6.23 Winter & Summer Behaviours Flashcards
What are the negatives of too warm a temperature in the hive?
Comb gets soft and melts or cannot pass messages through
Infertile drones
Cognitive developmental differences
Death of colony or individuals due to heat stress
How does the colony control CO2?
They have olfactory cells on their anteanne which are sensitve to gaseous co2. When this exceeds a 5000pm threshod a fanning response is insitgated. This is a tonic repsonse so the cells keep firing as long as they are stimulated (think fire alarm).
How does fanning help decrease Co2
They will stand at the hive entrance and fan their wings. The air flow is parallel to the surace they are clinging on to. Fanners will roganise themselves into chains to ensure the air keeps moving. The air is pulled out of the hive as wings are impellers
Why do bees fan air out rather than fan it in, when concerned with CO2?
They are constantly checking the hive temperature and CO2 rather than not getting that information input if they were blowing it in
How is water used to cool the nest?
Evaporative cooling where the worker will place water droplets on comb surface or on her tounge and let it evaporate to reduce heat. She may also place water droplets in larval cells to avoid desssication
How does a worker sense dmeand for water to be collected?
• She has receptors in her brain which will detect an increase in osmotic pressure of her haemolymph to make her realise she needs water (an internal factor)
• She may get approached by a water receiver who extends her tongue to touch the water collectors mouth parts but doesn’t have anything to share.
What doesn’t cause water collection?
High temepratures on their own
What does having the brood nest in the cnetre allow for with thermoregulation in mind?
The bees can expand and contract around this sapce to alter the temperature
Describe methods to keep the nest cool
o Bearding on the outside minimises the number of bees inside, whose metabolic heat will be contributing to the nest temperature
o Fanning cooling air flowing in
o Evaporative cooling from water
o Heat shielding on hot surfaces within the nest.
What is the humidty inside the bee nest?
40-70% - they decrease the rleative humidty around honey combs to help dehyrdate it.
How do the bees control humidity?
Either by evaporating water or by fanning
How does clustering help the colony survive?
the surface area to volume ratio is more efficnet for a cluster comapred with indivudals
What temeprature does clustering begin?
18 degrees celcius
At what temeprature does the clsuter no longer contract?
0 degrees celcisu
What temperature is the colony over winter?
When there is no brood prioudction it can drop to 20 dgrees but inner core will never reach below 13 degrees and wont be as low as 8 degrees
Who are the refuler bees in the winter cluster?
They trek backwards and forward to food stores and supply heater bees with food via trophallaxis
How is heat lost in the winter colony?
Through conduction into the combs as well as via convetion through the porpous cluster.
How do bees heat cells in winter?
They will place their thorax on cappings and vibrate. It is more efficnet to do this in a vacant cell as alll heat is used.
Why might some cells be left empty in the cluster area?
To act as tempoary food sotrae or to allow heater bees in
Describe water collection in winter?
They will need water to consume granulated sotres. When they are drinking cold water they will engage their throacic flight muscles to shiver and stay warm. She needs to keep temps above 25 degrees to be able to fly.
