The intergenic region of spliced-leader (SL-IR) genes from 105 Trypanosoma cruzi I (Tc I) infected biological samples, culture isolates and stocks from 11 endemic countries, from Argentina to the USA were characterised, allowing identification of 76 genotypes with 54 polymorphic sites from 123 aligned sequences. On the basis of the microsatellite motif proposed by Herrera et al. (2007) to define four haplotypes in Colombia, we could classify these genotypes into four distinct Tc I SL-IR groups, three corresponding to the former haplotypes Ia (11 genotypes), Ib (11 genotypes) and Id (35 genotypes); and one novel group, Ie (19 genotypes). Genotypes harbouring the Tc Ic motif were not detected in our study. Tc Ia was associated with domestic cycles in southern and northern South America and sylvatic cycles in Central and North America. Tc Ib was found in all transmission cycles from Colombia. Tc Id was identified in all transmission cycles from Argentina and Colombia, including Chagas cardiomyopathy patients, sylvatic Brazilian samples and human cases from French Guiana, Panama and Venezuela. Tc Ie gathered five samples from domestic Triatoma infestans from northern Argentina, nine samples from wild Mepraia spinolai and Mepraia gajardoi and two chagasic patients from Chile and one from a Bolivian patient with chagasic reactivation. Mixed infections by Tc Ia+Tc Id, Tc Ia+Tc Ie and Tc Id+Tc Ie were detected in vector faeces and isolates from human and vector samples. In addition, Tc Ia and Tc Id were identified in different tissues from a heart transplanted Chagas cardiomyopathy patient with reactivation, denoting histotropism. Trypanosoma cruzi I SL-IR genotypes from parasites infecting Triatoma gerstaeckeri and Didelphis virginiana from USA, T. infestans from Paraguay, Rhodnius nasutus and Rhodnius neglectus from Brazil and M. spinolai and M. gajardoi from Chile are to our knowledge described for the first time.

Ongoing discussion on the taxonomic status of Anastrepha fraterculus (Wiedemann) and limited biological knowledge of this species emphasize a need fo

The effects of male size and other morphometric traits as determinants of male mating success were evaluated under field cage conditions. Males of the laboratory Seib6-96 strain were released into field cages with males and females of a wild population from the Patagonian region. Mating pairs were classified as ‘successful’, while unmated flies were labeled as ‘unsuccessful’. Five morphometric traits were measured in a sample of 141 unsuccessful and 149 successful males: eye length (EL), head width (HW), thorax length (TL), face width (FW), and wing length (WL). An exploratory non-parametric Spearman’s rank correlation test indicated that mated males were in average larger for all traits (P < 0.01) except FW, indicating that with the exception of FW all traits are positively correlated with mating success. Step-wise multiple regression and principal component analysis + logistic regression indicated that the most likely targets of selection were TL, EL, and FW. The two former are positively corre... RESUMEN Se evaluaron los efectos del tamaño y otros rasgos morfométricos del macho como determinantes del éxito copulatorio en condiciones de jaulas de campo. Se liberaron en jaulas de campo machos de la línea de laboratorio Seib6-96 junto con machos y hembras de una población salvaje de la región Patagónica. Las parejas en cópula se clasificaron como “exitosas”, mientras que las moscas que no se aparearon se marcaron como “no exitosas”. En una muestra de 141 machos no exitosos y 149 exitosos se midieron 5 rasgos morfométricos: longitud del ojo (LO), ancho de la cabeza (ACb), longitud del tórax (LT), ancho de la cara (ACr) y largo del ala (LA). Un análisis exploratorio no paramétrico utilizando la correlación de rangos de Spearman indicó que los machos apareados eran en promedio más grandes para todos los rasgos (P < 0.01), salvo para ACr, indicando que, con la excepción de ACr, todos los rasgos están positivamente correlacionados con el éxito copulatorio. Análisis de regresión múltiple de a pasos (“step-...

Anastrepha fraterculus (Wiedmann), a South American fruit fly, is an economically important pest for fruit-bearing plants of the neotropical region. Some evidence indicates that the nominal A. fraterculus comprises multiple cryptic species. In the current work we analyzed genetic variability and structure in Argentine populations of A. fraterculus based on eight isoenzymatic loci and the restriction patterns of a fragment of &500 bp belonging to the 16 S mitochondrial ribosomal DNA. The isoenzymatic analysis indicated a significant excess of homozygotes (F _IS > 0), due to the fact that sampling sites probably do not constitute stable Mendelian populations. Genetic similarities ranged within values expected for conspecific populations and gene flow, estimated indirectly from the F _ST value, was high. The phenogram obtained by unweighted pair-group method with arithmetic average among populations shows disagreements with the expected result based on geographic distribution. Populations located in the neighborhood of Buenos Aires City show high diversity probably due to a high migration rate from different regions. The polymerase chain reaction (PCR)+restriction fragment-length polymorphism (RFLP) analysis of the mtDNA fragment involved 11 Argentine and one south Brazilian populations. The PCR product was digested by three endonucleases: Ssp-I, Ase-I, and Mnl-I. The observed patterns showed no variation within nor among the populations studied here but differed from the expected results based on the sequences recorded by other researchers for populations of north Brazil, Venezuela, and Mexico. The results so far obtained indicate that, despite the occurrence of macrogeographical variation, the Argentine and south Brazilian populations studied here belong to a single biological species.