The Bostrichidae of the Maltese Islands (Coleoptera)

Abstract The Bostrichidae of the Maltese Islands are reviewed. Ten species are recorded with certainty from this Archipelago, of which 6 namely, Trogoxylon impressum (Comolli, 1837), Amphicerus bimaculatus (A.G. Olivier, 1790), Heterobostrychus aequalis (Waterhouse, 1884), Sinoxylon unidentatum (Fabricius, 1801), Xyloperthella picea (A.G. Olivier, 1790) and Apate monachus Fabricius, 1775 are recorded for the first time. Two of the mentioned species (Heterobostrychus aequalis and Sinoxylon unidentatum) are alien and recorded only on the basis of single captures and the possible establishment of these species is discussed. Earlier records of Scobicia pustulata (Fabricius, 1801) from Malta are incorrect and should be attributed to Scobicia chevrieri (A. Villa & J.B. Villa, 1835). A zoogeographical analysis and an updated checklist of the 12 species of Bostrichidae recorded from the Maltese Islands and neigbouring Sicilian islands (Pantelleria, Linosa and Lampedusa) are also provided. Rhizopertha dominica (Fabricius, 1792) form granulipennis Lesne in Beeson & Bhatia, 1937 from Uttarakhand (northern India) was overlooked by almost all subsequent authors. Its history is summarized and the following new synonymy is established: Rhizopertha dominica (Fabricius, 1792) form granulipennis Lesne in Beeson & Bhatia, 1937 = Rhyzopertha dominica (Fabricius, 1792), syn. n. Finally, records of Amphicerus bimaculatus from Azerbaijan, of Bostrichus capucinus (Linnaeus, 1758) from Jordan and Syria, of Scobicia chevrieri from Jordan and Italy, of Xyloperthella picea from Italy, and of Apate monachus from Corsica (France) and Italy, are also provided.


Introduction
The larvae of most species of this family are wood borers, and as other saproxylic organisms they play an important role in the decomposition processes. They are thus significant for nutrient cycling in natural and semi-natural ecosystems, particularly forests (cf. Stokland et al. 2012). Several species of this family are of great economic importance since they can cause extensive damage to dry and dead wood, to seasoned sapwood timber, to bamboo, and to wooden or bamboo artifacts through the boring behavior of both adults and larvae. Moreover, several other species are pests of living trees and vines, a few species are store product pests attacking commodities such as grain and tubers. These beetles are frequently transported between countries, especially in wood packing materials such as crating and dunnage, and are often intercepted at ports and cargo distribution centres (cf. Haack and Slansky 1987, Geis 2002, Ivie 2002, Haack 2006, Liu et al. 2006, Bahillo de la Puebla et al. 2007, Liu et al. 2008, Lawrence 2010. The earliest record of the family comes from the mid Cretaceous (Peris et al. 2014). This family is now mainly represented in subtropical and tropical regions, and currently about 600 described species accommodated in 90 genera are known to occur worldwide (cf. Lawrence andSlipinski 2013, Zahradník andHáva 2014).
The knowledge on Maltese Bostrichidae was very limited, with only five previously recorded species. New data on Maltese Bostrichidae emerged from recent studies carried out on collections made from the Maltese Islands, the results of which are included in the present work.

Study area
The study area comprises all of the Maltese islands (c. 316 km²). Chetcuti et al. (1992), Schembri (1993Schembri ( , 1997 and Giusti et al. (1995) can be consulted for general environmental information on this Archipelago situated in the centre of the Mediterranean basin.

Nomenclature and classification
The suprageneric classification of the family and the nomenclature (family-group names and genus-group names) adopted in the present work follow Zahradník and Háva (2014), but the subfamilies follow Liu and Schönitzer (2011). The species are listed alphabetically as in Borowski and Węgrzynowicz (2007) and Ivie (2010).

Faunistic list
For each species, the following information is provided: nomenclatural combinations (listed chronologically-alphabetically) of the Maltese records found in the literature, literature records on the Maltese Islands, material examined, chorotype, data on ecology, and notes.
When possible, the following data was also provided for each record: island, municipality, locality of collection, altitude, date of collection, collector/s, collecting method, number of specimens, and, in parenthesis, literature reference or abbreviation of the depository. The records are listed in alphabetic order with respect to localities of collection. A semicolon separates different records; if these are from the same site, the name of the site is listed only at the beginning with the older record. When deemed useful for the discussion of some species, material examined from other countries ("Other material examined") is also provided.
Possible interpolations are given in square brackets; collecting data of Italian specimens that is originally written in Italian, is hereunder provided in English. Information on very old specimens is written in double quotation marks.

