability to optically quantify absolute Vmem with cellular resolution will allow a re-examination of its roles as a cellular signal.

The Mediterranean community represented in this paper is the result of more than 30 years of EU and nationally funded coordination, which has led to key contributions in science concepts and operational initiatives. Together with the establishment of operational services, the community has coordinated with universities, research centers, research infrastructures and private companies to implement advanced multi-platform and integrated observing and forecasting systems that facilitate the advancement of operational services, scientific achievements and mission-oriented innovation. Thus, the community can respond to societal challenges and stakeholders needs, developing a variety of fit-for-purpose services such as the Copernicus Marine Service. The combination of state-of-the-art observations and forecasting provides new opportunities for downstream services in response to the needs of the heavily populated Mediterranean coastal areas and to climate change. The challenge over the next decade is to sustain ocean observations within the research community, to monitor the variability at small scales, e.g., the mesoscale/submesoscale, to resolve the sub-basin/seasonal and inter-annual variability in the circulation, and thus establish the decadal variability, understand and correct the model-associated biases and to enhance model-data integration and ensemble forecasting for uncertainty estimation. Better knowledge and understanding of the level of Mediterranean variability will enable a subsequent evaluation of the impacts and mitigation of the effect of human activities and climate change on the biodiversity and the ecosystem, which will support environmental assessments and decisions. Further challenges include extending the science-based added-value products into societal relevant downstream services and engaging with communities to build initiatives that will contribute to the 2030 Agenda and more specifically to SDG14 and the UN's Decade of Ocean Science for sustainable development, by this contributing to bridge the science-policy gap. The Mediterranean observing and forecasting capacity was built on the basis of community best practices in monitoring and modeling, and can serve as a basis for the development of an integrated global ocean observing system. © Copyright © 2019 Tintoré, Pinardi.

Triatominae are blood-sucking insects that localise their hosts using a range of sensory signals to find food, and among them, the heat emitted by the hosts. Heat is one of the main short-range cues in vertebrate hosts, able to trigger alone the Proboscis Extension Response (PER) that precedes the bite. Previous studies demonstrated that heat responsiveness of fifth-instar nymphs is maximum to moderate temperatures (30–35°C) compatible with those of their vertebrate host’s body surface. This study investigated whether this thermal preference for biting is maintained along the life cycle of R. prolixus, from the first larval instar to male and female adults. The results showed that PER rates were at maximum around 30–35°C and decreased for a warmer temperature. The same thermal preference was maintained all along the life cycle, despite the increase in the size of the antennae linked to the growth. Interestingly, a decreased thermal responsiveness was stated in males as compared with larval instars and females. This decrease might reveal a lower motivation for host-seeking and might have an impact on males’s vectorial competence.

In spite of the mosquito Aedes aegypti being a vector of several infectious diseases, a limited number of studies has been undertaken on learning in this species. Moreover, larval stages have been neglected as model organisms, although they are active, aquatic and perform stereotyped behavioural responses, e.g. the escape response when disturbed. To study the learning abilities of mosquito larvae, we focused on habituation, a form of non-associative learning widely studied in vertebrates and invertebrates. Habituation was defined as the progressive and reversible decrease in response to a reiterative stimulus. We first aimed at confirming habituation of the escape response in mosquito larvae (4th instar). Then, we determined whether a mnesic trace was established. Larvae were individually stimulated with a visual danger stimulus inducing the escape response. We set up a protocol for testing larvae individually, allowing the control of different parameters that are crucial for the study of cognitive abilities. After 15 trials, the escape response of mosquitoes was significantly lower. A disturbance stimulus presented after the 15th trial, induced the escape response and reversed habituation. Retention was confirmed up to 1h after the last habituation trial. This original bioassay can be adapted for studying the physiology of learning and memory in mosquito larvae, for analysing the effects of chemicals in the water, the characterisation of the cognitive abilities related to the life history of different mosquito species across preimaginal stages.

