Egg laying and oophagy by reproductive workers in the polygynous stingless beeMelipona bicolor(Hymenoptera, Meliponini)

Abstract

-We studied queen-worker conflict over male production in a Melipona bicolor colony, having three physogastric queens and individually marked workers, by means of observations of the processes of cell oviposition. The gender that developed from these cells showed that queens produced mainly female offspring. The overall percentage of the males that were workers' sons was estimated between 27 and 82%. Forty-two times workers were seen to deposit a male egg, normally following the queen's oviposition, in the same cell and in sixteen cases, the reproductive worker ate the egg already present in the cell before ovipositing in it. Workers not only were more likely to lay their egg next to that of another worker than next to a queen's egg, they also were more likely to replace the egg already present when it was worker-derived. Their conduct agrees with predictions from kin-selection theory because workers are better served when rearing sons at the cost of other workers' sons than at the cost of queens' daughters. stingless bees / Melipona bicolor / kin conflict / worker reproduction / worker oophagy

Comparative Analysis of Worker Reproduction and Policing in Eusocial Hymenoptera Supports Relatedness Theory

“…Worker policing has been observed in 14 species of ants, bees, and wasps with known colony kin structure. Out of these, it occurs via egg eating in 10 species, egg eating and aggression in two species, and aggression only in another two species ( Velthuis et al 2005), and in one species where they do, in Melipona bicolor, it is associated with direct competition among egg-laying workers (Velthuis et al 2002;Koedam et al 2007) and thus represents workerdominance behavior rather than worker policing. Finally, the predominantly single-mated wasp genera Dolichovespula and Polistes and the low-paternity yellow jacket Vespula rufa all have queen policing and mutual egg eating by reproductive workers but not true worker policing Ratnieks et al 2006; T. Wenseleers, A. Tofilski, F. S. Nascimento, and F. L. Ratnieks, unpublished manuscript; table A1).…”

Cell-sealing efficiency and reproductive workers in the species Melipona bicolor (Hymenoptera, Meliponini): double standard and possible rogue conduct

“…Selfish workers are rarely seen to be directly restrained from reproducing, other than by reproductive non-queen sisters (Koedam et al 2007); this seems to be a general trend among stingless bees Tóth et al 2002). Here, it was seen that as with nonreproductive workers, the M. bicolor physogastric queens sometimes caused reproductive workers to interrupt sealing.…”

“…The egg-laying career of 14 reproductive workers was monitored and has been described elsewhere (Koedam et al 2007). When a worker abandoned the cell immediately after egg laying, her egg was considered trophic.…”

“…Together with the presumed use of chemical substances as a defense against replacement of queen-derived eggs (Koedam et al 2007), workers also block the cell opening with their bodies most of the time, while they are sealing the cell (Sakagami and Zucchi 1963). This "body-plugging" can be more or less continuous, since these workers do not need to interrupt their work to procure building materials for producing the cell caps, because the collars of recently constructed cells typically provide sufficient wax for this purpose (Sakagami 1982).…”

Five egg-laying queens in a single colony of brazilian stingless bees (Melipona scutellaris Latreille

“…Their colonies have a high level of social organization, almost always with a single queen (Peters et al 1999), which is a female morphologically differentiated and specialized in egg laying (Michener 1974;Koedam et al 2007). Studies on stingless bees' reproductive systems have been conducted with few species and remain unknown for the majority.…”