Broad Protein Spectrum in Stored Pollen of Three Stingless Bees from the Chaco Dry Forest in South America (Hymenoptera, Apidae, Meliponini) and Its Ecological Implications

Abstract

Protein content of pollen stored by three meliponine species was variable from 9.78% (less than half the value considered as optimal to brood development inApis mellifera) in typeCapparis tweediana-C. speciosato more than 26% in typeMaytenus vitis-idaeaand someProsopissamples. This pollen of low protein value was occasionally foraged (only six out of 75 masses analyzed ofG. argentina, but none in 86 masses ofT. fiebrigior in ten ofM. orbignyi). However, it is likely that amino acid deficiencies of certain pollens are compensated by randomly foraging on a broad spectrum of pollen plants. The large amounts of pollen stored in their nests might also be important in compensating these deficiencies. The only sample studied forM. orbignyishowed a protein value greater than the one required forA. melliferaand was dominated by typesAcacia praecoxandProsopis. As this species also prefersSolanumand other protein-rich pollen, more samples would need to be analyzed to establish whether protein requirements are high for thisMeliponaspecies. Pollen showing the highest protein content (>26%) belonged to highly nectariferous plants well represented in meliponine andApishoney such asProsopis,Maytenus, andZiziphus.