ISSN:
1432-1351
Keywords:
Photoperiodism
;
Models
;
Functional marker
;
Pieris brassicae
;
Optic centres
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Analysis of the formal properties of photoperiodic systems has emphasized the importance of two discrete phases of nocturnal light sensitivity (the so-called points A and B) in a variety of taxa. This has been exemplified in the lepidopteran, Pieris brassicae, among other species, since the illumination of either of these phases in an otherwise short-day cycle (diapause inducing) gives rise to a long-day effect (development without diapause). In this species, the photoreceptor of diel cycles and the clock-counter system are very likely brain located. Using cytochrome oxidase activity as a marker of energy metabolism, a neuroanatomical base in the brain involved in long-day responses elicited by light at points A and B was investigated. Present results reveal that (i) the level of energy metabolism in the optic centres is connected with the photoperiodic process, and (ii) the two points A and B can be discriminated at a functional level. Referring to the formal models, the possible function of the optic centres, either as a photoreceptor or as a (part of the) clock, is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00187323
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