Varroa destructor is an ectoparasitic honeybee mite and causal agent of varroosis which can lead to honey bee colonies death. Originally parasite of Apis cerana, during the first half of the last century, this mite shifted to a new host, Apis mellifera. This external parasitic mite is among the most damaging beekeeping pests, representing nowadays a vital threat to apiculture worldwide and is thought to be a crucial driver of the periodical colony losses in Europe and the USA. Moreover, V. destructor has gained resistance to the commonly used acaricides, fluvalinate and coumaphos increasing the difficulty for bee health control. In addition to Varroa resistance problem, there is an increasing concern about acaricides accumulation in bee hive products to account for food safety regulations (European Union regulations 2377/90 and 434/97). Bee researchers worldwide have tried alternative Varroa treatments, viewing reducing costs and residues in the honeybee products. Essential oils and their components, such as thymol, menthol, camphor, among others, have been studied as alternative agents for mite control.
From the beekeeping point of view, there are certain thresholds for economic injury and for irreversible colony damage. Moderate infestation rates may reduce the growth of the honeybee population and, therefore, the honey yield. The final breakdown of a honeybee colony is associated with the typical “parasitic mite syndrome” such as scattered brood, crawling or even crippled bees and unexplainable reduction of the bee population.
The main objective of this project is to work towards the development of a trap mechanism for Varroa control, combining natural kairomones used by Varroa for brood infestation with the miticide ability of natural products extracted from aromatic plants. Bee larvae produce volatile semiochemicals during a specific time of their life cycle that indicates the correct time for working bees to cap the brood. At the same time Varroa uses these volatiles to identify the correct time to infest the brood and hide within the larvae food until the comb is sealed. The identification of these compounds can therefore be used as bait to attract the mite. If attraction is oriented to a specific device that contains an acaricide, it can be developed a new mechanism for controlling bee health. The look for natural phytochemicals (essential oils and decoction waters) with varroacide activity from plants of the Portuguese medicinal and aromatic flora is here used as route towards a sustainable control of this pest, due to lower tendency to resistance development of Varroa to volatile compounds. The acaricide effect of the phytochemicals under studied will be test for activity and efficiency comparing with reference synthetic acaricides already in the market, but also for the toxicity in bees. Additionally, the kairomones effect in bee health and bee behaviour will be evaluated. To determine molecularly the produced compound (attractive) will develop several techniques that have as ultimate aims the large-scale production and easy purification of attractive.
The research units involved have the means and knowledge in the working area. The main research unit, Centro de Investigação de Montanha (CIM/ESA/IPBragança), has a renowned work in the field of beekeeping, biochemical analysis of plant compounds and molecular studies with eukaryotic organisms. The partner institution, Institute for Biotechnology and Bioengineering, Centre for Plant Biotechnology, Faculty of Science University of Lisbon (IBB/CBV/FC UL) has a solid work in the areas of phytochemistry, plant in vitro culture, morpho-anatomical and molecular biology. The integration of the National Federation of Portuguese beekeepers (FNAP) in the consortium, beyond the experience in the field, they will allow to guide the work towards the real needs of the beekeepers and develop usable tools. Additionally, they are able to aware beekeepers to alternative Varroa control techniques. The three institutions have developed during the last year extensive work in the characterization of different types of Portuguese propolis, whose results are now starting to be presented. The proposed work will also be the departure point for an application to a PhD Thesis grant during next FC T PhD grants call. Benefiting from the knowledge of both parts, the proposed work contributes to the national and international effort to acquire additional knowledge that allows creating measures to eradicate and or control the ectoparasite.
Bolsa de Investigação CBV (BI) no âmbito do projecto - Acta da 1ª reunião do júri de selecção
Acta da 2ª reunião do júri de selecção, após entrevistas.