ArticlePDF Available

Abstract and Figures

Lasius maltaeus Seifert, 2020 was recently described as a Maltese endemic ant based on quantitative morphology, after decades of uncertainties over the identity of the local population, which has a phenotype resembling L. emarginatus (Olivier, 1791). At the same time, Sicilian L. emarginatus populations were discovered to diverge in their mitochondrial DNA to a degree that suggested heterospecificity. Considering the biogeographic similarity of Malta and Sicily, with land bridges connecting them repeatedly until the last glacial maximum, we questioned the assumption that L. maltaeus was endemic to Malta. We integrated quantitative morphology and mtDNA in the study of the Maltese and southern Italian populations phenotypically close to L. emarginatus. We discovered that the range of L. maltaeus extends over most of Sicily, while the true L. emarginatus replace it in the northeastern sector of the island, the nearby Aeolian Islands, and the Italian peninsula. The distributions of L. emarginatus and L. maltaeus in Sicily follow biogeographic patterns recalling the island's complex paleogeographic history. Further investigations should verify the existence of truly Maltese endemic ants, since the status of other allegedly endemic species is not strongly supported.
Content may be subject to copyright.
Quantitative morphology and mtDNA reveal
that Lasius maltaeus is not endemic to the
Maltese Islands (Hymenoptera, Formicidae)
Mattia Menchetti1*, Enrico Schifani2*, Antonio Alicata3, Roger Vila1
1Institut de Biologia Evolutiva (CSIC-Univ. Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003
Barcelona, Spain 2Department of Chemistry, Life Sciences and Environmental Sustainability, University
of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy 3Department of Biological, Geological and
Environmental Sciences (DBGES), University of Catania, Via Androne 81, I-95124 Catania, Italy
Corresponding author: Mattia Menchetti (;
Academic editor: Francisco Hita Garcia|Received 15 October 2022|Accepted 5 December 2022|Published 17 February 2023
Citation: Menchetti M, Schifani E, Alicata A, Vila R (2023) Quantitative morphology and mtDNA reveal that
Lasius maltaeus is not endemic to the Maltese Islands (Hymenoptera, Formicidae). Journal of Hymenoptera Research
95: 129–142.
Lasius maltaeus Seifert, 2020 was recently described as a Maltese endemic ant based on quantitative
morphology, after decades of uncertainties over the identity of the local population, which has a phenotype
resembling L. emarginatus (Olivier, 1791). At the same time, Sicilian L. emarginatus populations were
discovered to diverge in their mitochondrial DNA to a degree that suggested heterospecicity. Considering
the biogeographic similarity of Malta and Sicily, with land bridges connecting them repeatedly until
the last glacial maximum, we questioned the assumption that L. maltaeus was endemic to Malta. We
integrated quantitative morphology and mtDNA in the study of the Maltese and southern Italian
populations phenotypically close to L. emarginatus. We discovered that the range of L. maltaeus extends
over most of Sicily, while the true L. emarginatus replace it in the north-eastern sector of the island, the
nearby Aeolian Islands, and the Italian peninsula. e distributions of L. emarginatus and L. maltaeus
in Sicily follow biogeographic patterns recalling the island’s complex paleogeographic history. Further
investigations should verify the existence of truly Maltese endemic ants, since the status of other allegedly
endemic species is not strongly supported.
ants, biogeography, Formicinae, Mediterranean islands, Sicily
* ese authors contributed equally to this study.
JHR 95: 129–142 (2023)
doi: 10.3897/jhr.95.96365
Copyright Mattia Menchetti et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC
BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
e ant genus Lasius Fabricius, 1804 is one of the most ecologically important ant
genera in the Holarctic realm (Hölldobler and Wilson 1990; Seifert 2018, 2020). It
currently counts 125 extant species (Bolton 2022), which belong to two major clades
and at least 10 species groups, many of which independently evolved social parasitism
(Maruyama et al. 2008; Boudinot et al. 2022).
e taxonomy of Lasius ants is considered among the most challenging among
Holarctic ants (Seifert 2018). In particular, the former subgenus Lasius s. str., which
is now known to represent two distinct lineages (the brunneus group and the niger
group, see Boudinot et al. 2022), has witnessed signicant taxonomic changes. It was
once thought to count only seven species (Wilson 1955), but since then this number
increased several times, especially in the last three decades (Van Loon et al. 1990;
Seifert 1991; Seifert 1992, 2020; Schlick-Steiner et al. 2003; Borowiec and Salata
2013; Seifert and Galkowski 2016; Salata and Borowiec 2018; Schär et al. 2022).
e West-Palearctic Lasius emarginatus (Olivier, 1791) is an iconic European spe-
cies characterized by a large geographic range and remarkable bicoloured appearance
(Seifert 2018). However, at least four additional cryptic species with a supercially
similar appearance were revealed during recent years (Seifert 2018, 2020): L. tebessae
Seifert, 1992 from the Maghreb (Seifert 1992, 2020); L. illyricus Zimmermann,
1935 ranging from the Balkans to the Caspian sea, in a large area sympatric with
L. emarginatus (Borowiec and Salata 2013; Schifani and Massa 2020; Seifert 2020);
the Iranian L. persicus Seifert, 2020, partly sympatric with L. illyricus (Seifert 2020);
and L. maltaeus Seifert, 2020 described from Malta.
e recent description of L. maltaeus came after a long debate on the identity of
this Maltese morphotype. Baroni Urbani (1968) attributed the local bicolored Lasius
ants with hairy scapes to L. emarginatus. However, Schembri and Collingwood (1981)
considered the workers’ head pilosity to be too dense, their frontal triangle too shiny
and the scapi of males to be too hairy compared to samples of L. emarginatus from
continental Europe, and instead proposed to classify the Maltese population as a red-
dish phenotype of L. niger (Linnaeus, 1758). Later on, the same authors changed
their opinion, dening the Maltese ants as representatives of a morphospecies dierent
from both L. niger and L. emarginatus (Schembri and Collingwood 1995). e issue
remained uninvestigated until Seifert (2020) included Maltese specimens in a large
West-Palearctic taxonomic revision based on quantitative morphology. He demon-
strated their distinctiveness from both L. niger and L. emarginatus, and described the
morphospecies as L. maltaeus, included within the L. emarginatus complex, empha-
sizing dierences in head pilosity in agreement to the comments by Schembri and
Collingwood (1981).