Zoogeography
Chorotypes, which were also used in the zoogeographical analysis, were assigned according to Vigna Taglianti et al. (1993Taglianti et al. ( , 1999 and are based on the distributions provided by the authors cited for each species. Moreover, the chorotypes of many species show extensions or more confined distributions when compared to the standard ones; these differences were mentioned only when the change is significant. For further information on global distributions, references cited in the text may be consulted. Gambetta and Orlandi 1982a, Gambetta 1983, Wang et al. 1996, Halperin and Geis 1999 brunneus, Geis 2002, Peters et al. 2002, Chikatunov et al. 2004, Bahillo de la Puebla et al. 2007 brunneus, Mattson et al. 2007, Krajewski and Mazurek 2009, Denux and Zagatti 2010, Geis 2012. According to Gambetta and Orlandi (1982b: 55), L. brunneus and Trogoxylon impressum (Comolli, 1837) are the two species of Lyctinae which are the most widespread in woods in Italian storage situations.
Notes. A species native to Asia which has been established throughout Europe for more than 150 years (Denux and Zagatti 2010). The recently collected material confirm its presence in Malta. In the nearby countries, the species is recorded from Tunisia (Lesne 1924, Normand 1936, Borowski 2007 but not from Sicily (cf. Audisio et al. 1995, Sparacio 1997, Chiappini et al. 2001, Nardi 2004a, Denux and Zagatti 2010. Accurate information and illustrations on the morphology of all stages of this species were provided by Nishimoto (1981, 1982) and Kucerová and Stesjkal (2008). Moreover the genitalia of both sexes was illustrated by different authors (e.g. Altson 1924: pls. 31-34, Gerberg 1957: pl. II, figs 15-16, Cymorek 1961: 81, fig. 3c, Iwata and Nishimoto 1982 Chorotype. Turanic-European-Mediterranean. This species is widespread from the Canary Islands to Turkmenistan; to the north it reaches Austria, Czech Republic, Germany, Hungary, Slovakia and Switzerland, moreover it has been introduced in some northern European states (Denmark, Finland, Norway and Sweden), into Argentina, Chile and USA (cf. Borowski 2007, Borowski and Węgrzynowicz 2007, Barriga and Cepeda 2009, and it is considered as an established alien in the latter two mentioned territories (Gerberg 1957). The species is possibly also establishment in China (cf. Peters et al. 2002), South Africa and Australia (Geis 2002), but for these territories this was not confirmed (Borowski and Węgrzynowicz 2007). This species was also recorded from Iraq (Knopt 1972) and was introduced to Benelux (Lucht 1987, Drumont andGrootaert 2011) and both countries must be added to its distribution which was summarized by Borowski (2007). Hopkins (1911: 137, as Lyctus impressus) in an Appendix to Kraus (1911), recorded this species also for "Cordova, Mex. [= Mexico]"; this record was overlooked since Lesne (1938) probably because this Appendix, which also included data on additional specimens, was added after the submission of the paper of Kraus (1911) (cf. Hopkins 1911 and Mexico was not included in the mentioned work.
Ecology. Originally, this species was only associated with wood but is now considered as a primary pest of all kinds of stored grains. Both larvae and adults are able to attack whole grain, causing considerable damage. The species is thought to have originated from the Indian subcontinent, and was introduced worldwide by commerce. It is an economically important pest since it can cause significant economic losses in terms of grain mass and nutrient depletion, and pose a public health risk from contamination by allergens, such as uric acid (cf. Potter 1935, Beeson and Bhatia 1937, Lepesme 1944, in all cases as Rhi. dominica, Fisher 1950, Aitken 1975, Maes 1995, Pollini 1998, in both cases as Rhi. dominica, Geis 2002, Gelosi and Süss 2001, Nguyen 2006, Borowski 2007, Liu et al. 2008, Denux and Zagatti 2010, Kenis and Branco 2010, Arthur et al. 2012, Edde 2012. This species can also damage books (Hoffman 1933, as Rhi. dominica).
Notes. The record from Malta by Hyde and Daubney (1960) was later overlooked by all authors (cf. Saliba 1963, Nardi 2004b, Borowski 2007. Thus this beetle must have been introduced in Malta at least since 1958 where it is now a well established species. In Italy, Rhyzopertha dominica was first collected in Sicily during the nineteenth century (cf. Bertolini 1874, as Rhi. pusilla Fabr. [= (Fabricius, 1798]; Ragusa 1896, as Rhi. pusilla), and since the 1950's it was widespread in all regions (cf. Norato 1957, Dal Monte 1958, as Rhi. dominica, Genduso 1963. According to Denux and Zagatti (2010: 348) the first European record of this species was from Czech Republic and is dated 1900, but the above Sicilian records, as well as those from other countries (cf. Reitter 1883, as Rhi. pusilla, Lesne 1901b), are older. Moreover, this species has been present in Europe at least since 3500-2551 BP, as testified by its archelogical presence in Spain and Greece (cf. King 2009). So the species was introduced and established before 1492 A.D. at least in Spain and Greece and must be considered as parautocthonous (cf. Zapparoli 2008: 98). Illustrations of its male and female genitalia were provided by Potter (1935: 474-475, figs 21-25), Lesne (1945: 149, figs 9-13, as Rhi. dominica) and Surtees (1961: 149, fig. 11, as Rhi. dominica).
The above specimens collected during 2002 are almost entirely black, probably for a post mortem colouration.
Notes. The above record of Aitken (1975) was based on material collected in UK from cargo originating from Malta. The presence of this species in Malta needs to be confirmed. Although Quercus ilex is present in Malta, its abundance is very scarce on the archipelago (cf. Haslam et al. 1977, Schembri 1993. Bostrichus capucinus is known from other similarly small Mediterranean islands, such as the nearby Pantelleria Island, three circumsardinian islands Pisano 1972, as Bostry. capucinus, Nardi andRatti 1995), two northern Adriatic islands (Müller 1923: 28, Schatzmayr and Müller 1925: 74, Luigioni 1929: 611, in all cases as Bostry. capucinus), and the Balearic Islands (cf. Español 1955, as Bostry. capucinus). Chorotype. A cosmopolitan species of Indo-Malaysian origins. It is mainly distributed in tropical and sub-tropical regions and restricted to 40° north and south of the equator (cf. Borowski 2007, Borowski and Węgrzynowicz 2007, Azmi et al. 2011 fig. 2). In the Mediterranean, it was intercepted in Israel, Italy and Spain (cf. Gambetta 1983, Geis 2002, Ratti 2002, 2004b, Bahillo de la Puebla et al. 2007, Ratti 2007, Azmi et al. 2011 (Westcott et al. 2006) must be added to the countries in which this species was intercepted (cf. Azmi et al. 2011), eventhough the former record was based on collection of death specimens (larvae and adults), which was later ignored (cf. Anderson et al. 1997, Geis 2002, Nardi 2004b, Borowski 2007, Denux and Zagatti 2010, Alexander and Anderson 2012.

