PARENT SESSION
Organized Oral Session 23: The use of spatially explicit data in ecological investigations
Organizer(s): K Conrad, J Holland, and L Rew
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 511 C, Level 5, Palais des congrès de Montréal
Spatio-temporal dynamics of individually marked beetles in relation to aphid distributions at different spatial scales.
Griffiths, Georgianne*,1, Winder, Linton1, Perry, Joe2, Alexander, Colin2, Holland, John3, 1 University of Plymouth, Devon, U.K.2 Rothamsted Research, Harpenden, U.K.3 The Game Conservancy Trust, Fordingbridge, U.K.
ABSTRACT- A novel technique was developed to individually mass-mark carabid beetles using an industrial laser. This allowed us to conduct field-scale mark-recapture studies to investigate individual-based spatio-temporal dynamics of the generalist predator Pterostichus cupreus in relation to their cereal aphid prey Metapolophium dirhodum and Sitobion avenae. The movements and distribution of marked P. cupreus were examined in relation to their hunger levels at the moment of release (hungry or satiated) within manipulated distributions of high and low aphid density at differing spatial scales. Hunger was determined by altering the diet of a captive population; hungry beetles were starved for three days prior to release whilst satiated beetles were also starved but fed on the day of release. Areas of high and low aphid density in a regular blocked design were successfully created at large and small spatial scales by spraying out areas using a weak pirimicarb solution during the aphid infestation stage. SADIE (spatial analysis by distance indices) software was used to describe and compare spatially referenced counts of P. cupreus, M. dirhodum and S. avenae from 81 sampling locations in each of the large-scale and small-scale aphid distributions. Preliminary results suggest that male and female P. cupreus differ considerably in their movement behaviour and response to aphid distributions.
Key words: Carabidae, mark-recapture, movement, spatial pattern