At the same time, an inventory of the Sicilian ant fauna highlighted a remarkable
genetic distance for the mitochondrial COI of L. emarginatus samples from Sicily com-
pared to those of the nearby Aeolian Islands and of peninsular Italy (Schär et al. 2020).
Lasius maltaeus is not endemic to the Maltese Islands 131
Similar results were also published from Corsica, yet the local population resembling
L. emarginatus was attributed to L. grandis Forel, 1909 based on morphology (Blatrix
et al. 2020; Seifert 2020). Sicily and the Maltese Islands are well-known for their strong
biogeographic similarity (e.g., ake 1985; Fattorini 2011; Salvi et al. 2014; Médail
2022), and were connected repeatedly by land bridges until the last glacial maximum
(Foglini et al. 2016) (light blue line Fig. 1). ese observations led us to investigate the
relationships between the Sicilian populations historically attributed to L. emarginatus
and L. maltaeus, questioning the endemic status of the latter.
Materials and methods
Ant specimens were manually collected and stored in 70–96% ethanol (Suppl. material
1: table S1, Fig. 1). Vouchers are deposited in the authors’ personal collections (see
Suppl. material 1: table S1):
MMBS M. Menchetti pers. coll., Barcelona, Spain;
ESPI E. Schifani pers. coll., Palermo, Italy;
AACI A. Alicata pers. coll., Catania, Italy;
BDEL R. Vila, Buttery Diversity and Evolution Lab coll.
Morphological analysis
e morphological study was performed using stereoscopic microscopes at 45–80×
magnication, in addition to photography-based morphometry. Species were identi-
ed using the keys provided by Seifert (2020).
Morphological measurements were obtained by taking pictures with a Carl Zeiss
Stemi 2000-C stereomicroscope at magnication 2.25× equipped with a CMEX PRO-
5 DC.5000p digital camera and ImageFocus 4 software (M. Menchetti) and at 5×
magnication using Canon MP-E 65mm f/2.8 1–5× macro lens analysed with the
software ImageJ (Schneider et al. 2012) (E. Schifani).
We measured a total of 22 workers of L. maltaeus from Malta and Italy (Sicily
and Calabria) and 13 workers of L. emarginatus from Italy (Sicily, Aeolian Islands,
Calabria and Emilia-Romagna). We recorded six characters, including one chaeto-
taxonomic and four morphometric characters needed to distinguish L. emarginatus
from L. maltaeus according to Seifert (2020), and the cephalic size. e acronyms and
character denitions follow Seifert (2020):
CL: maximum cephalic length in median line; the head must be carefully tilted
to the position with the true maximum. Excavations of posterior head and/or
clypeus reduce CL.
CW: maximum cephalic width; this is either across, behind, or before the eyes.
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
PoOc: postocular distance. Use a cross-scaled ocular micrometer and adjust the head
to the measuring position of CL. Caudal measuring point: median occipital
margin; frontal measuring point: median head at the level of the posterior eye
margin. Note that many heads are asymmetric and average the left and right
postocular distance.
MP6: length of the sixth (terminal) segment of maxillary palps.
nGen: with head in full face view, number of setae on head sides frontal of anterior
eye margin (gena). e bilateral sum is halved.
CS: arithmetic mean of CL and CW as less variable indicator of body size.
For all specimens we also calculated ratios (CL/CW, PoOC/CL and MP6/CL) and
the linear discriminant distinguishing L. maltaeus (D > 0) from L. cinereus Seifert, 1992,
L. emarginatus, L. illyricus and L. grandis (D < 0) at step 22a of the dichotomous key
by Seifert (2020): 45.42*PoOc/CL –0.183* CL/CW+55.63*MP6/CL +0.312*nGen
–25.59. Lasius emarginatus was distinguished from the other above-mentioned species
based on cuticle microsculpture, clypeal pubescence and setosity of the scapi following
Seifert (2020). All measurements are presented in mm.
Genetic analysis
A total of seven L. maltaeus and three L. emarginatus specimens belonging to dif-
ferent nests were selected for the genetic analysis. A few legs per specimens were
used. DNA-barcoding (mitochondrial gene cytochrome c oxidase I, COI, 658
bp) data was generated at two institutes: the Centre for Biodiversity Genomics,
University of Guelph, Canada, using the primers LepF1 and LepR1 (deWaard et
al. 2008); the Buttery Diversity and Evolution Lab (BDEL), following the proto-
col by Schär et al. (2020) and using the primers LCO1490/HC02198 (Folmer et
al. 1994). In the latter case, PCR products were visualized by gel electrophoresis
and sent to Macrogen Europe for Sanger sequencing. Raw sequences were edited
and aligned in Geneious Prime 2020.2.4 (Kearse et al. 2012). Chromatograms and
sequences have been inspected for the presence of, respectively, double peaks and
stop codons.
We also retrieved from GenBank a total of ten sequences of 658 bp identied
as L. emarginatus: one from Schär et al. (2018) (accession number LT977448), four
from Schär et al. (2020) (accession numbers MT606324, MT606325, MT606326,
and MT606327) and ve from Blatrix et al. (2020) (accession numbers MH138380,
MH138381, MH138384, MH138385, and MH138386). e haplotype network was
created using the program TCS 1.21 (Clement et al. 2000) and then graphically edited
with tcsBU (dos Santos et al. 2016) and Adobe Illustrator CC 2019. All the newly
generated sequences were submitted to GenBank (accession numbers OQ025622-
OQ025631, see also the Suppl. material 1: table S1) and to BOLD (dataset DS-ANT-
LMAL, doi:
Lasius maltaeus is not endemic to the Maltese Islands 133
Figure 1. Distribution of the samples of L. maltaeus (red) and L. emarginatus (yellow) investigated in this
study with quantitative morphology and/or molecular analysis. e shape of the points represents whether
the samples were identied with the linear discriminant (circles: ID in this study; triangles: ID by Seifert
2020; squares: no linear discriminant was used). Inner circles indicate whether molecular data (COI)
has been used (black circles: sequences generated in this study; white circles: sequences retrieved from
GenBank). Light blues lines in the map below indicate the coastline during the Last Glacial Maximum
(LGM). Main toponyms discussed in the text are highlighted in the map.
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
Samples identied by quantitative morphology and/or molecular analysis as L. maltaeus and
L. emarginatus were distributed allopatrically (Fig. 1). All samples from the Italian peninsula,
the Aeolian Islands and from north-eastern Sicily (Peloritani mountains and Etna) belonged
to L. emarginatus, while all samples from Malta and all other samples from Sicily (coming
from the north-western and south-eastern sectors) were identied as L. maltaeus (Fig. 1).
