Vespiculture in Polistes dominula and use of colonies for the detection of environmental pollutants (chemical and biological) in limited areas
The project is based on a breeding system called vespiculture, which consists of two phases. The first phase involves breeding in nurseries (greenhouses), where the founders, coming out of winter diapause, will discover new nests directly in containers of maximum size 10 x 10 x 10 cm. Alternatively, nests founded in nature will be transplanted into containers of the same type. During this phase, the initial colonies will be provided with food (adult wasps feed on sugary substances, while their carnivorous larvae are fed with insects collected from the environment) and building material.
Once the post-emergence stage is reached, which is after the birth of the first workers, the containers will be transferred to the field and opened to allow the wasps to forage in the environment, marking the beginning of the second phase. It's crucial that the larvae, upon completing their larval development, release the accumulated faeces at the bottom of the cells. These faeces (meconia) will remain in the nest throughout the life of the colony and beyond. Consequently, a Polistes nest serves as a container of information about the environmental conditions within an average radius of 200 meters from the colony's location.
By strategically placing colonies in specific areas, it becomes possible to create a map of the conditions of a given region and detect the presence of certain substances through chemical analysis. This system could be utilized to monitor environmental conditions around structures like industrial plants and road systems throughout the season. It would complement other biological and/or man-made detection systems. Additionally, analysing meconia abandoned in nests built in previous years and still on-site can provide information on past seasons. Microbiological analyses conducted on meconia can also offer insights into the presence of relevant microorganisms. Comparing the meconia and emerged workers during the controlled rearing period will serve as a cross-check for those done on the meconia of wild-reared wasps.
Nonetheless, the system does have limitations, with the main one being the sampling period limited to the active season, lasting about 3-4 months in temperate climate zones. However, analysing intact nests from previous years can still provide information about environmental changes over various seasons. The chemical and microbiological analyses will take place in the laboratories of the University of Florence, where suitable research tools are available. The project has the potential to be developed over several years and for various objectives.