Activity Levels and Environmental Preference of House crickets
Under Various Light and Humidity Conditions Syd Bliss and Anne
Haley
Slide 2
Influence on resting place Many abiotic factors influence
choice Testing light and humidity preferences House crickets
(Acheta domesticus)
Slide 3
Hypothesis Null: crickets show no preference and no behaviour
change in relation to light and humidity Alternate: crickets show
preference and behaviour change in relation to light and
humidity
Slide 4
Predictions Previously shown preference for dark enclosed
spaces (Keiruzel 1976) Water essential to invertebrate survival
Biochemical gradients, membrane fluidity, sustained periods of
activity (Mcluney & Date 2008)
Slide 5
Other factors Light is a cue in entrained rhythms Affected by
photoperiod, seasonal change and environmental response *Difficult
to maintain photoperiod, loosely based on 12:12 rhythm
Slide 6
Calls occur at night Stridulations function in: Mating Female
choice Sexual selection Male aggression Could affect choice in
light vs. dark
Slide 7
Influences Innate responses photo and thigmo-kinetic stimuli
Light and contact stimuli Supplemented by Hygrophilia and
thermophilia Affinity for moisture and heat
Slide 8
Methods Maintenance, manipulation and analysis
Slide 9
Maintenance Checked 3 times a week Food and water replenished
as needed 3 weeks under rough 12:12 photoperiod
Slide 10
Maintenance of crickets 30 adult males separated Glass tank at
room temperature Layer of mulch and egg carton shelters Dog food
and apple slices Moist sponges
Slide 11
Manipulation of Environment Light preferences: 15 W, 40 W and
100 W Desk lamp and garbage bag
Slide 12
Manipulation of Environment Humidity preferences: Desiccant of
calcium chloride Wet paper towel Studies done under red light
Slide 13
Setup: 24 lines 1 cm apart drawn 1 cm across width of tank
Paper divider taped to sides of tank Crickets could still travel
underneath
Slide 14
Analysis of behaviour One cricket to test each factor to reduce
errors Acclimatization period of 10 minutes 15 replicates, two
minute period to test factor (5 per light bulb)
Slide 15
Analysis of behaviour Two minute timer Counted number of lines
crossed Amount of time spent in half of tank measured
Slide 16
Analysis of behaviour One person monitored light half while
other person monitored dark half Same procedure for humidity
factors No changes in level of desiccant or humidity
Slide 17
RESULTS Light activity 15W mean lines crossed: light section =
19.80 (4.55) dark section = 26.40 (5.45) no significant difference
(independent t-test, t=0.93, df=8, p=0.38) 40W mean lines crossed:
light section = 9.20 (5.11) dark section = 8.20 (5.14) no
significant difference (independent t-test, t=10.14, df=8, p=0.89)
100W mean lines crossed: light section = 14.40 (9.60) dark section
= 8.40 (1.98) no significant difference (independent t-test,
t=-0.61, df=8, p=0.57)
Slide 18
Light time budget 15W mean time: light section = 65.12 sec
(10.46) (54.27%) dark section = 54.88 sec (10.41) (45.72%) no
significant difference (independent t-test, t=0.70, df=8, p=0.50)
40W mean time: light section = 69.0 sec (23.26) (57%) dark section
= 51.0 (23.26) (42.5%) no significant difference (independent
t-test, t=-0.55, df=8, p=0.60) 100W mean time: light section =
20.16 sec (14.90) (16.8%) dark section = 99.84 sec (14.90) (82.2%)
significant difference (independent t-test, t=3.78, df=8,
p=0.0054)
Slide 19
Humidity activity Dry Section: Mean lines crossed = 8.33 (3.79)
Medium Section: Mean lines crossed = 2.53 (1.64) Humid Section:
Mean lines crossed = 1.46 (1.52) no significant difference (ANOVA,
F=2.26, df=2, p=0.12) Post-hoc testing (Tukey HSD): no significant
difference between the conditions
Slide 20
Humidity time budget Dry Section: Mean time= 97.40 sec (9.94)
(81.17%) Medium Section: Mean time= 14.60 sec (7.19) (12.17%) Humid
Section: Mean time= 8.00 sec (7.75) (6.66%) significant difference
(ANOVA, F=36.34, df=2, p=5.75x10 -10 ) Post-hoc testing (Tukey
HSD): significant difference between medium vs. dry (p=0.00) and
humid vs. dry (p=0.00), no significant difference humid vs. medium
(p=0.82)
Slide 21
Discussion Investigating how crickets choose to spend their
time (resting place) based on 2 environmental abiotic factors Light
+ activity: intensity of light does not affect the activity level
of crickets o In contrast to other studies that reported House
crickets having very distinct levels of locomotor activity under
during light conditions, and activity peaks during darkness/ lowest
light level available (Harker 1961; Nowosielski & Patton 1963;
Cymborowski 1969, 1970; Azarin & Tyshchenk 1970; Kieruzel
1976). Photo: Jeff Morgan
Slide 22
Light + time budget: intensity of light does not affect the
time budget of crickets, except when there is a extreme difference
between the light level and darkness o In contrast to other studies
that reported studies prefer darkness over light negative
phototaxis (Federhen 1955; Kieruzel 1976) Not entrained on L:D
rhythm Not given adequate time to adjust to changing conditions
before time budgets were measured Photo: Ralph Neale
Slide 23
Humidity + activity: humidity does not affect activity levels
Humidity + time budget: crickets preferentially seek out dry
environments Inconsistencies in previous studies: o Ghouri and
McFarlane (1958) prefer dryness o Kieruzel (1976) prefer humidity
Humidity preferences in general have not widely been demonstrated
in most insects may be confounded with temperature Photo: Luiz
Fernandez GarciaPhoto: Milou Diable
