Percentages of botanical taxa recovered from pot-honey and pot-pollen samples in the melissopalynological analyses.
The demand for stingless bees’ products (pot-honey and pot-pollen) has increased. No formal quality standards have been defined, which is very complex, because of the variety of species and types of honey specific to each region. For this reason, it is important to deepen the understanding of stingless bees’ honey characteristics. From the above, the aim of this chapter is to present the advances in the characterization of botanical origin of stingless bees’ honey, and the analysis of their physicochemical properties in the Alto Balsas, Michoacán, Mexico, as a way to contribute to the strengthening of new local economic strategies, generating information on the quality of the honey produced in the region.
- botanical origin of honey
- melissopalynological analysis
- honey quality
- analytical electrochemistry
The work we present is part of a research project that has been carried out since 2014 to date, in the area that we refer to as
At the moment we identified a total of nine stingless bees’ species in the study area . Our inventory included a new registry of
Stingless bees have been of great economic importance for the production of honey, a product that has been used since ancient times, and particularly in the case of Mexico, have been part of the social and religious life of different cultural groups .
Through our experience we have observed two relevant phenomena in the context of the study region, while is true that local knowledge about use, management and ecological issues on stingless bees is persistent, is being lost intergenerationally together with the disuse of the products of these bees, accompanied by the decline in stingless bee populations [3, 5]. On the other hand, new expressions are arising which re-signify stingless bees and their ecological, economic and social importance expressing in the emergence of local initiatives that seek not only to promote the production of stingless bees’ honey, but also perspectives for their conservation .
In this context, we have oriented efforts toward the strengthening of the productive activity focusing on the honey characteristics that is being produced in the region. Primarily, we are interested in knowing the botanical origin of honey since its properties depend on the origin of the nectar or the secretions used by bees [6, 7]. Nectar (flower honey) are classified according to the main source where the bees collect the nectar being monofloral or multifloral [8, 9]. In addition, we consider relevant this source of information to understand the implications of environmental heterogeneity on the availability of resources for bees and their foraging patterns.
In a complementary way, we have been analyzing the physicochemical properties of honey. Recently the demand for natural, organic and homeopathic products has increased, including those of stingless bees. Although there are several works that seek to characterize the physicochemical properties particularly for the stingless bees’ honey [10, 11] have not yet been defined formal norms or quality standards, which is very complex because of the variety of species and types of honey specific to each region. For this reason, it is important to deepen the understanding of the physicochemical stingless bees’ honey characteristics.
From these perspectives, the aim of this chapter is to present the advances in the characterization of botanical origin of stingless bees’ honey, and the analysis of their physicochemical properties in the study area.
2. Study area
The Balsas River Basin covers eight states, particularly for Michoacán this basin can be divided into three sub regions, taking an altitudinal criterion: Alto Balsas, Medio Balsas, and Bajo Balsas (Tepalcatepec). The specific area of study falls inside the sub-region of Alto y Medio Balsas. The process of collecting honey samples was carried out mainly in the municipality of Madero (19° 10′, and 19° 33′ N and 100° 59′, 101° 22′ W), it borders to the north with the municipalities of Acuitzio, Morelia and Tzitzio; to the east with Tzitzio and Tiquicheo de Nicolás Romero; to the south with Carácuaro and Nocupétaro; to the west with Nocupétaro, Tacámbaro, and Acuitzio. It has an altitudinal gradient that goes from 800 to 2900 m and has a temperate humid climate with summer rains (Cw) and in the south it is warm subhumid with summer rains (Aw). It has an annual rainfall of 1654.5 mm and its temperature ranges from 7.5 to 23.9°C . In the municipality, the pine-oak forests are predominant and it presents a small portion of tropical dry forest. At the moment, a total of 62 species of api-botanical interest have been recorded, of which 65% provide nectar, 22% nectar and pollen, and 13% pollen to bees . The most representative families are Asteraceae, Leguminosae, and Lamiaceae. It has been described that there are two flowering peaks, one that goes from March to May corresponding to the dry season and another that goes from September to November, which corresponds to the rainy season, specifically in the fall .
3. Collection and analysis of pot-honey and pot-pollen samples
For the analysis of the botanical origin, samples of pot-honey and pot-pollen were collected during May 2017 (dry season) and December 2017, from four species of stingless bees:
|Date of collect||May/2017||May/2017||May/2017||May/2017||December/2017||December/2017||December/2017||December/2017|
|Localities||Piumo||San Pedro Piedras Gordas||Etucuaro||Etucuaro|
We analyzed also honey physicochemical properties of the most frequently used stingless bees’ species:
|Species||Mt||V||Se||Humidity (%)||pH||Ash content (%)||Reducing sugars (%)||F (%)||S (%)||HMF (mg kg−1)|
4. Pot-pollen and pot-honey characteristics
4.1 Botanical origin based on melissopalynological analysis
Melissopalynological study showed polylectic behavior of
Respect to pot-pollen samples, the pot-pollen analyses gave evidence of polliniferous preferences of only one resource in all four stingless bee species. The best polliniferous plants were Rhamnaceae (85.3%) for
4.2 Physicochemical characteristics
In relation to the chemical parameters obtained from the stingless bees’ honey samples analyzed (Table 2), higher moisture content was observed than the levels set in the Mexican standard (or practical values) for
Just as there are differences between pot-honey and the honey of
However, it is possible to observe certain relevant patterns. As shown in Table 3, the first two components of the PCA explain 66% of the variation in the data. The most important variables in the first component are the percentage of ash and pH, with antagonistic effects. In the second component, reducing sugars and pH are the most relevant variables, also with antagonistic interactions. In the biplot (Figure 1), two groups are distinguished; the pot-honey samples that were obtained from hives managed by meliponiculture techniques (M) are separated from the pot-honey samples that were obtained by direct extraction of wild nests (E).
|% of variance||36.78||29.18||13.69||12.31||4.62||2.13||1.29|
|% of cumulative variance||36.78||65.97||79.65||91.96||96.58||98.71||100.00|
There is a group of three samples of honey (M) that are strongly influenced by the reducing sugars and that showed the highest values of this parameter (
In general terms, stingless bees from the study region use both arboreal and herbaceous species as resources, either from local vegetation or from introduced vegetation. It is interesting to note that
There is few information about physicochemical composition of stingless bee honey, and non-official quality control standards have been developed in Mexico or any country. Existing honey standards, for
In a relevant way we documented in the pot-honey samples analyzed that they present an HMF content below the Mexican norm, and even below the limit of detection, which indicates that this honey is of excellent quality and had a good handling both when storing and when transporting. Regarding the moisture content, the analyzed samples presented high values not only with respect to the Mexican norm but also to other samples from other regions of Mexico. This may be due to the fact that honey was freshly collected with little storage time.
The content of total reducing sugars and fructose is higher in the honey of
We consider that there is a need to generate information that allows us to establish general guidelines of quality for stingless bees’ honey, and for this, it requires a wide sample of honey samples systematically generated including: diversity of species, ecosystems or vegetation types, seasonality of production and strategies of management to develop more precise statistical analyzes.
The work presented was done thanks to the financing of the “Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT)” of the “Dirección General de Apoyo al Personal Académico (DGAPA),” through the project “Efectos del manejo y transformación del paisaje sobre las poblaciones de abejas nativas sin aguijón en la Cuenca del Balsas, Michoacán, México (TA200416),” National Autonomous University of Mexico. We would like to sincerely thank to the Meliponicultores Michoacanos del Balsas group and all meliponicultores and colmeneros of the study area for their help, interest and involvement