RESUMEN
Adenocalymma bracteatum is a shrub of dense foliage and yellow flowers, easily found on grasslands areas in Central Brazil. The aim of this study was to determine the reproductive biology and the flower visitors of A. bracteatum in a pasture area nearby Ivinhema city, MS (Brazil). The flowering peak occurs in winter. The flower reflects ultraviolet light. Anthesis begins at 6:30h, and pollen and nectar are the resources to visitors. We captured 1,038 floral visitors. The bees Apis mellifera (L.), Trigona sp., Trigona spinipes (Fabricius), (Hymenoptera: Apoidea) and the ant Cephalotes sp. (Hymenoptera: Formicidae) were the main visitors. The reproductive tests indicate that A. bracteatum is self compatible, justifying its expansion in altered environments; however, the largest reproductive success was dependant on cross-pollination and self-pollination, evidencing the pollinators importance. Adenocalymma bracteatum presents melittophilous syndrome and bumblebees were the main pollinators in the area. The correlations observed between the climatic variables and the main pollinator species were low or medium.
Asunto(s)
Animales , Bignoniaceae/fisiología , Flores , Insectos , PolinizaciónRESUMEN
The causal mechanisms shaping and structuring ecological communities are among the most important themes in ecology. The study of insect-plant interactions in trophic nets is pointed out as basic to improve our knowledge on this issue. The cerrado tropical savanna, although extremely diverse, distributed in more than 20 percent of the Brazilian territory and filled up with rich examples of multitrophic interactions, is underexplored in terms of biodiversity interaction. Here, this ecosystem is suggested as valuable to the study of insect-plant interactions whose understanding can throw a new light at the ecological communities' theory. Three distinct systems: extrafloral nectary plants or trophobiont herbivores and the associated ant fauna; floral herbivores-predators-pollinators; and plants-forest engineers and associated fauna, will serve as examples to illustrate promising new pathways in cerrado. The aim of this brief text is to instigate young researchers, mainly entomologists, to initiate more elaborated field work, including experimental manipulations in multitrophic systems, to explore in an interactive way the structure that maintain preserved viable communities in the Neotropical savanna.
Os mecanismos causais que moldam e estruturam as comunidades ecológicas estão entre os mais importantes temas da ecologia. O estudo das interações inseto-planta nas redes tróficas é apontado como básico para alavancar nossos conhecimentos no assunto. Os cerrados (savana tropical), embora extremamente diversos e distribuídos em uma área superior a 20 por cento do território brasileiro, com ricos exemplos de interações multitróficas, são pouco explorados em termos de biodiversidade interativa. Aqui, esse ecossistema é sugerido como possuidor de bons modelos para o estudo das interações insetoplanta, cuja compreensão pode lançar uma nova luz na teoria das comunidades ecológicas. Três sistemas distintos: plantas com nectários extraflorais ou herbívoros trofobiontes e a fauna de formigas associadas; herbívoros florais-predadores-polinizadores; e planta-engenheiros das florestas e a fauna associada, irão servir de exemplo para ilustrar esses novos e promissores caminhos de investigação científica no cerrado. O objetivo principal desse breve texto é instigar jovens pesquisadores, principalmente entomologistas, a iniciarem estudos de campo mais elaborados, incluindo manipulações experimentais em sistemas multitróficos, para explorar de modo interativo a estrutura que mantém preservadas as comunidades das savanas neotropicais.