Key Event Title
|Level of Biological Organization|
Key Event Components
Key Event Overview
AOPs Including This Key Event
|AOP Name||Role of event in AOP|
|nAChR activation - colony death 1||KeyEvent|
|Metabolic stress - Colony loss||KeyEvent|
|Immune system - Colony loss 2||KeyEvent|
|nAChR activation - colony loss 5||KeyEvent|
|nAChR activation - colony loss 6||KeyEvent|
|nAChR activation - colony loss 7||KeyEvent|
|Varroa mite and abnormal foraging leads to colony loss/failure||KeyEvent|
|Weather to abnormal foraging to colony loss/failure||KeyEvent|
|Nosema to energy to colony loss/failure||KeyEvent|
Key Event Description
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
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)."
How It Is Measured or Detected
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"
Domain of Applicability
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.
Brodschneider, R., Crailsheim, K., 2010. Nutrition and health in honey bees. Apidologie 41
Jones, J.C., Oldroyd, B.P., 2006. Nest thermoregulation in social insects. Adv. Insect Physiol.
Free, J.B., 1959. The transfer of food between the adult members of a honeybee community.
Bee World 40 (8), 193–201.
Winston, M.L., 1987. The Biology of the Honey Bee. Harvard University Press.
Seeley, T.D., Visscher, P.K., 1985. Survival of honeybees in cold climates: the critical timing
of colony growth and reproduction. Ecol. Entomol. 10 (1), 81–88.
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,
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
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.
Toth, A.L., Robinson, G.E., 2005. Worker nutrition and division of labour in honeybees.
Anim. Behav. 69, 427–435.
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.