International audience

International audience; Major emergency efforts are being mounted for each vector-borne disease epidemiological crisis anew, while knowledge about the biology of arthropods vectors is dwindling slowly but continuously, as is the number of field entomologists. The discrepancy between the rates of production of knowledge and its use and need for solving crises is widening, in particular due to the highly differing time spans of the two concurrent processes. A worldwide web based search using multiple key words and search engines of onsite and online courses in English, Spanish, Portuguese, French, Italian and German concerned with the biology of vectors identified over 140 courses. They are geographically and thematically scattered, the vast majority of them are on-site, with very few courses using the latest massive open online course (MOOC) powerfulness. Over two third of them is given in English and Western Africa is particularity poorly represented. The taxonomic groups covered are highly unbalanced towards mosquitoes. A worldwide unique portal to guide students of all grades and levels of expertise, in particular those in remote locations, is badly needed. This is the objective a new activity supported by the Special Programme for Research and Training in Tropical Diseases (TDR).

Learning and memory plays an important role in host preference and parasite transmission by disease vector insects. Historically there has been a dearth of standardized protocols that permit testing their learning abilities, thus limiting discussion on the potential epidemiological consequences of learning and memory to a largely speculative extent. However, with increasing evidence that individual experience and associative learning can affect processes such as oviposition site selection and host preference, it is timely to review the recently acquired knowledge, identify research gaps and discuss the implication of learning in disease vector insects in perspective with control strategies.

Blood-sucking vectors must overcome thermal stress caused by intake of proportionally large amounts of warm blood from their hosts. In response to this, Heat Shock Proteins (HSPs) such as the widely studied HSP70 family (the inducible HSP70 and the cognate form HSC70, known for their role in preserving essential cellular functions) are rapidly up-regulated in their tissues. The triatomine Rhodnius prolixus is an important vector of Trypanosoma cruzi , the causative pathogen of Chagas’ disease, and is also a model organism for studying insect biology and physiology. In this work, we observed that the expression of Rhodnius prolixus HSP70 was rapidly up-regulated in response to thermal shocks (0 °C and 40 °C) and also during the first hours after feeding on blood. HSP70/HSC70 RNAi knockdown elicited important alterations in R. prolixus physiological responses triggered by blood meal and starvation. HSP70/HSC70 knockdown insects showed lower resistance to prolonged starvation in comparison to appropriate controls, dying between 32 and 40 days after dsRNA injection. After blood feeding, the physiological effects of HSP70/HSC70 knockdown were more prominent and the insects died even earlier, within 14–20 days after feeding (21–27 days after dsRNA injection). These bugs showed impaired blood processing and digestion, reduced energetic metabolism and the midgut immune responses were compromised. Our findings suggest that HSP70/HSC70 depletion affected R. prolixus in starvation or fed conditions. After feeding, the arrival of blood in the digestive tract of knockdown insects fails to activate essential signaling pathways involved in blood processing, producing several alterations in their physiological processes enough to generate a premature death.

