“…While it is clear that increased protein supply can be beneficial to developing larvae and insufficient protein supply can result in larval malnutrition with clear adverse effects (Tasei and Aupinel 2008, Brodschneider and Crailsheim 2010, Di Pasquale, Salignon et al 2013, Hass, Brachmann et al 2018, there is only limited support for a simple relationship between crude protein concentration and bee fitness (Babendreier, Kalberer et al 2004, Tasei and Aupinel 2008, Brodschneider and Crailsheim 2010, Di Pasquale, Salignon et al 2013. It is likely that in addition to protein content, other quality markers such as lipid content, amino acid composition and secondary metabolites might play an important role in determining pollen quality for bees (Maurizio and Grafl 1980, Day, Beyer et al 1990, Pernal and Currie 2000, Tasei and Aupinel 2008, Nicolson and Human 2013, Nicholls and Hempel de Ibarra 2017, Hass, Brachmann et al 2018, Ruedenauer, Wöhrle et al 2018. In contrast to nectar quality (sugar concentration), there is only some evidence that bees can reliably separate high from low quality pollen and adjust their collecting behavior according to their needs (Nicholls and Hempel de Ibarra 2017).…”