Mountain Pine Beetle Flashcards
How does blue stain fungus create better food for larvae?
Enhances nitrogen saturation in affected wood.
What are critical beetle success factors?
Finding the right tree - older and or stressed
Signal pheremones between species to orchestrate a mass attack
Blue stain fungus that infects tree upon first bite - vectored by beetle maxillae
Timing of emergence and maturation
Varied dispersal behaviour spreading risk
Host defences to beetles?
Primary resin ducts (constituent) and
secondary resin ducts - traumatic (conversion of other tissue to resin ducts) more fluid, free flowing, more toxins.
Sink tree vs source tree?
Less than 25 cm beetles reduced survival in winter - sink
Over 25 cm tree beetles increased winter survival - source
What are the age thresholds for beetle attack
0-40: too small
40-80: most resistant
80+: most susceptible. Old and right size
What are the critical pheremones produce by pine beetle?
Aggregation and anti aggregation
How many eggs to a brood? How long to hatch?
60-80 eggs per beetle, two weeks to hatch
How many larval stages ?
How frost hardy are the stages
L1-L4. From L4 to pupa to adult
Egg very low
L1 and l2 med
L3 l4 high
Pupa low
What is important to beetle lifecycle timing.
Life cycle should be timed for larvae to be in l3 and l4 stage through the coldest part of winter. Larvae shut down during most frost hardy stage to overwinter but l1 and l2 will continue developing to synchronize population.
Green attack?
Current Attack. Can only be detected from ground by examining pitch tubes. This is the most important stage for us to know about but can’t be seen from air.
Red attack?
One year after initial attack, tree has died and turns red. Beetles already gone. Does not do managers any good.
Grey attack?
Two - three years after initial attack. Window of higher fire hazard
What do beetles do to survive winter?
Produce glycerol, a slow increase in concentration in response to phenological cues.
Glycerol can allow beetles to survive up to -40. -20 at the beginning of winter and end of winter as it is still accumulating glycerol or breaking it down respectively.
What do larvae do when they wake up from winter stasis?
Resume feeding -> pupate -> teneral adult which continues maturation feeding to form flight muscles and mycangia (grooves in mouthparts).
What does the tree die of
Shut down of vascular system. Blockage of water
Phloem is eventually girdled, shutting down the sugar transportation system of the tree.
What time period are bark beetles flying at? Why are the attacks so successful?
A temperature indicator cues beetles to wake up and fly all in about a 10 - 12 day period. Beetles are synced to temp for emergence.
When beetles are out in mass numbers, pheremones are much more effective. Since it is dry, stressed trees also have a reduced ability to pitch out and defend against invasion.
How is beetle flight syncronized ?
Beetles wake up at a set temperature
Syncronized with seasons to fly at driest time of year where flight is improved and trees are stressed.
How and when does pine beetle dissipate
- flight timed for late July - early August depending on temperature
- 70 % long dist 30 % short dist
- 2.5 % above canopy by convection
- fly downwind until they detect suitable kairomone ( if wind above 7k beetles won’t fly.)
- if it’s bright and warm out beetles will keep flying
At a landscape level what pattern does bark beetle make?
Salt and pepper effect
Where do most beetles fly?
Between the brush and the lower canopy of forests
How are kairomone And pheremone interconnected?
Kairomones (attract pioneer)
Pheremones (mass attack) where pioneers attract mates.
How to treat beetle infested logs
Cut into 2 foot lengths to dry them out
Or burn them
Or mill them
What do beetles make pheremones for?
Mass attack
Anti aggregation.
What is maturation feeding?
When young adults feed on spores of blue stain fungus. Enhances sexual maturation.
