Pheromon-Forschungen in Siebenbuergen

1996

S. 221-258

68 Lit. Ang.

Unselbständiges Werk

200094409

The paper is a synthesis of the studies carried out by the Experimental Entomology Laboratory, during 1978-1993 in Transylvania, in the pest lepidoptera sex pheromones. In the first part of the paper there are presented some general considerations concerning the place, role and the importance of sex pheromones, as part of semiochemicals, as well as the data of start pioneering continuity of pheromonal researches in the Institute of Chemistry and in the Biological Research Institute from Cluj-Napoca. Sex pheromones were synthetised for 28 lepidoptera species, the reproductive and pheromonal behaviour have been studied in laboratory for 12 species, attractivity, specificity and behaviour have been studied in natural conditions, for 98 species. In laboratory conditions have been analysed the following aspects: (a) the role of sex pheromone in reproduction (using mating behaviour analysis and antennectomy); (b) mating behaviour in relation to sex pheromone (calling behaviour, male response behaviour in female locating and courtship); (c) the attractivity of natural (from virgine females and sex pheromone crude extracts) and synthetic sex pheromone through olfactometer tests; (d) factors that influenced the attractivity of sex pheromone in laboratory (temperature, photoperiode, age, dose, minor compounds, synergic comounds or analogues). The studies were made especially for Mamestra brassicae, Xestia c-nigrum, Eilema complana balcanica, Lacanobia oleracea, Phragmatobia fuliginosa, Malacosoma neustria, Ostrinia nubilalis. As part of these, there are also presented some aspects of male behaviour in female locating and courtship which were comparatively studied along the evolutive line from Eilema complana to Xestia c-nigrum. The bioassays were carried out especially with olfactometer with cages or glass tubes and the positive response were appreciated through 9 parameters (R1, R2, R3, R4, dR1, dR2, DE1, DE2, CS). The male response behaviour was analysed with 8 (I-VIII) behavioural steps elaborating the pattern of relative importance of quality response to pheromones (or other semiochemicals). In field experiments, the male response behaviour to sex pheromone was characterised by 6 behavioural steps in the 12 Lepidoptera species, on the basis of direct flight observations at the traps, the platform for study of behaviour and cages. Other aspects were studied too, like: (a) periodicity of male response behaviour; (b) the comparative attractivity of both synthetic and natural sex pheromone; (c) the attractivity and specificity of synthetic sex pheromone and factors (climatics, biotics, populationals, dependent by the sex pheromone and traps) which influenced flight and number of trapped males; (d) the use of synthetic sex pheromone in monitoring (the evaluation of flight periods and adults emergence; behavioural studies, dynamics of populations; the appearance of new pest lepidoptera in the area, corelations among capture - oviposition - atack frequency - damage; ecological studies. Afinity, similarity, diversity, abundance population distribution patterns); (e) studies concerning the possibility of synthetic sex pheromone use in direct control (mass trapping and desorientation). Systematic investigation for many years have been carried out in Transylvania on Mamestra brassicae (14 years), Xestia c-nigrum (7 years), Agrotis segetum, Agrotis exclamationis, Agrotis ypsilon (4 years), Autographa gamma and Ostrinia nubilalis (3 years). The other 26 species, sympatric with Mamestra brassicae and species captured in the traps with variants of (Z)-11-Hexadecenylacetate, have been studied, too. The comparative observations with both light and sex pheromone traps were found important for the understanding of reproductive statuus and behaviour of Lepidoptera populations in the field.