Cold shock and rapid cold-hardening of pharate adult flesh flies (Sarcophaga crassipalpis): effects on behaviour and neuromuscular function following eclosion |
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Authors: | JONATHAN D. KELTY KATHLEEN A. KILLIAN RICHARD E. LEE |
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Affiliation: | Department of Zoology, Miami University, Oxford, Ohio, U.S.A. |
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Abstract: | Abstract. Little is known about the nature of injury due to cold shock, or its prevention by rapid cold-hardening, in insects. To understand these phenomena better at the system level, physiological and behavioural comparisons were made between control, cold shock injured, and rapidly cold-hardened flesh flies, Sarcophaga crassipalpis Macquart (Diptera, Sarcophagidae). Cold shock impaired the proboscis extension reflex in response to 0.125,0.5 and 1.0 M sucrose solutions. Cold shock-injured flies were unable to groom effectively and spent only 12.5% of the first 5 min following general dust application producing ineffectual leg movements. In contrast, control and rapidly cold-hardened flies exhibited normal grooming behaviour spending 92.4% and 94.1% of the first 5 min following generalized dust application grooming. Cold shock also decreased the mean resting membrane potential of tergotrochanteral muscle fibres from -65.9 mV in control flies to -41.6 m V. Conduction velocities of the three motor neurone populations innervating the tergotrochanteral muscle were all significantly lower in cold-shocked flies than in control or rapidly cold-hardened flies. Finally, cold shock impaired neuromuscular transmission as evidenced by a lack of evoked end plate potentials. |
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Keywords: | Sarcophaga crassipalpis cold shock rapid cold-hardening nervous system muscle |
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