Dictyoptera ( Blattodea , Isoptera ) , Orthoptera , Phasmatodea and Dermaptera Chapter 13 . 3

Abstract For convenience, we treat all “polyneopteran” orders together. Five orders of hemimetabolous “Polyneoptera” include species alien to Europe, namely Blattodea, Isoptera, Orthoptera, Phasmatodea and Dermaptera. A total of 37 species alien to Europe have been recorded. Th ese belong to 14 diff erent families. Most of these species show a detritivorous feeding regime (22 spp.), whereas 12 species are phytophagous and two are predators. Th e majority of species were fi rst observed between 1900 and 1975. Unlike other arthropod groups, the mean number of polyneopteran species newly recorded per year showed no acceleration since 1975. Th e alien “Polyneoptera” mostly originated from Central/ South America and Asia (10 species each, 27.0%), followed by Africa (7, 18.9%). Germany hosts the largest number of alien Polyneoptera (15 spp.), followed by Denmark (14), Spain (11) and France (10). All but one alien species represent unintentional introductions. More than 75% of the species are associated with artifi cial habitats (houses, buildings and greenhouses) and cultivated areas. Blattodea and Isoptera have huge economic and/ or medical importance. Th e cost of treatments and sanitary measures against termites and cockroaches, in particular, is signifi cant in Europe.


Introduction
For convenience, we group all the orders belonging to the "Polyneoptera" assemblage into the same chapter.Th is non-monophyletic assemblage of eleven "orthopteroid" orders includes fi ve orders which contain species alien to Europe.Some of these orders are very familiar such as grasshoppers (Orthoptera), cockroaches (Blattodea), termites (Isoptera), earwigs (Dermaptera) and walking sticks (Phasmatodea).Lesser known groups include web-spinners (Embioptera), angel insects (Zoraptera) and ice-crawlers (Grylloblattodea).We describe here the characteristics of the species alien to Europe.
Blattodea contains over 4500 species worldwide, with about 150 species in Europe.Th ey are among the mos t ancient winged insects, the earliest fossils dating back to the Carboniferous.Th e group is well defi ned by a combination of characters: eggs usually contained in oothecae (egg cases), leathery forewings, male genitalia asymmetrical and cerci* with one or more segments.Most cockroaches are tropical and found in a wide variety of habitats such as dead or decaying leaves or trees, caves, under stones, in nests of social insects etc. Cockroaches are mostly scavengers eating organic material.Less than 1% (30 species) are associated with humans, but these species contribute to the unpopular reputation of these insects.Cockroaches exhibit diverse reproductive biology.Most species have sexual reproduction, but some populations of Pycnoscelus surinamensis are parthenogenetic.Th ese hemimetabolous insects produce hardened oothecae deposited on a substrate or membraneous oothecae that are incubated in a brood sac within the female's body.Some species exhibit a high level of parental care.
Isoptera consists of over 2600 species (mostly tropical).Termites are the oldest social insect group with complex societies dating back at least to the early Cretaceous (140 Mya).Only 12 species occur in Europe.Recent studies have shown that Isoptera are basically social cockroaches forming a monophyletic clade within the Blattodea, most likely the sister group of the Cryptocercidae (woodroaches) (Inward et al. 2007).Termites are the only hemimetabolous insects that exhibit true social behavior.Th ey build large nests housing an entire colony.Th ese colonies contain adult reproductives (one queen and one king) plus hundreds or thousands of immatures that serve as workers and soldiers.Termites are important decomposer animals in lowland tropical ecosystems.Th ey mostly feed on dead plant material and are able to digest cellulose with the help of symbiotic gut symbionts.
Orthoptera comprises more than 20000 species worldwide and 1044 species in Europe belonging to two suborders, Caelifera (grasshoppers) and Ensifera (ladykids).Th is group of median-sized insects is well characterized by (1) long hind legs modifi ed for jumping; (2) hardened, leathery forewings (tegmina) which are spread in fl ight and covering membranous hindwings at rest; (3) unsegmented cerci; and (4), a pronotum usually with large descending lateral lobes.Orthopterans are common in most terrestrial habitats, but are more diverse in the tropics.Th ey are mostly phytophagous and include some outstanding agricultural pests (locusts and certain katydids).
Phasmatodea (also known as Phasmida) comprises 3000 species worldwide with only 15 species known in Europe.Stick-insects are found in nearly all temperate and tropical ecosystems.Species are mostly nocturnal and phytophagous.Phasmatodea bears several common morphological characters that clearly defi ne the order: an emarginated labrum, a pair of exocrine glands located inside the prothorax, and a thorax fused with the fi rst abdominal sternum.Phasmids undergo an incomplete metamorphosis (four to eight instars), with the young nymphs resembling miniature, albeit wingless, adults.
Dermaptera comprises about 1800 species and about 80 species in Europe.Th ese small-to median-sized insects have the head prognathous* and are clearly characterized by two or more apomorphies: long unsegmented (not always forceps-like) cerci, and details of hindwing structure.Th e biology of Dermaptera is poorly known.Most species appear to be omnivorous but some are phytophagous and a few are predators.Th e development is hemimetabolous.Earwigs have larvae (four to fi ve instars) that resemble the adult, except that the wings are only buds.
Several characteristics group species in these orders together.Th e polyneopteran group treated here comprises mostly phytophagous species (consuming fresh plants, dead wood or leaves), but some species are detrivorous.None of the species alien to Europe is parasitic and very few are predators.Th ese species are rarely transported with cultivated plants, even if eggs of stick-insects are introduced with soil.Consequently, polyneopterans are rarely introduced into Europe through the plant trade.Most species are relatively large and conspicuous, the smallest insects belonging to Isoptera and Dermaptera.All of them are hemimetabolous and consequently their larvae are biologically similar to adults.Th e diversity of these groups in the Holarctic region is relatively limited and most species are tropical.Th ese characteristics may partly explain the relatively low number of species in the alien fauna that has colonized Europe, compared to worldwide Polyneopteran diversity.

