Arthropod communities within the olive canopy as bioindicators of different management systems

Arthropods, within the olive tree canopy, which can act as bioindicators of different management systems (conventional, integrated and organic), were collected in costal Croatia during 2007-2009. The aim of the research was to determine the arthropod orders present in each of the observed olive groves, to identify the number of individuals in each order, and to set potential bioindicators of different management systems. In order to do that, arthropods were collected from the olive canopies at three locations (Supetar, Kaštel Stari and Duilovo). After the samples were sorted according to orders, and determined according to arthropods determination keys. Olive groves were characterised by the same growth conditions and environment, with differences in agricultural management systems. In this investigation, 7882 arthropods were collected, belonging to 17 orders. It was found that Diptera, Heteroptera and other Hemiptera individuals, excluded Cicadidae and Psyllidae family individuals, could be defined as potential bioindicators of olive groves under different management systems. The number of Araneae and Coleoptera individuals significantly differed in all researched olive groves. So, these orders can be considered as bioindicators of different management systems. The knowledge obtained in this research can potentially be exploited in olive production in the future. Obtained results represent an important contribution to the inventory of arthropods in olive canopy. Also, this research significantly improves understanding of both harmful and beneficial entomofauna in olive groves and consequently contributes to better understanding of the total entomofauna in Croatia.