Few immigrant phytophagous insects on woody plants in Europe: legacy of the European crucible?

Abstract

Exotic phytophagous insects are invading forest ecosystems worldwide. So far, 109 invasive insects on woody plants, 57 from North American (NA), and 52 from Asia (A) have established populations in European forests. Four orders account for about 84% of the immigrants: Homoptera 39%, Lepidoptera 13%, Coleoptera 19%, and Hymenoptera 13%. The majority of these invasive species (63% of NA and 77% of A) live on deciduous trees, of which 36% have been introduced from NA and Asia. The remaining insect species (37% NA and 25% A) live on various conifers, of which 53% have also been introduced. Most (57%) of the NA insects feeding on coniferous plants live upon their introduced, native host plants. These data suggest that many NA immigrant phytophagous species in Europe have been successful in establishing permanent populations because their native hosts preceded or accompanied them into Europe and/or were asexually reproducing species. We propose that fewer invasive phytophagous insects have become established in European compared to North American woodlands because of the unique legacy of the European Pleistocene/Holocene crucible (i.e. endless cycles of populations contracting into highly disparate, dispersed metapopulation refugia and eventually expanding out of them) on European species and ecosystems that caused highly diminished heterogeneity. This translates to fewer and less penetrable tri-trophic niches in Europe due to fewer and less available host plants, but greater zootic resistance per niche derived from more competition-hardened competitors and possibly natural enemies. Moreover, many European species are probably superior invasion specialists because the crucible favored traits that are conducive to success in highly subdivided, and extinction-prone metapopulations: asexual reproduction, polyploidy, and other traits especially conducive to persistence under stress, and explosive growth/spread under amelioration.

Aproceros leucopoda (Hymenoptera: Argidae): An East Asian pest of elms (Ulmus spp.) invading Europe

“…Blank, unpubl.). The majority of insects, including sawflies, introduced into new areas are parthenogenetic (Benson, 1962;Pschorn-Walcher, 1982;Mattson et al, 2007). Their ability to establish themselves after introduction is far greater than in bi-sexual species, as a female can give rise to a new colony without "wasting" time searching for a sexual partner.…”

Box Tree Moth (Cydalima perspectalis, Lepidoptera; Crambidae), New Invasive Insect Pest in Croatia

“…Alien species can significantly impact the functional properties of ecosystems, disrupt food webs, displace indigenous species, even threaten food and water supplies [6]. Hundreds of species are intentionally and unintentionally moved worldwide [7] and these introductions have been accelerated all over the world due to the increasing mobility of people and goods over the past decades [8] with varied modes of entry and transportation routes [9]. Numerous alien insect species, many introduced only in the last 20 years, have become successfully established in various ecosystems in Croatia [10].…”

Traits related to biological invasion: A note on the applicability of risk assessment tools across taxa

“…Life history and environmental traits related to invasion, highlighting the suggested differences between invasive and native insects that were found through an extensive literature review. Parasitoids more likely to establish than predators (Kimberling 2004) A, C Taxon Diptera and Lepidoptera fastest to disperse, Coleoptera slowest (Paynter and Bellgard 2011) Invasive species predominantly Hemiptera (56.4 %), Lepidoptera (14.9 %), and Hymenoptera (12.9 %) (Matosevic and Zivkovic 2013); Invasive species predominantly Homoptera (39 %), Coleoptera (19 %), Lepidoptera (13 %), and Hymentoptera (13 %) (Mattson et al 2007); Invasive species predominantly Coleoptera, Sternorrhyncha, and Psocoptera (Kenis et al 2007); Homoptera and Lepidoptera most likely to establish (Peacock and Worner 2008) C Feeding method Miners, borers, and leaf-rollers disperse faster than external feeders, and root-, rosette-, and seed-feeders (Paynter and Bellgard 2011) Internal feeders more likely to establish than external feeders (Kimberling 2004) Insects that use single host species are more likely to establish than those that use multiple hosts (Mondor et al 2007) C Diet breadth Diet breadth or Host specificity Invasive insects have a wide diet breadth (generalist) compared to natives (Moller 1996, Cervo et al 2000, Kasper et al 2004, Kimberling 2004, Moeser and Vidal 2005, Snyder and Evans 2006, Mondor et al 2006, Ward and Masters 2007…”