Faunistic analysis of flower-visiting hymenoptera in cerrad\ue3o fragment in Itirapina, SP

As abelhas s\ue3o consideradas os mais eficientes polinizadores. Desse modo, possuem papel indiscut\uedvel na reprodu\ue7\ue3o das plantas, aumento da qualidade e quantidade de frutos e sementes e, conseq\ufcentemente, na manuten\ue7\ue3o dos ecossistemas. O cerrado \ue9 um dos ecossistemas mais afetados pelo crescimento das atividades humanas, diminuindo drasticamente sua biodiversidade. A an\ue1lise faun\uedstica al\ue9m de identificar as esp\ue9cies e o tamanho das popula\ue7\uf5es, tamb\ue9m pode indicar o grau de impacto ambiental numa determinada \ue1rea. O levantamento dos himen\uf3pteros visitantes florais foi realizado quinzenalmente, no per\uedodo de mar\ue7o de 2003 a fevereiro de 2004, em \ue1rea de cerrad\ue3o, com aproximadamente 40 ha, na Esta\ue7\ue3o Experimental de Itirapina, SP. Foram coletados 181 indiv\uedduos, e a fam\uedlia Apidae apresentou maior n\ufamero de esp\ue9cies e abund\ue2ncia de indiv\uedduos. As abelhas, Apis mellifera com 55,8%, seguida de Trigona spinipes com 14,4% e Exomalopsis (Exomalopsis) sp. com 8,3% foram as predominantes. Dentre as abelhas coletadas, 30,8% das esp\ue9cies s\ue3o sociais e 69,2% das esp\ue9cies s\ue3o solit\ue1rias. Do total de himen\uf3pteros coletados, 59,7% preferiram o per\uedodo da manh\ue3 e 40,3% o per\uedodo da tarde para forrageamento e/ou visita. O \uedndice de diversidade de esp\ue9cies (H) (Shannon-Wiener) foi 1,6933, a vari\ue2ncia (H) foi 0,0123 e o \uedndice de uniformidade (E) foi 0,5652, seguindo padr\ue3o encontrado em outras \ue1reas de cerrado.Bees are considered one of the most efficient pollinators. Therefore, they have indisputable role in the plants reproduction, since they increase the quality and quantity of fruit and seeds, and thus they help the ecosystems maintenance. Cerrado is one of the most affected ecosystems due to the growth of human activities, drastically reducing its biodiversity. The faunistic analysis identifies the species and the size of the populations, and can also indicate the degree of environmental impact on a particular area. Surveys on flower-visiting hymenoptera in a "cerrad\ue3o" area, with 40ha, in the Experimental Station of Itiparina (SP), were conducted every fifteen days from March 2003 to February 2004. From 181 insects collected, the Apidae family was represented by the largest number of species and individuals. The species Apis mellifera (55.8%), Trigona spinipes (14.4%) and Exomalopsis (Exomalopsis) sp. (8.3%) were the most prevalent in the area. Among the bees species collected, 30.8% were classified as sociable and 69.2% as solitary. Considering all hymenoptera collected, 59.7% preferred the morning period and 40.3% the afternoon period for foraging and/or visiting. The Diversity index (Shannon-Wiener) H was 1.6933, V(H) = 0.0123 and Uniformity index E = 0.5652, following pattern found in other areas of cerrado