Students of the evolution of social behavior got a big boost with the publication of the newly sequenced honeybee genome in October 2006. The honeybee (Apis mellifera) belongs to the rarified cadre of insects that pool resources, divide tasks, and communicate with each other in highly structured colonies. Understanding how this advanced state of organization evolved from a solitary lifestyle has been an enduring question in biology.
In a new study published in PLoS Biology, Mindy Nelson, Kate Ihle, Gro Amdam, and colleagues reveal one possible path to community by showing that a single gene controls multiple traits related to honeybee sociability. First characterized for its role in reproduction, the gene, vitellogenin, is widely found in egg-laying insects, which depend on it for egg cell development.
A honeybees lot in life depends on its age, gender, and caste. Reproduction falls to the queen and drones, while essentially infertile females, the workers, perform all the other duties required to support the colony. As young adults, workers tend larvae and perform assorted tasks in the hive. After about three weeks, they switch from domestic chores to foraging, and eventually specialize in pollen or nectar collection.
Scientists began to suspect that the protein synthesized from the vitellogenin genevitellogeninmight affect these social life history traits in honeybees as it became clear that the protein supported an array of functions not directly linked to egg-laying. For example, sterile workers synthesize vitellogenin to make the royal jelly they feed larvae. It can also prolong the lifespan of both workers and the queen by reducing oxidative stress.
As bees undergo the complex behavioral shift demanded by the change in job description, their physiology changes too: they have higher levels of juvenile hormone and lower levels of vitellogenin. It was speculated that these two physiological factors repress each other
'"/>
Contact: Natalie Bouaravong
press@plos.org
415-568-3445
Public Library of Science
5-Mar-2007