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?