Formiche (Hymenoptera Formicidae) e industrie alimentari: risultati di un quindicennio di osservazioni

[Autom. eng. transl.] Infestations of Hymenoptera Formicides in the food industries, as well as in buildings of the urban environment, can be counted among the less easily solved entomological problems, because often the measures put in place to counter them have only partial and temporary effects. The genera and species of ants that occur most frequently are a relatively limited number; their different presence is influenced by variables including the geographical and environmental location of the industrial plants and the different types of foodstuffs and processing of the different situations. In the literature the genera of Formicidae cited as most commonly recurring in food industries are, by frequency or gravity of infestation, Linepithema, Monomorium, Paratrechina, Solenopsis, Tetramorium. In this work we summarize the observations made by the Institute of Entomology of Piacenza over a period of about fifteen years. The samples were obtained, in industrial plants of various Italian regions, both through light traps and through direct collection; sometimes it was found in contaminated food substrates. The genera of Formicidae identified during the research are: Hypoponera, Linepithema, Pheidole, Tetramorium, Monomorium, Solenopsis, Lasius. We can also mention occasional samplings of Crematogaster and Messor. What is missing is the genus Paratrechina, sometimes cited for Italy but, in fact, rather sporadic. More often, workers are detected in the premises, but sometimes winged individuals of some species are found in abundance in the interior, caught by light traps: a sign of insufficient isolation of the rooms from the outside or even swarming that occurred directly in the interior, given the many possibilities regarding the location of the nests. Our observations, besides confirming already known acquisitions, indicate that sometimes less known ants or not at all typical of food industries, attributable to different genera, can also be found. Among these we note, quite unusual, but with consistent presence of winged, gen. Hypoponera (with H. punctatissima), found in an industry in central Italy. However, there are no indicative elements of contamination of food matrices by this species, or of harmfulness of other nature. The risk of passive introduction into Italy of other non-native species, in addition to those already present for some time, is not to be underestimated, due to the intense international trade and trade in the current era characterized by globalization phenomena. Prevention and control must take into account the variables presented by these social insects characterized by remarkable biological plasticity, heterogeneity of environmental preferences and more or less marked synanthropy.