ECOETHOLOGICAL ANALYSIS OF THE INTERACTION BETWEEN ISOPRENE AND THE BEHAVIOR OF COLLEMBOLA

Evidence from many sources indicates that the rate of decomposition ca n be related to the chemical-physical characteristics of the leaves, s uch as their thickness and C and N content. Whereas some data indicate s that Collembola show clear feeding preferences, little is known abou t the substances responsible for Collembola feeding preferences; In th is paper preliminary data on the avoidance behaviour of Sinella coeca towards isoprene, an important secondary plant metabolite, are reporte d. The animals demonstrated a clear avoidance reaction even at concent rations of 10(-1) mu M; despite isoprene volatility, observations made over two consecutive days demonstrated that the clustering of specime ns on the food without isoprene persisted over time, probably in relat ion to the release of aggregation pheromones that stabilize the initia l choice. The evident avoidance behaviour shown by Sinella coeca warra nts further studies in order to describe the defensive potential of is oprene to a broad spectrum of herbivores. The possibility that isopren e may affect litter decomposition rates is discussed.