Sucrose feeders.

<p>(a) <i>Ad libitum filter</i> feeder. (b) Transitional <i>ad lib</i> tube feeder. (c) Honey bee forager inside rate restricted feeder port. (d) Rate restricted sucrose.</p

Mean (+SE) GRS (sucrose sensitivity) of bees after three days exposure to either 10% or 30% concentration sucrose solution followed by one day of additional exposure to 30% concentration sucrose solution.

<p>No significant differences in sensitivity were found regardless of original conditioning.</p

Factors impacting volume of 30% sucrose solution collected.

*<p>Hive ID includes error caused by colony source of bees and temporal pattern of data collection. Hive ID includes error caused by Colony source of bees and temporal pattern of data collection (Generalized Linear Mixed Model, N = 138, **** = p<.0001).</p

Mean (+SE) GRS (sucrose sensitivity) of bees after three days exposure to either 10% or 30% concentration sucrose solution. Letters signify significant difference (p<0.05).

<p>Mean (+SE) GRS (sucrose sensitivity) of bees after three days exposure to either 10% or 30% concentration sucrose solution. Letters signify significant difference (p<0.05).</p

Factors impacting volume of 10% sucrose solution collected treating GRS as an Ordinal Variable.

<p>Note that there is a significant interaction effect of ovariole number and GRS (sucrose sensitivity). Hive ID includes error caused by Colony source of bees and temporal pattern of data collection (Generalized Linear Mixed Model, N = 131, * = p<0.05, **** = p<.0001).</p

Proposed mechanism for ovary impact of foraging bias.

<p>The ovary (1) tunes sucrose sensitivity (2), which impacts nectar collection decisions (3). This would indirectly impact pollen collection (4) due to physical limitations on collection quantity (Photos: 1. O. Kaftanoflu; 2. J. S. Engen; 3.&4. Z. Huang).</p

Linear relationship of crop load estimate (based on time spent on feeder) compared to manually expressed crop load weight.

<p>Linear relationship of crop load estimate (based on time spent on feeder) compared to manually expressed crop load weight.</p

Mean (+SE) GRS (sucrose sensitivity) of bees collected on 10% or 30% sucrose feeder. Letters signify significant difference (p<0.05).

<p>Mean (+SE) GRS (sucrose sensitivity) of bees collected on 10% or 30% sucrose feeder. Letters signify significant difference (p<0.05).</p

Mean (+SE) volume of sucrose collected by bees collected on 10% or 30% sucrose feeder. Letters signify significant difference (p<0.05).

<p>Mean (+SE) volume of sucrose collected by bees collected on 10% or 30% sucrose feeder. Letters signify significant difference (p<0.05).</p

Gonadotropic and Physiological Functions of Juvenile Hormone in Bumblebee (<i>Bombus terrestris</i>) Workers

<div><p>The evolution of advanced sociality in bees is associated with apparent modifications in juvenile hormone (JH) signaling. By contrast to most insects in which JH is a gonadotropin regulating female fertility, in the highly eusocial honey bee (<i>Apis mellifera</i>) JH has lost its gonadotrophic function in adult females, and instead regulates age-related division of labor among worker bees. In order to shed light on the evolution of JH signaling in bees we performed allatectomy and replacement therapies to manipulate JH levels in workers of the "primitively eusocial" bumblebee <i>Bombus terrestris</i>. Allatectomized worker bees showed remarkable reduction in ovarian development, egg laying, <i>Vitellogenin</i> and <i>Krüppel homolog 1</i> fat body transcript levels, hemolymph Vitellogenin protein abundance, wax secretion, and egg-cell construction. These effects were reverted, at least partially, by treating allatectomized bees with JH-III, the natural JH of bees. Allatectomy also affected the amount of ester component in Dufour's gland secretion, which is thought to convey a social signal relating to worker fertility. These findings provide a strong support for the hypothesis that in contrast to honey bees, JH is a gonadotropin in bumblebees and lend credence to the hypothesis that the evolution of advanced eusociality in honey bees was associated with major modifications in JH signaling.</p></div