The genomes of two key bumblebee species with primitive eusocial organization

Abstract

BackgroundThe shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats.ResultsWe report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits.ConclusionsThese two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-015-0623-3) contains supplementary material, which is available to authorized users.

Insect antimicrobial peptides act synergistically to inhibit a trypanosome parasite

“…AMPs are classified based on their molecular structure as well as on the presence of particular amino acid residues [1]. The number of different AMPs present in any one organism varies considerably, with more than 50 in some insects [6], six in the honeybee, Apis mellifera [7], with the recently sequenced bumblebees having only four [8,9].…”

Transitional Complexity of Social Insect Immunity

“…Therefore, honey bees would not rely on innate immunity as much as solitary insects. However, more recent comparative genomic studies of multiple insect genomes across different levels of social organization, indicated that eusociality by itself does not appear to affect the number of immunity-related genes in hymenopteran ants and bees (Wurm and Keller, 2010;Smith et al, 2011;Simola et al, 2013;Roux et al, 2014;Barribeau et al, 2015;Grozinger and Robinson, 2015;Kapheim et al, 2015;Sadd et al, 2015) or isopteran termites (Terrapon et al, 2014;Korb et al, 2015), challenging the previous hypothesis of eusociality causing relaxed selection on innate immunity. While these further analyses have supplied evidence that eusociality by itself is not associated with the reduction in immune-gene counts, the old claim is still being propagated in the recent literature (e.g., Nish and Medzhitov, 2011;Gadau et al, 2012;Mattila et al, 2012;Schöning et al, 2012;Evison et al, 2013;Meunier, 2015).…”

Comprehensive processing of high-throughput small RNA sequencing data including quality checking, normalization, and differential expression analysis using the UEA sRNA Workbench

“…This is an experiment on the effects of hypoxic conditions on MCF7 cells (Camps et al 2014), organized into a time series of four points, each with two biological replicates, Normoxia (N00), Hypoxia at 16 h (H16), Hypoxia at 32 h (H32), and Hypoxia at 48 h (H48). The additional examples presented in the Supplemental Information are based on publicly available B. terrestris data (GSE64512) consisting of two samples, with four biological replicates each (Sadd et al 2015) and a publicly available A. thaliana data (GSE35562, GSM1178880 to GSM1178882 for the wild-type and GSM1178883 to GSM1178885 for the Hen1-8 mutant) consisting of two samples, with three biological replicates each (Zhai et al 2013).…”