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Response of body temperature to solar radiation in restrained nymphal migratory grasshoppers (Orthoptera: Acrididae): influences of orientation and body size
Author(s) -
LACTIN DEREK J.,
JOHNSON DAN L.
Publication year - 1997
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1997.tb01150.x
Subject(s) - acrididae , biology , orthoptera , radiation , interception , insolation , relative humidity , atmospheric sciences , convection , zoology , physics , thermodynamics , ecology , optics , climatology , geology
. .We restrained forty‐nine nymphal migratory grasshoppers (Melanoplus sanguinipes) in a series of orientations to the sun and measured rate of temperature change due to radiation intercepted, compensating for temperature loss by convection and greybody reradiation. Direct solar radiation affected body temperature significantly, but diffuse radiation did not. The coefficient of direct solar heating ( H dir ), varied from 0.603 to 0.690 depending on how radiation interception was estimated, and on whether insect size was expressed as mass or as a function of length. H is the rate of temperature change as a proportion of the maximum rate assuming complete conversion of all incident radiation to heat. None of the H dir estimates was significantly different from visible‐spectrum absorbance to (0.722), suggesting that the latter is a reasonable approximation of H dir In simulations, equilibrium body temperature elevation decreased with body size where energy influx was expressed as the amount intercepted (W) , but increased with body size when expressed as insolation as (W m‐ 2 ) because at a specified insolation, the amount of energy intercepted increases with body size. Expressing energy influx as the amount intercepted reveals the underlying biophysical mechanisms which determine body temperature. This paper presents a model of body temperature elevation in which fundamental physical processes are assembled to provide good estimates. This basis in physics implies that the model can can be applied with confidence to conditions other than those in which it was derived.