An amendment to this paper has been published and can be accessed via the original article.

Additional file 1: Table S1. Populations, specimen details and haplotype codes of 106 Rhodnius ecuadoriensis bugs used in morphometric and/or molecular analyses. A summary table with the numbers of bugs used in each analysis is also provided.

ABSTRACT Rhodnius ecuadoriensis (Hemiptera, Reduviidae) is an important vector of both Trypanosoma hemoflagellates, Trypanosoma cruzi and Trypanosoma rangeli, in Ecuador and Peru. Ecotopes of sylvatic and domestic/peridomestic habitats have been reported in Ecuador. Meanwhile in Peru, to the best of our knowledge, findings of sylvatic populations in their different ecosystem regions have not yet been documented. Could this be the product of a lack of appropriate studies on wild populations of triatominae in Peruvian environments? In order to elucidate this topic, we take advantage of new insights in geometric morphometry as a tool to help differentiate between wild populations and the corresponding domestic/peridomestic ones, collected in their respective environments. When analyzing our results, we confirmed the efficacy of this technique in our study, and furthermore, we believe that it could be a proper tool for rangeliosis and Chagas disease vector control surveillance in Ecuador and Peru. Keywords: Morphometric geometry, sylvatic, domestic/peridomiestic populations distinction, Rhodnius ecuadoriensis. RESUMEN Rhodnius ecuadoriensis (Hemiptera, Reduviidae) es un importante vector de los tripanosomas Trypanosoma cruzi y Trypanosoma rangeli en el Ecuador y Perú. Se han reportado ecotopos de hábitats silvestres y domésticos/peridomésticos en Ecuador. Sin embargo, en Perú, hasta donde sabemos, no se ha documentado hallazgos de dichas poblaciones silvestres. ¿Podría este ser el caso de una falta de estudios focalizados en la búsqueda de poblaciones silvestres de triatominos dentro de los diferentes ecosistemas del Perú? Para elucidar este tema, aplicamos nuevas perspectivas en morfometría geométrica, como una herramienta que podría auxiliar en la diferenciación de poblaciones silvestres de aquellas domésticas/peridomésticas, colectadas en sus respectivos ambientes naturales. Al analizar nuestros resultados, se confirmó la utilidad de esta técnica dentro de nuestro estudio, y esto nos llevó a creer asimismo que serviría como un elemento apropiado en el control vectorial de la enfermedad de Chagas y de la rangeliosis, en Ecuador y Perú. Palabras claves: Geometría morfométrica, silvestre, diferenciación de poblaciones domesticas/peridomesticas, Rhodnius ecuadoriensis.

It has been suggested that attempts to eradicate populations of tsetse (Glossina spp.) using stationary targets might fail because smaller, less mobile individuals are unlikely to be killed by the targets. If true, tsetse caught in stationary traps should be larger than those from mobile baits, which require less mobility on the part of the flies.

We previously constructed a single molecular clock to date insect evolution that remains a cornerstone within entomological dating. The insect clock predicts that triatomine bugs, the vectors of South American trypanosomiasis, originated with the formation of South America. We addressed this hypothesis using the insectivorous reduviid bugs and their phylogenetic relationship with the haematophagous reduviid bugs, as well as their biogeographic distribution. Putative paraphyly or monophyly of Triatominae, by non-haematophagous reduviids, have both previously been hypothesized and identified. We sampled a broad range of predatory reduviids, viz. Ectrichodiinae, Emesinae, Hammacerinae, Harpactorinae, Reduviinae, Salyavatinae, Steniopodainae and Vesciinae, including both New World and Old World representatives and sequenced the nuclear 28S ribosomal gene locus and the mitochondrial loci 5' cytochrome oxidase 1 (cox1 [COI]), cox1 3', cytochrome oxidase 2 (cox2 [COII]) and cytochrome oxidase b (cob [cytb]). Robust evidence for the monophyly of Triatominae was observed in 5/5 loci using codon/nucleotide (28S) based maximum likelihood phylogenies, 3/5 loci using codon-based Bayesian phylogenies and in cox2 using amino acid Bayesian phylogenies. Several South American members of the Reduviinae, that are morphologically and phylogenetically a sister group to triatomine bugs, have a modal divergence date with the Triatominae of 109-107 million years ago (MYA). This creates a scenario where the closest (non-haematophagous) ancestor to triatomine bugs evolved immediately prior to the breakup of Gondwanaland whilst the triatomine bugs evolved 95MYA, putatively linking the origin of haematophagous behaviour to the origin of South America and in particular infers a delayed onset to the evolution of haematophagy. The placement of the enigmatic tribe Bolboderini as an ingroup to the Triatominae monophyly, confirms the 95MYA node as the most ancient in the subfamily.

