Pollen Preference Patterns by Tetragonisca angustula (Apidae: Meliponini) in a Boliviano-Tucumano Forest.

Native bees are important pollinators in neotropical forests. Tetragonisca angustula (Latreille) (Apidae: Meliponini) is a stingless bee widely distributed from the south of Mexico to Argentina. We characterized the patterns of preference of T. angustula for pollen in relation to the richness and abundance of plant species in the Tucumano-Boliviano Forest. During two field campaigns in different seasons (winter and spring), six colonies of T. angustula were studied. Pollen from flowers of plant species in the study area (pollen offer) and pot-pollen in each hive (pollen demand) were collected and their plant family of origin identified. Pollen from Asteraceae was more abundant in the winter than in the spring. Pollen of Solanaceae in the winter and Bignoniaceae in the spring were the most selected by the worker bees. Pollen from plants outside the sampling area was also found in the pots; it was mainly from Asteraceae. Tetragonisca angustula workers showed a polylectic foraging behavior, being able to use in a dynamic way the resources that are present in their environment at different times of the year; occasionally, it selected less abundant specific resources likely based on their nutritional value. More studies are needed to evaluate aspects of pollen quality consumed by this bee.

Age-related anomalies of electrocardiograms in patients from areas with differential Seroprevalence of Chagas disease in Southern Bolivia.

INTRODUCTION: Chagas disease currently affects some 6 million people around the world. At the chronic stage, cardiomyopathy occurs in about 20-30% of infested people. Most prevalence studies have focused on young to adult people due to the drastic consequences of acquiring the pathogen and the possibility to cure the disease at this age; the prevalence of this disease, the effect of patients' sex and the consequences to senescent people have been largely neglected. This study looks to characterize the seroprevalence of Chagas disease and its relation with occurrence of electrocardiographic anomalies associated with sex and age, and to compare rural and urban populations in Bolivia. METHODOLOGY: Seroprevalence of Chagas disease was determined in blood samples and electrocardiograms were performed on seropositive individuals. RESULTS: The rural population showed higher seroprevalence than the urban population (92% and 40%, respectively). The proportion of Chagasic cardiac anomalies in seropositive persons was highest in patients of the 50-59 age group (36%) as compared with the 40-49 (8%) and the ≥60 (17%) age groups. CONCLUSIONS: Higher seroprevalence in rural population was attributable to a higher probability to encounter the vector in rural areas. Increased exposure to infection and to development of the disease symptoms together with increased lethality of the disease as patients age explains the age-related Chagasic electrocardiographic anomalies. Since rural and urban populations showed different reactions under Chagas disease and the rural population was mainly of guaraní stock, the genetic and environmental determinants of the results should be further explored.