Heterobostrychus aequalis (Waterhouse
Ecology. Polyphagous species attacking some 36 unrelated host-plant genera; this species breeds not only in logs, but also in planks, furniture, plywood and roots of manioc (cf. Fisher 1950, Kalshoven 1963a, 1963b, Horion 1972, Gambetta 1983, Wang et al. 1996 aequalis, Geis 2002, Maes 2005, Aguilera 2006, Bahillo de la Puebla et al. 2007, Sitticaya et al. 2009, Robinson 2013. Notes. First record for Malta. This species become established in some countries where it was accidentally introduced. Temperatures of 17 °C and below are said to be unsuitable for the species to breed (cf. Ivie 2002, Azmi et al. 2011. Thus, considering the warm climate of the Maltese Islands, (Chetcuti et al. 1992), it is highly likely that the species is already an established one. The above specimen was collected with a light trap on a terrace, mainly surrounded by agricultural land (P. Sammut, pers. comm., 2002).
Chorotype. A cosmopolitan species native to tropical eastern Asia, and widespread in the intertropical regions of the world. In Europe, it was intercepted in France, Germany, Great Britain, Italy, Poland, Russia, Spain and Ukraine, but its establishment was never confirmed. Moreover, the species is not reported from North Africa and the Middle East (except from Yemen) (cf. Vrydagh 1955, Poggi et al. 1994, Peck et al. 1998, Geis 2002, Ratti 2004, Maes 2005, Iwata and Nakano 2006, Liu et al. 2006, Peres Filho et al. 2006, Westcott et al. 2006, in all cases as S. conigerum Gerstäcker 1855, Bahillo de la Puebla et al. 2007, Borowski 2007, Borowski and Węgrzynowicz 2007, Barriga and Cepeda 2009, as S. conigerum, Savoldelli and Regalin 2009, Price et al. 2011, Brustel and Aberlenc 2014.
Notes. This alien species is a new record for the central Mediterranean area. Due to its polyphagy, it is frequently exported with wooden packing material (cf. Bahillo de la Puebla et al. 2007). The Maltese climate (Chetcuti et al. 1992, Schembri 1997 is unsuitable for its establishment (J. Borowski, pers. comm. 2012), but in an indoor site of northern Italy, this species was able to complete its development and to spread the infestation (Savoldelli and Regalin 2009).   (Lesne 1904, Vrydagh 1956, in both cases as S. Chevrieri Villa [sic!], Nardi 2004b) and Sinai (cf. Alfieri 1976, as S. chevrieri Villa [sic!]), but these two regions were overlooked by Borowski (2007). The above record from Jordan is the first for this country (cf. Sharaf et al. 1983, Borowski 2007. Ecology. Polyphagous species, with development taking place in death or debilitated branches of several woody plants. The following are plants known to be infested by this species and are present in Malta (cf. Haslam et al. 1977 In central Italy (Marche region), this species (see above) was reared also from wood of Salix sp. and Corylus avellana, that represent new host-plant records for this Bostrichid (see above listed literature).
This species is often collected at light (Angelini 1996a, Chikatunov et al. 2006, Baena and Zuzarte 2013 and by window flight traps. Using these traps, large number of specimens were collected in forests of Quercus calliprinos, Pinus halepensis and P. brutia from northern Israel (Buse et al. 2010), in Q. suber forests from southern France (Brin et al. 2005, Brin andBrustel 2006), in an oak-hornbeam forest (Querco-Carpineto boreoitalicum) from northern Italy (Nardi and Zahradník 2004), in Quercus ilex forests of Sardinia, in a floodplain remnant of northern Italy (Nardi, unpublished data) and in mixed beechwoods of central Italy (Redolfi De Zan et al. 2014).
The nomenclatorial problems for Apate Fabricius, 1775 were discussed by Borowski and Węgrzynowicz (2009). Table 1 summarized the species of Bostrichidae recorded from the Maltese Archipelago and neigbouring Sicilian Islands with each assigned to a chorotype. Altogether 12 species are known: 4 from Pantelleria, 1 from Linosa, 1 from Gozo, 9 from Malta and 1 from Lampedusa; and only Scobica chevrieri is recorded from four islands (except from Linosa).

