- Env. Resistance
Physical Factors- Reactions (+ / -) to Stimlus
- tropism (orientation ... to/from)
- taxis (movement ... to/from)
- kinesis (intensity of activity ... more/less)
- Temperature
- thermoregulation
- poikilotherms
- bug temp. varies with "weather"
- ecto / endo
- ectotherms - external heat source
- endotherms - generate heat (flight generates heat)
- ranges of temp.
- optimal (20-25 C)
- active (~0 to ~35 C) ... rough figures
- dormancy
- diapause
- "arrested development" ... winter
- triggered by photoperiod
- broken by heat sum
- quiescence/ estivation
- temporary shut-down
- lethal temp. depends on
- species
- life stage
- duration of exposure
- time of year
- prev. weather
- low temp
- decreased activity (less feeding ... may starve)
- slower dev. - longer time as larva - predation
- freeze to death ... ice crystals in body
- high temp
- increased activity (kinesis) ... then estivation, then ...
- ... death
- accum. of toxins
- dessication
- starvation
- Light (UV - IR)
- some insects see UV and/or near IR
- spider silk reflects UV ...
- some insects have heat (IR) detectors
- "fire beetles" (5 km)
- purple reprod. buds vs. green veg buds (7º diff.)
- flight stimuli
- only day
- only night
- only dusk/dawn
- reaction to light L1 +, L4 -
- why L1 + and L4 -
- cold spring ...
- warm spring ...
- Moisture
- activity (kinesis)
- some defoliators no feed if air saturated (prolonged rain?)
- some insects no fly in rain (or wind)
- abnormal weather can ↓ pop'n
- late/early frost
- cool spring
- extreme cold
- hot/dry summer
- heavy rains/wind (mating, flight, feeding)
- lack of snow
- climate change?
