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Bulletin de la Société royale belge d’Entomologie/Bulletin van de Koninklijke Belgische Vereniging voor Entomologie, 153 (2017): 109–112
Woodlice of the green houses at Ghent Botanical Garden and
Botanic Garden Meise with two new exotic species for Belgium
(Isopoda: Oniscidae)
Pallieter DE SMEDT1,2, Gert ARIJS2, Stijn SEGERS2 & Pepijn BOERAEVE²
1 Forest & Nature Lab, Ghent University, Geraardsbergsesteenweg 267, B-9090 Melle (Gontrode), Belgium
(Corresponding author, e-mail: Pallieter.desmedt@ugent.be)
2 SPINICORNIS, Mispeldonk 2, B-2820 Bonheiden, Belgium (e-mail: info@spinicornis.be)
Abstract
In countries with a mild climate, greenhouses are often the only places, where exotic species can
survive outside their native range. This is certainly the case for woodlice, of which the greenhouse
fauna is relatively well studied in neighbouring countries. In Belgium, inventories of woodlice in
greenhouses are very scarce. Here we report woodlouse inventories in Ghent Botanical Garden and
Botanic Garden Meise during 2015-2017, resulting in fourteen species of which five are exotic. Two
species are mentioned for the first time in Belgium being Nagurus cristatus (Dollfus, 1889) and
Reductoniscus costulatus Kesselyák, 1930. An overview of woodlouse inventories in greenhouses in
Belgium is given.
Keywords: Belgium, Distribution, Greenhouse fauna, Nagurus cristatus, Reductoniscus costulatus,
Woodlouse
Samenvatting
Verwarmde kassen zijn, door hun constant en warmer klimaat, vaak de enige plaatsen waar exotische
soorten kunnen overleven buiten hun natuurlijk verspreidingsgebied. Dit is ook zo voor pissebedden,
waarvan de fauna van verwarmde kassen vrij goed bestudeerd is in onze buurlanden. In België zijn
deze inventarissen schaars. In dit artikel rapporteren we enkele inventarisaties van pissebedden in de
plantentuin in Gent en Meise gedurende 2015-2017. Dit resulteerde in veertien soorten waarvan vijf
uitheems zijn. Twee soorten werden voor de eerste keer in België waargenomen nl. Nagurus cristatus
(Dollfus, 1889) en Reductoniscus costulatus Kesselyák, 1930. Een overzicht van inventarisaties van
pissebedden in verwarmde kassen in België is weergegeven.
Résumé
Les serres sont, en raison de leurs températures élevées, souvent les seuls endroits dans les pays à
climat doux, où des espèces exotiques peuvent survivre car elles y trouvent des conditions similaires à
celles de leur pays d’origine. C'est le cas en effet pour les cloportes exotiques. La faune des serres est
relativement bien étudiée dans les pays voisins. En Belgique, les cloportes exotiques sont rares. Lors
d’un inventaire aux jardins botaniques de Gand et de Meise effectué en 2015-2017, quatorze espèces
de cloportes dont cinq exotiques ont été trouvées. Parmi ces dernières, deux espèces sont mentionnées
pour la première fois de Belgique : Nagurus cristatus (Dollfus, 1889) et Reductoniscus costulatus
Kesselyák, 1930. Nous donnons aussi un aperçu des cloportes des serres en Belgique.
Introduction
Greenhouses are very often the only places where exotic species can survive in temperate regions.
Many species are introduced via the import of exotic plants and can often establish viable populations
inside the greenhouses. Although many species are not able to survive outside greenhouses it sounds
reasonable that they might be able to do this once the outside climate gets more suitable. Therefore, it
110
is interesting to know which species occur in greenhouses to evaluate the change that they will
establish populations in the wild. Woodlice in greenhouses and heated environments in e.g. zoos are
studied relatively well in the Netherlands (BERG et al., 2008) with eight species that are restricted to
greenhouses. Studies from Belgium are however extremely scarce. In Belgium, only two species are
known to exclusively occur in greenhouses being Cordioniscus stebbingii (Patience, 1907) and
Trichorina tomentosa (Budde-Lund, 1893) while some others were first reported from greenhouses
but appeared to be native with the discovery of wild populations e.g. Trichoniscus pygmaeus Sars,
1898, Haplophthalmus danicus Budde-Lund, 1880 and Armadillidium nasatum Budde-Lund, 1885
(BAGNALL, 1907). The last note on woodlice from greenhouses in Belgium dates back to 1973
(KERSMAEKERS, 1973), while the last reported inventory was done in 1956 (POLK & VAN OYE, 1956).
