First published online January 27, 2004
Journal of Experimental Biology 207, 723-733 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00807
Temperature regulation in burying beetles (Nicrophorus spp.: Coleoptera: Silphidae): effects of body size, morphology and environmental temperature
Melissa J. Merrick* and
Rosemary J. Smith
Department of Biological Sciences, Idaho State University, Pocatello,
ID 83209-8007, USA

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Fig. 1. The relationship between temperature excess (post-flight
TthxTa) and ambient air
temperatures. As ambient temperature increases, the temperature differential
between the thorax and the environment decreases, finally becoming negative at
ambient temperatures above approximately 30°C. Tthx,
thoracic temperature; Ta, ambient air temperature.
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Fig. 2. Four examples of sustained, continuous flight (flight time 1239 min)
for four N. hybridus individuals and subsequent post-flight cooling
(12 min). The horizontal line represents
Tthx=Ta and the vertical line denotes
cessation of flight. The filled diamond indicates the mean thoracic
temperature measured during the flight. Mean flight temperatures were
33.5°C (A), 31.5°C (B), 33.01°C (C) and 27.83°C (D). Mean
flight temperature for post-flight Tthx taken via
the `grab and stab' method was 29.9±3.1°C.
Tthx, thoracic temperature; Ta,
ambient air temperature.
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Fig. 3. The relationship between post-flight thoracic temperature
(Tthx) and operative flight temperature
(Te) for the three species. Slopes from the regression of
Tthx on Te were used as an index of
thermoregulatory performance.
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Fig. 4. An example of a 24-h observation period, illustrating the thermal
environment a beetle may experience throughout the day and how beetle activity
corresponds to operative temperatures. Beetle activity is defined as the
number of beetles caught while flying into a trap in addition to beetles seen
flying in the vicinity of the traps but not landing. An asterisk indicates one
observation where an N. investigator individual was found walking on
the ground near a can.
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Fig. 5. Predicted thoracic temperature (Tthx) during flight for
N. hybridus, the largest species, N. guttula and N.
investigator. Operative temperatures (Te) measured
throughout an entire day in late July 2001 were then used to predict the
flight Tthx for the three species using the regression of
post-flight Tthx against the Te
developed for each species. The bars represent possible flight times
throughout the day for the three species. Flight times were estimated based on
the minimum and maximum thoracic temperatures recorded for each species
following a flight trial.
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© The Company of Biologists Ltd 2004