The status of Vespa Orientalis in Malta : a preliminary study

Abstract

Recent years have seen a sharp rise in the population of Vespa orientalis Linnaeus, 1771 in the Maltese islands, generating great concern, especially, among the beekeeper community. This social insect belonging to the Vespidae family has long been considered a major predator to honey bees throughout the Mediterranean Basin. The primary objective of this study is to determine the status of Vespa orientalis in Malta with regard to distribution, abundance and seasonality. The study explores the relationship between these hornets and their surrounding environment as well as with various meteorological variables. Three methods of data collection were applied, namely; monitoring with baited traps, questionnaires and qualitative field observations. The study revealed that in 2019, the Vespa orientalis active season extended from the last week of April until the second week of November. The first to appear are the queens, followed by the worker hornets. Drones on the other hand were only observed late in the season. The hornet population was mostly concentrated around apiaries and urban areas situated in the Northern-Harbour, Southern-Harbour and South-Eastern districts. They were, however, scarce in the Northern and Western districts. Even within the same habitats as in the previously mentioned districts. There was no correlation between the number of honey bee colonies and the presence of hornets within the apiary sites. The study also revealed that during their active season, the presence of Vespa orientalis is not dependent on changes in meteorological variables.