ISSN:
1432-1351
Keywords:
Circadian rhythms
;
Feeding effects
;
Locomotor activity
;
Ground beetles
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Effects of food supply on daily periodic locomotor activity in the ground beetle Carabus auronitens were recorded in the laboratory with the animals exposed to natural daylight and photoperiod. Inspection of individual actograms exhibits that in most cases feeding leads to strongly reduced and more or less irregularly distributed activity for a period of up to 4 days. In terms of quantitative parameters, the animals respond to food supply by an immediate reduction of mean amounts of daily activity. This is achieved through the reduction of duration (as a consequence of reduced burstlengths instead of burstnumber) and, less distinctly, the reduction of intensity. The initial levels of parameters are reattained after 4 days. Direct comparison by means of standardized (i.e. level-independent) relative parameter functions demonstrates close concordance between the amount and duration of daily activity; however, distinct synchronous change of intensity is apparent as a consequence of food supply only. This means that any variation of activity amounts is due to changing duration rather than to intensity variation. In analogy to the feeding-dependent parameter dynamics, also the proportion of animals with strong synchronization to the natural light/dark cycle is considerably reduced by food supply. The feeding-dependent reduction of activity is paralleled by temporarily reduced activity of proteolytic enzymes in the beetles. It is argued that, for the purpose of energy saving, the animals will remain inactive as long as reduced enzyme activity inhibits further consumption and digestion of food.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00209617
