As major pollinators and honey producers, honeybees make a major contribution to both the ecosystem and agriculture. They are also highly social insects, living in one of the most sophisticated societies found in non-vertebrates. The Honeybee Genome Sequencing Consortium has now reported in Nature1 the complete genome sequence of the European honeybee, Apis mellifera. Participating in the consortium was Michel Solignac and his team2 from Gif-sur-Yvette, who were responsible for the genetic mapping. “We hope that the genome sequence will help us understand the contribution of genetics to behavior,” comments Solignac.
Comparison of different insects' genome sequences indicates that the honeybee genome has evolved more slowly than that of other insects such as the fruit fly and the malaria mosquito. As a result, honeybee sequences show greater similarity to vertebrate sequences than most other insect sequences known so far. This is true for the honeybee's genes and gene families associated with circadian rhythms, learning, and memory. There is also evidence that systems controlling development in other insects have been adapted in the honeybee to control changes in behavior (from hive worker to forager, for example).
Extensive genome sequence analysis has proved a rich vein of information. Honeybees have, for example, a particularly large number of genes for odorant receptors– consistent with both the need to recognize flower types and the importance of pheromones in communication between bees and in kin recognition. The honeybee also has numerous genes for making royal jelly proteins, whereas the fruit fly has only one such protein. Again, this reflects the social behavior of the insect, feeding its young and ensuring caste development (queens and workers). More surprisingly, the honeybee has relatively few genes involved in innate immunity or defense mechanisms; the lifestyle of this insect as a social animal living in crowded environments leaves it vulnerable to viral and bacterial diseases and parasites of all kinds. These are the first results: Further analysis will certainly give more insights into the relationships between genetics and social behavior.
1. The Honeybee Genome Sequencing Consortium, “Insights into social insects from the genome of the honeybee Apis mellifera,” Nature. 443: 931-949. 2006.
2. Evolution, Génomes et Spéciation: Evolution, genomes and speciation (CNRS lab).