Lecture 5 Flashcards
what are the physiological constraints of an insect?
size -rate of heat gain or loss
respiration - water loss
what is the relationship with body size & heat loss?
body size incres = lose heat more quickly
how do insects respond to the cold?
temp regulation - endothermic or ectothermic regulation
temp compensation - cold tolerance
what is an ex of endothermic regulation?
honey bees maintain warm hive throughout the winter
what are some strategies of ectothermic regulation?
microhabitat
colouration
migration
how is shivering accomplished in insects? & Exs? (3)
uncoupling wings - vibrate bodies (ex: bumble bees)
opposing muscles - muscles work at the same time (ex: moths)
insulation - fur decres the cooling effect, incres wind velocity = incres rate of temp loss (ex: winter moth)
basking
allow heat & sun to warm body
what are the 2 forms of basking?
lateral basking (ex: cabbage white butterfly)
dorsal basking
is shivering an endothermic or ectothermic response to the cold?
endothermic
is basking an endothermic or ectothermic response to the cold?
ectothermic
explain the colour change & thermoregulation process. Who does this?
chromatophores are affected by temp (cells change pigemnt levels in response to cold)
when it gets colder, the cells create darker pigment to absorb more light & heat
green darner butterfly
describe the gregarious (aggregation) behaviour of the eastern tent catepillar
create silk tents for protection & bask as a community to maintain temp
increasing their volume to decres SA
Lower SA:V ration to conserve heat
enables them to have a higher metabolism process food faster
describe the gregarious (aggregation) behaviour of the honey bee
aggregate into a hive
packs in the hives are constantly moving & rotating creating heat
consume honey enabling them to conserve body heat
what are 4 insects that can withstand cold temps?
snow scorpion
ground beetle
snow flea
golden rod gall fly
what insects survives the coldest temps? & what temp?
golden rod gall fly at -87C
how do ground beetles withstand cold temps?
cryoprotectants (glycerol) to prevent freezing
non-freezing injury
cold shock - membrane failure, enzyme or io imbalance
damage/death
freezing injury
mechanical damage
recrystallization
osmotic shock
freeze tolerance
control where freezing occurs
extracellular ice can be tolerated
use ice nucleators initiate ice formation at warmer temps to prevent the insect from freezing suddenly at the super cooling point
enables the insect to adjust more slowly to osmotic pressures
build up their store of compounds that reduce the level of ice formation
ice nucleators
compounds that induce ice formation
what are the ice nucleator compounds?
food
PROs
ice crystals
calcium phosphate
uric acid
super cooling point
temp point where the insect freezes
freeze avoidance
prevent freezing to avoid ice damage
what are the strategies of freeze avoidance?
cryoprotectants - lower super cooling point to prevent freezing
antifreeze PROs - bind to ice crystals
evacuate gut with bacterial freeze
what are the cryoprotectant compounds? (3)
glycerol
ethylene glycol
trehalose (sugar)
midge larvae are active at what temp?
43 C
cryptobiosis-dehydrate
cytobiosis: ability to survive a state without metabolism
dehydrate - stops metabolism in high temps
shield & ex
wax emerges from the insect’s pores, layer where air is trapped
ex: Nambi Desert Tenebriondi Beetle
describe fog catchers in the desert
drink dew to increase their moisture
- build a ridge in the sand to catch dew
- drink dew in sand
have bumps & valleys that collect water that runs down their back & into the moth
describe the bumps on the fog catchers in the desert
hydrophilic - no wax
describe the valleys on the fog catchers in the desert
hydrophobic - contain wax
describe convective cooling in a dragonfly
obelisking - stick abdomen in the air to reduce direct contact with the sun
stilting & ex
bodies are off the ground
ex: tiger beetles
convection run & ex
runs at 1 m/s
ex: desert tenebrionid
evaporative cooling (3)
from the nectar they drink
cool hives
wings used as fans
panting & ex
spiracles move air through the body
ex: locust
sweat & ex
pores release moisture that evaporates
ex: mosquitos
cryptonephridial complex
absorb water through their anus
what are the 3 main ways that insects survive adverse conditions?
cryoprotectants
behavioural traits
exchange of air temp around them
