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Circadian rhythmicity in cockroaches: effects of early post‐embryonic development and ageing
Author(s) -
PAGE TERRY L.,
BLOCK GENE D.
Publication year - 1980
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.1365-3032.1980.tb00235.x
Subject(s) - cockroach , biology , circadian rhythm , nymph , moulting , period (music) , darkness , instar , rhythm , medicine , endocrinology , ageing , zoology , physiology , ecology , larva , botany , physics , genetics , acoustics
. Effects of early post‐embryonic development and ageing on the circadian rhythm of locomotor activity in the cockroach, Leucophaea maderae , were investigated. Cockroach nymphs (first to fourth instars) were found to exhibit a circadian rhythm of activity generally similar to that of adults, but there appeared to be a significant change in pacemaker period (τ) early in nymphal development, and nymphs exhibited regular fluctuations in activity level which may be related to the moulting cycle. Mean τ of adults was remarkably stable with age – no significant change was found in either males or females throughout the life span of the adult. There was, however, a small but significant difference between the average period (τ) of adult males (τ= 23.72 ± 0.12h) and adult females (τ= 23.84 ± 0.13 h). Lighting conditions during post‐embryonic development were found to have major effects on τ of adults. Males raised in constant darkness had a significantly shorter period (τ= 23.52 ± 0.11 h) than males raised in LD 12:12, and adult males and females which had been raised in non‐24‐h light cycles (T = 22 h or 26 h) exhibited major differences in τ from animals raised in LD 12:12 which persisted for several months. Animals exposed as adults to non‐24‐h light cycles also showed ‘after‐effects’ on τ, but the magnitude of the effect was much less than that exhibited by animals exposed as nymphs.