Victoria Badalamente
November 7, 2014
Bio Lab: Section J
Professor Jen Niese
The Effects of Temperature on Respiration and the Metabolic Rate in Crickets
Introduction:
Temperatures have astounding results on ectothermic animals (Cossins and Bowler, 1987). We saw this
with our experiment on Acheta domesticus, more commonly known as house crickets. An ectothermic
animal is a cold-blooded animal. Some animals can control the production of heat to maintain a body
temperature generated by metabolic reactions. These animals are warm-blooded. Another name for
them is Endotherms, they depend on and are capable of the internal generation of heat. Endotherms
convert the food they eat into energy which then gives off heat in order to regulate their internal
temperature. When they are in warmer environments Endotherms can produce sweat to cool off their
body’s temperature. The house crickets we used for this experiment were Ectotherms. This means that
they are dependent on external sources in order to maintain their body heat. Ectotherms tend to do
better in warmer climates because their muscle activity runs much faster when it is warm out, when the
climate is much colder, cold-blooded animals tend to be sluggish. The metabolic rate can be determined
by the rate of carbon dioxide production or the rate of oxygen consumption. What effects the
metabolic rate most in house crickets is their body mass and surrounding temperature. My hypothesis
for this experiment was, as temperature decreased so would the metabolic rate in house crickets. Other
scientist have found that “the ecological and physiological patterns and processes that account for
observed variation in the metabolic rate in insects are not yet fully understood, especially in regard to its
adaptive significance” (Addo-Bediako et al., 2002).
Methods:
First I measured the weight of the crickets then, in order to find the metabolic rate of the house cricket I
first placed the cricket into the respirometer with the chemicals drierate and ascarrate. The purpose of
the two chemicals was to eliminate water vapor and carbon dioxide in the respirometer. Then after
placing a drop of water in the manometer I was able to measure the time it took for one ml of oxygen to
be used by the cricket. Then repeating the following steps I then measured the time it took for one ml
of oxygen to be used by the cricket while it was surrounded by ice.
Figure 1. Cricket Respirometer
Cricket
1
2
3
4
5
6
7
8
9
10
Averag
e
Room Temp
Metabolic Rate 1 ml
Temperature
of oxygen per
°Celsius
second
Cold Temp
Metabolic Rate
Temperature
1ml of oxygen
°Celsius
per second
22
22
22
22
22
22
22
22
22
22
2.9
9.2
22.8
8.3
10.4
2.6
77.9
43.5
18.8
12.8
1
1
1
1
1
1
1
1
1
1
11.3
4.4
45.7
3.4
0.0
7.5
40.7
0.0
11.7
6.9
22
20.9
1
13.2
Results:
The metabolic rate decreased as temperature decreased, see Table 1 and Figure 2.
Table 1: Metabolic Rate of All Crickets
This table contains the class results of the metabolic rate of crickets.
Figure 2: The Effect of Temperature on Crickets
The sample size used for this graph was 6 crickets.
Discussions:
My initial hypothesis was that as the temperature decreased so would the cricket’s metabolic rate. The
data shown does support my hypothesis. The findings I found for the ectotherms (ho use cricket), would
not be the same for endotherms. If this experiment was done on endotherms their body metabolic rate
would remain constant because they have ways of controlling their internal body temperature. My
results do match up with other scientists. For example: one study, although much more in depth did find
that temperature did have an effect on the metabolic rate of ectotherms.
Literature Cited
Addo-Bediako, A., Chown, S. L. and Gaston, K. J. (2002). Metabolic cold adaptation in insects: a largescale perspective. Funct. Ecol. 16,332 -338.
Cossins, A. R. and Bowler K. (1987). Temperature Biology of Animals. London: Chapman and Hall.
Prestwich, K. N. and Walker, T. J. (1981). Energetics of singing in crickets: effect of temperature in three
trilling. 143,199 -212.