WG Meeting "Pesticides and Beneficial Organisms" of the IOBC location:Dubrovnik (Croatia) date:7-9 October 2009
Managed honey bees (Apis mellifera) are the most economically valuable pollinators of fruit crops worldwide. However, bee populations suffered significant declines in recent years, and the extensive use of crop protection products is considered by many beekeepers to be at least partially responsible for it. With the ultimate goal to provide new insights for the development of novel objective methodologies to detect and quantify sublethal effects of pesticides, we have conducted a research project in which a multidimensional approach was followed to identify and evaluate such side effects. Herein we combined molecular (functional genomics/proteomics) and histological techniques, as well as behavioural studies, in order to identify molecular and/or physiological determinants associated with behavioural effects induced by sublethal contaminations. During the season of 2008, we intensively monitored a set of bee hives that were contaminated with sublethal doses of commonly used crop protection agents (active ingredients fenoxycarb, imidacloprid and indoxacarb). Although no direct (short-term) toxic effects were observed (as could be expected from the experimental setup using sublethal intoxications), our data provide evidence for some medium-term detrimental effects, as significant differences for several colony vitality parameters were obtained a couple of weeks after treatment. Based on the outcomes of behavioural studies as well as molecular analyses we postulate that these effects are at least partially caused by the aberrant onset of foraging, i.e. abnormal timing of bees’ shift from in-hive nursing activities to outside food gathering activities.