Taxonomy of alien species
A total of 37 species alien to Europe have been recorded.Th ese species belong to fi ve diff erent orders and 14 diff erent families (Table 13.3.1;Figure 13.3.1).Blattodea account for 18 species and is the order with by far the greatest number of aliens to Europe.Eleven species belong to Orthoptera, four to Phasmatodea, while Dermaptera and Isoptera include two alien species each.Within Orthoptera, Ensifera are well representated with seven species (63% of Orthoptera).Among these alien species, 22 are detritivorous, 12 phytophagous and two are predators, the biology of one species being unknown.Th is results show that within invasive Polyneoptera, a majority of species are detritivorous or phytophagous (94%).Table 13.3.2presents some species of the same orders considered as alien in Europe (native to a European region but introduced in another through human activity).

Blattodea
Blaberidae.Th is small family contains ten species in Europe, all of them introduced from tropical countries.Th ese cockroaches are ovoviviparous, some species being parthenogenetic.Several Blaberidae species have been introduced into urban areas of Europe.Among them, Blaberus atropos is a native to South America that exhibits a death's-head markings on the mesonotum and metanotum.Nauphoeta cinerea lives mostly around the outside of buildings but also occurs in houses.Panchlora nivea is commonly associated with bananas and palm trees.Th is species was introduced in Northern Europe with shipments of bananas.Pycnoscelus surinamensis, a Malaysian cockroach, as been introduced several times to Europe.It occurs in greenhouses and cannot live outdoors.Its European populations appear to be parthenogenetic.Th is trait has been wrongly identifi ed to explain the strong invasive ability of this cockroach (Grandcolas et al. 1996).Rhyparobia maderae, an afrotropical cockroach, was probably transported to southern Europe with banana shipments and occurs indoors.
Blattellidae.Among the ca.135 species of Blatellidae occurring in Europe, only two species, Nyctibora laevigata and Supella longiplapa, have an alien origin, both having been introduced from tropical regions.Th e last one is an afrotropical species with synanthropic habits, occurring in houses and greenhouses in Europe.Th ese long-legged cockroaches carry the eggcase externally.Blattidae.Only six species are known in Europe, all of them having been introduced from tropical or subtropical regions.Blatta orientalis, Periplaneta spp.and Neostylopyga rhombifolia are synanthropic species that have long been introduced to Europe.A more recent arrival is that of Shelfordella lateralis, the Turkestan cockroach, which has been discovered in 2007 in Cagliari, Sardinia.Th is species has previously been introduced in the 1970s in the Southern United States (California, Texas, Arizona) probably with military people coming back from the Middle East (Fois et al. 2009).Th ese blattid species mostly develop indoors, in heated buildings but can also develop in greenhouses and in the city streets.

