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transforming these stimuli into organic energies. Owing to these organic energies organisms should form a self-contained entity which can develop and survive amidst the constantly changing condi- tions of its environment. JORDAN took over from MuLLER the notion that organisms form a self-contained entity, but

In: Netherlands Journal of Zoology

of "specific energies" of JOHANNES MÜLLER who was one of FREUD'S teachers. In this connection FREUD's definition of instinct (Trieb) may be quoted: "By an 'instinct' is provisionally to be under- stood the psychical representative of an endosomatic, continuously flowing source of stimulation, as

In: Archives Néerlandaises de Zoologie

compared with the feeding material, should raise the caloric value of the animal tissue formed during growth as compared with that of the assimilated food. In addition, terrestrial habits, case bearing and small feeding efficiency may be responsible for a high energy loss. The amount of litter, produced

In: Archives Néerlandaises de Zoologie

'S discussion of elastic mechanisms in movement and energy recovery. Elastic mechanisms, seldom mentioned in the literature thirty years ago, are now a critical consideration for studies of locomotion, respira- tion and feeding. In addition to functional morphology in the classical mode, experimental work on

In: Netherlands Journal of Zoology

(MEDAWAR, 1952; WILLIAMS, 1957), and 3) ageing evolved because finite resources of energy have been divided between reproductive effort and maintenance of the soma in a species-specific balance, resulting in a limited reproductive period and a disposable soma (KIRKWOOD, 1977). In addition to these insights

In: Netherlands Journal of Zoology

coupling (one could think of prohibition of disturbance by wind, or of spilling of energy). The distribution of the coupling mechanism in the order Lepidoptera seeming of interest, representatives of the main groups have been studied. The result is shown in Table I and Fig. 2. In both, I followed the

In: Netherlands Journal of Zoology

recognized: insectivorous, folivorous, frugivore- folivorous and omnivorous. These categories also reflect the different ways in which protein needs are met, i.e. by eating mature leaves or by obtaining animal food. Fruit is a main energy source. The adopted strategy greatly influences the social

In: Netherlands Journal of Zoology

costs (for labour, buildings, energy and others). These factors are quite obvious in view of the powerful economic interests in- volved. Their impact has transformed many farms into industriallike projects, in which the adaptability of the animals involved has scarcely been taken into account. This

In: Netherlands Journal of Zoology

. Nat. 110: 317-320. CORNELL, H. & D. PIMENTEL, 1978. Switching in the parasitoid Nasonia vitripennis and its effect on host competition. - Ecology 59: 297-308. ELNER, R. W. & R. N. HUGHES, 1978. Energy maximisation in the diet of the shore crab, Carcinus maenas (L.). - J. Anim. Ecol. 47: 103

In: Netherlands Journal of Zoology

wing beat frequency (REED et al., 1942; UNWIN & COR- BET, 1984), which affects energy expenditure (CURTSINGER & LAURIE AHLBERG, 1981) and thermoregulation (KAMMER & HEINRICH, 1978; * Address for correspondence. 16 LARSSON, 1990). Relative wing length is therefore likely to be a charac- ter on which

In: Netherlands Journal of Zoology