The thermal sense of triatomine bugs, vectors of Chagas disease, is unique among insects. Not only do these bugs exhibit the highest sensitivity to heat known in any animal up to date, but they can also perceive the infrared radiation emitted by the body of their warm-blooded hosts. The sensory basis of this capacity has just started to be unravelled. To shed additional light on our understanding of thermosensation, we initiated an analysis of the genetic basis of the thermal sense in Rhodnius prolixus. We tested the hypothesis that a TRPV (transient receptor potential vanilloid) channel receptor is involved in the evaluation of heat in this species. Two different approaches were adopted. Initially, we analysed the expression of a TRPV candidate for this function, i.e., RproIav, in different tissues. Subsequently, we tested the effects of capsaicin and capsazepine, two molecules known to interact with mammal TRPV1, using three different behavioural protocols for evaluating thermal responses: (1) proboscis extension response (PER), (2) thermopreference in a temperature gradient and (3) spatial learning in an operant conditioning context. Bioinformatic analyses confirmed that the characteristic features typical of the TRPV channel subfamily are found in the RproIav protein sequence. Molecular analysis showed that RproIav is expressed in R. prolixus, not only in the antennae, but also in other body structures bearing sensory organs. Behavioural experiments consistently revealed that capsaicin treated insects are less responsive to heat stimuli and prefer lower temperatures than non-treated insects, and that they fail to orient in space. Conversely, capsazepine induces the opposite behaviours. The latter data suggest that triatomine thermoreception is based on the activation of a TRP channel, with a similar mechanism to that described for mammal TRPV1. The expression of RproIav in diverse sensory structures suggests that this receptor channel is potentially involved in bug thermoreception. This constitutes solid evidence that thermosensation could be based on the activation of TRP receptors that are expressed in different tissues in R. prolixus. Whether RproIav channel is a potential target for the compounds tested and whether it mediates the observed effects on behaviour still deserves to be confirmed by further research. Fil: Zermoglio, Paula Florencia. Université François Rabelais de Tours; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Latorre Estivalis, Jose Manuel. Fundación Oswaldo Cruz; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Crespo, José Emilio. Université François Rabelais de Tours; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Lorenzo, Marcelo Gustavo. Fundación Oswaldo Cruz; Brasil Fil: Lazzari, Claudio Ricardo. Université François Rabelais de Tours; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Insect repellents are known since many decades ago and constitute a major tool for personal protection against the biting of mosquitoes. Despite their wide use, the understanding of why and how repellents repel is relatively recent. In particular, the question about to what extent insects other than mosquitoes are repulsed by repellents remains open. We developed a series of bioassays aimed to test the performance of well established as well as potential repellent molecules on the Chagas disease vector Rhodnius prolixus. Besides testing their ability to prevent biting, we tested the way in which they act, i.e., by obstructing the detection of attractive odours or by themselves. By using three different experimental protocols (host-biting, open-loop orientation to odours and heat-triggered proboscis extension response) we show that DEET repels bugs both in the presence and in the absence of host-associated odours but only at the highest quantities tested. Piperidine was effective with or without a host and icaridine only repelled in the absence of a living host. Three other molecules recently proposed as potential repellents due to their affinity to the Ir40a+ receptor (which is also activated by DEET) did not evoke significant repellency. Our work provides novel experimental tools and sheds light on the mechanism behind repellency in haematophagous bugs. Fil: Zermoglio, Paula Florencia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Martin Herrou, Hadrien. Centre National de la Recherche Scientifique; Francia Fil: Bignon, Yohan. Centre National de la Recherche Scientifique; Francia Fil: Lazzari, Claudio Ricardo. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Metabolic rate is a positive function of body weight, a rule valid for most organisms and the basis of several theories of metabolic ecology. For adult insects, however, the diversity of relationships between body mass and respiration remains unexplained. The aim of this study is to relate the respiratory metabolism of a parasitoid with body weight and foraging activity. We compared the metabolic rate of groups of starving and host-fed females of the parasitoid Eupelmus vuilleti recorded with respirometry for 7 days, corresponding to the mean lifetime of starving females and over half of the lifetime of foraging females. The dynamics of carbohydrate, lipid and protein in the body of foraging females were quantified with biochemical techniques. Body mass and all body nutrients declined sharply from the first day onwards. By contrast, the CO 2 produced and the O 2 consumed increased steadily. Starving females showed the opposite trend, identifying foraging as the reason for the respiration increase of feeding females. Two complementary physiological processes explain the unexpected relationship between increasing metabolic rate and declining body weight. First, host hemolymph is a highly unbalanced food, and the excess nutrients (protein and carbohydrate) need to be voided, partially through excretion and partially through respiration. Second, a foraging young female produces eggs at an increasing rate during the first half of its lifetime, a process that also increases respiration. We posit that the time-varying metabolic rate contributions of the feeding and reproductive processes supplements the contribution of the structural mass and lead to the observed trend. We extend our explanations to other insect groups and discuss the potential for unification using Dynamic Energy Budget theory.

