Ecologia de Bruchidae na predação pré-dispersão de sementes de Albizzia lebbeck (Benth.) em arborização

Abstract

The predispersal seeds predation for insects is of highest important for reducing the production of seeds and your germination capacity due the damages provoked by insects in larval development in seeds reducing the energy reservations of the embryo drastically when of the attack in the cotyledons affecting the development and seedling establishment in the field and mortality of the seeds when of the attack directly to the embryonic axis. Due to the low number of works accomplished with the species Albizzia lebbeck in arborization in relation to ecology and behavior of the insects predators, it was aimed at to evaluate and quantify the damages so much in seeds as the occurrence and population flotation of the insects and your influence on seeds viability with emphasis of the phase of maturation of the fruits, time and collection sites in different levels of pollution of the air for self-driven vehicles. Pods of A. lebbeck in arborization were collected at the campus of UFRRJ and BR 465 at the Km 32 of the old Estrada Rio-São Paulo (Nova Iguaçu) and Km 47 (Seropédica), municipal districts of the State of Rio de Janeiro and transported to the Laboratory of Forest Entomology, DPF, IF, UFRuralRJ for the analyses. Meeting as result the premature maturation of fruits of larger length, smaller infestation level for insects due to the low number of individuals in oviposition in the first pods and increase of the infestation for insects in pods of late maturation and sites with larger level of pollution of the air, the same being verified in the end improvement of the seeds in quarantine, enrolling in the general evaluation, percentage of 9% of intact seeds (healthy), 31% of aborted seeds and 60% of damaged seeds being this of 83% in trees located in the central bed in a garden of the Highway (Km 32), 43% to your margin (Km 47) and 42% in trees located in area of conservation of the Botanical Garden of UFRRJ. Meeting percentage of 92.68% of insects predators of seeds distributed in the following species: Bruchidius sp. (57.39%), Merobruchus paquetae (33.98%), Stator limbatus (0.27%) and a type of Lepidoptera non-identified (1.04%) and, the remaining of the emergent insects (7.32%), belonging to the order Hymenoptera. The individuals of the species Bruchidius sp. they presented period of very defined emergency with peak in the middle of September (about 135 days after the observation of the first oviposition in the field) and the species M. paquetae occurrences medium quite homogeneous, with low number of individuals and few variations along the whole emergency period in pods in quarantine. The largest bruchids number happened in area with larger level of pollution of the air, being the species Bruchidius sp. predominant in pods of trees located in the central bed in a garden of the highway and the species M. paquetae in trees located to the margin of the highway with 20 meters of distance. The number of insect bruchids was reduced with the decrease of the pollution of the air in arborization that was reflected in smaller rate of damaged seeds and larger number of germinated seeds.