This chapter relates factors of vector host parasite associations that highlight the evolutionary course of Chagas disease, and how these interactions account for the observed distribution of the disease in domestic and sylvatic cycles in the Americas. It also presents changes in prevalence and distribution of Chagas disease in Central and South America in recent times and particularly in response to control programs. It reports on the global dispersal of Chagas disease due to migrant South and Central American populations to Europe, North America, Japan, and Australia. Finally, it highlights the need for nonendemic countries to maintain and develop an awareness of Chagas disease as a consequence of globalization. A full understanding of the etiology and epidemiology of Chagas disease across its distribution was to prove elusive and complex, and remains under intense investigation to the present day. The difficulty in completely defining the epidemiology of Chagas disease is attributable to several factors. A further factor that contributes to the complexity of Chagas disease as a zoonosis is the variety of vectors involved, being not simply represented by a range of related species or genera, as is the case for all other insect vectors, associated with any given disease. In addition to vector transmission, a small percentage of cases are attributable to unscreened blood transfusions, congenital transmission, and incidences of oral transmission by contamination of food.

The genus Panstrongylus is currently composed of 13 species, several of which are involved in the transmission of Trypanosoma cruzi to humans in South and Central America. Some species exhibit minor morphological differences possibly associated with adaptation to different silvatic ecotopes or domestic environments. We present a distillation of past and recent literature pertaining to the biology of this group. In particular, we summarise the current status of the genus according to systematic and recent phylogenetic studies. In light of recent evidence suggesting polyphyly/paraphyly of the genus we have investigated the possible mechanisms of morphological convergence/divergence. By assessing postembryonic ontogeny we reveal that the distinctive head shape of Panstrongylus can be derived from a Triatoma-like head late in development. A comprehensive phylogenetic study is therefore required to elucidate their relationship with Triatoma spp., and other genera of the tribe Triatomini. We also present a comparative summary of biology, ecology and epidemiological significance for each species in the genus. This reveals that knowledge of many species is fragmentary or lacking. This is mainly due to the fact that, except for few species with synanthropic traits (P. megistus and P. lignarius [formerly P. herreri]), important vectors of Chagas disease in Brazil and Peru, the majority are sylvatic species, associated with a wide variety of habitats and wild animals (many of them reservoirs of Trypanosoma cruzi). However, trends to invade human dwellings and to establish domestic colonies have been observed in several species in the genus (P. geniculatus, P. rufotuberculatus, P. lutzi, P. chinai), while others are opportunistic species (e.g. P. lignarius in the Amazon basin flying from wild ecotopes to houses on occasion without colonizing). Nevertheless, they can play some role in the transmission of sylvatic T. cruzi to humans. Research on the genus Panstrongylus requires some focus on investigating the natural ecology of these species. This knowledge would add to our understanding of their evolutionary potential and may assist in predicting new epidemiological scenarios, for which new control strategies need to be devised.

Evolution & DevelopmentVolume 9, Issue 6 p. 525-526 Developmental buffering: how many genes? James S. Patterson, James S. Patterson Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UKSearch for more papers by this authorChristian Peter Klingenberg, Corresponding Author Christian Peter Klingenberg Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK*Author for correspondence (email: cpk@manchester.ac.uk)Search for more papers by this author James S. Patterson, James S. Patterson Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UKSearch for more papers by this authorChristian Peter Klingenberg, Corresponding Author Christian Peter Klingenberg Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK*Author for correspondence (email: cpk@manchester.ac.uk)Search for more papers by this author First published: 30 October 2007 https://doi.org/10.1111/j.1525-142X.2007.00193.xCitations: 16Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume9, Issue6November/December 2007Pages 525-526 RelatedInformation

The nature of developmental buffering processes has been debated extensively, based on both theoretical reasoning and empirical studies. In particular, controversy has focused on the question of whether distinct processes are responsible for canalization, the buffering against environmental or genetic variation, and for developmental stability, the buffering against random variation intrinsic in developmental processes. Here, we address this question for the size and shape of Drosophila melanogaster wings in an experimental design with extensively replicated and fully controlled genotypes. The amounts of variation among individuals and of fluctuating asymmetry differ markedly among genotypes, demonstrating a clear genetic basis for size and shape variability. For wing shape, there is a high correlation between the amounts of variation among individuals and fluctuating asymmetry, which indicates a correspondence between the two types of buffering. Likewise, the multivariate patterns of shape variation among individuals and of fluctuating asymmetry show a close association. For wing size, however, the amounts of individual variation and fluctuating asymmetry are not correlated. There was a significant link between the amounts of variation between wing size and shape, more so for fluctuating asymmetry than for variation among individuals. Overall, these experiments indicate a considerable degree of shared control of individual variation and fluctuating asymmetry, although it appears to differ between traits.