Isoptera
Kalotermitidae.Th is family comprises only four species in Europe, of which only Cryptotermes brevis is alien to Europe.Th is species infests dry wood and can damage woodwork, furniture and fl oors.C. brevis has been found both in Northern and Southern Europe but it has been more widely introduced to tropical countries.Recent studies showed that the early European shipment of exports from coastal Peru and Chile caused the release and initial dispersal of C. brevis from its natural range (Scheff rahn et al. 2009).
Rhinotermitidae.Th is family comprises seven species in Europe, including one alien species originating from North America, Reticulitermes fl avipes (= R. santonensis (Feytaud); see Austin et al. 2005), where it is considered to be a signifi cant pest.Subterannean termites in the genus Reticulitermes Holmgren (Isoptera: Rhinotermitidae) are the major termite pests infesting wooden structures in Europe and the near East.

Dermaptera
Anisolabididae.Th is family comprises 12 species in Europe.Euborellia stali, of Asian origin, preys on stem borers associated with rice entering the borer tunnel.Th is widespread species has recently been introduced in Italy.
Labiduridae.Only two species of Labiduridae are known from Europe, including a species originating from tropical/subtropical regions, Nala lividipes.Th is species is considered as a pest with local economic importance, but it is rare in Europe.

Orthoptera Acrididae (Caelifera).
Th is diverse family (about 350 species in Europe) only contains four species alien to Europe.Furthermore, the status of two of them, Notaustorus albicornis and Dociostaurus tartarus, is unclear, and these species could be native to Southeastern Europe.

Bradyporidae (Ensifera).
A total of 84 species occur in Europe, one of them being possibly alien to Europe, Ephippigerida nigromarginata, originating from Africa.

Gryllidae (Ensifera).
A total of 83 species of gryllids occur in Europe, but only one is an alien species.Gryllodes sigillatus is probably native to southwestern Asia and has been spread by commerce to diff erent part of the world.Th is species is found indoors.
Myrmecophilidae (Ensifera).Th is small family of crickets contains 11 European species, one having been possibly introduced to Europe, the cryptogenic Myrmecophilus americanus.Myrmecophilus ant crickets are symbionts associated with ant nests.Th ey are kleptoparasitic and feed on food resources in ant nests and induce ants to regurgitate liquid food.M. americanus is associated with an invasive ant species Paratrechina longicornis.
Phaneropteridae (Ensifera).Only one alien species, Topana cincticornis, has been recorded to be compared with the 149 species of this family native to Europe.Th is species, of South American origin, has only been observed in France (Morin 2001).
Rhaphidophoridae (Ensifera).Th is family contains 53 species in Europe.Only one of them is alien to Europe, Tachycines asynamorus.Th is oriental species mostly develops indoors (houses, greenhouses) in Northern Europe but also outdoors during the summer in Southern Europe.
Tettigoniidae (Ensifera).Th is family contains 221 species in Europe, two of them (namely Copiphora brevirostris and Phlugiola dahlemica) having been introduced from Central and South America.Th e latter species was described inhabiting greenhouses in the Botanical Gardens of Berlin (Weidner 1938).

Phasmatodea
Phasmatidae.Th e family contains only four species in Europe, all of them introduced and occurring in Southern Great Britain.Th ree of these species (Th e Prickly Stick Insect, Acanthoxyla geisovii, Th e Unarmed Stick Insect, Acanthoxyla inermis, and the Smooth Stick Insect, Clitarchus hookeri) arrived from New Zealand with plants, most likely as eggs in the soil (Lee 1993).Th e last species Carausius morosus is native of the Oriental region but was also introduced in Germany (Weidner 1981).Some stick insects used as pets may also have escaped from captivity but we have no data about that.
In conclusion, the only group of polyneopterans with a signifi cant number of introduced species compared to the native European fauna is that of cockroaches (Figure 13.3.1).Blaberidae and Blattidae are represented in Europe only by exotic species nonintentionally introduced by humans.

