The Asian tiger mosquito ( Aedes albopictus, Diptera: Culicidae) has spread rapidly in the last 30 years from its native region in Southeast Asia. In Argentina, studies on its potential distribution suggest that this species could be found in temperate zones of the province of Buenos Aires. However, since its initial detection in 1998 Ae. albopictus is bounded to the subtropical province of Misiones. To evaluate the presence and abundance of Ae. albopictus in the Northeast of Argentina, we preliminarily evaluated the presence of this vector by analyzing its presence in tires of 20 cities belonging to the province of Misiones and four cities in Northern Corrientes, and then performed an evaluation of the vector in the towns where the vector was detected. Aedes albopictus was present only in two cities of Misiones: Eldorado and Colonia Aurora. Aedes aegypti and Ae . albopictus accounted for 86% of the individuals collected in the domiciles of both towns. In Colonia Aurora both species were in similar abundances suggesting a co-dominance. The present study extends the austral distribution of Ae. albopictus in Argentina to the city of Colonia Aurora where the highest abundance recorded in Argentina was detected. Nevertheless, the reasons of its bounded distribution in the region are not known.

We assessed the prevalence of infection with Trypanosoma cruzi, parasite genotypes (discrete typing units, DTUs), and the host-feeding sources of domestic and peridomestic Triatoma infestans Klug and Triatoma eratyrusiformis Del Ponte in eight rural communities of the subandean Calchaqui valleys in northwestern Argentina. We sought to analyze their epidemiological role in the context of routine vector surveillance and control actions. Infection with T. cruzi was determined by optic microscopy or polymerase chain reaction (PCR) amplification of the hypervariable region of kinetoplast DNA minicircles. Parasite genotypes were identified through a multi PCR-based strategy. Bloodmeal contents were tested with a direct ELISA assay against nine antisera. Human sleeping quarters (domiciles) and peridomestic dry-shrub fences concentrated most of the T. infestans and T. eratyrusiformis infected with T. cruzi, respectively. The most frequent host-feeding sources of T. infestans were chickens (73.1%) in peridomiciles and humans (73.3%) in domiciles, whereas T. eratyrusiformis fed more often on cavid rodents (92.6%), which thrived in the dry-shrub fences. The main T. cruzi DTU identified in both vectors was T. cruzi I (TcI). Triatoma eratyrusiformis was implicated in the local circulation of TcI among cavies and perhaps mice, but infection with other typically domestic DTUs (TcVI and TcII/TcV/TcVI) indicated overlap between (peri)domestic transmission cycles in both vector species. Because dry-shrub fences were not targeted for routine insecticide spraying, they may act as sources of (peri)domestic reinfestation. Triatoma eratyrusiformis is an emergent secondary vector of T. cruzi and plays a significant role in the local transmission of T. cruzi.

Aedes albopictus (Diptera: Culicidae) distribution is bounded to a subtropical area in Argentina, while Aedes aegypti (Diptera: Culicidae) covers both temperate and subtropical regions. We assessed thermal and photoperiod conditions on dormancy status, development time and mortality for these species from subtropical Argentina. Short days (8 light : 16 dark) significantly increased larval development time for both species, an effect previously linked to diapause incidence. Aedes albopictus showed higher mortality than Ae. aegypti at 16 °C under long day treatments (16 light : 8 dark), which could indicate a lower tolerance to a sudden temperature decrease during the summer season. Aedes albopictus showed a slightly higher percentage of dormant eggs from females exposed to a short day, relative to previous research in Brazilian populations. Since we employed more hours of darkness, this could suggest a relationship between day‐length and dormancy intensity. Interestingly, local Ae. aegypti presented dormancy similar to Ae. albopictus, in accordance with temperate populations. The minimum dormancy in Ae. albopictus would not be sufficient to extend its bounded distribution. We believe that these findings represent a novel contribution to current knowledge about the ecophysiology of Ae. albopictus and Ae. aegypti, two species with great epidemiological relevance in this subtropical region.

Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) are worldwide vectors of dengue and yellow fever viruses. These species coexist in many countries and the biotic interactions between them can influence their abundances and distributions. In Argentina, Ae. aegypti is widely distributed in the north and center regions of the country, with temperate and subtropical climate, while both are sympatric only in the northeastern area of the subtropical region. Interspecific and intraspecific larval competition for food was evaluated to assess if their interaction influences on patterns of abundance and distribution. Finite rates of increase and survivorship for each species were estimated and the effects of mosquito density ratio and detritus availability were determined. The Lambda (λ´) index of population performance of both showed there is no competitive exclusion pattern. However, survival of Ae. albopictus was negatively affected by the presence of Ae. aegypti. These results suggest one possible explanation for the codominance pattern of both species display in rural regions of the southernmost distribution of Ae. albopictus in South America. They also show Ae. aegypti as a potential biotic barrier for the expansion of Ae. albopictus as was reported in regions of the United States.

In Argentina, the distribution of Aedes albopictus (Skuse) is limited to two provinces with a subtropical climate and few records. This study aims to describe and compare assemblies of Culicidae that breed in artificial containers in two areas with different degrees of urbanisation where Ae. albopictus is present and to evaluate possible biotic interactions. We sampled container larval habitats of an urban (Eldorado city) and a rural environment (Colonia Aurora village). We performed generalized linear mixed models to evaluate which variables (containers characteristics or environment) are associated with the presence and abundance of Ae. albopictus, Aedes aegypti Linneaus and Culex quinquefasciatus Say, and the presence of mosquito predators (Lutzia bigoti (Bellardi) and Toxorhynchites spp.). Also, the relationship between the most abundant species was quantified in each environment using Hurlbert's C8 association coefficient. Ae. aegypti was the most abundant species in the urban environment, while Cx. quinquefasciatus and Ae. albopictus were the most abundant in the rural area. Predators were more present in the rural environment and affected the abundance of Aedes mosquitoes. Regarding the C8 index, Ae. aegypti was negatively associated with Ae. albopictus in the urban area, whereas in the rural area these species presented a significantly positive relationship. These results show that in urban environments the high abundance of Ae. aegypti could be affecting the Asian tiger mosquito as evidenced by local studies of food larval competition. Also a greater presence of predators could be affecting Ae. albopictus in rural environments.