COMPARATIVE MORPHOMETRIC ANALYSIS of shape variation in the wings of different tsetse species reveals close accordance with the phylogenetics of these species indicated by DNA sequence analysis. In practice, the morphometric analysis is economical and simple to carry out, suggesting that this could become a useful surrogate or complementary tool for large-scale studies of tsetse population genetics, designed to identify discrete population targets amenable to local elimination.

T SETSE-FLIES OCCUR THROUGHOUT MOST of sub-Saharan Africa, over an area approaching 10 million km. They suck blood and transmit a range of trypanosome species, including those that cause human sleeping sickness, and others that are responsible for a fatal syndrome of anaemia and wasting in cattle known as ‘nagana’ (from a Zulu word meaning to be low or depressed in spirit). Not only does this limit the availability of meat and dairy products, it also curtails the availability of oxen or horses for transport and ploughing. This severely restricts agricultural production. Without oxen, only small areas of land can be tilled by hand, leaving communities vulnerable to food shortages, hunger, and even famine. Since the 1960s, the incidence of sleeping sickness has risen steadily, with epidemic outbreaks in several areas. The World Health Organization (WHO) now estimates that over 300 000 people are infected with African trypanosomiasis, and the UN Food and Agriculture Organization estimates that economic losses due to the livestock infections may reach around US$4.5 billion each year. Because African trypanosomes are able to present successive waves of different surface proteins (a process known as ‘antigenic variation’), it is unlikely that an effective vaccine can be developed. Treatment is possible, but relies largely on antiquated drugs such as melarsoprol, which is — loosely speaking — a mixture of arsenic and anti-freeze that will kill up to 10% of those treated (although all would succumb to the disease without treatment). There are other drugs with less severe side effects, and the WHO has now arranged that these can be provided free of charge to national treatment programmes. But it is a difficult task to find, diagnose, and treat all the patients who require such care. Recognizing the problems of tsetseborne trypanosomiasis, the heads of state and government of the 36 affected countries, meeting at the 2000 OAU summit in Togo, declared as priority the aim of ‘rendering Africa free of tsetse in the shortest time possible’. In response, the OAU (now the African Union) has set up a Pan-African initiative (known as AU-PATTEC) to promote and coordinate national and regional programmes to eliminate the problem of tsetse and trypanosomiasis. Several countries have already reflected this goal in their official poverty reduction strategy papers, developing or revitalizing their national programmes, and the African Development Bank is now providing a series of grants and loans through PATTEC to assist the first six countries (Ethiopia, Uganda, Kenya, Mali, Burkina Faso and Ghana) in their tsetse elimination programmes. Further grants are under discussion. Techniques to eliminate tsetse have been known since the eradication of Glossina palpalis from the Island of Principe in 1914, using a form of sticky traps carried by plantation workers. Today, a series of highly effective techniques is available, including an array of odour-baited traps and targets, sequential aerial spraying with ultra-low doses of biodegradable insecticides, and, where necessary, SIT — the use of sterilized male flies to reduce the already low reproductive rate of wild tsetse. The ‘proof-ofprinciple’ of this technological package was successfully demonstrated by eradication of tsetse (Glossina austeni) from the Island of Zanzibar during the 1990s. Zanzibar is now a nett exporter of meat and dairy produce, where previously it was a nett importer when tsetse and trypanosomiasis limited cattle and agricultural production. But this demonstration of the feasibility of tsetse elimination has been criticized, on the grounds that Zanzibar is a relatively small island whereas Africa is a rather large continent. So, the African Union, together with other organizations supporting the PATTEC initiative, is harnessing modern techniques of population genetics and geographic information systems (GIS) in order to find the ‘biological islands’ of tsetse distribution within the continent of Africa, so that these populations can be progressively targeted for elimination. The work is supported by the Leverhulme Trust in England, through a network currently involving research institutions in 19 African countries, the United Kingdom, France, and the United States. The article on page 132 of this issue presents the first study resulting from this new initiative. It is a comparison between gene sequencing and the developing science of morphometry as a means to differentiate tsetse populations. The techniques of geometric morphometry are statistically complex, but offer a very rapid way to screen large numbers of individuals (similar techniques are now used by the US immigration services to identify travellers by means of morphometric analysis of photographs taken when you present your passport). Those familiar with Greek mythology will perhaps recognize the concept of Procrustean analysis, through which shapes are compared by measuring the deformations required to superimpose one shape on another. (Procrustes was reputed to fit his victims into a bed — stretching them if they were too short, cutting their extremities if they were too long.) And although morphometrics relies on phenetic rather than genetic characters, the preliminary study reported here reveals strong congruence between the two, offering hope that the large-scale analysis required in preparation for effective tsetse elimination can be carried out quickly and at low cost. ❑

Abstract For the first time, the eggs and all instars of a species of the Indian genus Linshcosteus are described using morphometrics and optical and scanning electron microscopy. Linshcosteus karupus Galvão, Patterson, Rocha & Jurberg, 2002 was recently described from near Kalakkadu, Tamil Nadu State, southern India. In addition, current knowledge and the importance of morphological studies of immature Triatominae are discussed.

