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 - predators limit the expansion of such declining stands by reducing Ips numbers - interactions could be approached by measuring dispersal of each guild member - Ips pini (stem colonizer) - Thanasimus dubius (predator) - Dendroctonus valens (root colonizer)

I. pini (Scolytidae) T. dubius (Cleridae) D. valens (Scolytidae) 1 - Introduction: gap formation in red pine forests

2 - Objectives of the project Main objective: to measure dispersal of three insects associated to red pine stands decline - on the same geographical area (Wisconsin) - using the same methods (mark recapture) - I. pini (bark beetle) - T. dubius (predator) - D. valens (bark beetle, root)

2 - Objectives of the project - 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 - differences of dispersal related to - sex - size (Cronin et al., 2000)

Spring Green Mirror Lake Kettle Moraine 3 - Field sites

4 - Methods Mark recapture - funnel traps baited with appropriate semiochemicals - T. dubius and D. valens caught are marked with a spot of paint on the pronotum - 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 SpeciesIpsdienol + lanierone Δ-3 carenefrontalin + α-pinene I. pini D. valens“0”+ + +“0” T. dubius

4 - Methods Mark recapture grid - grid of traps (cross shape pattern) set at 50,100, 200, 300, 400, 500, 750, 1000, 1250, 1500, 1750 and 2000 m.

4 - Methods Mark recapture grid (including a pocket of decline)

5 – Expected schedule Set grids of traps Infest logs Capture/release Time Sites MLSGKM March 8-10, May1 st : Early - Mid May T. dubius D. valens I. pini (*) 2 nd : Mid June (**) I. piniT. dubius D. valens (*) depending on infestation success (**) only one attempt might take place Timetable of mark recapture tasks Legend: ML = Mirror Lake, SG = Spring Green, KM = Kettle Moraine