INFLUENCE OF THE QUEEN INHIBITORY SUBSTANCE OF HONEYBEE 

 ON THE DEVELOPMENT OF SUPPLEMENTARY REPRODUCTIVES 

 Ш THE TERMITE KALOTERMES FLAVICOLLIS 



Влияние экзогормона медоносной пчелы на появление дополнительных половых 

 особей у термита Kalotermes flavicollis 



I. HRDf, V. J. A. NOVAK and D. SKROBAL 



(Entomological Laboratory of Czechoslovak Academy of Sciences, Praha 

 and Apicultural Research Institute, Prostëjov, Czechoslovakia) 



The existence of an inhibitory substance secreted by functional reproducti- 

 ves and accepted by the other colony members was ascertained by Light 

 (1944) in the termite genus Zootermopsis and its activity proved and in many 

 directions elucidated by Lus cher in Kalotermes flavicollis (F.). Another sub- 

 stance with a similar effect was discovered and thoroughly studied by Butler 

 (1954 etc.) in the honeybee {Apis mellifera L.). These substances are known 

 under the collective name exohormones (ectohormones, pheromones). The ana- 

 logy of the inhibitory effect on the development of ovaria lead Carlisle and 

 Buttler (1956) to test an extract of queen-bees containing the above- 

 mentioned inhibitory queen substance on females of the crab Leander serratus 

 (Rath.). Possitive results of these experiments suggest the probable broad 

 unspecificity of the bee exohormone. So far as we know, the efficiency of this 

 substance has not yet been tested on other insect species. 



In our experiments we tested the efficiency of an extract prepared of one- 

 and more-years-old queen bees on the groups of pseudergats of the termite 

 Kalotermes flavicollis (F.). The used termites originated from laboratory 

 breeds of middle-sized colonies; The original material was collected in Yogo- 

 slavia in the environs of Dubrovnik. We performed two series of experiments 

 with groups containing twenty individuals each. Extract in 96 p. с alcohol 

 was used evaporated in vacuum and emulgated in destilled water in proportion 

 of 1 ml : 1 queen. For each experimental colony 1 ml extract was put on the 

 filtering paper 30 x 20 mm of size and after drying laid into the chamber 

 of the respective group as the only food. Control groups obtained the same 

 filter paper without extract. The number of suplementary reproducti\^es 

 developed and their letality were ascertained in 2 — 6 days intervals during 

 one month. 



In control groups the larvae developing to supplementary reproductives 

 could be found as early as after 4—8 days (registered according to appearance 

 of the pigmented imaginai eye-discs). After 12—14 days when the superfluous 

 supplementary reproductives were eliminated their number was stabilized to 



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