Leaf litter species preference in the pill bug (Armadillidium
sp.)
Emily ByrneKevin Isherwood
Greg McGuire Jonathan O’Keefe
The pill bug, Armadillidium sp.
• Widespread terrestrial crustacean
• Susceptible to desiccation• Physiological adaptations• Behavioural adaptations
• Respiratory mechanisms
Habitat preference• Flexible diet comprised primarily of decaying
matter
• Moist, dark environments
• Decaying > fresh leaf litter
Species- specific leaf litter
• High quality litter> low quality litter• Panlasiui (2011)• Oak, Quercus agrifolia, > Blue Gum, Eucalyptus
globulus
• Tuck & Hassall (2003)• Dicotyledon litter > grass litter
• Morisawa et al. (2002)• Japanese Cedar, Cryptomeria japonica – natural
repellant
Current study
• Investigate if the pill bug, Armadillidium sp. has a preference for local leaf litter species
• Hypothesis: individuals will prefer broad-leaf species
Experiment 1: Leaf litter species preference
• 3 trials• Wet leaves• Dark
environment
20 pill bug
s
Picea rubens
Quercus rubens
Thuja occidentalis
Acer saccharum
_x0006_Spruce
_x0006_ Maple
_x0006_ Cedar
_x0004_ Oak _x0005_ Dead
0
1
2
3
4
5
6
7
8
9
10
Leaf litter species
Num
ber o
f pill
bug
s
Experiment 2: Effects of moisture and humidity
• Spruce dried in oven
• Maple dunked in well water
20 pill
bugs
Dry Spruce Wet Maple
0
5
10
15
20
25
Leaf litter condition
Num
ber o
f pill
bug
s
Discussion
• Hypothesis: preference for broad leaf species
• Drying of leaves potentially a major contributor
Discussion
• Cloudsley-Thompson & Constantinou 1987 • Presence of a thigmokinetic response
• Takeda 1980 • Possible aggregation pheromones
Questions?