Discussion
For Sicily and Tunisia, 22 (Catara and Barbagallo 1980, Benfatto and Longo 1985, Audisio et al. 1995, Nardi 2004b, 2004b, Suma and Russo 2005, Muscarella et al. 2013) and 30 species respectively (Borowski 2007) of Bostrichidae are recorded. The relatively small number of species recorded from the Sicilian Channel Islands (Tab. 1) is probably due to the limited surface area, by the absence of many host plants, and the absence of certain habitats such as moutain and sub-mountain ranges.
Species of bostrichids are easly transported with infested woods and cereal, and are frequently observed in harbour areas (cf. Aitken 1975, Contessi 1991, Contessi and Mucciolini 1993, Peck et al. 1998, Haack and Cavey 2000, Geis 2002, Nicoli Aldini 2003, Ratti 2004, Borges et al. 2006, Haack 2006, Liu et al. 2006, Majka 2007, Ratti 2007, Beiriger 2010, Humble 2010, Leal et al. 2010, Price et al. 2011. The interception in Malta of other alien species from warm climatic regions is highly likely, and their possible establishment could also be promoted by global warming (cf. Parmesan 2006, Franceschini et al. 2009, Walther et al. 2009, Fronzek et al. 2010, Robinet and Roques 2010, Roques 2010, Thuiller et al. 2011).   The Mediterranean area is one of the most significantly altered biodiversity hotspots on Earth, since it has been intensively affected by human activity for millennia. As a result, only 4.7% of its primary vegetation remained unaltered and the landscape has been repeatedly transformed (cf. Myers et al. 2000, Cuttelod et al. 2008, Geri et al. 2010, Carroll et al. 2012. This transformation has negatively influenced xylophagous insect populations, especially in small and isolated environments, like those of islands (cf. Becker 1975, Howart and Ramsay 1991, Becker 1992, Crisp et al. 1998, Mantisi 2001, Pasta and La Mantia 2002. In this framework, half of bostrichid species recorded from the Maltese Islands (Amphicerus bimaculatus, Bostrichus capucinus, Scobicia chevrieri, Xyloperthella picea, Apate monachus), are included in the European Red list of saproxylic beetles (Nieto and Alexander 2010: 29), but luckily all belong only to the IUCN category "LC" (Least Concern).