Effects of herbicide exposure on haemocyte morphology in a ground beetle. 93rd National Congress of the Italian Society of Experimental Biology.

Persistence of agrochemical residues has become a seri-ous threat for human health. Especially herbicides usage,which is considered a fundamental practice to maximizecrop productivity, leads to soil and trophic web contamina-tion [1]. Suitable tools and markers are required to predictand prevent risks for humans, animals and environment.Insects provide useful services in agroecosystems, such aspollination and pest control. Carabid beetles, in particular,are considered beneficial organisms inhabiting cropland,acting as biocontrol agents and being well known bioindi-cators. In this study, we investigated the variations of haemo-cyte morphology in Harpalus (Pseudoophonus) rufipes(DeGeer 1774) in response to a pendimethalin-based herbicide(PND) exposure. PND is one of the most commonly used her-bicides in agriculture, and the circulating haemocytes repre-sent the principal effectors of cellular immune response ininsects [2]. Beetles were field collected, and treated in lab-oratory, simulating the exposure to PND at the recommend-ed field rate (4L per ha). To assess cytological and ultrastruc-ture analyses of haemocytes, withdrawals were performedat different time points after the initial exposure (0, 2, 7 and21 days). PND was found to cause cytotoxic effects on thecirculating haemocytes mainly during the first week of expo-sure. Cells appeared irregular in shape, featured by vac-uolization of the cytoplasm and condensation of perifericchromatin. Swelling of membranes occurs in differentorganelles, suggesting an altered permeability due to PNDand necrotic, apoptotic cells and autophagic bodies wererecorded in the haemolymph. A recovery was monitored at21 days after exposure, in agreement with information onPND soil degradation. Our results showed that sublethaldoses of PND severely alter morphology and functionality ofhaemocytes with consequences for animals’ immunocompe-tence and potential effects on vulnerability to pathogens.This study demonstrates H. rufipesbeing a suitable modeland a useful bioindicator in ecotoxicological studies.Moreover, variations in haemocytes morphology represent agood marker of exposure to pesticides. This informationcould improve the knowledge of herbicide effects on non-tar-get species, in order to preserve beneficial insects and bio-diversity in agrosystems.