Are Stingless Bees a Broadly Polylectic Group? An Empirical Study of the Adjustments Required for an Improved Assessment of Pollen Diet in Bees
This research describes simple calculations for pollen diet studies to improve the understanding of bee natural history. The stingless bees (tribe Meliponini) have been classified as broadly polylectic as they utilize more than 10% of the pollen host species of the entire melittophilous flora at a site or more than 25% of the available plant families. However, when considering pollen types, it was not possible to classify three bee species in this manner. For this reason, different calculation adjustments on foraged and available items were applied. For the former, two threshold values (10% and 5%), to identify abundant and discard minor and contaminant pollen resources, were used. For each threshold value, the number of pollen types and the number of pollen species ascribed to each pollen type were calculated. For the available items, spatial and temporal adjustments were estimated. When these adjustments were applied, in some cases bees were identified at higher specialization categories; broad polylectic was recorded only in six cases for Melipona orbignyi and Tetragonisca fiebrigi. As previously suggested for the other categories, contaminant and minor pollen types should also be excluded in polylectic bees. The threshold values of 10% for species and 25% for families are too high to reach broad polylecty. In addition, no direct comparisons between pollen types and pollen species could be made when working with the palynological data. Thus, simple values were proposed to assess pollen diet of generalist bees: the maximum number of foraged items per nest (contaminants not considered) and the maximum percentage value of foraged versus available items (adjusted). These belong to a wider range of values that can be recognized as degrees of polylecty, allowing for a more precise identification.
I am especially thankful to Patricia Vit for her kind invitation to participate in this book and Alicia Basilio for recommending me, Nora Brea for her help in English language, David Roubik and Nora Brea for providing suggestions and critical comments on the manuscript, and Arturo Roig-Alsina for the identification of bees. This study was supported by CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas).
- Cane JH, Sipes S. 2006. Characterizing floral specialization by bees: analytical methods and a revised lexicon for oligolecty. pp 99–122. In Waser NM, Ollerton J, eds. Plant-Pollinator Interactions. From specialization to generalization. The University of Chicago Press; Chicago, USA. 488 pp.Google Scholar
- De Klerk P, Joosten H. 2007. The difference between pollen types and plant taxa: a plea for clarity and scientific freedom. Eiszeitalter und Gegenwart / Quaternary Science Journal 56: 162–171.Google Scholar
- Erdtman G. 1960. The acetolysis method, a revised description. Svensk Botanisk Tidskrift 54: 561–564.Google Scholar
- Michener CD. 2007. The bees of the world, 2 edn. The Johns Hopkins University Press; Baltimore, USA. 953 pp.Google Scholar
- Michener CD. 2013. The Meliponini. pp 3–17. In Vit P, Pedro SRM, Roubik DW, eds. Pot honey: A legacy of stingless bees. Springer; New York, USA. 175 pp.Google Scholar
- Minckley RL, Roulston TH. 2006. Incidental mutualisms and pollen specialization among bees. pp 69–98. In Waser NM, Ollerton J, eds. Plant-Pollinator Interactions. From specialization to generalization. The University of Chicago Press; Chicago, USA. 488 pp.Google Scholar
- Prado DE. 1993. What is the Gran Chaco vegetation in South America? I. A review. Contribution to the study of flora and vegetation of the Chaco. V. Candollea 48: 145–172.Google Scholar
- Roubik DW. 1982. Seasonality in colony food storage, brood production and adult survivorship: studies of Melipona in tropical forest (Hymenoptera: Apidae). Journal of the Kansas Entomological Society 55: 789–800.Google Scholar
- Roubik DW. 1989. Ecology and natural history of tropical bees. Cambridge University Press; New York, USA. 514 pp.Google Scholar
- Roubik DW, Aluja M. 1983. Flight ranges of Melipona and Trigona in tropical forest. Journal of the Kansas Entomological Society 56: 217–222.Google Scholar
- Vossler FG. 2013b. Estudio palinológico de las reservas alimentarias (miel y masas de polen) de “abejas nativas sin aguijón” (Hymenoptera, Apidae, Meliponini): un aporte al conocimiento de la interacción abeja-planta en el Chaco Seco de Argentina. Doctoral Thesis. Universidad Nacional de La Plata; La Plata, Argentina. 152 pp.Google Scholar
- Vossler FG. 2014. A tight relationship between the solitary bee Calliopsis (Ceroliopoeum) laeta (Andrenidae, Panurginae) and Prosopis pollen hosts (Fabaceae, Mimosoideae) in xeric South American woodlands. Journal of Pollination Ecology 14: 270–277.Google Scholar
- Zuloaga FO, Morrone O, Belgrano MJ. 2008. Catálogo de las plantas vasculares del cono sur (Argentina, Sur de Brasil, Chile, Paraguay y Uruguay). Volumes 1–3. Monographs in Systematic Botany from the Missouri Botanical Garden 107: 1–983, 985–2286, 2287–3348.Google Scholar