Page 1 - vol64-2011-215-222deidun

Bulletin of Insectology 64 (2): 215-222, 2011
ISSN 1721-8861

Morphological variability in and distributional data on
Phaleria bimaculata populations from

islands of the Central Mediterranean area

Alan DEIDUN1, Federico MARRONE2, Ignazio SPARACIO3, Marco ARCULEO2, Tiziana CURATOLO2, Arnold
SCIBERRAS4, Jeffrey SCIBERRAS4, Sabrina LO BRUTTO2
1IOI-MOC, University of Malta, Msida, Malta
2Dipartimento di Biologia ambientale e Biodiversità, Università di Palermo, Italy
3Casa Editrice Danaus, Palermo, Italy
4Paola, Malta

Abstract

This study aimed to collect new taxonomic and distribution data on Phaleria bimaculata (L.) (Coleoptera Tenebrionidae) from
Sicily (southern Italy), the circum-Sicilian islands and the Maltese archipelago. Particular attention was paid to the diagnostic
morphological features observed in the populations sampled, focusing on the subspecies Phaleria bimaculata marcuzzii Aliquò.
P. bimaculata individuals were collected from 20 different locations, of which 2 were located in the Sicilian mainland, 9 in
circum-Sicilian islands and 9 in the Maltese Islands. In addition, four Phaleria acuminata Kuster populations were also recorded
along southern Sicilian shores. The two Phaleria species were never recorded in sympatry within the current study. Geometric
morphometrics were deployed to quantify and analyze the intra-specific differentiation in the shape of two external anatomical
structures, i.e. the pronotum and the elytra. The elytra of the individuals from the Aeolian island of Vulcano, locus typicus of the
ssp. marcuzzii, were more elongated and elliptical in comparison to the Maltese and the Sicilian individuals, underscoring the de-
gree of genetic differentiation within different populations of the species.

Key words: Phaleria bimaculata, Phaleria bimaculata marcuzzii, sandy beaches, Central Mediterranean, morphology, Geometric
morphometrics.

Introduction Within the Maltese archipelago, previous entomologi-
cal surveys (Mifsud and Scupola, 1998; Deidun et al.,
The genus Phaleria Latreille (Coleoptera Tenebrioni- 2010) reported the sympatric occurrence of P. bimacu-
dae) includes several species of psammophilic polysap- lata and the congeneric P. acuminata on two sandy
rophagous and saprophagous tenebrionids. In Europe, beaches (Golden Bay and Mgiebah). Such sympatry had
nine Phaleria species have been recorded to date (de already been reported in different areas of the Mediter-
Jong, 2010), with many subspecies of uncertain system- ranean (e.g. in Morocco by Colombini et al., 2008). Ac-
atic value. cording to Deidun et al. (2010), the two species nor-
mally occupy different beach zones; for instance, at
In Sicily and the Maltese Islands, two Phaleria spe- Golden Bay and Mgiebah (Malta) P. bimaculata had a
cies are known to occur, i.e. Phaleria bimaculata (L.) more seaward distribution than P. acuminata.
and Phaleria acuminata Kuster, whilst the presence of
Phaleria reveillierei Mulsant et Rey, reported only from The current study was conceived in order to collect
poorly-preserved specimens (collected from Sicily) and new taxonomic and distribution data on P. bimaculata in
found in the Natural History Museum of Budapest Sicily, the circum-Sicilian islands and Maltese archipel-
(Canzoneri, 1968; Aliquò and Soldati, 2010), needs to ago, paying special attention to diagnostic morphological
be confirmed. features encountered in the populations sampled, espe-
cially regarding the subspecies P. bimaculata marcuzzii,
P. bimaculata s.l. is a polymorphic species with a whose locus typicus was included in the sampling area.
Mediterranean chorotype (Löbl and Smetana, 2008),
which is restricted to beaches characterized by a coarse Materials and methods
grain size ranging from coarse sand to pebbles and cob-
bles (Canzoneri, 1968; Fattorini, 2008). Within the Ital- Sampling
ian populations, the following subspecies have been de- A total of 49 sandy beaches on different Central Medi-
scribed: Phaleria bimaculata adriatica Rey along the
Adriatic coast of peninsular Italy (Canzoneri, 1968; terranean island archipelagos (Maltese, Pelagian,
Bonometto and Canzoneri, 1970); Phaleria bimaculata Egadian, Aeolian) and on the Sicilian mainland were
jonica Canzoneri along the Ionian coast of the Italian sampled once over the March-October 2010 period. The
regions of Calabria and Apulia (Canzoneri, 1968); and full list of sampled sandy beaches is given in table 1,
Phaleria bimaculata marcuzzii Aliquò in the Aeolian whilst figure 1 gives the location of the sampled sites.
Islands (locus typicus: Vulcano; Aliquò, 1993). In addi- The supralittoral zone of these beaches was sampled by
tion, P. bimaculata populations from the Egadian Is- means of individual pitfall traps or by means of constel-
lands are considered by Canzoneri (1970) to be different lations of pitfall traps, each of which consisted of five
from the nominal subspecies.