RESEARCH WORK
Foraging selectivity of the stingless bee Melipona beecheii Bennett at the EEPF "Indio Hatuey", Matanzas
¹Estación Experimental de Pastos y Forrajes "Indio Hatuey" Central España Republicana, CP 44280, Matanzas, Cuba.
E-mail. leydis.fonte@indio.atenas.inf.cu
²Universidad Agraria de La Habana, Cuba
ABSTRACT
The work was conducted at the EEPF "Indio Hatuey" to determine the foraging selectivity of stingless bees (Melipona beecheii Bennett) through the analysis of honey and pollen samples. A floristic inventory of the area had been previously made around the apiary location, taking into consideration the bees' flight radius. The stair method was used in the silvopastures, and in the case of the living fences the trees were counted every 10 meters and this was shown in the sketch of the sampled area. In the groves and yards all trees where counted and classified, and in the herbaceous stratum the step method was applied. The pollen grains of guava (Psidium guajava) and mastic tree (Bursera simaruba) predominated in both kinds of samples, followed by the pollen grains of touch-me-not (Mimosa pudica), mimosa (Mimosa pigra), orange and lemon tree (Citrus ssp.).The stingless bees were concluded to show marked foraging selectivity for the guava and mastic tree flowers, and that the Station has the sufficient melliferous potential for them to develop favorably, on a sustainable feeding basis.
Key words: Melipona beecheii, pollen analysis, foraging.
Around 30% of human food comes from plants pollinated by bees (Leal, 2010). Pollination is a vital process in the ecosystems; which depends, to a large extent, on the symbiosis between species, i.e., pollinator and pollinated. This link is established through the collection of nectar (as carbohydrate source) and flower pollen (as protein source), made by bees to feed and survive. Likewise its principal products are honey, propolis, royal jelly, wax and poison which are directly used by mankind.
Landaverde, Zamora and Aguilar (2006), based on the Malipona beecheii floral preferences, pointed out as important sources of pollen the following ones: touch-me-not (Mimosa pudica, from the Fabaceae family) and the shrubs Conostegia xalapensis, from the Melastomataceae family, and Solanum asperum (Solanaceae family). The shrubs that provided nectar belong to the families Asteraceae (among them, Montanoa hibiscifolia) and Solanaceae (Cestrum sp.) The trees represented in the pollen and nectar samples collected by the stingless bee were: Ecuador laurel (Cordia alliodora, Boraginaceae family), Heliocarpus mexicanus, from the Tiliaceae family, cedar (Cedrela odorata, Meliaceae family) cherry (Prunus sp., Rosaceae family), sweetgum (Liquidambar styraciflua, Hammamelidaceae family), Solanum diphyllum, from the Solanaceae family, and exotic trees such as rose apple (Syzigium jambos, Myrtaceae family).
In Cuba the need for pollinators increases everyday because of the development of urban and suburban agriculture, which include in their programs the cultivation of vegetables, flowers, fruits, herbs and spices, and medicinal plants, among others. The study of the wild bee behavior together with the study of the stingless bee behavior can be an alternative to increase pollination levels of the urban and suburban zones, and of the growing sheds (León, 2000).
Despite its great work as pollinator, the autochthonous stingless bee has been highly damaged because of environment deterioration, loss of the vegetation that provides for them nectar, pollen and places for living; and because of the use of chemical pesticides. This frailty of the species is an adaptative disadvantage, but, in turn, it is an indicator of environmental health (Villanueva et al., 2005; Genaro, 2006; Leal, 2010).
The fact that in the EEPF "Indio Hatuey" there is a meliponary since more than five years ago (Fonte, 2007), demonstrates the existence of enough diversity and floristic density to satisfy the species requirements in a healthy environment.
In this sense, the objective of this research was to determine the foraging selectivity of the stingless bee in agricultural areas of this institution, through the analysis of honey and pollen samples.
The study was conducted at the EEPF "Indio Hatuey", Perico municipality, Matanzas province, Cuba, which is located at 22°48'7" latitude North and 81°2' longitude West at 19,01 masl.
In this region the climate has two well defined seasons: the rainy season from May to June, when 70-80% of rainfall occurs, and the dry season (November-April). The annual average rainfall is 1200 mm, mean temperature is 25°C, and the relative humidity is 60-70% during the day, and 80-90% atnight. The soil is Ferralitic Red, with slightly acid pH (6,2-6,4).
A floristic inventory of the area was made in 2009 (Milera et al. unpublished data), around the meliponary, based on the bees' flight radius. The stair method was used in the silvopastures, in which -after knowing the planting distance of the trees in the row- the rows were counted by paddock or blocks from left to right and were numbered in a field sketch. After that, the sampling started for the first row, counting the trees in the first 10 meters; then, the trees of the second one were counted, in parallel, and tree counting continued in the next 10 m, and thus successively, row by row, like steps, until the end of the paddock. Later, the same was done, but, from back to front in the next row, in the same way as described above.
