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Boll. Soc. Entomol. 136/3 29-11-2004 17:56 Pagina 239

Mutillid wasps of the Italian minor islands 239

Stenomutilla (Stenomutilla) argentata (Villers, 1789)
Stenomutilla argentata var. bifasciata (Klug, 1829); Zavattari, 1912: 3 (San Pietro).

EXAMINED MATERIAL. Sant’Antioco: 1 , 12.VII.1999, L. Fancello (MR). San Pietro: 1 ,
qØ

Carloforte, 5.XI.2002, L. Fancello (MR); 2 , X.1997 (without indication of the collector)
qq

(MR).

Stenomutilla (Stenomutilla) hottentotta (Fabricius, 1804)
Stenomutilla argentata bifasciata (Klug, 1829); Matteini Palmerini, 1992: 197 (Levanzo).

EXAMINED MATERIAL. Favignana: 1 , 31.V.1986, R. Arnone (MR); 1 , 2.V.1991, R. Poggi
qq

(MSNG). Marettimo: 1 , 15.IV.1974, M. Romano (MR). Levanzo: 1 , 1.V.1979, B. Massa
qq

(MR).

FAUNAL AND ZOOGEOGRAPHICAL REMARKS

Thirty-eight taxa of Mutillid wasps, equal to 52% of the whole Italian fauna, are
recorded for the islands taken into consideration. This seems to be a rather high per-
centage, considering the relatively small surface of these insular areas. Even if it is likely
that further investigations will add more taxa to the present list, increasing the faunal
knowledge of the islands so far not exhaustively studied, the available data testify the
outstanding zoogeographical interest of the Italian minor islands. Ronisia barbara, Smi-
cromyrme lampedusia, Dasylabris atrata and D. juxtarenaria occur in Italy only on
Lampedusa and on other islands of the Sicily Channel. Smicromyrme suberrata is record-
ed in Italy only from Lampedusa and a continental locality in Calabria, even if its apparent
absence in Sicily and/or in Southern Italy could depend on research faults. Furthermore,
77.7% of the Italian endemic taxa (see Invrea, 1964; Pagliano, 1995; Lelej, 2002) oc-
cur on minor islands, mainly on the circumsardinian ones.

Faunal and geographical data concerning thirty-one islands on which Mutillid wasps
occur are given in Table 1. The relationships between number of species and various
geographical parameters were tested for ten islands considered adequately explored (Asi-
nara, Giglio, Isola dei Conigli, Lampedusa, Levanzo, Lipari, Maddalena, Pianosa,
Sant’Antioco and San Pietro). The results showed the existence of a highly significant
correlation between log species and log area (r = 0.929, P < 0.0001). Species richness
seems to be related to island size, as it happens in other invertebrate groups living on
Italian minor islands (cf. Minelli, 1984; Balletto, 1996). Besides area there are many
more variables which could affect the species richness of an island (Hamilton et al., 1964;
Hamilton & Rubinoff, 1967; Abbot, 1974; Williamson, 1981). For other insect groups
in the Mediterranean islands, the most important of these proved to be the distance of
the island from the continental area and its maximum altitude (Baroni Urbani, 1971;
1973; Hockin, 1980). Concerning the insular assemblages of Mutillid wasps, however,
no significant correlations emerged between number of species and maximum altitude
(r = 0.738, P = 0.01), or distance from the main coast (r = 0.485, P = 0.15).

In order to evaluate the similarities of the faunas under consideration, a compar-
ison between pairs of islands (or islands and continental areas) was performed using