Polinização entomófila de Cucurbita moschata Poir em áreas agrícolas nos municípios de Viçosa e Paula Cândido, Minas Gerais, Brasil / Entomophilic pollination of Cucurbita moschata Poir in areas agricultural on the municipal district of Viçosa and Paula Cândido, Minas Gerais, Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The objectives of this work were to determine Cucurbita moschatas pollinator entomofauna in the region of Viçosa, Minas Gerais, to study these insects behavior on flowers and to evaluate their importance on pollinating this plant, while verifying the role of each individual pollinator. In addition, to analyze aspects from flower biology and daily activity pattern of flowervisiting insects. The stigma was receptive from 5:00h to 12:00h and the viability of pollen grains was 96,68%. The most common bee species were Trigona spinipes, Trigona hyalinata, Apis mellifera and Melipona quadrifasciata. Bee activity was higher between 7:00h and 10:00h, and there were differences on the most abundant species of bees on the different study areas. The visitation behavior of A. mellifera, M. quadrifasciata,and Bombus morio were similar. They visited flowers for nectar collection, positioning themselves vertically between the corolla and the sexual structures of the flowers, with the back directed toward the floral axis, which allowed the removal of pollen from the anthers of flowers with stamens and its deposition on the stigma of flowers with pistils. T. spinipes and T. hyalinata foraged in groups and monopolized the sources, preventing other species from landing on the flowers which they occupied. The bees visited the flowers only for nectar collection no pollen collection was observed, even though its bodies were full of grains after visits to the flowers with stamens. There was no fruit production when the flowers were prevented from receiving insect visits or from flowers visited only once by T. spinipes. When flowers were visited only once either by M. quadrifasciata, B. morio, A. mellifera or T. hyalinata, there was no difference in percentage of fruit production. There was no difference on fruit production when the flowers have received natural or manual pollination (F=2,53; gl=1; p=0,11). However, manually pollinated flowers produced longer fruits. No differences were found in the weight, number of seeds and diameters of the anterior, median and posterior portions of the fruits, according to the type of treatment (opened or manual). A multiple regression analysis showed that, under the study sites conditions, there was no effect from the abiotic variables temperature, relative air humidity and luminosity on the total number of captured bees. According to a simple regression analysis with the data of luminosity and number of individuals of A. mellifera, there is a 98% probability that light explains the number of captured A. mellifera individuals (r2=0,13; p=0,02). However, this species activity patterns might be associated with the intense foraging from the Trigona species that monopolize the flowers and show aggressive behavior.

ASSUNTO(S)

pollination bees abelhas zoologia aplicada cucurbita moschata cucurbita moschata polinização

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