ABSTRACT
The boll weevil causes serious damage to the cotton crop in South America. Several studies have been published on this pest, but its phenology and behavior under the tropical conditions prevailing in Brazil are not well-known. In this study the feeding behavior and main food sources of adult boll weevils throughout the year in Central Brazil was investigated. The digestive tract contents of insects captured in pheromone traps in two cotton fields and two areas of native vegetation (gallery forest and cerrado sensu stricto) were analyzed. The insect was captured all through the year only in the cerrado. It fed on pollen of 19 different plant families, on Pteridophyta and fungi spores and algae cysts. Simpson Index test showed that the cerrado provided greater diversity of pollen sources. In the beginning of the cotton cycle, the plant families used for pollen feeding were varied: in cotton area 1, the weevil fed on Poaceae(50 percent), Malvaceae and Smilacaceae (25 percent each); in cotton area 2 the pollen sources were Malvaceae (50 percent), Asteraceae (25 percent) and Fabaceae and Clusiaceae (25 percent each); in the cerrado they were Chenopodiaceae (67 percent) and Scheuchzeriaceae (33 percent). No weevils were collected in the gallery forest in this period. After cotton was harvested, the family Smilacaceae was predominant among the food plants exploited in all the study areas. These results help to explain the survivorship of adult boll weevil during cotton fallow season in Central Brazil and they are discussed in the context of behavioral adaptations to the prevailing tropical environmental conditions.
Subject(s)
Animals , Feeding Behavior , Weevils/physiology , BrazilABSTRACT
In orden to determine the sequential prevalence of pollen grains and fungi spores in the city of Caracas by the volumetric method of collection and its on the population at risk. The first multidisciplinary team of aerobiological research was structured through a protocol designed for five experimental stages namely: a) Determination of the climatological parameters, relative humidity, speed and wind direction, precipitation and atmospheric stability, through simultaneous records of meteorological status located in the metropolitan area of Caracas: b) Collection, identification, classification and determination of the local distribution of the important pollen grains existing in the zone under study: c) Collection, identification and classification of the most important fungi spores in the area; d) Preparation of the first pollinic calendar of Caracas and e) Evaluation of possible implication of the environment and the response through the IgE antibody in the selected patients in the area under study. Our results show: 1) The climatic conditions existing during the sampling period coincide with the analysis of the last 20 years in the Valley of Caracas. 2) The Venezuelan Central University (UCV) station was elected as the most representative point for permanent sampling. 3) An ideal statistical method is obtained in order to determine the spatial arrangement in the sampler rod of a dense type of spores typical of the area under study. 4) The firdt pollinic calendar of Caracas was structured and 5) A seasonal tendency of the IgE response is shown. These results suggested concept of poliseasonality and antigenic polysensitization, and between individual seasonality with a specific reactivity and, finally, between tropical mixed seasonality with the expression of combined respiratory pathologies in our environment
Subject(s)
Allergens/immunology , Spores, Fungal/isolation & purification , Hypersensitivity/immunology , Pollen/isolation & purificationABSTRACT
In order to search a uniform criteria for sampling aerobiological particles, three sites were selected along the of Caracas. The distribution of vegetation, topographical and meteorological parameters were monitored. Pollen and spores were collected at each site during 24 hr at 6 min-intervals with a Rotorod sampler. Pollen counts were similar in all sites and much less abundant than spores. Cladosporium was the most abundnt spore and grass pollen represented more than 50% of the pollen grains. Results showed that the three sites could be selected as suitable sampling area for airbone pollen and spores. Nevertheless, we recommend the selestion of the most accesible and central site for a long-term sampling