The factors affecting the sexual behaviour of Panstrongylus megistus were studied under laboratory conditions. A general description of mating behaviour is presented for this species. The effect of the time elapsed after the first imaginal feeding on the mating frequency, the motivation of males to mate and the rejection behaviour by females, were analyzed. We also determined the number of copulas accepted by females of this species. Finally, the possible existence of a sexual chemical signal promoting male aggregation around mating couples was evaluated. Results showed that mating frequency increased with the time elapsed since the first adult meal. Despite the number of male copulatory attempts did not change as a function of time, the rejection behaviour of females became gradually less frequent. Females rejected mating by means of body flattening on the substrate, abdominal movements, evasion or stridulation. After a single copula, females did not usually accept to mate again. Neither male nor female aggregation around mating couples was observed, suggesting the absence of a sexual assembling pheromone in P. megistus. Fil:Lorenzo, M.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Lazzari, C.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Manrique, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome (∼702 Mb), including 15,456 putative protein-coding genes, and completed comprehensive genomic analyses of this obligate blood-feeding insect. Although immunedeficiency (IMD)-mediated immune responses were observed, R. prolixus putatively lacks key components of the IMD pathway, suggesting a reorganization of the canonical immune signaling network. Although both Toll and IMD effectors controlled intestinal microbiota, neither affected Trypanosoma cruzi, the causal agent of Chagas disease, implying the existence of evasion or tolerance mechanisms. R. prolixus has experienced an extensive loss of selenoprotein genes, with its repertoire reduced to only two proteins, one of which is a selenocysteine-based glutathione peroxidase, the first found in insects. The genome contained actively transcribed, horizontally transferred genes from Wolbachia sp., which showed evidence of codon use evolution toward the insect use pattern. Comparative protein analyses revealed many lineage-specific expansions and putative gene absences in R. prolixus, including tandem expansions of genes related to chemoreception, feeding, and digestion that possibly contributed to the evolution of a blood-feeding lifestyle. The genome assembly and these associated analyses provide critical information on the physiology and evolution of this important vector species and should be instrumental for the development of innovative disease control methods., La lista completa de autores que integran el documento puede consultarse en el archivo, Este documento tiene una corrección (ver documento relacionado)., Centro Regional de Estudios Genómicos, Instituto de Investigaciones Bioquímicas de La Plata

International audience; Prof. Josué Núñez passed away on August 19th 2014 at the age of 89. He was a pioneer in the field of insect physiology and a founder of the study of behavioural physiology in Argentina and other Latin-American countries such as Brazil and Venezuela. Josué was born in 1924, in the city of Tapalqué, a small town in the middle of the province of Buenos Aires, Argentina. After a basic education in the prestigious ''Colegio Nacional de Buenos Aires'', he studied biology at the University of Buenos Aires, where he obtained his PhD in 1953. Throughout his long and fructiferous scientific career, he worked in different reputed laboratories around the world. Thanks to grants from the Alexander-von-Humboldt foundation, he stayed several years in Germany, 1983, after the end of Argentina's worst military dictatorship, he returned to his country, where he was appointed as a Full Professor of the University of Buenos Aires and as a Principal Investigator of the Argentinean National Research Council. During this period of national reconstruction, he played a most significant role for the development of biological studies and the training of young students. He participated actively in the creation of a new curriculum in biological sciences, incorporating several areas of study and research such as Animal Physiology, Behavioral Physiology and Insect Physiology, which were relegated until then. In addition, he founded, together with Hector Maldonado, the first laboratory of Behavioural Physiology, and later the laboratory of Insect Physiology, contributing thereby to the training of several generations of students, many of whom occupy currently chairs and professorships in Argentina and Europe. Josué Núñez retired officially in 1990 but continued his scientific activities in an intensive way thanks to a nomination as a Consultant Professor of the University of Buenos Aires, a position he kept until 2008. In 2007, he was elected as a member of the Buenos Aires Academy of Sciences. Josué Núñez was passionate about insects and made several seminal contributions on insect morphology, physiology and behaviour. His work was extremely inventive and was characterized by the development and successful employ of self-made ingenious tools and experimental devices, such as regulated artificial feeders for honeybees and haematophagous bugs, aimed at quantifying responses in unrestrained, free-behaving insects under controlled conditions. His main study models were precisely blood-sucking bugs and honeybees, and his original contributions underlie the strong ''feeling for the organism'' he had when posing relevant scientific questions. Among his numerous contributions, one can cite the discovery of prothoracic glands and the first experimental evidence of neuro-hormonal control of diuresis in Coleop-tera, the nervous control of both the mechanical properties of the cuticle and the diuretic activity in Rhodnius blood-sucking bugs, the neural regulation of ingestion in dipterans, the use of repellent pheromones during foraging in honeybees, the control of crop-filling in honeybees that led to the hypothesis of a trade-off between individual and colony-wide foraging efficiency, mediated by communication , in social insects, and the perception of infrared radiation in haematophagous bugs, among others. Josué Núñez received several prestigious distinctions from the Argentinean scientific community such as the Konex Prize for science and technology, awarded twice to him, in 1993 and 2003. He himself, however, never regarded these many awards as very important; humility and a devoted commitment to science characterized his style, which was always accompanied by a high dose of sense of humour, something that everyone who had the privilege of working under his direction remembers fondly. Josué exerted a strong influence on his numerous students, to whom he transmitted his passion, curiosity and scientific rigour. He recognized that students and young scientists need to learn to be independent, so he gave them independence. His collaborators will never forget the endless discussions about their ongoing projects, his unorthodox manner, nor the long and intellectually enriching, open-end talks on subjects as eclectic as the beginnings of insect physiology, fractals, complex systems, bio-mimetics, bio-food and eco-engineering, always accompanied by litres of mate, an Argentinean typical infusion. Our sadness over Josué's death is somehow alleviated by the fact that his scientific legacy will enrich us for many generations to come and by the happy memories of the rich years that we were allowed to spend with him.

