Atypical giant male production in royal cells of Plebeia flavocincta (Hymenoptera: Apidae: Meliponini): insights into their morphometric and behavioral traits

Giant male production, previously regarded as a rare event in meliponine bees, was observed at a high frequency in sampled royal cells of Plebeia flavocincta, a poorly studied stingless bee species native to northeastern Brazil. Our study is the first to document giant males in this species and to quantify their occurrence among the sampled royal cells. Out of 24 royal cells monitored across 11 colonies from six distinct meliponaries in three municipalities of Ceará State, Brazil, 54.17% (n = 13) yielded giant males, whereas only 45.83% (n = 11) produced gynes. Morphometrically distinct from normal males (p < 0.05), these giant males exhibited anatomical disproportionality and atypical behaviors, including absence of phototactic response, impaired locomotion, and apparent genital sensitivity. We argue that this phenomenon in managed P. flavocincta colonies across different sites is unlikely to be accidental. Instead, it may reflect a colony-level investment that diverts nutritional resources in royal cells toward the production of atypical males whose reproductive advantages remain unknown, rather than producing young queens, thereby potentially reducing reproductive efficiency. Our findings therefore suggest that giant male production in royal cells may limit gyne availability for reproductive management, with possible consequences for colony splitting practices in meliponaries.