Morphological analysis
Quantitative morphological data are summarized in Table 1 and raw data is available in
the Suppl. material 1: table S2. All specimens were unambiguously classied as either
L. maltaeus or L. emarginatus according to the linear discriminant scores even without
considering nest means of multiple workers, while all individual characters overlapped
between the two species (Table 1, Figs 2, 3). For what concerns L. maltaeus, our data
slightly extend the minimum and maximum range of all investigated characters except
for the maximum range of PoOC and CW.
Table 1. Summary of the morphological dierences between L. maltaeus (n=22) and L. emarginatus
(n=13) specimens measured in this study. All morphometric characters are reported in mm as mean
± standard deviation (minimum, maximum). e raw data is available in Suppl. material 1: table S2.
L. maltaeus L. emarginatus
CL 0.96 ± 0.07 (0.79, 1.11) 0.99 ± 0.05 (0.91, 1.05)
CW 0.9 ± 0.07 (0.73, 1.03) 0.93 ± 0.07 (0.82, 1.02)
PoOC 0.22 ± 0.02 (0.17, 0.25) 0.22 ± 0.02 (0.19, 0.25)
MP6 0.22 ± 0.02 (0.18, 0.26) 0.21 ± 0.01 (0.18, 0.23)
nGen 13.36 ± 2.45 (8, 18) 7.04 ± 1.83 (4, 10)
CS 0.93 ± 0.07 (0.76, 1.07) 0.96 ± 0.05 (0.87, 1.03)
CL/CW 1.07 ± 0.03 (1.01, 1.14) 1.07 ± 0.07 (1.01, 1.25)
PoOC/CL 0.23 ± 0.01 (0.20, 0.25) 0.22 ± 0.01 (0.21, 0.24)
MP6/CL 0.23 ± 0.02 (0.21, 0.26) 0.21 ± 0.01 (0.2, 0.22)
D 1.91 ± 0.83 (0.76, 3.92) -1.35 ± 0.84 (-3.17, -0.17)
Figure 2. Frontal view of the head and lateral view of a L. maltaeus worker from Sicily (voucher
Lasius maltaeus is not endemic to the Maltese Islands 135
Genetic analysis
We generated ten COI sequences with a length of 658 bp. e haplotype network
analysis (Fig. 4) based on a total of 20 COI sequences (8 for L. maltaeus and 12 for
L. emarginatus) show two distinct haplogroups that match the morphological spe-
cies identication. Within the L. maltaeus haplogroup, the two L. maltaeus colonies
analysed from Malta had distinct haplotypes, both shared with the Sicilian popula-
tions: one shares the haplotype with a colony from the Hyblean Plateau (voucher
MM21B061a1 from Cavagrande del Cassibile, Siracusa) and the other with samples
from the mountains in the area of Palermo (voucher MM18A053a1 from Monte
Moarda and sequence MT606327 from Monte Pellegrino). A total of ve haplotypes
were found in L. maltaeus, with a maximum intraspecic mtDNA divergence of 0.6%,
while in L. emarginatus we found six haplotypes and a maximum intraspecic mtDNA
divergence of 1.1%. e minimum and maximum interspecic mtDNA divergence
found were, respectively, 2.9% and 3.8%.
Figure 3. Morphological dierences between L. maltaeus (red) and L. emarginatus (yellow) specimens
according to cephalic size (CS) and the linear discriminant D from Seifert (2020) (green dashed line: < 0
L. emarginatus, > 0 L. maltaeus). Circles represent the specimens measured in this study, while triangles
indicate the specimens from Seifert (2020). Sequenced specimens present an inner circle, which is black if
generated in this study or white if obtained from GenBank (i.e. from Schär et al. 2020). Note that indi-
vidual specimens may be misidentied by the discriminant scores, but not nest means of multiple workers
according to the data provided by Seifert (2020).
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
Quantitative morphology and mtDNA data agree and allow for the unambiguous
distinction of L. emarginatus from L. maltaeus. Our results demonstrate that the range
of the latter mostly resides in Sicily (where it shows the larger haplotype diversity),
making it a Siculo-Maltese endemic rather than a Maltese endemic species. e long
history of doubts over the identity of the Maltese populations, culminating with the
description of L. maltaeus (Schembri and Collingwood 1981,1995; Seifert 2020), per-
haps reects the great interest of naturalists for the biodiversity of smaller islands, while
the Sicilian populations were long overlooked. As a consequence of this discovery,
at least two species of the L. emarginatus complex inhabit Italy, while further inves-
tigation should check for the possible presence of L. illyricus (Schifani 2022). As a
result, L. balearicus Talavera, Espadaler & Vila, 2015 from Mallorca (Balearic Islands),
L. cypereus Seifert, 2020 from Cyprus, and L. kritikos Seifert, 2020 and L. tapinomoides
Salata & Borowiec, 2018 from Crete are the only Lasius species known to occur in a
single island (Talavera et al. 2015; Salata and Borowiec 2018; Seifert 2020).
e vicariance between L. emarginatus and L. maltaeus in the broader context of the
Siculo-Maltese archipelago and Italian peninsula follows a fascinating biogeographic
pattern that reects the complex paleogeographic history of the region. e region of
Trapani and Palermo Mountains in north-western Sicily, and the Hyblaean plateau in
south-eastern Sicily (recurrently linked to Malta by land bridges), represent the two
most ancient sectors of the island to have emerged from the sea perhaps even before
the upper Pliocene (Masini and Sarà 1998; Guarino and Pasta 2018). Both regions are
recognized as well-dened biogeographic provinces hosting a signicant number of
endemic fauna and ora (Brullo et al. 1995, 2011; Guarino and Pasta 2018; Schifani
Figure 4. Haplotype network of L. maltaeus and L. emarginatus mitochondrial COI sequences. Colour
and size of the circles indicate geographical origin and number of the samples, respectively.