In the case of the living fences, the trees were counted every 10 m and this was shown in the sketch of the sampled area. In the groves and backyards all trees were counted and classified, while in the herbaceous stratum of paddocks the step method was applied; this consisted in drawing diagonals by which the sampler walked and made observations of the existing vegetation; every double step in small areas; every four steps in medium areas and every eight steps in large ones. To make the reading the grass species that coincided with the toecap of the shoe was taken as reference.
It is located in the middle of a grove which is situated in the small animal facility of the EEPF "Indio Hatuey". It has four beehives in wooden boxes (40 cm long by 10 cm wide) of the Pablo Nogueira Neto PNN model (Nogueira, 1997). These boxes were brought from Jagüey Grande, Matanzas province, on March 23rd, 2007.During the development period of these bees it was not necessary to use supplements.
Two samplings were made in 50% of the beehives; one during the rainy season (July, 2011) and another one during the dry season (February, 2012). From each beehive, an amphora containing pollen and another containing 25 mL of honey were taken. Sample collection was conducted at the same time (9:00 a.m.).
The pollen study was made in the Cuban Institute of Ecology and Systematics (IES) according to the methods of acetolysis and hot aqueous solution of sodium or potassium carbonate (Sánchez, 2011).
Tables 1 and 2 showed the plants that predominate in the flight radius of the M. beecheii colony, according to the floristic inventory of the area.
The most abundant species among the ligneous plants were: Morus alba (10 350), Leucaena leucocephala (4 515), Gliricidia sepium (2 573), ALbizia lebbeck (1 122), Psidium guajava (286), Moringa oleifera (241), Mangifera indica (183), Persea americana (134) and Cocus nucifera (76).
In the herbaceous stratum the following predominated: Panicum maximum, Brachiaria decumbens, Brachiaria purpurascens, Dichanthium caricosum, M. pudica and Mimosa pigra. Also, plants were found of tree marigold (Tithonia diversifolia), belonging to the forage and seed production areas of the Institution and Dichrostachys cinerea which covered 10% of the grazing area of the dairy unit.
The pollen analysis in both seasons, rainy and dry, showed the presence of pollen grains from five species (M. pigra, M. pudica, P guajava, Bursera simaruba and Citrus spp.), in the pollen and honey amphorae (tables 3 and 4). The first three plants coincided with the predominant plants of the flight radius inventory. Regarding abundance, small amounts of pollen grains were found in the honey samples.
The presence was detected of pollen types that could not be identified, because they are not included in the IES collection, which could be from cherimoya (Anona reticulata), sapote (Pouteria sapota) and peach tree (Prunus persica), inventoried in the flight radius of the colonies.
The stingless bees showed remarkable foraging selectivity for the flowers of P. guajava, M. pudica, M. pigra and B. simaruba; in the case of guava it is justified by the abundance of these plants around the meliponary, with a density of 937,7 plants/ha and by its contributions as a polliniferous plant. This is in correspondence with the results obtained in Trinidad by Ramalho et al. (1989) and Manrique (1999), who said that the Melastomataceae, Myrtaceae, Solanaceae and Fabaceae plant families are principal nectar and pollen sources for the stingless bee, and that the most important pollen source for two Melipona species in that country was P. guayaba (Myrtaceae).
The mastic tree although not abundant in the farm-, touch-me-not and mimosa showed good results. In the case of M. pudica, and M. pigra, there is coincidence with the report in the pollen study conducted by PROMABOS (2006), which demonstrated that M. pudica is a very important pollen source for stingless bees. That is why, a wider sampling in number and time could enrich the findings and, probably, include more species of the silvopastoral system area
Besides the melliferous or polliniferous values of the botanical species in the flight radius, the study of the flowering period should not be obviated, to ensure a great variety of feed for the maintenance of the meliponary during a large part of the year and the productions during the harvest period (table 5).
In this sense, Ordetx (1964) stressed the importance of the location of the principal pollen and nectar species in a specific area, because the knowledge of the flowering cycle of each species is useful in the tasks of beehive preparation and tending, to obtain the maximum utilization of the area.
Figure 1 shows the flowering diagram of the principal species represented in the pollen analysis, which allows inferring the amount of nectar and pollen for the stingless bees during the year at the EEPF "Indio Hatuey". In the rainy and dry seasons there was enough pollen and nectar to sustain the beehives and for adequate production. March, April, May and September were the months with the highest amount of flowers, because three plant species were present each month; the most representative was guava, followed by touch-me-not and the mastic tree.
This favorable situation allows ignoring artificial feeding in the rainy season, when trees have more leaves and flowers are scarce, and rainfall rapidly washes off the pollen and nectar in them.
The stingless bees of the EEPF "Indio Hatuey" showed marked foraging selectivity for the flowers of P. guajava, M. pigra, M. pudica y B. simaruba.
In the rainy and dry seasons there was enough pollen and nectar to sustain the beehives and for adequate production; March, April, May and September were the months with the highest amount of flowers; with the presence of three plant species.
