Study site and species
This study was performed in the meliponary housed at the Botany Department of Embrapa Amazônia Oriental (1º26′11.52″S, 48°26′35.50″W), Belém, Pará, Brazil, during the dry season of 2016 (September and October), and the rainy seasons of 2017 and 2018 (May). Five species of stingless bees were studied (Fig. S1): Melipona flavolineataFriese, 1900, Melipona fasciculata Smith, 1854,Scaptotrigona aff. postica Latreille, 1807,Frieseomelitta longipes (Smith, 1854) and Plebeia minima(Gribodo, 1893). These species were chosen because they are well adapted to housing in wooden hives, resistant to handling and manipulation, and can be multiplied for use in crop pollination (Contrera et al. 2011; Jaffé et al. 2015; Leão et al. 2016). Melipona flavolineataoccurs in the Brazilian states of Ceará, Maranhão, Pará and Tocantins;M. fasciculata occurs in the states of Maranhão, Mato Grosso, Pará, Piauí and Tocantins; S. aff. postica and F. longipes occurs in the state of Pará; and P. minima in the states of Acre, Amapá, Amazonas, Maranhão, Mato Grosso and Pará, besides Peru, Bolivia, and Suriname (Pedro 2014).
For the experiment, eight colonies of M. flavolineata , eight colonies of M. fasciculata , nine colonies of F. longipes , 12 colonies of P. minima and 13 colonies of S. aff.postica were used. These colonies were left undisturbed and without supplemental feeding during the three months prior to the experiment and were kept in individual wooden shelters (Contrera and Venturieri 2008), distanced at least 2 meters from each other. To reduce the possibility of drifting (i.e., foragers returning to wrong colonies; see Oliveira et al. 2021), the entrances of neighboring colonies were arranged in opposing directions.