Millipedes and centipedes in German greenhouses (Myriapoda: Diplopoda, Chilopoda)

Abstract A review is given of all the literature records of millipedes and centipedes that have been found in German greenhouses together with additional records for 29 such sites. Species lists are given for 46 greenhouses investigated throughout Germany. Thirty-five diplopod and 18 chilopod species were found to occur in greenhouses, of which 15 (3 Chilopoda, 12 Diplopoda) are restricted to this type of habitat. First records for Germany include Anadenobolus monilicornis (Porat, 1876), Epinannolene cf. trinidadensis Chamberlin, 1918, Epinannolene sp., Mesoiulus gridellii Strasser, 1934, Leptogoniulus sorornus (Butler, 1876), Rhinotus purpureus (Pocock, 1894), Cryptops doriae Pocock, 1891, Lamyctes coeculus (Brölemann, 1889) and Tygarrup javanicus (Attems, 1907). The millipedes Oxidus gracilis (C. L. Koch, 1847) and Amphitomeus attemsi (Schubart, 1934) and the centipedes Lithobius forficatus (Linnaeus, 1758) and Cryptops hortensis (Donovan, 1810) are the species most frequently found in greenhouses.


Introduction
Greenhouses provide different environmental conditions for animal colonization and survival compared with natural or synanthropic habitats outside. Greenhouses are characterized by a lack of frost and higher, usually constant temperatures, high humidity, permanent, regular watering, the presence of plants from mostly tropical countries and lack of or only low amounts of leaf litter and dead wood provide a more or less unique ecosystem inside such artificial buildings.
Examples of possible pathways of introduction of myriapods in the greenhouses can be found in Attems (1901) and Kraepelin (1901). Myriapods from all developmental stages (eggs, juveniles, adults) can be introduced easily within soil and other substrates associated with plants during shipment.
The apparent first record of a myriapod species from greenhouses in Germany is that by Schnur (1857), who recorded "Scolopendra germanica C. L. Koch, 1837". This species should be referred to either Cryptops hortensis (Donovan, 1810) or C. parisi Brölemann, 1920(Attems 1930. Which of these two species in fact was found by Schnur (1857) cannot be certain now today because the specimens have been lost. Another species recorded by Schnur (1857) is Mecistocephalus maxillaris (as Geophilus maxillaris). The identity of this species is doubtful and its specific status requires verification (Bonato and Minelli 2004). The same is true for the records by Latzel (1895) (Mecistocephalus guildingii Newport, 1844, later repeated as M. maxillaris by Jeekel (1964a)) and Eichler (1952). Latzel (1895) recorded Oxidus gracilis (as Paradesmus gracilis), M. maxillaris, Lithobius forficatus and Paraspirobolus lucifugus (as Spirobolus dictyonotus Latzel, 1885) (Fig. 1) from a hothouse in a nursery in Hamburg and Poratia digitata (as Scytonotus digitatus Porat, 1899) from a tannery near Hamburg. The record of P. lucifugus was wrongly referred to the tannery in Bergedorf near Hamburg by Schubart (1934).

Materials and methods
In total, data for 46 greenhouses has been compiled (Table 1). Records from botanical gardens were not included if they had been made outside the greenhouses. Altogether we provide data for 53 species (35 Diplopoda and 18 Chilopoda) found in German greenhouses.

City
Name of locality Literature (Re-)Investigated in this study

Bayreuth
Bayreuth Ecological Botanical Garden × Berlin Berlin Old Botanical Garden Eichler 1952 Berlin-Dahlem Botanical Garden Boettger 1929, Eichler 1952, Golovatch et al. 2001, Schubart 1934, Schubart 1929a × Berlin Zoological Garden × (Cemetary) nurseries, without exact locality Schubart 1929a, Schubart 1957 Horticulture company in Berlin-Zehlendorf View from the top-of-the-tree-path in the greenhouse 'Gondwanaland', Zoological Garden Leipzig. Photograph: N. Lindner. The present investigation is based on a comprehensive review of the literature and an analysis of the collections of the Senckenberg Museum of Natural History Görlitz (SMNG), the Museum of Natural History Berlin (ZMB), as well as of the data available in the Global Biodiversity Information Facility (GBIF, http://www.gbif.org, Edwards et al. 2000) and in the database on soil zoology, Edaphobase (http://www.edaphobase.org, Burkhardt et al. 2014).
In addition the myriapod faunas of 29 German greenhouses were investigated or reinvestigated by us (Table 1). For this part of our study Norman Lindner (Leipzig) provided highly valuable material from greenhouses in Berlin, Dresden, Konstanz, Leipzig and Potsdam. Altogether we collected more than 1800 specimens belonging to 41 species (29 Diplopoda, 12 Chilopoda). The sampling was done mainly by hand searching under stones or rotten plants and logs. Pitfall traps were used only in the Palm Garden in Frankfurt in 2008 by Heußler (2009), whose diploma thesis results are also included in the present study.
Material from these new samples has been mainly deposited in the Myriapoda collections of the Senckenberg Museum of Natural History Görlitz (SMNG). Record data is available online via the data portals of GBIF and Edaphobase. The full data sets with detailed information on site parameters, microhabitats and collection methods are available as Suppl. material 1. An overview of species and the cities is given in Suppl. material 2.
The natural distribution area is given for each species.

