Hormonal and Genetic Control of Behavioral Integration in Honey Bee Colonies

Abstract

The ability of insect colonies to adjust the division of labor among workers in response to changing environmental and colony conditions, coupled with research showing genetic effects on the division of labor in honey bee colonies, led to an investigation of the role of genetics and the environment in the integration of worker behavior. Measurements of juvenile hormone(JH) titers and allozyme analyses of worker honey bees suggest that two processes are involved in colony-level regulation of division of labor: (i) plasticity in age-dependent behavior is a consequence of modulation of JH titers by extrinsic factors, and (ii) stimuli that can affect JH titers and age-dependent behavior do elicit variable responses among genetically distinct subpopulations of workers within a colony. These results provide a new perspective on the developmental plasticity of insect colonies and support the emerging view that colony genetic structure affects behavioral organization.

Senescence in the worker honey bee Apis Mellifera

“…We set up five single-cohort colonies (Robinson et al, 1989), each initially composed of ca. 10,000 one-day-old bees.…”

“…Worker bees respond to changing social conditions by accelerating, delaying, or reversing their typical pattern of behavioral maturation. For example, if there is a shortage of foragers or large numbers of young larvae in the hive, some bees delay their transition to foraging and become "overage" nurses (Robinson et al, 1989). We studied age-specific stress resistance in overage nurses that did not did not experience the extrinsic risk factors associated with foraging.…”

Ultrastructural modifications in the venom glands of workers of Apis mellifera L. (Hymenoptera: Apidae) promoted by topical application of juvenile hormone

“…The juvenile hormone III is the only form found in the workers of A. mellifera (Fluri et al 1982, Robinson & Ratnieks 1987, Robinson et al 1989) and the titer of this proximal region degenerates first, which contradicts the results presented here but agrees with observations in other glands (Cruz-Landim & Mello 1981, Silva & Silva de Moraes 1999, in which the glandular degeneration begins hormone increases with the age of the worker, being that immediately after emergence, at the first day of adult life, these bees present approximately 5 pmol of this hormone for every 100 ml of haemolymph, but at 21 days of age they present about 20 pmol per 100 ml of haemolymph (Fluri et al 1982, Robinson & Ratnieks 1987. Thus, the variations in the levels of juvenile hormone during adult life, mainly during the transition from performing activities inside the colony to foraging, affect the secretory cycle of the venom gland, as was shown through the ultrastructural analysis.…”

“…The level of juvenile hormone in the haemolymph of workers rises when they progress from performing tasks inside the colony to tasks outside the colony (Akamatsu et al 1975, Rembold 1976, Robinson 1987. Adult workers of A. mellifera present low titers of juvenile hormone in the haemolymph during the first two weeks of adult life, when they perform tasks related to brood care (Rutz et al 1976, Fluri et al 1982, and higher titers when they become foragers from the third week of life (Robinson et al 1989;Huang et al 1991Huang et al , 1994Robinson 1992). The rise in the titer of juvenile hormone induces a precocious foraging behavior (Robinson 1985, Sasagawa et al 1989, Sullivan et al 2000, thus suggesting that the mechanism through which this control is attained is through the effect of the juvenile hormone over the glandular development of the workers.…”

Cognitive aging is linked to social role in honey bees (Apis mellifera)

“…We use experimental colonies of same-aged bees (single cohort colonies, Robinson et al, 1989) and reverted foragers (socially reversed colonies, Robinson et al, 1992a). We combine these setups with behavioral observations to obtain workers of known age, known social role and known duration of foraging.…”