Native bees as putative pollinators of the avocado Persea americana Mill. cv. Hass in Colombia

Abstract

Hymenoptera, especially bees, play a fundamental role in increasing the fruitiness and quality of the avocado through proper pollination. This study proposed to determine hymenopteran floral visitor fauna and potential pollinators of the Hass avocado cultivar in Colombia. The research was carried out on a single plot of land on a farm during two consecutive flowering periods (Aug-Sep. 2013/ Feb-Mar. 2014), randomly selecting four trees for the sampling and changing them every week. Hymenoptera richness did not differ significantly between flowering periods. Besides Apis mellifera, a wide diversity of floral visitors was found in the cultivar studied. Thirteen families of Hymenoptera were recorded, among them, three bee species of the Meliponini tribe: Scaptotrigona barrocoloradensis (Schwarz) (37%), Partamona cf. aequatoriana Camargo (32%) and Tetragonisca angustula (Latreille) (17.65%). Bees carried pollen from 18 botanical families, the most frequent were: Asteraceae (30.08%), Lauraceae (28.02%) and Urticaceae (19.49%). Although A. mellifera has the highest diversity and abundance in its pollen load, the stingless bees together transported about half of the available avocado pollen (47.53%). These bees stood out for having greater specificity in their pollen load, on surveying the insect body areas where they transport pollen. In A. mellifera, P. cf. aequatoriana and S. barrocoloradensis, avocado pollen adheres mainly to the legs while in T. angustula the greater pollen adherence was in the head and thorax. Although A. mellifera was the main pollinator, as a result of greater visit frequency and pollen load, the potential importance of the native bee species for pollination services is discussed.