Lasius maltaeus is not endemic to the Maltese Islands 137
et al. 2020; Schmitt et al. 2021). On the other hand, the Etna and Peloritani regions
of north-eastern Sicily, have a distinct geology and paleogeographic history and appear
biogeographically more similar to the Italian peninsula or other Mediterranean re-
gions: the Etna is fairly recent, emerging only about 570 thousand years ago, while the
Peloritani alongside Calabria rotated counterclockwise from the Sardinian-Corsican
microplate into their current position during the Alpine Orogeny (Stöck et al. 2008;
Sciandrello et al. 2015; Scalercio et al. 2020; Schmitt et al. 2021).
e fauna and ora of north-western and south-eastern Sicily are more inuenced
by colonization from the Africa’s Maghreb region compared to the north-east, which
hosts more species from continental Europe (Masini and Sarà 1998; Stöck et al. 2008;
Sciandrello et al. 2015; Alicata and Schifani 2019; Schifani et al. 2020, 2022a, b).
e case of the green toads Bufotes boulengeri siculus (Stöck et al., 2008) and Bufotes
viridis balearicus (Boettger, 1880) is particularly striking as the distribution of these
two subspecies (the rst of Maghrebian origin, the second one European) mirrors
those of L. maltaeus and L. emarginatus respectively (Stöck et al. 2008; Dufresnes et
al. 2019). Among other ants, the distribution of Aphaenogaster trinacriae Alicata &
Schifani, 2019 resembles that of L. maltaeus within Sicily, while Formica clara Forel,
1886 and Solenopsis orbula Emery, 1875 may be restricted to the north-east of the
island (Alicata and Schifani 2019; Schifani et al. 2021, 2022b). However, western
and southern Sicily may also have acted as a refugium for relict European lineages, as
recently shown among butteries (Scalercio et al. 2020). Based on the available mor-
phological and molecular data, it is possible that the sister species of L. maltaeus is the
European L. emarginatus, but phylogenetic evidence for a broader number of species
(e.g., including the Maghrebian L. tebessae) is needed to conrm this.
e ant faunas of Malta and Sicily share most species and the Siculo-Maltese archi-
pelago may be considered as a single bioregion (Wang et al. 2022). e observation that
the Maltese and Sicilian populations of L. maltaeus are not genetically dierentiated and
share two dierent COI haplotypes, suggest recent exchanges between the two (involving
multiple queens), which is congruent with the hypothesis that the species exploited land
bridges during the last glacial period. Beyond the case of L. maltaeus, our results question
the existence of Maltese endemic ants. While Lasius maltaeus becomes the fourth Siculo-
Maltese endemic species after Aphaenogaster orii Emery, 1915, Temnothorax lagrecai
(Baroni Urbani, 1964), and Temnothorax marae Alicata, Prebus & Schifani, 2022 (Ali-
cata and Schifani 2019; Schifani et al. 2022c), there are three remaining species which are
currently considered Maltese endemics: Aphaenogaster melitensis Santschi, 1933, Strongy-
lognathus insularis Baroni Urbani, 1968, and Temnothorax splendidiceps (Baroni Urbani,
1968) (Baroni Urbani 1968; Boer 2013). Each of them belongs to a taxonomically unre-
solved species group and their validity should be reassessed. In particular, the characters
allegedly distinguishing S. insularis from its southern Italian counterpart S. destefanii
Emery, 1915 were never quantied (Baroni Urbani 1968; Sanetra et al. 1999). A similar
situation occurs with T. splendidiceps and the Sicilian endemic T. laestrygon (Santschi,
1931), with the dierence that the species status of both is poorly supported because
no character has been described to distinguish them from T. exilis in its current concept
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
(Baroni Urbani 1968; Salata et al. 2018). Finally, concerning A. melitensis, some mor-
phological data are available, but the identity of the Sicilian morphotypes corresponding
to the old A. ionia concept requires further investigation (authors’ unpublished data) and
the whole group awaits a comprehensive revision (Schifani et al. 2022d).
Estimated speciation times for ants (and especially Formicinae, see Schär et al.
2018, 2020) are on average longer than in many other insect groups and the short
time of separation between Malta and Sicily suggests allopatric speciation of isolated
Maltese populations to be unlikely.
We wish thank Antonio Adorno, Simone Costa, Emanuele Genduso, Roberto Ri-
trovato, Norian Saliba and Roberto Viviano for the specimens provided, and Cecíl-
ia Corbella for help in the laboratory. We thank Sebastian Salata, iago Silva, one
anonymous reviewer and the editor Francisco Hita-Garcia for their comments on an
earlier version of this manuscript. Support for this research was provided by ‘La Caixa
Foundation (ID 100010434) to Mattia Menchetti (grant LCF/BQ/DR20/11790020).
Morphological data, specimen collection data and GenBank accession numbers are
available in the Suppl. material 1. Sequences are also available in the BOLD dataset
Alicata A, Schifani E (2019) ree endemic Aphaenogaster from the Siculo-Maltese archipelago
and the Italian Peninsula: part of a hitherto unrecognized species group from the Maghreb?
(Hymenoptera: Formicidae: Myrmicinae). Acta Entomologica Musei Nationalis Pragae
59(1): 1–16.
Baroni Urbani C (1968) Studi sulla mirmecofauna d’Italia. IV. La fauna mirmecologica delle
isole Maltesi ed il suo signicato ecologico e biogeograco. Annali del Museo Civico di
Storia Naturale “Giacomo Doria” 77: 408–559.
Blatrix R, Aubert C, Decaens T, Berquier C, Andrei-Ruiz MC, Galkowski C (2020) Contribution
of a DNA barcode to an assessment of the specicity of ant taxa (Hymenoptera: Formicidae)
on Corsica. European Journal of Entomology 117: 420–429.
Bolton B 2022 An online catalog of the ants of the world. [accessed
Borowiec L, Salata S (2013) Ants of Greece – additions and corrections (Hymenoptera:
Formicidae). Genus 24(3–4): 335–401.
Boudinot BE, Borowiec ML, Prebus MM (2022) Phylogeny, evolution, and classication of the
ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae).
Systematic Entomology 47(1): 113–151.
Lasius maltaeus is not endemic to the Maltese Islands 139
Brullo S, Minissale P, Spampinato G (1995) Considerazioni togeograche sulla ora della
Sicilia. Ecologia Mediterranea 21: 99–117.
deWaard JR, Ivanova NV, Hajibabaei M, Hebert PDN (2008) Assembling DNA barcodes. In:
Martin CC, Martin CC (Eds) Environmental Genomics. Methods in Molecular Biology,
vol 410. Humana Press, Totowa & New Jersey, 275–294.
