138 



D. MEYER 



by a proportional decrease in activity. An increase in température during the 

 photophase normally has no visible effect while such an increase during the 

 scotophase induces a proportional increase in activity. It would appear that 

 a change in environmental conditions effected before an experiment begins 

 may influence the results to a great extent. 



7. It has been found that behaviour is dépendent upon âge and sex of moths, 

 though it could also be demonstrated that behaviour is influenced by the 

 sexual partner in the rearing box. 



8. Interrelations between différent behavioural éléments and the number of 

 eggs laid were examined. Certain corrélations were found but they appeared 

 to be inconclusive. In the absence of twilight conditions, neither the typical 

 activity of this period nor increased egg laying occur. In spite of this, the 

 fecundity of moths subjected to twilight conditions compared with those 

 denied thèse conditions does not seem to be higher. It is therefore suggested 

 that the missing twilight activity is compensated for during other periods of 

 the day. 



LITERATUR 



Andersen, F. 1965. Population density of grain pests. Sleep in moths. Ârsberetiung 



Statens Skadedyrlaboratorium. Danemark. P. 60. 

 Aschoff, J. 1965. Circadian Clocks. North Holland Publishing Company, Amsterdam. 



479 pp. 



Auer, C. 1961. Ergebnisse zwôlfjâhriger quantitativer Untersuchungen der Populations- 

 bewegungen des grauen Làrchenwicklers Zeiraphera griseana Hiibner im 

 Oberengadin. Mitt. Schweiz. Anst. forstl. Versuchsw. 37: 175-263. 



— 1968. Erste Ergebnisse einfacher stochastischer Untersuchungen liber die Vrsachen 



der Popu/ationsbewegung des grauen Làrchenwicklers ( Zeiraphera diniana, 



Gn.) im Oberengadin 1949/66. Z. angew. Entomol. 59: 187-211. 

 Ball, H. J. 1965. Photosensitivity in the terminal abdominal ganglion of Periplaneta 



americana (L.). J. Insect Physiol. 11: 1311-1315. 

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logist 96: 792-800. 



— 1 968. The cyclic population dynamics of the Grey Larch Tortrix, Zeiraphera griseana 



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Bassand, D. 1965. Contribution à l'étude de la Diapause embryonnaire et de l'Embryo- 

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 doptera : Tortricidae) . Rev. Suisse Zool. 72: 429-542. 



Beck, S. D. 1968. Insect Photoperiodism. Verl. Académie Press, New York. 288 pp. 



Belton, P., R. Kempster und K. Nair, 1967. A device for programming the intensity of 

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