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Title:Endothermy in cicadas (Homoptera:Cicadidae)
Author(s):Sanborn, Allen Francis
Doctoral Committee Chair(s):Heath, James E.
Department / Program:Molecular and Integrative Physiology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Entomology
Biology, Animal Physiology
Biology, Zoology
Abstract:Endogenous heat production in insects of the family Cicadidae was studied in order to determine the functional significance of endothermy in cicadas.
Measurements of body temperature (T$\sb{\rm b}$) in the field demonstrate that endothermic cicadas regulate T$\sb{\rm b}$ with solar radiation as well as endogenous heat production. T$\sb{\rm b}$'s of endothermically active cicadas are approximately the same as T$\sb{\rm b}$'s of cicadas with access to solar radiation. Plotting T$\sb{\rm b}$ as a function of ambient temperature (T$\sb{\rm a}$) illustrates that endothermic cicadas thermoregulate during daylight hours and during their dusk activity period. In contrast, the ectothermic species Tibicen similaris (Smith and Grossbeck) becomes a thermoconformer after sunset. Thermal responses of a particular species are related to their activity patterns and their habitat.
Dorisiana bonaerensis (Berg) and Quesada gigas (Olivier) raise T$\sb{\rm b}$ in the field with the heat produced in flight. Tibicen winnemanna (Davis) and Fidicina mannifera (Fabricius) can raise T$\sb{\rm b}$ with or without flight. Proarana bergi (Distant) and Proarna insignis Distant produce fine shiver-like movements of the thoracic musculature to increase T$\sb{\rm b}$.
For the family Cicadidae, cooling rate as a function of thoracic mass is described by the equation y =.026248x$\sp{-.162033}$. The calculated rate of oxygen consumption as a function of thoracic mass is described by the equation y =.533758x$\sp{.863008}$. Cicadas in the laboratory endothermically increase T$\sb{\rm b}$ to the same range measured in the field.
Changes in acoustic behavior in the endothermic T. winnemanna are related to changes in body temperature.
Measurements of timbal muscle temperature (T$\sb{\rm m}$) in the field demonstrate that T$\sb{\rm m}$ is elevated above T$\sb{\rm a}$ during activity. T$\sb{\rm m}$ increases as the acoustic output progresses from the "warm-up" buzz to full production of the calling song. Measurements of the inferred period of muscle contraction from song recordings and the contraction kinetics of isolated timbal muscles measured in the laboratory show that temperature of the timbal muscle must be elevated above T$\sb{\rm a}$ in order for the cicada to produce the calling song.
Endothermy may serve (1) to uncouple reproductive behavior from environmental constraints; (2) to circumvent possible thermoregulatory problems; (3) to permit the utilization of habitats unavailable to strictly ectothermic cicadas; (4) to reduce predation; (5) to optimize broadcast coverage and sound transmission; and/or (6) to reduce acoustic interference.
Issue Date:1990
Rights Information:Copyright 1990 Sanborn, Allen Francis
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9114398
OCLC Identifier:(UMI)AAI9114398

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