Abnormal, Foraging activity and behavior

Text from LaLone et al. (2017) Weight of evidence evaluation of a network of adverse outcome pathways linking activaiton of the nicotinic acetylcholine receptor in honey bees to colony death. Science of the Total Environment 584-585, 751-775:

"As eusocial insects, honey bees rely on theworker bee caste to forage for nectar, pollen, andwater. Foraged water can be used for evaporative cooling of the hive during warm weather (as reviewed by Jones and Oldroyd, 2006). Nectar and pollen collected by the foragers are the sole food source for the colony, with nectar providing carbohydrates and pollen providing lipids, protein, vitamins, and essential minerals (Brodschneider and Crailsheim, 2010). Upon returning to the hive, forager bees identify non-foraging, food-storing hive bees and deliver their collection by regurgitating nectar carried back in their honey stomach (i.e., foregut of proventriculus; Free, 1959). The hive bees place the nectar in wax cells for processing into honey. Hive bees also aid foragers in unloading pollen from the pollen baskets (corbicula) on the forager's hind legs and place it in cells where it is mixed with nectar to form bee bread, which is stored for consumption by the colony (Winston, 1987). Foragers consume only small amounts of the food they collect. Hive bees consume the food they receive in order to produce proteinrich royal jelly and brood food, which they use to nourish both the queen and the developing brood (Winston, 1987). During winter, the colony survives on the pollen and nectar that was stored as bee bread and honey over the spring, summer, and fall seasons (Seeley and Visscher, 1985). The act of foraging is a perilous and metabolically challenging task that is typically carried out by worker bees in the later stages of life (Woyciechowski and Moroń, 2009). However, the timing of the role change from hive bee to forager can vary depending on the needs of the colony. There are environmental, hormonal, and social cues that determine when and how often foragers search for food and fluid, includingweather, abundance or scarcity of food resources, magnitude of food stockpiled in the hive, health of the colony, and size of the brood (Dreller and Tarpy, 2000). Such cues initiate physiological changes involved in the transition of a worker bee to foraging, which include changes to flight muscles andmetabolic rate. These changes accommodate the reported 70-fold increase in oxygen consumption needed to sustain physical and cognitive activities of the forager bee (Kammer and Heinrich, 1978). It has been documented that the volume of neuropil in mushroom bodies is increased by approximately 15%, and the somata of the Kenyon cells decreased by approximately 29% in foragers compared to day-old bees (Withers et al., 1995). Change in lipid stores also occurs in forager bees prior to foraging, whereby their abdominal lipid is reduced to approximately half that of nurse bees (Chang et al., 2015; Toth and Robinson, 2005). Further, there is lowprotein content in the forager's fat body cells, and vitellogenin (Vtg; egg

yolk) protein production is significantly reduced, while juvenile hormone levels are significantly increased (Toth and Robinson, 2005). Another change which occurs at the stage where worker bees become foragers is that their flight muscle fiber thickness decreases and diameter of the myofibrils, which contain the contractile filaments, increases in preparation for prolonged flight during foraging (Correa-Fernandez and Cruz-Landim, 2010)."

Text from table 2 in LaLone et al. (2017) Weight of evidence evaluation of a network of adverse outcome pathways linking activaiton of the nicotinic acetylcholine receptor in honey bees to colony death. Science of the Total Environment 584-585, 751-775:

"• Radio-frequency identification tagging technology to track the frequency and duration of individual foraging events, flight time, foragers homing ability, duration of time spent at a feeder, and duration between feeding • Video tracking software for measures of total distance traveled and time spent in social interaction • Weigh bee-collected pollen from hive entrance trap • Pollen load can also be assessed by scoring the size of amount of pollen in the forager’s corbiculae (pollen basket) relative to the size of the worker bee • Nectar loads from individual forager bees can be measured with a pocket refractometer after inducing regurgitation • Video foragers returning to hive and measure waggle dance circuits performed • Food storage can be measured by visual inspection or digital imaging of the combs with the objective to estimate the percent of cells filled with nectar (uncapped), honey (capped), or pollen"

LaLone, C.A., Villeneuve, D.L., Wu-Smart, J., Milsk, R.Y., Sappington, K., Garber, K.V., Housenger, J. and Ankley, G.T., 2017. Weight of evidence evaluation of a network of adverse outcome pathways linking activation of the nicotinic acetylcholine receptor in honey bees to colony death. STOTEN. 584-585, 751-775.

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Woyciechowski, M., Moroń, D., 2009. Life expectancy and onset of foraging in the honeybee (Apis mellifera). Insect. Soc. 56 (2), 193–201.

Dreller, C., Tarpy, D.R., 2000. Perception of the pollen need by foragers in a honeybee colony. Anim. Behav. 59 (1), 91–96.

Kammer, A.E., Heinrich, B., 1978. Insect flight metabolism. Adv. Insect Physiol. 13, 133–228.

Withers, G.S., Fahrbach, S.E., Robinson, G.E., 1995. Effects of experience and juvenile hormone on the organization of the mushroom bodies of honey bees. J. Neurobiol. 26 (1), 130–144.

Chang, L.H., Barron, A.B., Cheng, K., 2015. Effects of the juvenile hormone analogue methoprene on rate of behavioural development, foraging performance and navigation in honey bees (Apis mellifera). J. Exp. Biol. 218 (11), 1715–1724.

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Correa-Fernandez, F., Cruz-Landim, C., 2010. Differential flight muscle development in workers, queens and males of the eusocial bees, Apis mellifera and Scaptotrigona postica. J. Insect Sci. 10, 85.