The presence of invasive rodents such as rats or mice on Mediterranean islands, which are rich in biodiversity and have a large human presence, poses a serious threat to these delicate ecosystems, as well as causing serious damage to human activities.

In these environments, rodent control is frequently carried out through rodenticides based on anticoagulant active ingredients, which, if used without following the appropriate guidelines, can have serious environmental impacts due to the possible direct or secondary poisoning of other species. There is also the possibility of genetic resistance developing to these substances. This makes it more difficult to control rodent populations and increases the amount of rodenticides released into the environment.

In a new study published in the journal Science of the Total Environment, the result of a collaboration between the Department of Biology and Biotechnology Charles Darwin of Sapienza University of Rome and the Istituto di ricerca sugli ecosistemi terrestri (CNR), the phenomenon of genetic resistance to rodenticides was investigated on Italian islands, confirming a rather widespread presence of resistant mice on 7 of the 11 islands studied.

“In this work, which represents the first investigation of resistance to anticoagulant rodenticides carried out on several Mediterranean islands”, says Francesco Gallozzi of Sapienza University, “we analysed particular mutations of the VKORC1 gene, involved in resistance phenomena, in domestic mice (Mus domesticus) and identified 6 new mutations never before found in domestic mice and 4 new mutations never before identified in rodents”.

The cooperation of several organisations, including NEMO srl, which is directly involved in rodent management on the Italian islands and has been actively contributing to the eradication of invasive rodents on many of them, was essential in order to obtain samples from the various islands.

The study, carried out as part of the activities of the National Biodiversity Future Centre and in particular of Spoke 5 on urban biodiversity in which Sapienza University is participating, brought to light the need for a more conscious use of rodenticides to enable effective management of invasive rodents and to minimise the impacts of these substances on non-target species.

"If resistance to rodenticides develops, alternative methods of controlling them must be considered," says Riccardo Castiglia, study coordinator. "Otherwise, we run the risk of causing irreparable damage to the environment and biodiversity. 

References:

A survey of VKORC1 missense mutations in eleven Italian islands reveals widespread rodenticide resistance in house mice - Francesco Gallozzi, Lorenzo Attili, Paolo Colangelo, Davide Giuliani, Dario Capizzi, Paolo Sposimo, Filippo Dell'Agnello, Rita Lorenzini, Emanuela Solano, Riccardo Castiglia - Science of The Total Environment 2024 https://doi.org/10.1016/j.scitotenv.2024.176090

Further Information

Riccardo Castiglia
Department of Biology and Biotechnology Charles Darwin
riccardo.castiglia@uniroma1.it

Francesco Gallozzi
Department of Biology and Biotechnology Charles Darwin
francesco.gallozzi@uniroma1.it