Alien Mantids in Italy and Europe: How to Recognize and Understand Their Impact

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Mantids are insects belonging to the order Mantodea, well known for their characteristic hunting posture and predatory habits. With more than 2400 described species worldwide, these insects are mostly widespread in tropical regions, but can also be found in temperate climates. Equipped with front legs called raptorial legs, mantises are generalist predators that hunt insects and other animals and may even prey on reptiles, small birds and small mammals. Their life cycle includes a mating phase that is also well known, in which the female, in some cases, devours the male immediately after or during mating, a behaviour known as sexual cannibalism. This behaviour has fuelled many legends about these fascinating insects, but is actually relatively rare in nature and often depends on the species and also on food availability.

In Europe, the best-known and most widespread mantis is the praying mantis, Mantis religiosa, easily recognisable by its green or brown colouration and the characteristic black spot on its front legs: it is widespread in almost every part of the continent and is known to be an extremely efficient predator. Another species widespread mainly in southern European areas is the conspicuous Empusa pennata, easily distinguishable by its elongated gait, feathery antennae in males and pronounced crest on the head. These two species are the most common, representative of Mediterranean environments, where they play an important role as predators of small invertebrates. Ameles spallanziana is another common species throughout Southern Europe, which is very small in size and therefore often goes unnoticed. However, in recent decades, a number of alien mantid species have arrived and become established in Europe, causing concern among entomologists.

In recent years, the number of reports of alien mantids in Europe has increased. Among the non-native species are some that have arrived accidentally through international trade or the transport of goods. The introduction of alien species is an issue of significant ecological importance , as these new species can compete with native species, alter ecological balances and, in some cases, threaten local biodiversity. Although alien mantids, to date, do not appear to have a significant environmental impact, monitoring their spread and studying their feeding habits are crucial factors in understanding whether and how they might affect European ecosystems.

Hierodula tenuidentata and Hierodula patellifera have recently been reported in Italy. Both originate from Asia: H. tenuidentata is native to Central Asia, while H. patellifera is widespread in South-East Asia. The former was first detected in Europe in 2016, while the latter was found in France as early as 2013 and shortly after in Italy in 2015. These species are distinguished from Mantis religiosa by their larger size and more uniform colouration, with the exception of two white spots on the wings. H. tenuidentata has a spread that is expanding throughout eastern and southern Europe, while H. patellifera has been found mainly in Italy and some areas of Spain. In Italy, both have spread to different regions, especially in northern and central Italy, probably due to passive transport and for the first time they are both found cohabiting in the same range.

Another alien species that has attracted attention is Spodromantis viridis, native to sub-Saharan Africa and found in Sardinia since 2011. This mantis is more robust than Mantis religiosa and Empusa pennata, and has a bright green colouration. It has been reported in various regions of Italy, particularly in southern areas, and in Spain. Its presence, however, may be due to a natural expansion of its range, favoured by climate change, although accidental introduction cannot be ruled out. S. viridis is easily distinguished from its native species by its larger size and more compact shape, as well as the lack of the cephalic crest typical of E. pennata.

Currently, there is no scientific evidence to indicate that alien mantids pose a threat to Italian or European ecosystems. In fact, no significant negative impacts on native species populations or the local ecological balance have been observed. However, it is important to continue monitoring their presence and to report any new findings to the competent bodies or via citizen science platforms . Reporting new species is essential to better understand their spread and assess potential future risks. However, it is not necessary to take control measures just yet, but rather to promote greater awareness of the issue, both to monitor and study the expansion of currently present species and to limit the accidental introduction of other species.

The introduction of alien species is a growing global phenomenon that represents one of the main threats to biodiversity. Maintaining the health of natural ecosystems also means avoiding the introduction of species that could alter them, undermining the balance of native species. It is essential to adopt preventive measures and regulations that limit the accidental introduction of exotic species and promote the conservation of natural habitats. Only through collaboration between institutions, citizens and the scientific community can we ensure the protection of biodiversity and ecosystems, essential resources for our future.