Dufresnes C, Mazepa G, Jablonski D, Oliveira RC, Wenseleers T, Shabanov DA, Auer M, Ernst
R, Koch C, Ramírez-Chaves HE, Mulder KP, Simonov E, Tiutenko A, Kryvokhyza D,
Wennekes PL, Oleksandr IZ, Korshunov OV, Al-Johany AM, Peregonstev EA, Masroor
R, Betto-Colliard C, Denoël M, Borkin LJ, Skorinov DV, Pasynkova RA, Mazanaeva LF,
Rosanov JM, Dubey S, Litvinchuk S (2019) Fifteen shades of green: the evolution of
Bufotes toads revisited. Molecular Phylogenetics and Evolution 141: 106615. https://doi.
Fattorini S (2011) Biogeography of tenebrionid beetles (Coleoptera: Tenebrionidae) in
the circum-Sicilian islands (Italy, Sicily): Multiple biogeographical patterns require
multiple explanations. European Journal of Entomology 108(4): 659–672. https://doi.
Foglini F, Prampolini M, Micallef A, Angeletti L, Vandelli V, Deidun A, Soldati M, Taviani
M (2016) Late Quaternary coastal landscape morphology and evolution of the Maltese
Islands (Mediterranean Sea) reconstructed from high-resolution seaoor data. Geological
Society, London, Special Publications 411: 77–95.
Folmer O, Black M, Hoeh W, Lutz R, Vrijenhoek R (1994) DNA primers for amplication
of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates.
Molecular Marine Biology and Biotechnology 3: 294–299. https://pubmed.ncbi.nlm.nih.
Guarino R, Pasta S (2018) Sicily: the island that didn’t know to be an archipelago. Berichte Der
Reinhold-Tuxen-Gesellschaft 30: 133–148.
Hölldobler B, Wilson EO (1990) e ants. Harvard University Press, Oxford, USA, 746 pp.
Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A,
Markowitz S, Duran C, ierer T, Ashton B, Meintjes P, Drummond A (2012) Geneious
Basic: an integrated and extendable desktop software platform for the organization and
analysis of sequence data. Bioinformatics 28(12): 1647–1649.
Maruyama M, Steiner FM, Stauer C, Akino T, Crozier RH, Schlick-Steiner BC (2008) A DNA
and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for
the evolution of social parasitism and fungiculture. BMC evolutionary biology 8(1): 1–15.
Masini F, Sarà M (1998) Asoriculus burgioi sp. nov. (Soricidae, Mammalia) from the Monte
Pellegrino faunal complex (Sicily). Acta Zoologica Cracoviensis 41: 111–124. http://www.
Médail F (2022) Plant biogeography and vegetation patterns of the Mediterranean islands. e
Botanical Review 88: 1–67.
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
Salata S, Borowiec L (2018) A new species of the ant genus Lasius Fabricius, 1804 from
Crete (Hymenoptera, Formicidae). ZooKeys 789: 139–159.
Salata S, Borowiec L, Trichas A (2018) Taxonomic revision of the Cretan fauna of the genus
Temnothorax Mayr, 1861 (Hymenoptera: Formicidae), with notes on the endemism of ant
fauna of Crete. Annales Zoologici (Warsaw) 68(4): 769–808.
Sanetra M, Güsten R, Schulz A (1999) On the taxonomy and distribution of Italian
Tetramorium species and their social parasites (Hymenoptera Formicidae). Memorie della
Società Entomologica Italiana 77: 317–357.
Salvi D, Schembri PJ, Sciberras A, Harris DJ (2014) Evolutionary history of the Maltese wall
lizard Podarcis lfolensis: insights on the ‘Expansion–Contraction’ model of Pleistocene
biogeography. Molecular Ecology 23(5): 1167–1187.
Scalercio S, Cini A, Menchetti M, Vodă R, Bonelli S, Bordoni A, Casacci LP, Dincă V, Balletto
E, Vila R, Dapporto L (2020) How long is 3 km for a buttery? Ecological constraints and
functional traits explain high mitochondrial genetic diversity between Sicily and the Italian
Peninsula. Journal of Animal Ecology 89(9): 2013–2026.
Schär S, Talavera G, Espadaler X, Rana JD, Andersen Andersen A, Cover SP, Vila R (2018)
Do Holarctic ant species exist? Trans‐Beringian dispersal and homoplasy in the Formicidae.
Journal of Biogeography 45(8): 1917–1928.
Schär S, Menchetti M, Schifani E, Hinojosa JC, Platania L, Dapporto L, Vila R (2020)
Integrative biodiversity inventory of ants from a Sicilian archipelago reveals high diversity
on young volcanic islands (Hymenoptera: Formicidae). Organisms Diversity & Evolution
20(3): 405–416.
Schär S, Talavera G, Rana JD, Espadaler X, Cover SP, Shattuck SO, Vila R (2022) Integra-
tive taxonomy reveals cryptic diversity in North American Lasius ants, and an overlooked
introduced species. Scientic Reports 12(1): 1–12.
Schembri SP, Collingwood CA (1981) A revision of the Myrmecofauna of the Maltese Islands
(Hymenoptera, Formicidae). Annali del Museo Civico di Storia Naturale “Giacomo Doria
83: 417–442.
Schembri SP, Collingwood CA (1995) e myrmecofauna of the Maltese Islands. Remarks and
additions (Hymenoptera Formicidae). Bollettino della Società Entomologica Italiana 127:
Schifani E, Massa B (2020) First record of Lasius illyricus Zimmermann, 1935 (Hymenop-
tera, Formicidae) from Armenia. Far Eastern Entomologist 398: 24–28. https://doi.
Schifani E, Scupola A, Alicata A (2020) Morphology, ecology and biogeography of Myrmecina
sicula André, 1882, rediscovered after 140 years (Hymenoptera, Formicidae). Biogeographia
35: 105–116.
Schifani E (2022) e new Checklist of the Italian Fauna: Formicidae. Biogeographia 37:
Lasius maltaeus is not endemic to the Maltese Islands 141
Schifani E, Giannetti D, Csősz S, Castellucci F, Luchetti A, Castracani C, Spotti Fa, Mori
A, Grasso DA (2022a) Is mimicry a diversication-driver in ants? Biogeography,
ecology, ethology, genetics and morphology dene a second West-Palaearctic Colobopsis
species (Hymenoptera: Formicidae). Zoological Journal of the Linnean Society 194(4):
Schifani E, Alicata A, Menchetti M (2022b) Following the Apennines: updating the distribution
of Formica clara and F. rubarbis in Italy (Hymenoptera, Formicidae). Biogeographia 37:
Schifani E, Prebus MM, Alicata A (2022c) Integrating morphology with phylogenomics to
describe four island endemic Temnothorax species from Sicily and Malta (Hymenoptera,
Formicidae). European Journal of Taxonomy 833: 143–179.
