Lecture 33 Flashcards
what are the 2 phenomena assoc with temp related changes?
Increased mean temps
Increased freq, severity & duration of extreme temp events
what are the 4 changes occurring in the envr?
- Increased bias towards warmer than average temperature events
- Increased frequency, severity & duration of phenomena like heat waves & drought
- Warmer winter temperatures, changes in snow and ice cover duration
- Changes to growing season length
Earlier on set of spring-like conditions
Later onset of winter-like conditions
what components of insects are affected by ambient temps? (5)
physiology, development, growth, adult size & behaviour
what type of relationship do insects have b/w development rate (highest) & development time ?
inverse
what temp is the lower development threshold? & what is occurring at this time?
0C
no growth or development, dormant
what temp is the upper development threshold? & what is occurring at this time?
~33C
no development
May not die, but cell damage occurring
what climate regions will insects be effected the most by climate change?
temperate
how is the growing season changing due to climate change?
earlier onset of spring-like conditions & later onset of winter-like conditions combines to increase the length of the growing season in temperate regions
what impacts of climate change have already been observed? (5)
growing season
severe weather events
winter
spp distributions
trophic interactions
what effect does the change in the growing season have on Multivoltine herbivorous pests (aphids)?
of gens is determined by the growing conditions
since there is a longer growing season, aphids will benefit b/c they can produce more gens & increase their pop even more
how does a change in growing season effect insects that are in synchrony with their hosts & vice versa?
Climate induced increases in asynchrony in plant-insect interactions are occurring
Increasing spring temps don’t necessarily influence plant & insect pops similarly since the cues used to time development & other activities may differ (ex: temp, daylight, host phenology)
what is an ex of insect-host interactions suffering from asynchrony due to change in growing season?
Bumble bees in subalpine meadows
how is pollination success & deficits by Bumble bees in subalpine meadows being effected by the change in growing season?
Observing greater pollination deficits b/c there is a greater mismatch at the time the plants are flowering & the queens are active
Flowering is occurring before pollinators are present
flowering occurs once the snow is gone, only queen bees present at this time
how is climate change affecting severe weather events?
change increases the frequency & severity of extreme weather events including heat waves, droughts, floods & other storms
how do heat waves affect insects?
Upper temp reached = no development & can be harmed
Optimal temp for development is not too far from temps that impact fecundity & growth
Incres freq &/or severity of extreme temps leads to _____ development times (impaired)
longer
describe how changes in extreme weather events will affect aphids & their parasitoids?
not equally affected by temp, aphids & their parasitoids have diff optimal temps of development
Temps might be beneficial to aphids, but damage to the parasitoid developing within it
severe weather events will impair development of ______ to a greater extent than the growth of development of the aphid
parasitoid
why is it a concern that parasitoids & aphids are affected differently by severe weather events?
Parasitoids are less able to control aphid pests when they experience severe temps –> impacts bio control
what factors affect overwinter survival in insects under climate change?
- Warmer mean winter temps
- Changes in snow & ice cover duration – important insulator for insects that overwinter in soil
- Earlier onset of spring-like conditions
- Later onset of winter-like conditions
what is an ex of a spp affected by the change of winters?
mountain pine beetle
how does a change in winter affect the mountain pine beetle?
well-adapted to cold temps & winter is the only source of mortality
severe winters are occurring less & have been too infrequent to control the damage caused by the beetles
They have also shifted range north b/c winter temps are no longer limited
how does a change in winter affect the gypsy moth?
Overwinter as eggs on the trunks of trees
Snow cover increases insulation & also limits predation by rodents
what are the 3 ways that insect spp ranges have changed?
shifts
expansions
contractions
what insects were recorded to shift their range northwards in Odonates in Great Britain? Why is this a concern?
dragonflies & damselflies
since GB is an island, they can only go so far before they will become extinct
how have the butterflies in NA & Europe changed their range?
increasing their ranges northward & to higher elevations
what are 2 insects that have expanded their ranges northward?
dragonflies & damselflies in GB
heat-adapted dragonflies in NA & Europe
how have insects contracted their ranges & why?
in latitude & elevation
b/c areas where they previously received their proper cues no longer do
what spp has contracted its range? What is occurring? What factors are affecting it?
cold-adapted butterflies in NA
require experiencing a cold time of conditions during their winter diapause, they don’t come out of it properly & it interferes with their lifecycle
offspring are dying, but summer conditions are suitable
Snow coverage duration or level of moisture
range shifts
o expansions in one direction & contractions in another
how has Edith’s Checkerspot in Western NA distributions changed?
range shifts
expansion northwards, where it was originally found it has been driven extinct
what is the main selection pressure on reproduction?
is synchrony b/w offspring requirements & food availability
how are the great tits being affected by climate change?
trophic interactions
Egg laying & nest building activity is synchronized with peak caterpillar activity (birds feed on caterpillars)
Increasing asynchrony during peak food abundance & chick activity (& need to be fed)
overall reduction in fitness
why is it difficult to assess the overall impacts of climate change?
due to higher level processes like trophic interactions & landscape effects
