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Quantifying dispersal of bark beetles and their predators. Arnaud COSTA Laboratory of Insect Ecology, Southern Illinois University, Carbondale, Illinois. 1 - Introduction: gap formation in red pine forests. potential interactions between below and above ground herbivory.
Quantifying dispersal of bark beetles and their predators Arnaud COSTA Laboratory of Insect Ecology, Southern Illinois University, Carbondale, Illinois
1 - Introduction: gap formation in red pine forests potential interactions between below and above ground herbivory - interactions could be approached by measuring dispersal of each guild member - predators limit the expansion of such declining stands by reducing Ips numbers - Dendroctonus valens (root colonizer) - Ips pini (stem colonizer) - Thanasimus dubius (predator)
1 - Introduction: gap formation in red pine forests T. dubius (Cleridae) D. valens (Scolytidae) I. pini (Scolytidae)
2 - Objectives of the project - T. dubius (predator) - D. valens (bark beetle, root) Main objective: to measure dispersal of three insects associated to red pine stands decline - I. pini (bark beetle) - on the same geographical area (Wisconsin) - using the same methods (mark recapture)
2 - Objectives of the project • - differences of dispersal related to • sex • size • (Cronin et al., 2000) - how far do these insects fly? *Dispersal quantile: percentage of beetles dispersing at a particular distance a study of predator-prey movement examined for the first time on the same geographical scale
3 - Field sites Mirror Lake Kettle Moraine Spring Green
4 - Methods Mark recapture - T. dubius and D. valens caught are marked with a spot of paint on the pronotum - funnel traps baited with appropriate semiochemicals - I. pini will be marked with fluorescent powder while emerging from infested logs - insects will be released at the center of a grid of traps
4 - Methods Semiochemicals / lures
4 - Methods - grid of traps (cross shape pattern) set at 50,100, 200, 300, 400, 500, 750, 1000, 1250, 1500, 1750 and 2000 m. Mark recapture grid
4 - Methods Mark recapture grid (including a pocket of decline)
5 – Expected schedule Timetable of mark recapture tasks Legend: ML = Mirror Lake, SG = Spring Green, KM = Kettle Moraine (*) depending on infestation success (**) only one attempt might take place