Therefore, an update on woodlice in Belgian greenhouses could be interesting more than 60 years after
the last inventory. This was the reason to undertake some short visits to the greenhouses of Ghent
Botanical Garden and Botanic Garden Meise in 2015-2017 to evaluate the presence of woodlouse
species in greenhouses.
Surveys
During four inventories between 2015 and 2017 to Ghent botanical garden and one to Botanic Garden
Meise, we found a total of fourteen woodlouse species mostly underneath stones and flowerpots
(Table 1). Five out of fourteen species can be considered as exotic, of which two species and one
genus mentioned for the first time in Belgium. These are Nagurus cristatus (Dollfus, 1889),
Reductoniscus costulatus Kesselyák, 1930 and Synarmadillo spec. A visit to Botanic Garden Meise in
May 2016 did not result in additional species but resulted in a second location for N. cristatus. The
two new species and new genus are shortly discussed below. The collected specimens are deposited in
the private collection of Pallieter De Smedt.
Table 1. Species reported from greenhouses in Belgium by BAGNALL (1907, 1908), POLK & VAN OYE (1956)
and this study. KERSMAEKERS (1973) reported again T. tomentosa from the botanical gardens of Ghent but this
single observation was not reported in the table. X: presence of the species, (X) species of which BAGNALL
(1907) did not report if it was collected in Brussels or Antwerp, X* specimens collected at Ghent botanical
garden in Juli 1949 that were stored at the Natural History Museum in Leiden (the Netherlands) and re-identified
by POLK & VAN OYE (1956). POLK & VAN OYE (1956) reports a woodlouse of the genus Rhyscotus. He
mentions that the specimen was send to Prof. Vandel in Toulouse but after this, there has been no report of the
species anymore. Therefore, we did not include it in the list.
BAGNALL
1907, 1908
POLK & VAN OYE
1956
This study
2015-2017
Brussel Antwerp Ghent Antwerp Ghent Meise
Androniscus dentiger Verhoeff, 1908 X X X* X X
Armadillidium nasatum Budde-Lund, 1885 X X X X X
Armadillidium vulgare Latreille, 1804 X
Cordioniscus stebbingi (Patience, 1907) X X* X
Cylisticus convexus (De Geer, 1778) (X) (X)
Haplophthalmus danicus Budde-Lund, 1880 X X X
Haplophthalmus mengii (Zaddach, 1844) X
Nagurus cristatus (Dollfus, 1889) X X
Oniscus asellus Linnaeus, 1758 (X) (X) X X
Philoscia muscorum (Scopoli, 1763) (X) (X) X
Platyarthrus hoffmannsseggii Brandt, 1833 X
Porcellio dilatatus Brandt, 1833 X X X
Porcellio scaber Latreille, 1804 (X) (X) X* X X X
Porcellio spinicornis Say, 1818 X X
Porcellionides pruinosus (Brandt, 1833) (X) (X) X
Reductoniscus costulatus Kesselyák, 1930 X
Synarmadillo spec. X
Trichorina tomentosa (Budde-Lund, 1893) X X X
Trichoniscus pusillus s.l. (X) (X)
Trichoniscus pygmaeus Sars, 1898 X X X
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Fig. 1. Nagurus cristatus (photograph: Gert Arijs). Fig. 2. Reductoniscus costulatus (photograph: Walte
r
P. Pflieger).
Nagurus cristatus (Dollfus, 1889) Belg. sp. nov.
