RESUMEN
Trigona spinipes Fabricius (Apidae: Meliponini), is a common stingless bee widely seen in urban and rural areas in Brazil, popularly known as irapuá, arapuá or bee-dog. Although these bees are considered pollinators of some cultivated plants, they are better known for the damage they cause in different crops. During experimental agroecological cultivation of Artemisia (Artemisia annuaLinn, Asteraceae), in Jaguariúna (SP, Brazil), stingless bees Trigona spinipes (Fabricius) were observed sucking phloem sap directly from the plant, a phenomenon not yet described in scientific literature. This study aimed to register and describe the phloem sap-sucking behavior performed by T. spinipesfor the first time, as well as to assess the potential impact of this behavior on A. annuacultivation. The behavior and the material collected by bees and the severity of attack were also analyzed. The aging and premature death of observed A. annuaspecimens occurred because of extensive lesions caused by T. spinipes, confirming the negative consequence of sap-sucking attacks of T. spinipesbees on the plants. Factors that could induce this unusual behavior were presented, pointing out the need for future studies on the development of strategies to protect plants, without causing damage to the T. spinipesbee populations, which are elements of Brazilian bee fauna and, therefore, protected by law.
Asunto(s)
Animales , Abejas/química , Artemisia annua/citología , Floema/química , Plantas Medicinales , Agricultura OrgánicaRESUMEN
Para avaliar o efeito do comportamento de três espécies de abelhas na polinização e produção de morangos, flores primárias dos cultivares Oso Grande (OS) e Sweet Charlie (SC) foram expostas a diferentes tratamentos de polinização: OS - uma e quatro visitas por Trigona spinipes (Apidae), uma visita por Dialictus sp (Halictidae) e quatro visitas mistas (Apis mellifera e T. spinipes); OS e SC - uma e quatro visitas por A. mellifera (Apidae). As variáveis avaliadas foram: peso fresco, número de aquênios dos frutos, taxa de fecundação e tempo de permanência da abelha na flor. Os tratamentos revelaram que T. spinipes pode ser considerada uma polinizadora tão eficiente das flores de OS quanto A. mellifera, pois seus resultados não apresentaram diferença significativa e ambas polinizaram de forma mais adequada a região apical dos frutos. Dialictus sp permaneceu mais tempo junto aos estames e polinizou mais adequadamente a região lateral do receptáculo que as outras espécies resultando, entretanto, em frutos com uma taxa de fecundação inferior e deformados, sem valor para o mercado in natura. O comportamento dessas três espécies de abelha sugere que deve haver um efeito complementar na polinização natural do cultivar OS, que pode levar os frutos ao seu potencial máximo de desenvolvimento. Sugere-se que o produtor de morango não elimine os ninhos de irapuá (T. spinipes) das proximidades, maneje as floradas do entorno e mantenha faixas de vegetação natural próximas a cultura, visando obter uma maiorvariedade de espécies de abelhas, garantindo assim, uma melhora na polinização e, conseqüentemente, na produção de frutos.
In order to evaluate the effect of the behaviour of three bee species on strawberry pollination and production, primary flowers of the cv. Oso Grande (OS) and Sweet Charlie (SC) were exposed to different treatments of pollination: OS was exposed to one and four visits of Trigona spinipes (Apidae); one visit of Dialictus sp (Halictidae); and to four combined visitations (Apis mellifera - Apidae - and T. spinipes). Both cultivars were exposed to one and four visits of A. mellifera. The evaluated traits were: fresh weight, number of achenes, fertilisation rate and length of visits.The results showed that T. spinipes can be considered as an efficient pollinator of OS flowers as A. mellifera, because evaluated traits did not show significant differences and both pollinated more adequately on their apex region. Dialictus sp stayed the longer on stamens than the two other species, and pollinated more adequately the lateral region of the receptacle resulting,however, in fruit with lower fertilisation rates and not marktable in natura. The behavior of these three species, suggests a complementary effect on the natural pollination of the cv. OS, resulting in fruits that can reach its maximal potential development. It is suggested to strawberry growers that do not eliminate T. spinipes nests, manage nearby blooms and preserve strips of vegetation close by, in order to obtain a larger variety of visiting bee species, assuring a higher pollination rate and, consequently, higher fruit production.