Discussion
The present study is the second comprehensive survey of German greenhouse myriapods since Eichler (1952) and is derived from both the existing literature and our own extensive sampling. Eichler (1952) We collected more than 1800 specimens belonging to 41 species (29 Diplopoda, 12 Chilopoda), which makes a total of 53 species (35 Diplopoda and 18 Chilopoda) (Suppl. material 2).
Six centipedes and 12 millipedes are herewith recorded for the first time from German greenhouses: Cryptops doriae, Henia vesuviana, Lamyctes coeculus, Lithobius mutabilis, Pachymerium ferrugineum, Tygarrup javanicus, Anadenobolus monilicornis (Fig. 3 Leptogonoiulus sorornus (Fig. 4) and the two species of genus Epinannolene are recorded for the first time in Europe. While the first species of Epinannolene fits quite well the original description of E. trinidanensis by Chamberlin (1918), the second one is probably an undescribed species, closely related to Epinannolene alticola (Silvestri, 1898) and E. exilio (Brölemann, 1904). The colourful Caribbean species Anadenobolus monilicornis was only recorded in Gondwanaland, Zoological Garden Leipzig.
A total of 34% (i.e. 18 species) are species introduced from other continents (Suppl. material 2): 15 % of those recorded have their origin in Southern and Central America, 13% in Asia, 4 % in Australia, and only 2 % in Africa.
Most of the alien species in German greenhouses are also known from other such places in Europe. There are a few species recorded from other European greenhouses which we have not found in Germany yet. These could also be expected to possibly be introduced to or occur in German greenhouses -species such as Mecistocephalus guildingii (Barber 2009), Prosopodesmus panporus Rundle, 1980 (Blower andRundle 1980), and Haplopodoiulus spathifer (Brölemann, 1897) (Read 2008) recorded in Great Britain, Tuoba poseidonis (Verhoeff, 1901)  Sixty-six per cent of all recorded species (35 in total) are of European origin. Two examples of the successful establishment of indigenous species in greenhouses are Lithobius forficatus and Blaniulus guttulatus. L. forficatus, followed by Cryptops hortensis, is the most frequently found centipede in German greenhouses. The former normally inhabits natural habitats and areas of human settlement and is frequently found in houses and cellars. Likewise, among indigenous millipedes B. guttulatus is the most commonly found. In Germany it prefers synanthropic habitats and occurs on arable and waste land, while, especially in the west and southwest of Germany, it is also known from human settlements (Schubart 1934).
About 25% of the recorded species are found exclusively in greenhouses, especially in heated ones, and are thus unlikely to establish outside. The parthenogenetic species Amphitomeus attemsi (Fig. 5), Cylindrodesmus hirsutus and Poratia digitata are very frequent (with A. attemsi being the second most common millipede species) and were found in many of the greenhouses investigated.
The East Asian species Oxidus gracilis, which is the most frequent millipede in greenhouses, was observed outdoors in two sites in Mainz, Rhineland-Palatinate (2003 during winter, albeit only in very large compost heaps or large accumulations of rotting material with evenly warm-humid conditions. In other European countries O. gracilis is also common in greenhouses, city parks and gardens (Stoev and Korsós 2010). Other species, like the North African C. truncorum and the European species B. tenuis, C. palmatus and N. kochii, are restricted to anthropogenic, synanthropic habitats and greenhouses. C. vulnerarius is hitherto known only from a garden in Waltrop, North Rhine-Westphalia (Decker and Hannig 2011) suggesting that this species can also survive in urban habitats. Although currently there are no outdoor records of M. gridellii known from Germany, this species, originally reported from Italy, is known from several urban sites in adjacent Austria (Gruber 2002) and could also inhabit similar biotopes (e.g. gardens, parks or subterranean passageways) in Germany. The tiny (2.9-3.2 mm) parthenogenetic Amphitomeus attemsi is a common species in greenhouses.