MATERIAL: Ghent, greenhouse, 31UES5053, 5.II.2015, 2ƂƂ, leg. & det. Pallieter De Smedt ʊ
10.VII.2015, 2ƂƂ, leg. & det. Pallieter De Smedt ʊ 18.XII.2015, 50 ex., det. Pallieter De Smedt ʊ
17.III.2017, 10 ex., det. Pallieter De Smedt ʊ Meise, greenhouse, 31UES9342, 1.V.2016, 1Ƃ, det.
Gert Arijs.
The species (Fig. 1) is pantropical and occurs in greenhouses in temperate regions (SCHMALFUSS,
2003). Nagurus cristatus was very common in the subtropical greenhouses where it mostly occurred
underneath flowerpots on concrete. All collected specimens were females. Males are very rare and the
species reproduces asexual (BERG & WIJNHOVEN, 1997). The species was also found in greenhouses
at Botanic Garden Meise. See GREGORY (2014) for drawings of the species.
Reductoniscus costulatus Kesselyák, 1930 Belg. sp. nov.
MATERIAL: Ghent, greenhouse, 31UES5053, 5.II.2015, 1ex., leg. & det. Pallieter De Smedt.
The species (Fig. 2) is known form the Seychelles, Mauritius, Malaysia and Hawaiian Islands but also
occurs in greenhouses in Europe (SCHMALFUSS, 2003). Only one specimen was found underneath a
stone on humid soil in the tropical greenhouse. The habitat corresponds to sightings in greenhouses in
the Netherlands where this species is found under humid conditions (BERG et al., 2008). See
GREGORY (2014) for drawings of the species.
Synarmadillo spec.
MATERIAL: Ghent, greenhouse, 31UES5053, 5.II.2015, 1ex., det. Pallieter De Smedt. (The specimen
got lost for further identification.)
A single individual of the genus Synarmadillo was found in the tropical greenhouse at Ghent botanical
garden. After collection, the specimen got lost. Therefore, it was not possible to identify the individual
to species level. In a Dutch greenhouse Synarmadillo pallidus Arcangeli, 1950 has been reported.
A species originally described from Zaïre (SCHMALFUSS, 2003). In the Netherlands, this species has
been found in only one greenhouse and is absent from Germany and the UK (BERG et al., 2008).
Therefore, it is not certain if the specimen at Ghent botanical gardens is the same species.
SCHMALFUSS (2003) reports more than 20 species within the genus Synarmadillo.
The nine native species (Table 1) recorded in the greenhouses from Ghent and Meise are all very
common or common in Belgium. Armadillidium vulgare and Platyarthrus hoffmannsseggii are
recorded for the first time inside greenhouses in Belgium.
112
Discussion
Twenty woodlouse species have been recorded in Belgian greenhouses up to date of which five can be
considered as exotic. Four of these species are widespread in greenhouses across the Netherlands
(BERG et al., 2008) and the rest of Europe (SCHMALFUSS 2003) and are easily transported via
horticultural trade. Therefore, they can be expected to occur in many greenhouses in Belgium as well.
Only the status of the Synarmadillo species remains somewhat unclear. Hopefully, a second specimen
can be found in the near future to identify the species. Furthermore, there are three other species
recorded in Dutch greenhouses (BERG et al., 2008) and no less than 17 species are known from
greenhouses in the UK (GREGORY, 2014). Inventories in Belgian greenhouses can probably extend
table 1 with some of these species. Alongside the exotic species, also some native species are
frequently found in greenhouses like P. scaber, H. danicus, T. pygmaeus, A. dentiger and A. nasatum.
The latter two occur, outside greenhouses, mostly on anthropogenic disturbed areas like graveyards in
the northern part of the country. In the southern part of Belgium, they are not anthropogenic. The other
three species are common in most areas in Belgium.
We hope that this article can encourage people to have a closer look at woodlice in Belgian
greenhouses, both botanical greenhouses and in zoos. In Belgium, there is no report of woodlouse
inventories in zoos while there is evidence that zoos can harbour some interesting species (BERG et al.,
2008).
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