Temporal trends
Th e dates of introduction of most alien cockroaches are largely unknown although it is likely that most of these synanthropic species were introduced to Europe long ago, following human movements and trade.For instance, the fi rst record for Blatta orientalis dates back to 1500 in a region corresponding at present to the Czech Republic.
Finally, fi rst records in Europe of alien Polyneoptera, excluding four species considered as cryptogenic, were obtained for 21 out of the 33 remaining alien species (64 %).Most of these 21 species were fi rst observed between 1900 and 1975.Interestingly, the mean number of new records per year has not accelerated during the last 200 years, unlike most other groups of arthropods (Figure 13.3.2).On the average, less than one species was newly observed every fi ve years during the period 1900 to 2006.

Origin of alien species
A region of origin could be traced for 35 (95%) of the alien Polyneoptera introduced to Europe.Central/South America and Asia, with 10 species each (27.0 %), provided equally the greatest part of these alien species followed by Africa (7 spp.; 18.9 %) (Figure 13.3.3).Th is pattern largely diff ers from the one observed in most other groups of insects where South America contributes much less to the alien fauna.Indeed, most Blattodea are of tropical origin and generally became sub-cosmopolitan species that occur in buildings and exceptionally outdoors in Europe.Within Orthoptera, most Ensifera also have a tropical origin and several species can presently survive only within greenhouses in Europe.To the contrary, Caelifera are mostly Palaearctic species that naturally occur in areas adjacent to Europe.Alien Isoptera originate from North and South America.Most alien Phasmatodea originate from Australasia and were introduced into England with plants.

Distribution of alien species in Europe
Alien polyneopteran species and families are not evenly distributed throughout Europe and large diff erences exist between countries (Figure 13.3.4;Table 13.3.3).Th e number of taxonomists and the intensity of studies and sampling may also have infl uenced these diff erences.Little information is available for some central and northeastern European countries, and consequently these areas appear to host comparatively less alien species.
Germany hosts the largest number of alien Polyneoptera (15 spp.), followed by Denmark (14), Spain (11) and France (10).Most European countries host a low number of introduced species (fi ve or less).No correlation with the country surface area has been found.However, it appears that northern countries in Europe host globally more alien species.

Main pathways to Europe
Th e main pathway for introduction of most polyneopteran species alien to Europe is unknown.Where known, most introductions were unintentional.Whilst Blattodea species have followed humans and have long been introduced in Europe probably as stowaways as more recently observed for Blaberus atropos, Panchlora nivea, and Rhyparobia maderae found within banana shipments (Sein 1923).Some recent invaders also seem to have been introduced through wood transport (Isoptera) or introduction of plant material (Phasmatodea and Ensifera).
Nauphoeta cinerea has been introduced intentionally and only one species (Euborellia stali) have been introduced for biological control purposes.

Most invaded ecosystems and habitats
A large proportion of polyneopteran species alien to Europe (>75%) are associated with artifi cial habitats (houses, buildings and greenhouses) and cultivated areas (Figure 13.3.5).Th e proportion is somewhat lower (>55%) for the species alien to countries within Europe.Th ese results are mostly linked to the strong associations of some Blattodea, Isoptera and Ensifera with humans.Only few species (10 spp.) have yet colonized natural and semi-natural habitats (grasslands, heathland or coastal habitats).

