(Epi)Genetic Mechanisms Underlying the Evolutionary Success of Eusocial Insects

Abstract

Eusocial insects, such as bees, ants, and wasps of the Hymenoptera and termites of the Blattodea, are able to generate remarkable diversity in morphology and behavior despite being genetically uniform within a colony. Most eusocial insect species display caste structures in which reproductive ability is possessed by a single or a few queens while all other colony members act as workers. However, in some species, caste structure is somewhat plastic, and individuals may switch from one caste or behavioral phenotype to another in response to certain environmental cues. As different castes normally share a common genetic background, it is believed that much of this observed within-colony diversity results from transcriptional differences between individuals. This suggests that epigenetic mechanisms, featured by modified gene expression without changing genes themselves, may play an important role in eusocial insects. Indeed, epigenetic mechanisms such as DNA methylation, histone modifications and non-coding RNAs, have been shown to influence eusocial insects in multiple aspects, along with typical genetic regulation. This review summarizes the most recent findings regarding such mechanisms and their diverse roles in eusocial insects.

DNA methylation is associated with codon degeneracy in a species of bumblebee

“…Epigenetic mechanisms have been proposed as a possible method for caste determination in multiple social insect species (reviewed in Sieber et al 2021 ). The majority of research in this area has focused on DNA methylation, which is the addition of a methyl group to a cytosine nucleotide.…”

Reproductive Potential Impacts Body Maintenance Parameters and Global DNA Methylation in Honeybee Workers (Apis mellifera L.)

“…This expanding of knowledge on RW, suggesting putting them "between queens and workers", creates new possibilities for studies on mechanisms of the evolutionary success of the social insects as well. This is particularly important, as DNA methylation has been proved to be involved in the caste phenotypic plasticity and shaping the behavior of worker subcastes [15,68,69].…”

Neuromodulators and neuroepigenetics of social behavior in ants

“…1 Similarly to bees, young ant workers generally act as nurses for the colony's young and transition into foragers as they age. 2 These age-dependent changes also occur in the queen, where young mated queens perform all tasks including foraging and nursing of the first ants of the colony, and then switch to only reproductive behaviors as the colony matures. 1 In general, the new offspring of a mature colony may develop into morphologically distinct individuals, including workers, queens, and males, giving rise to the caste system.…”

“…The social behavior of an individual ant largely depends both on age and on the developmentally predefined stereotyped identity 1 . Similarly to bees, young ant workers generally act as nurses for the colony's young and transition into foragers as they age 2 . These age‐dependent changes also occur in the queen, where young mated queens perform all tasks including foraging and nursing of the first ants of the colony, and then switch to only reproductive behaviors as the colony matures 1 …”