Schifani E, Alicata A, Menchetti M, Borowiec L, Fisher BL, Karaman C, Kiran K, Oueslati W,
Salata S, Blatrix R (2022d) Revisiting the morphological species groups of West-Palearctic
Aphaenogaster ants (Hymenoptera: Formicidae) from a phylogenetic perspective: toward an
evolutionary classication. Arthropod Systematics & Phylogeny 80: 627–648. https://doi.
Schlick-Steiner BC, Steiner FM, Schödl S, Seifert B (2003) Lasius austriacus sp. n., a Central
European ant related to the invasive species Lasius neglectus. Sociobiology 41(3): 725–736.
Sciandrello S, Guarino R, Minissale P, Spampinato G (2015) e endemic vascular ora
of Peloritani Mountains (NE Sicily): Plant functional traits and phytogeographical
relationships in the most isolated and fragmentary micro-plate of the Alpine orogeny. Plant
Biosystems 149(5): 838–854.
Schmitt T, Fritz U, Delno M, Ulrich W, Habel JC (2021) Biogeography of Italy revisited:
genetic lineages conrm major phylogeographic patterns and a pre-Pleistocene origin of
its biota. Frontiers in Zoology 18(1): 1–13.
Seifert B (1991) Lasius platythorax n. sp., a widespread sibling species of Lasius niger
(Hymenoptera: Formicidae). Entomologia Generalis 16(1): 69–81. https://doi.
Seifert B (1992) A taxonomic revision of the Palaearctic members of the ant subgenus Lasius
s. str. (Hymenoptera, Formicidae). Abhandlungen und Berichte des naturkundemuseums
Görlitz 66: 1–67.
Seifert B (2018) e Ants of Central and North Europe. Lutra Verlags- und Vertriebsgesellschaft,
Tauer, Germany, 408 pp.
Seifert B (2020) A taxonomic revision of the Palaearctic members of the subgenus Lasius s.
str. (Hymenoptera, Formicidae). Soil Organisms 92(1): 15–86.
Seifert B, Galkowski C (2016) e Westpalaearctic Lasius paralienus complex (Hymenoptera:
Formicidae) contains three species. Zootaxa 4132(1): 44–58.
Stöck M, Sicilia A, Belore NM, Buckley D, Lo Brutto S, Lo Valvo M, Arculeo M (2008)
Post-Messinian evolutionary relationships across the Sicilian channel: mitochondrial and
Mattia Menchetti et al. / Journal of Hymenoptera Research 95: 129–142 (2023)
nuclear markers link a new green toad from Sicily to African relatives. BMC Evolutionary
Biology 8(1): 1–19.
Talavera G, Espadaler X, Vila R (2015) Discovered just before extinction? e rst endemic
ant from the Balearic Islands (Lasius balearicus sp. nov.) is endangered by climate change.
Journal of Biogeography 42(3): 589–601.
ake MA (1985) e biogeography of the Maltese islands, illustrated by the Clausiliidae.
Journal of Biogeography 12(3): 269–287.
Van Loon AJ, Boomsma JJ, Andrasfalvy A (1990) A new polygynous Lasius species
(Hymenoptera; Formicidae) from central Europe. Insectes Sociaux 37(4): 348–362.
Wang R, Kass JM, Galkowski C, Garcia F, Hamer MT, Radchenko A, Salata S, Schifani E,
Yusupov ZM, Economo EP, Guénard B (2022) Geographic and climatic constraints on
bioregionalization of European ants. Journal of Biogeography.
Wilson EO (1955) A monographic revision of the ant genus Lasius. Bulletin of the museum
of comparative Zoology at Harvard College 113: 1–201.
Supplementary material 1
e collecting data and voucher identiers of the specimens
Authors: Mattia Menchetti, Enrico Schifani, Antonio Alicata, Roger Vila
Data type: morphological data, specimen collection data, GenBank accession numbers
Explanation note: e Suppl. material presents the collecting data and voucher
identiers of the specimens we analysed as well as the morphological data and the
GenBank accession numbers of the sequences produced/analysed in this study.
Copyright notice: is dataset is made available under the Open Database License
( e Open Database License
(ODbL) is a license agreement intended to allow users to freely share, modify, and
use this Dataset while maintaining this same freedom for others, provided that the
original source and author(s) are credited.
ResearchGate has not been able to resolve any citations for this publication.
Full-text available
Abstract Aim Biogeographical regionalization is scant for most insect groups due to shortfalls in distribution and phylogenetic information, namely the Wallacean and Darwinian shortfalls respectively. Here, we focused on the European ants and compared new techniques to classical analyses based on regional lists and taxonomic methods. We asked the following: (1) Can grid-based regionalizations using novel distribution data improve biogeographical transitions? and (2) Can phylogenetic approaches reveal new insights regarding ant evolutionary history? Location Europe and Anatolia. Taxon Ants (Formicidae). Methods First, we developed a refined database integrating the occurrences of 747 ant species across 207 regions of Europe and Anatolia, based on newly expert-validated records derived from the existing Global Ant Biodiversity Informatics database. Using range estimates for these species derived from polygons and species distribution modelling, we produced species assemblages in 50 × 50 km grid cells. We calculated taxonomic and phylogenetic turnover of ant assemblages, then performed a hierarchical clustering procedure to delineate biogeographical structure. Results At both the regional list and grid assemblage levels, the Mediterranean has higher turnover and more biogeographical regions than northern Europe, both taxonomically and phylogenetically. Delineations based on grid assemblages detected more detailed biogeographical transitions, while those based on regional lists showed stronger insularity in biogeographical structure. The phylogenetic regionalization suggested a very similar spatial structure but varied affinities between assemblages in comparison to the taxonomic approach. Main Conclusions Here, we integrated expert-validated regional lists, species distribution modelling and a recent phylogeny to tackle Wallacean and Darwinian shortfalls for an important insect group by developing a next-generation map of biogeographical regionalization for European ants. The results of this study suggest strong constraints from geographical barriers and potential effects of climatic history on ant distributions and evolutionary history, and also provide baseline spatial information for future investigations of regional insect distributions.
