ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The establishment of the characteristic adult flight and its motor pattern has been followed behaviourally and electrophysiologically in locusts of exactly known ages. In the last two larval instars there is repetitive firing in the flight muscles but the alternation of antagonists typical of adult flight is not present (Pig. 3). Alternation can first be seen late in the last larval instar and the full adult pattern is recognizable in most animals by day 3 of adult life. Competent flight behaviour is established by day 4 or 5. In this period the coupling between elevator and depressor neurones improves and the pattern stabilizes (Figs. 4 and 6) but the time course of the whole process varies considerable between individuals. After this the only major change is an increase in wingbeat frequency from about 15–20 Hz at fledging to 25–35 Hz in the second or third week (Fig. 5). Fixing the wings immovably at fledging, so eliminating normal sensory feedback and practice, does not prevent the co-ordinated pattern from developing (Fig. 8). Muscle firing frequency with the wings fixed remains in the range 13–20 Hz throughout life, which may represent the natural frequency of the intrinsic oscillator (Fig. 10). Input from all the sense organs of the wings has a direct effect on the motor pattern in young animals (Fig. 9) and it is suggested that the increase in wingbeat frequency is due to changes in the phasic sensory input from the wings as the muscles grow and the cuticle thickens.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00645357