International audience; Infrared detection withoutspecialized infrared receptors in the bloodsucking bug Rhodniusprolixus. J Neurophysiol 112: 1606–1615, 2014. First published June18, 2014; doi:10.1152/jn.00317.2014.—Bloodsucking bugs use infraredradiation (IR) for locating warm-blooded hosts and are able todifferentiate between infrared and temperature (T) stimuli. This paperis concerned with the neuronal coding of IR in the bug Rhodniusprolixus. Data obtained are from the warm cells in the peg-in-pitsensilla (PSw cells) and in the tapered hairs (THw cells). Both warmcells responded to oscillating changes in air T and IR with oscillationsin their discharge rates. The PSw cells produced stronger responses toT oscillations than the THw cells. Oscillations in IR did the reverse:they stimulated the latter more strongly than the former. The reversalin the relative excitability of the two warm cell types provides acriterion to distinguish between changes in T and IR. The existence ofstrongly responsive warm cells for one or the other stimulus in apaired comparison is the distinguishing feature of a “combinatorycoding” mechanism. This mechanism enables the information providedby the difference or the ratio between the response magnitudesof both cell types to be utilized by the nervous system in the neuralcode for T and IR. These two coding parameters remained constant,although response strength changed when the oscillation period wasaltered. To discriminate between changes in T and IR, two things areimportant: which sensory cell responded to either stimulus and howstrong was the response. The label warm or infrared cell may indicateits classification, but the functions are only given in the context ofactivity produced in parallel sensory cells.

The effectiveness of a trap for triatomines baited with yeast cultures has been previously demonstrated for Triatoma infestans in laboratory assays. We report here results from laboratory assays testing yeast traps for Triatoma sordida, Triatoma brasiliensis, Triatoma pseudomaculata, and Panstrongylus megistus. All assays were conducted in an open experimental arena 100 cm X 100 cm, with two traps placed at opposite sides of the arena. One of the traps contained a yeast culture, and the other trap contained a saccharose solution as a control. Two series of experiments were done, one without a refuge for the insects and one with a refuge. The results obtained clearly demonstrated that the yeast-baited traps were effective in the laboratory in capturing both T. sordida and P. megistus. For T. sordida, yeast-baited traps captured significantly more bugs than did the control traps (t test P value = 0.03). For P. megistus, when a refuge was provided during the assay, yeast-baited traps also captured significantly more bugs than did the control traps (t test P value = 0.006). In the experiments with T. brasiliensis and T. pseudomaculata, both traps captured some insects, but the yeast traps captured many fewer bugs than was true with the T. sordida and P. megistus bugs. These results indicate that, in the laboratory, yeast traps can capture considerable numbers of T. sordida and P. megistus in one night. We discuss the potential use of yeast traps for detecting and capturing both triatomine species.Con anterioridad se ha demostrado la eficacia de las trampas cebadas con cultivos de levaduras (TCL) para capturar Triatoma infestans en experimentos de laboratorio. En el presente estudio se describen los resultados obtenidos con estas trampas para capturar T. sordida, T. brasiliensis, T. pseudomaculata y Panstrongylus megistus, también en experimentos de laboratorio. Todos los experimentos fueron realizados en un recinto experimental abierto de 100 cm por 100 cm, con dos trampas colocadas en sitios opuestos. Una de ellas contenía un cultivo de levaduras, mientras que la otra contenía una solución de sacarosa como control. Se realizaron dos series de experimentos: una con y la otra sin un refugio para los insectos. Los resultados obtenidos demostraron claramente la eficacia de las TCL para capturar tanto T. sordida como P. megistus en el laboratorio. Las TCL capturaron un número significativamente mayor de T. sordida que las trampas de control (t de Student; P = 0,03). Cuando se les proporcionó un refugio a los insectos, las TCL también capturaron un número significativamente mayor de P. megistus que las trampas de control (t de Student; P = 0,006). Ambos tipos de trampas capturaron algunos ejemplares de T. brasiliensis y T. pseudomaculata, aunque el número capturado en una noche con las TCL fue muy inferior al de T. sordida y P. megistus. Estos resultados indican que, en el laboratorio, las TCL pueden capturar un número considerable de T. sordida y P. megistus en una noche. Se analiza la posible utilización de las TCL para detectar y capturar estas dos especies de triatominos.

