Investigating Eusociality in Bees while Trusting the Uncertainty

Abstract

particularly with Apis mellifera Linnaeus, 1758 -the honeybee. This has long been a species with close proximity of mankind (the species of Apis are distributed all over the Old World), with economic interest because of honey production (pollination became a hotly debated topic more recently, e.g., Oldroyd, 2007; Cameron et al., 2010; Potts et al., AbstractPhylogenetic hypotheses and estimates of divergence times have already been used to investigate the evolution of social behavior in all lineages of bees. The interpretation of the number of origins of eusocial behavior and the timing of these events depends on reliable phylogenetic hypotheses for the clades in which these lineages are nested. Three to six independent origins of eusocial behavior are interpreted to have occurred in bee taxa that differentiated in the Late Cretaceous, or much later in the Paleogene. Only two groups of bees exhibit the behaviors that qualify their members to be considered obligate (i.e. 'fixed-caste') eusocial, the honey bees (Apini) and the stingless bees (Meliponini). The evolutionary history of corbiculate bees remains uncertain in many respects, but phylogenetic research has been paving the path for comprehensive comparative approaches likely to shed light on the origin of diversity of forms and behaviors of these bees. In total, corbiculate bees encompass about 1,000 species, roughly 5% of the described species diversity of bees. These bees are rather heterogeneous in terms of social organization, particularly stingless bees and orchid bees, which display a fascinating range of behavioral variation. Using phylogenetic tools, it has been possible to infer that caste polymorphism, division of labor and other traits of corbiculate bees probably started evolving over 80 million years ago. Phylogenetic hypotheses must be interpreted as more or less uncertain scenarios for studying the biological diversity, but when trusted they can provide powerful tools to investigate the evolution of social behaviors.

Comparative morphology of the mandibles and head structures of corbiculate bees (Hymenoptera: Apidae: Apini)

“…To the left (Hypothesis 1), synoptic tree of most hypotheses based on morphological and behavioural datasets; to the right (Hypothesis 2), synoptic tree of hypotheses based on molecular datasets; to the bottom (Hypothesis 3), synoptic tree of an alternative hypothesis commonly recovered with molecular datasets. For more details on concurrent phylogenetic hypotheses for the corbiculate relationships, see Cardinal & Packer () and Almeida & Porto (). Filled circles represent unique changes; open circles represent homoplasious changes; values above circles are character numbers; values below circles are character‐state changes; character‐state changes inside the boxes are the ones treated as delayed transformations in the optimizations ( DELTRAN ).…”

“…It seems that too much attention, however, was given to the issue of single/dual origin of ‘obligate’ (i.e. fixed‐caste, sensu Almeida & Porto, ) eusociality to the detriment of answering some equally important questions: why is Apina grouping with Euglossina in almost all molecular hypotheses published so far if there is little morphological support for this grouping? Why are molecular and morphological datasets so incongruent in this specific case?…”

“…Another point that contributes to the already inflated ‘corbiculate controversy’ is the discussion of the single/dual origin of ‘obligate eusociality’ (fixed‐caste eusociality, sensu Almeida & Porto, ) in the Apina–Meliponina–Bombina clade. It might be plausible to suggest that the cluster of traits that define fixed‐caste eusociality could have arisen more than once in corbiculate bees.…”

The relevance of the mesosomal internal structures to the phylogeny of Augochlorini bees (Hymenoptera: Halictinae)

“…For Augochlorini, the internal characters helped to attenuate the possible discrepancies of morphological and molecular hypotheses. For Apini, the internal characters only favoured the morphological most common hypothesis (Euglossina (Bombina (Apina Meliponina))), thus maintaining the discrepancies of molecular and morphology data sets on the phylogeny of corbiculate bees (see the alternative scenarios on Almeida & Porto, 2014).…”

Why, when and where did honey bee dance communication evolve?

“…However, because the phylogenetic relationships among the corbiculate bees are still not resolved (reviewed in Almeida and Porto, 2014) it remains unclear when honey bee ancestors evolved higher eusociality. If it evolved twice, once in the Meliponini and once in the Apini (Cameron, 1993;Koulianos et al, 1999;Cameron and Mardulyn, 2001;Cardinal and Danforth, 2011), then higher eusociality evolved after the two groups separated c. 80 million years ago (Cardinal and Danforth, 2011).…”