AsianScientist (Sep. 23, 2015) – A research group from Japan has identified chemosensory proteins (CSPs) that play important roles in communications between worker ants. CSPs may represent a starting point for elucidation of the molecular mechanisms involved in the sophisticated system of communication that supports ants’ complex societies, and the evolution of these mechanisms. These findings were published in Scientific Reports.
Being social insects, ants form highly organized societies on the basis of very close communication between individuals, mediated by pheromones and other chemical substances. Information about the genomes of several ant species has been obtained to date, and genes linked to chemosensitivity in ants have been shown to be diverse. However, the modes of expression and functioning of these genes in chemosensory organs remained largely unknown.
This research group previously showed that one type of CSP, CjapCSP1, binds with cuticular hydrocarbons that play important roles in ant inter-individual communication, and that this is linked to nestmate recognition behavior by worker ants.
In the present research, Assistant Professor Hojo Masaru and colleagues from Kobe University extracted RNA from the antennae of the Japanese carpenter ant (Camponotus japonicus), with support from the laboratory of Professor Inoue Kunio. They comprehensively analyzed the genes expressed on the antennae using a next-generation DNA-sequencer and supercomputer at the National Institute for Basic Biology, thus revealing the nucleotide sequences of 11 novel CSPs.
The research group then performed molecular phylogenetic and evolutionary analyses using sequence information for CSPs from various insect species, and analyzed the CSP expression levels by quantitative polymerase chain reaction. The group thus succeeded in identifying two CSPs, CjapCSP12 and CjapCSP13, that are particularly diverse among ants, and that are expressed specifically by the principal chemosensory organs of worker ants, especially the antennae.
In addition, detailed investigation of the expression loci of these genes showed that, as in the case of CjapCSP1, which is linked to receptors of cuticular hydrocarbons, they are co-expressed inside the antennae.
These findings suggest that complex CSPs that have evolved specifically in ants have cooperative modes of operation in the antennae, and have the capacity to recognize complex individual information transmitted by cuticular hydrocarbons.
Hojo comments, “This provides a starting point for elucidation of the molecular basis for, and evolution of, the sophisticated communication seen in ant societies. We therefore hope that these findings will make major contributions to future work on elucidation of the molecular mechanisms supporting the complex social organization seen in ants, and the evolution of these mechanisms.”
The article can be found at: Hojo et al. (2015) Antennal RNA-Sequencing Analysis Reveals Evolutionary Aspects of Chemosensory Proteins in the Carpenter Ant, Camponotus japonicus.
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Source: Kobe University.
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