The modulation of rhythmic behaviour in the pulmonate slug Limax pseudoflavus by season and photoperiod

Autor: Douglas J. G. Ford, Anthony Cook
Rok vydání: 1994
Předmět:
Zdroj: Journal of Zoology. 232:419-434
ISSN: 1469-7998
0952-8369
Popis: Freshly caught samples of slugs were maintained at constant temperature and humidity but at day lengths (from 5 h 50 min to 16 h darkness) appropriate to the time of year at which they were collected. The duration of their feeding and crawling activities as well the total time spent active was recorded by time-lapse cinematography. Total activity was significantly higher in autumn and spring than in summer and winter. The activity period was symmetrically disposed about the midpoint of the dark period except for two samples in autumn. At scotoperiods longer than about 12 h, activity onset was delayed relative to the start of the dark period and activity cessation was advanced relative to the end of the period, resulting in the short duration of activity seen in winter. At scotoperiods of less than 12 h the duration of activity was relatively independent of scotoperiod. In spring the total time spent crawling was composed of relatively few bouts of long duration whereas in the autumn the number of bouts was greater and their duration shorter. The winter was characterized by slugs making single journeys to and from the food. While emerged these slugs stayed in close association with the food but not necessarily feeding on it. These data are discussed in terms of comparisons with homoiothermic nocturnal animals. It is concluded that seasonal responses in poikilothermic animals are likely to be limited by the hazards of winter even when such animals are maintained in apparently non-limiting conditions.
Databáze: OpenAIRE
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