The simple eyes (ocelli) of recently emerged adult Triatoma infestans exhibit a narrow elongated "pupil", surrounded by a ring of brown-reddish pigment, the "iris". This pupil does not respond to changes in the illumination, but varies in size after the imaginal ecdysis. This change corresponds, internally, with the growth of the corneal lens and the associated retina up to an age of about 20 days. This has not been previously observed in an insect. The use of this characteristic for recognising young adults of this species is suggested.

The projections of mechanosensory hairs located on the dorsal and lateral head of the adult haematophagous bug Triatoma infestans were analyzed by means of cobalt filling. Axons run into the anterior and posterior tegumentary nerve and project through the brain to the ventral nerve cord. The fibres are small in diameter and run as a fascicle. Some branches run into suboesophageal and prothoracic centres; others run as far as to the mesothoracic ganglion. These sensory projections resemble that of wind-sensitive head hairs of the locust. The functional role of this sensory system in this species is discussed.

Despite the incredible success of insects in colonizing almost every habitat, they remain virtually absent in one major environment – the open sea. A variety of hypotheses have been raised to explain why just a few insect species are present in the ocean, but none of them appears to be fully explanatory. Lice belonging to the family Echinophthiriidae are ectoparasites on different species of pinnipeds and river otters, i.e. they have amphibious hosts, who regularly perform long excursions into the open sea reaching depths of hundreds of meters (thousands of feets). Consequently, lice must be able to support not only changes in their surrounding media, but also extreme variations in hydrostatic pressure as well as breathing in a low oxygen atmosphere. In order to shed some light on the way lice can survive during the diving excursions of their hosts, we have performed a series of experiments to test the survival capability of different instars of Antarctophthirus microchir (Phthiraptera: Anoplura) from South American sea lions Otaria flavescens, when submerged into seawater. These experiments were aimed at analyzing: (a) immersion tolerance along the louse life; (b) lice’s ability to obtain oxygen from seawater; (c) physiological responses and mechanisms involved in survival underwater. Our experiments showed that the forms present in nondiving pups – i.e. eggs and first-instar nymphs – were unable to tolerate immersion in water, while fol- lowing instars and adults, all usually found in diving hosts, supported it very well. Furthermore, as long as the level of oxygen dissolved in water was higher, the lice survival capability underwater increased, and the recovery period after returning to air declined. These results are discussed in relation to host ecology, host exploitation and lice functional morphology. Fil: Leonardi, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina Fil: Lazzari, Claudio Ricardo. Université François Rabelais; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Blood is a rich source of nutrients and, except for the possible presence of parasites, otherwise sterile. However, being haematophagous is a risky task, as the food circulates inside vessels hidden beneath the skin of mobile hosts, able to defend themselves from biting or even predate on blood-sucking species. Thus, in order to minimize the contact with the host, blood-sucking insects need to pierce the host-skin without being noticed and gather blood in relatively high amounts and as quick as possible. Large blood-meals produce a strong osmotic misbalance at its ingestion and toxic metabolites as by products of its digestion. In addition, the rapid ingestion of a fluid which temperature can exceed that of the insects by 20°C or more and account for many times the insect’s own body weight also implies a rapid transfer of heat into the insect’s body. Thus, the inner temperature of the insect could exceed the physiological limits of certain functions, causing deleterious effects [2]. Numerous studies report the impact of temperature on different behavioural [3] and physiological processes such as development [4-6], metabolism [7, 8], blood-feeding and reproduction [9] of mosquitoes and insects in general.