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A contribution to the history of Bacillus in Sicily

Tinti, 1991) (see Table l and Figure 3 for a generai scheme of reproduction modes in the
genus Bacillus).
This is the first practical confinnation of the evolutionistic theory put forward by some
authors on hybridogenetic organisms. For this reason, this representative of Iblean fauna
takes on enormous importance, as it testifies to the genuine possibility that an amphigonic
organism, evolved to the hybridogenetic stage, might select parthenogenesis as a further
adaptation. This is also important because, for the first time, hybridogenesis is being
considered as a vital genetic-evolutionistic adaptation. This could bave highly interesting
reverberations for other animai classes and call for renewed discussion of the very idea of
"species" (Veroli, 1995).
B. lynceorum, the longest species in the genus, is the triploid rossius-atticus-grandii,
probably a cross between B. grandii grandii and a diploid Fl hybrid B. atticus x B. rossius
redtenbacheri which (unusually) produced fertile eggs (Brock, 1991: 20; Manaresi et al.,
1992).
In the 1980s, together with the discovery of new Sicilian taxa, some further locations
in Italy for Bacillus atticus Brunner von Wattenwyl, 1882 were discovered, which was
previously only recorded from Attic, Epirus and Peloponnese (in Greece) according to
Nascetti and Bullini (1982), La Greca (1984, 1996a), Agostini and Scali (1989) and on the
Dalmatian coasts (Muller, 1957). During the Pleistocene era (La Greca, 1996a), this taxon
arrived in the Iblean region by crossing what is now Apulia and Calabria and spread
throughout the whole of Sicily. In fact, the micro-plate of African origin that formed the
Iblean region, during the Pliocene era, was again separated from the north of Sicily (see
Figure 4). B. atticus on the Italian coasts displays a genetic differentiation from its
counterpart in Greece and in the Dalmatian area. In 1982, the researchers Nascetti and
Bullini named the Italian population as new sub-species B. atticus caprai. Strangely, this
subspecies is not cited in Failla et al. (1994).

l
Species Mode of reproduction
Bacillus rossius amphigony (*), parthenogenesis (**)
Bacillus atticus parthenogenesis

Bacillus grandii (***) amphigony

Bacillus whitei parthenogenesis, hybridogenesis, gynogenesis androgenesis
Bacillus lynceorum parthenogenesis
Bacillus rossius-grandii grandii hybridogenesis, androgenesis

Bacillus rossius-grandii benazzii hybridogenesis, androgenesis, gynogenesis

Table l. Reproduction modes in the Italian representatives of the genus Bacillus.
(*) Centrai and southem Italy; (**) Centrai and northem Italy; (***) Ali three
subspecies of the taxon.

Of additional interest were the fmdings of specimens of the natural hybrid Bacillus
atticus-rossius, along the coast near Alimini, in Apulia. However, these insects are
completely sterile. Again, with respect to the Sicilian phasmids, it is doubtful whether the two
inter-species hybrids B. rossius-grandii grandii of the Iblean region and B. rossius-grandii

Phasmid Studies, 6(1): 5