Pollen spectra of honeys from the Middle Delta of the Paraná River (Argentina) and their environmental relationship

Abstract

The aim of this study was to characterize honeys from the Middle Delta of Paraná River (Argentina) through pollen analysis and basic sensorial analysis, as well as assessing the vegetation contribution of this freshwater wetland as a source of nectar for Apis mellifera. Sixty-five samples were studied, out of which 109 pollen types, belonging to 53 plant families, were identified. The families Asteraceae and Leguminosae provided the greatest diversity of pollen types. Multifloral honeys were predominant (> 70%). Monofloral honeys were from Type Polygonum hydropiperoides (7), Sagittaria montevidensis (5), Eupatorium spp. (3), Pontederiaceae (2) and Salix humboltiana 1. Regional honeys are mistakenly called "Catay honeys" (Polygonum spp.) due to the wide distribution of species of this genus and the intense activity of honey bees observed on them. However, in the samples studied, Type Polygonum hydropiperoides varied from < 1% to 81% showing similar sensorial characteristics, among which the absence of crystals stands out. Pollen spectra of the "Catay honeys" reflect the surrounding freshwater wetland vegetation; when they present a value of > 25% taxa that do not belong to this ecosystem, they differ in their sensorial characteristics, particularly the presence of crystals. Pollen types such as Type Polygonum hydropiperoides, Sagittaria montevidensis, Eupatorium spp., Pontederiaceae, Nymphoides indica, Mimosa vellosiella, Vigna luteola, Cleome sp. and Type Solanum glaucophyllum, are suggested as geographical markers. According to the current knowledge, we propose to characterize these honeys considering their geographical origin instead of their botanical origin.