Full-text available
The West-Palearctic region is a diversity hotspot for the ant genus Aphaenogaster. Species in this region are characterized by high morphological variation, which has led to their subdivision into different infrageneric groups. The very first classification in three subgenera, dated 1915, was gradually replaced by eight species-groups. To probe the evolutionary consistency of these species groups, we sequenced 46 species from all eight species-groups and biogeographic sectors of the region, using one mitochondrial (COI) and six nuclear markers (EPICs), and interpreted the results by integrating qualitative morphology. Our results demonstrate the non-monophyly of all formerly recognized subgenera and species-groups, except for the crocea group. We use the phylogeny and morphological characters to propose a new classification of six monophyletic species-groups (crocea, gibbosa, graeca, pallida, sardoa, subterranea). The pallida, subterranea and sardoa (formerly testaceopilosa) groups attain monophyletic status by reassigning a few taxa. The gibbosa group is to be considered exclusively Western-Mediterranean until further assessments of similar Eastern species. The new graeca group is established by including former members of the splendida and subterranea groups, while the polyphyletic cecconii, obsidiana, and splendida groups are dismissed. Notably, the first is not part of the tropical Deromyrma clade as previously thought, while at least two independent clades which require further investigation are composed of species from both the cecconii and splendida groups, suggesting repeated morphological convergences based on similar ecological adaptations. Finally, A. cardenai is confirmed to be a significantly divergent lineage. In addition, three Aphaenogaster species are moved to different genera: Messor asmaae (Sharaf, 2018) comb. nov., Messor isekram (Bernard, 1977) comb. nov., and Pheidole sarae (Sharaf, 2018) comb. nov. Further studies should address the evolutionary relationships between the clades recovered in this study.
Full-text available
Temnothorax (Myrmicinae, Crematogastrini) is one of the most diverse Holarctic ant genera, and new taxonomic advancements are still frequent worldwide. The Mediterranean region, a global biodiversity hotspot characterized by a complex geographic history, is home to a substantial portion of its described diversity. Sicily is the region’s largest island and, as ongoing investigations are revealing, it is inhabited by a long-overlooked but highly diverse ant fauna that combines multiple biogeographic influences. We combined qualitative and quantitative morphology of multiple castes with phylogenomic analysis based on ultra-conserved elements (UCEs) to describe four species of Temnothorax endemic to Sicily and the neighboring Maltese Islands (Sicilian Channel). Three of these species, T. marae Alicata, Schifani & Prebus sp. nov., T. poldii Alicata, Schifani & Prebus sp. nov. and T. vivianoi Schifani, Alicata & Prebus sp. nov., are new to science, while a redescription clarifies the identity of T. lagrecai (Baroni Urbani, 1964). These descriptions highlight the current difficulties of delimiting monophyletic Temnothorax species groups based on morphological characters. The intra-insular endemicity patterns we revealed highlight the importance of Mediterranean paleogeography to contemporary ant diversity and distribution in the region.
Full-text available
I present the updated version of the ‘Checklist of the Italian Fauna’ for what concerns ants (Insecta: Hymenoptera: Formicidae), which is part of the broader effort to produce an updated comprehensive checklist of the Italian fauna about 25 years after the first edition. The present list is the fourth Italian checklist of ants to be published since 1916, and refers to the state of art on November 2020. A simplified version of the data set is available as a supplementary file to this paper, while the full data set will be accessible in a regularly updated form from the LifeWatch Italy Data Portal ( Compared to the previous list by Poldi and others, published in 1995, the new one contains changes retrieved from 86 literature sources, including 17 published between 1921 and 1995 (which were missed in the previous checklist) and 69 published from 1996 to 2020. These references add 50 new species, including 9 new endemic species, as well as 68 nomenclatural changes and 88 distribution novelties at the regional level to the previous checklist. A total of 267 species and subspecies belonging to 7 ant subfamilies and 42 genera are part of the new list. The knowledge of the Italian ant fauna is rapidly improving on several fronts, and such dynamism is well-testified by the several novelties from 10 articles published after this dataset was compiled, to be included in the first future update of the on-line checklist. A further new list with extensive comments, detailed species distribution and biogeographic consideration will be desirable as soon as the situation stabilizes.
Full-text available
Biological invasions are a grave threat to ecosystems. The black garden ant (Lasiusniger) is a pest species in Europe. Current literature states that L. niger occupies a disjunct native distribution in the Holarctic, however, based on recent work, we re-evaluate this distribution. The native range of L. niger is reconsidered based on phylogenetic relationships (nine mitochondrial and nuclear markers, 5670 bp), DNA-barcoding (98 Holarctic specimens), morphometry (88 Holarctic specimens, 19 different measurements) and subjective assessment of phenotype. The potential spread of this species is estimated using ecological niche modeling. Lasius niger is more closely related to other Palearctic species than to the Nearctic ants known under this name. The latter are described as a distinct species, L. ponderosae sp. nov. However, DNA-barcoding discovered established populations of L. niger in metropolitan areas in Canada (Vancouver and Halifax). We describe a morphometrical method to delineate L. ponderosae sp. nov. and L. niger. MtDNA diversity and divergence is high within L. ponderosae sp. nov., but low within L. niger. More than 1,000,000 km2 are suitable as a habitat for L. niger in North America. This case emphasizes the critical role of integrative taxonomy to detect cryptic species and identify potential biological invasions in their nascent stages.
Full-text available
Formica clara is an ant species that was historically confused with other congeneric species such as F. rufibarbis until recent taxonomic developments. Due to such misunderstanding, while F. clara is known to occur across a very large Eurasian range, its actual distribution in the Mediterranean is often scarcely known. The distribution of F. clara and F. rufibarbis in Italy is remarkably obscure since almost all records, which spanned across the whole Italian peninsula and Sardinia, were published between 1834 and 1969, at times when the two species were treated as a single taxon. The few modern records of the species testify the presence of F. rufibarbis in the Alps, and F. clara in the Alps, the Po Plain and Sardinia. Here we present some new distributional data on the two species, extending the geographic range of F. rufibarbis south to the Northern Apennines (225 km) and that of F. clara throughout the Italian Peninsula south to Sicily (900 km). These results significantly change the previous understanding of F. rufibarbis as a widespread species while suggesting F. clara to be a common mountain species through the whole Apennines. Further investigations will be needed to verify whether F. rufibarbis occurs farther south.