For the first time all instars of a species of the genus Belminus are described based on laboratory F1 generation specimens from adults caught in department of Cesar, Colombia. Ontogenetic morphometrics of postembryonic head development was made, suggesting that the greatest changes occur between the 1st and 2nd instars.

For the first time, the eggs and all instars of a species of the Indian genus Linshcosteus are described using morphometrics and optical and scanning electron microscopy. Linshcosteus karupus Galvao, Patterson, Rocha & Jurberg, 2002 was recently described from near Kalakkadu, Tamil Nadu State, southern India. In addition, current knowledge and the importance of morphological studies of immature Triatominae are discussed.

Mixed infestation of nymphs and adults of Rhodnius prolixus Stal, 1859 and Panstrongylus geniculatus Latreille, 1811 was detected in 3 (15%) of 20 dwellings in El Guamito, an endemic focus of Chagas disease in Lara State, Venezuela. In one of the houses, both species were positive for Trypanosoma cruzi: 14.3% (R. prolixus) and 20% (P. geniculatus ). The overall infection rate in 143 of 352 R. prolixus was 16.1%. Parasites isolated from R. prolixus were identified as T. cruzi I by random amplified polymorphic DNA analysis. Dot-enzyme-linked immunosorbent assays of 36 R. prolixus showed that 58.3% of the R. prolixus had fed on humans. The gut contents of one fifth-instar nymph of P. geniculatus that was positive for T. cruzi also reacted with anti-human serum. A questionnaire was used to gather data on the demographic and socioeconomic characteristics of the population. An indirect immunofluorescent test, an indirect hemaglutination test, and an ELISA were used to detect the presence of antibodies against T. cruzi in 84 of 86 inhabitants and in 15.5% of people more than 20 years old. The relative risk (RR) of infection was greater in men than in women (RR = 1.61, 95% confidence interval = 0.54-4.80). Of the people more than 15 years old, 36.6% had no formal education. All respondents recognized triatomine bugs, but they did not relate them to Chagas disease transmission. A total of 85.7% of the houses were "ranchos" suitable for the colonization of triatomine bugs. The possible domiciliation of P. geniculatus and the implications of competition with R. prolixus for resources are discussed. Since there is no clear separation of food sources, abiotic factors such as microclimatic variation within houses may be critical to predict the outcome of the process of competition and potential domestication of this generally sylvatic species.

Trypanosoma cruzi, the causative agent of Chagas disease, has at least two principal intraspecific subdivisions, T. cruzi I (TCI) and T. cruzi II (TCII), the latter containing up to five subgroups (a-e). Whilst it is known that TCI predominates from the Amazon basin northwards and TCII to the South, where the disease is considered to be clinically more severe, the precise clinical and evolutionary significance of these divisions remains enigmatic. Here, we present compelling evidence of an association between TCI and opossums (Didelphis), and TCII and armadillos, on the basis of key new findings from the Paraguayan Chaco region, together with a comprehensive analysis of historical data. We suggest that the distinct arboreal and terrestrial ecologies, respectively, of these mammal hosts provide a persuasive explanation for the extant T. cruzi intraspecific diversity in South America, and for separate origins of Chagas disease in northern South America and in the southern cone countries.

A new species of the genus Linshcosteus Distant, 1904 (Hemiptera: Reduviidae: Triatominae) is described from specimens collected near Kalakkadu, Tamil Nadu state, southern India. Specimens were found in deep crevices between rocks, in a region of semi-arid scrub jungle. The distinctiveness of the new species was demonstrated by a morphometric analysis including the five previously described species of Linshcosteus, all from India. Nine measurements of the head were used in an isometric size-free principal component analysis. In terms of discrete morphology the new species, Linshcosteus karupus sp.n. Galvão, Patterson, Rocha & Jurberg differs from the most similar one, L. kali Lent & Wygodzinsky, 1979, by its very prominent anterolateral projections of the pronotum, by the length to width ratio of the pronotum, by the pilosity of the head and several other characters, including phallic structures. A revised key is presented for the six species of the genus.