Ecological and economic impact
While most 'Polyneoptera' species introduced to Europe have only limited ecological or economic impact, two orders are considered as important pests: Blattodea and Isoptera.Blattodea have great medical signifi cance (Baumholtz et al. 1997) and several species of cockroaches represent a potential threat to human health and well-being.Th ese species are the most common household insect pests and there are two areas of concern regarding their potential for causing disease in humans.First, cockroaches are recognized as being an important source of indoor allergens.Th ese allergens are found in their body, saliva and faecal matter.Th ey cause asthmatic reactions in humans and are also implied in skin reactions.In recent studies, a strong association has been found between the presence of cockroaches and increase in the severity of asthma symptoms in individuals who are sensitive to cockroach allergens.Finally, oedema of the eyelids and dermatitis has been attributed to cockroaches.
Second, because of high humidity, high temperature and presence of food, cockroaches normally breed well in houses, grocery stores, restaurants and hospitals.Th ey feed on a variety of foodstuff s (meat, grease, candies, chocolate, cheese, bread and other unprotected materials), regurgitate fl uid from their mouth, and deposit faeces on foodstuff s.Because of their movement between waste and food materials, cockroaches can acquire, carry, and directly transfer to food and eating utensils the bacterial pathogens that cause food poisoning, diarrhea (Burgess and Chetwyn 1981), or typhoid.About 40 species of bacteria pathogenic to humans have been naturally found in or on cockroaches.Among them are found, several agents of dangerous infections such as bubonic plague (Yersinia pestis (Lehmann and Neumann) van Loghem), dysentery (Shigella alkalescens (Andrewes)), diarrhea (Shigella paradysenteriae Duval-Sonne), uri-   (Goddeeris 1980).Helminth eggs have been found naturally occurring in cockroaches, or appear in the faeces (Cochran 1999).Furthermore several virus, protozoa and fungi have been reported as occurring naturally in cockroaches and could also be transmited by these insects.However, proving unequivocally that cockroaches transmit disease to humans remains diffi cult (Baumholtz et al. 1997).However, costs associated with cockroaches are also linked to their control, either directly or indirectly through the use of pesticides that may facilitate emergence of pathogen resistance to some chemicals.Cockroaches are suspected to be important agents in the transmission of antibiotic resistant microbes in livestock production systems.Livestock production uses antibiotics therapeutically but this facilitates the emergence of resistant bacteria that may subsequently aff ect the human population.Finally, cockroaches can also damage household items, by eating glue in wallpaper, books, and furniture.
Th e second group of 'Polyneoptera' with huge economic impact is termites.Termites play a critical ecological and agricultural role and some of them are pests.Some species (e.g.Cryptotermes brevis) has been introduced by human activity to almost every part of the world and cause severe damage to wooden structures.Reticulitermes Holmgren (Isoptera: Rhinotermitidae) are the major termite pests infesting structures and trees in Europe and the near East (Lohou et al. 1997).Th is genus contains the most signifi cant termite pests of North America (the R. fl avipes (Kollar) complex) and Europe (the R. lucifugus (Rossi) complex), and signifi cant pest species in Asia (R. speratus (Kolbe)).Consequently, some of these species are susceptible to become major pests if they are introduced to Europe in the future.In Germany, R. fl avipes appears to have been introduced on multiple occasions from USA with pine (Pinus spp.) logs (Harris 1962;UNEP 2000;Weidner 1978).Th is species had caused signifi cant damage and costs for repair and control.Th e overall cost of treatments against termites in Europe may account for 1 billion euros by 2005 (UNEP 2000) whilst the estimated cost of termite damage could reach $20 billion annually (Su 2002).Holst (1986)

Figure
Figure 13.3.1.Relative importance of the families of Blattodea, Isoptera, Orthoptera, Phasmatodea, and Dermaptera in the alien and native entomofauna in Europe.Families are presented per order in a decreasing ranking based on the number of alien species.Species alien to Europe include cryptogenic species.Th e number over each bar indicates the number of species observed per family.

Figure 13
Figure 13.3.2.Temporal changes in the mean number of new records per year of 'Polyneoptera' alien to Europe from 1492 to 2006.Cryptogenic species excluded.Th e number above the bar indicates the number of species introduced.

Figure 13
Figure 13.3.3.Origin of the species of Polyneoptera alien to Europe.

Figure 13
Figure 13.3.5.Main European habitats colonized by the 'Polyneoptera' species alien to Europe and alien in Europe.Th e number over each bar indicates the absolute number of alien species recorded per habitat.Note that a species may have colonized several habitats.

Table 13 .3.2.
Phasmatodea and Dermaptera species alien to Europe.List and characteristics.Status: A Blattodea, Isoptera, Orthoptera, Phasmatodea and Dermaptera species alien in Europe.List and characteristics.Country codes abbreviations refer to ISO 3166 (see appendix I).Habitat abbreviations refer to EUNIS (see appendix II).Last update 01/03/2010.