Full-text available
Warm-adapted species survived the cold stages of the past glacial-interglacial cycles in southern European peninsulas and recolonized major parts of Central and Northern Europe in the wake of postglacial warming. However, many of the genetic lineages which differentiated within these refugia predate even the Pleistocene. One of these refugia is the Italian Peninsula with its surrounding islands. In this meta-analysis, we compiled phylogeographic patterns of multiple species across this region. We transformed existing geographic information on 78 animal and plant species (with a total of 471 genetic lineages) within 17 predefined areas into presence/ absence matrices. We elaborated three matrices: (i) only old lineages exclusively distinguished by deep splits, (ii) only young lineages distinguished by shallow (i.e. recent) splits, and (iii) presence/absence of the respective species. To infer biogeographic relationships between the predefined areas, we performed bootstrapped neighbour joining cluster analyses on these three matrices. In addition, we reviewed the geological history of Italy to identify causes of the observed biogeographic patterns. We found Sardinia and Corsica to be biogeographically closely linked with each other, and that they diverge strongly from all other regions. Sicily also diverges strongly from all other regions, while the intra-island differentiation was comparatively low. On the Italian mainland, Calabria exhibited the most pronounced biogeographic differentiation, often with several lineages present, resulting from old vicariance events within the region. Furthermore, southern Apulia and the Po Plain with adjoining areas of northern peninsular Italy displayed considerable distinctiveness. Admixture prevailed in the areas between these three regions. The ancient isolation of Sicily, as well as Sardinia plus Corsica, resulted in endemic lineages with only moderate recent exchange with adjacent mainland regions. Pronounced diversification occurs within the Italian Peninsula. The complex tectonic activities, such as shifting (micro)plates, submergence of major parts of peninsular Italy with the genesis of numerous Pliocene islands, in combination with the climatic cycles during the Pleistocene have most likely generated the current biogeographic pattern of species. Immigrations from the Balkan Peninsula into northern Italy partly accounted for the distinctiveness of this region.
Within the Formicidae, the higher classification of nearly all subfamilies has been recently revised given the findings of molecular phylogenetics. Here, we integrate morphology and molecular data to holistically address the evolution, classification, and identification of the ant genus Lasius, its tribe Lasiini, and their subfamily Formicinae. We find that the crown Lasiini originated around the end of the Cretaceous on the Eurasian continent and is divisible into four morphologically distinct clades: Cladomyrma, the Lasius genus group, the Prenolepis genus group, and a previously undetected lineage we name Metalasius gen.nov., with one extant species M. myrmidon comb. nov. and one fossil species, †M. pumilus comb. nov. The crown of the Lasius genus group is considerably younger than that of the Prenolepis genus group, indicating that extinction has played a major role in the evolution of the former clade. Lasius itself is divided into two well-supported monophyletic groups, which are approximately equally speciose. We present evidence that temporary social parasitism and fungiculture arose twice independently in Lasius. In addition, we recover the paraphyly of three Lasius subgenera and propose replacing all subgenera with an informal species group classification: Lasius = Acanthomyops syn.rev., = Austrolasius syn.nov., = Cautolasius syn.nov., = Chthonolasius syn.nov., = Dendrolasius syn.nov. Total-evidence analysis reveals that the Baltic-region amber fossil species †Lasius pumilus and †Pseudolasius boreus are misplaced to genus; we, therefore, create Sussuido gen. nov. to accomodate †S. boreus comb. nov. and transfer †L. pumilus to Metalasius. Further, we transfer †Sussudio and †Glaphyromyrmex out of the Lasiini, considering the former to be incertae sedis in the subfamily, and the latter a member of the Formicini (tribal transfer). Two final taxonomic actions are deemed necessary: synonymy of Lasius escamole with Liometopum apiculatum syn.nov. (subfamilial transfer), and transfer of Paratrechina kohli to Anoplolepis (tribal transfer, forming A. kohli comb.nov.). ZooBank Article LSID:‐33C3‐43B2‐ADAD‐6807DC5CB6D8 Author ZooBank LSIDs: Borowiec:‐605B‐4C4B‐ABDB‐D4D96075CE48. Boudinot:‐60BA‐4379‐964D‐A56EB582E16D. Prebus:‐795E‐455C‐B66F‐7F6C32F76584
The West-Palaearctic Colobopsis ant populations have long been considered a single species (Colobopsis truncata). We studied the diversity of this species by employing a multidisciplinary approach and combining data from our surveys, museum and private collections, and citizen science platforms. As a result, we have revealed the existence of a second species, which we describe as Colobopsis imitans sp. nov., distributed allopatrically from Co. truncata and living in the Maghreb, Sicily and southern Iberia. While the pigmentation of Co. truncata is reminiscent of Dolichoderus quadripunctatus, that of Co. imitans is similar to Crematogaster scutellaris, with which Co. imitans lives in close spatial association, and whose foraging trails it habitually follows, similar to Camponotus lateralis and other ant-mimicking ants. The isolation between Co. imitans and Co. truncata seems to have occurred relatively recently because of significant, yet not extreme, morphometric differentiation, and to mtDNA polyphyly. Both Co. imitans and Co. truncata appear to employ mimicry of an unpalatable or aggressive ant species as an important defensive strategy; this ‘choice’ of a different model species is motivated by biogeographic reasons and appears to act as a critical evolutionary driver of their diversification.
With about 11,100 islands and islets of which ca. 250 are regularly inhabited by human, the Mediterranean Sea represents one of the regions of the world with the most islands and archipelagos. These numerous islands represent a significant component of the Mediterranean biodiversity, notably with the presence of range-restricted species and peculiar vegetation types. The aim of this review is to provide a balanced view of this highly diverse phytoecological heritage, but also taking into account the medium sized islands and the smaller ones that have not been highlighted so far. Mediterranean islands constitute both a museum for ancient lineages (paleoendemic taxa) and cradle for recent plant diversification. The complex historical biogeography (paleogeographical events of the Neogene, Messinian salinity crisis, climatic and eustatic changes of the Pleistocene, influence of glacial events) has profoundly influenced the current patterns of plant diversity. These insular landscapes were also precociously impacted by prehistoric man, possibly by Neanderthals. Among the 157 large Mediterranean islands (i.e. with a surface area exceeding 10 km2), 49 have a surface greater than 100 km2. The main patterns and dynamics of vegetation on the largests islands (Balearic Islands, Corsica, Sardinia, Sicily, Croatian islands, Greek islands, Crete, Cyprus) are summarized. Then, the specific ecosystem functioning (disturbance, plant-animal interactions) and vegetation structures of the small Mediterranean islands (i.e. a surface area less than 10 km2 or 1000 ha), are highlighted by evoking successively the small rocky islands, the volcanic ones, and the sandy and flat islands. Owing to their uniqueness and fragility, Mediterranean islands urgently need some integrated and ambitious conservation planning, aiming at the long-term preservation of their outstanding biotic and cultural heritage.