Taxonomy and phylogeny of the Central European bug genus "Psallus" (Hemiptera, Miridae) and faunistics of the terrestrial Heteroptera of Basel and surroundings (Hemiptera)

True bugs or Heteroptera are a biologically diverse, species-rich group containing some
37,000 species described worldwide (Schaefer & Panizzi, 2000). It is the largest taxon of
endopterygotan insects and constitutes a well-supported monophylum within the order
Hemiptera. Species are usually trophically specialised; they are phytophagous, zoophagous or
mycophagous (Schuh & Slater, 1995). For their often specialised feeding habits, many species
are economically important as crop pests, biological control agents of phytophagous insect
pests (Schaefer & Panizzi, 2000) or as vectors of human diseases (Schofield & Dolling, 1993;
Schaefer, 2000; Garcia et al., 2000). The last one is, however, without significance in Central
Europe. Some bugs constitute an important protein source in human diet (Fritsche Gitsaga,
2000).
Within the Heteroptera the plant bugs or Miridae constitute the largest family with more
than 10,000 described species (Schuh, 1995). It is expected that the family may contain twice
as many species (Wheeler, 2001). Even though the mirids contain many economically
important species, its taxonomy and systematics contains many unsolved problems. This is a
result of the large number of included taxa and the uniformity of external morphology of
many genera. Current problems exist at species level where some taxa are ill-defined or where
many species can be identified only by male genitalic characters, and at genus level where
phylogenetic considerations are missing for many taxa.
The first list of Swiss Heteroptera containing 50 species is part of Füessly’s (1775)
catalogue of insects from Switzerland. Several additional records were inlcuded in general
works of 18th and 19th century entomologists (Sulzer, 1771, 1776; Razoumowsky, 1789;
Roemer, 1789; Schellenberg, 1800; Meyer-Dür, 1843). The only catalogue dealing with Swiss
bugs was provided by Frey-Gessner (1864a, b, 1865, 1866a, b, 1871a). Basel and the
surrounding region have, compared to the rest of Switzerland, a distinct fauna and flora due to
the geografical position and the relatively dry climate. The region is open to the Rhône valley
via the "Burgunderpforte" from where mediterranean floristic and faunistic elements may
immigrate. The first part of the present thesis deals with the ill-defined mirid genus Psallus
(Phylinae, Phylini). One aim was to test the monophyly of Psallus and to propose, based on
the study of the Central European species, a classification applicable to the world fauna. The
second goal was to investigate the female genitalia in view of taxonomic and phylogenetic
significance. Female genitalia are so far rarely used for species definition within mirids
(exeptions e. g. Calocoris, Rosenzweig, 1997) in contrast to other families (e. g. Nabidae,
Péricart, 1987). As for Psallus the few species of which the female genitalia have been
described so far (Kullenberg, 1947; Seidenstücker, 1972; Matocq, 1989, 1997) suggest this
may be an useful set of characters. A third aim of the present study was to provide keys for
the identification of the Central European species based exclusively on male and female
genitalic characters.
The second part of the present study deals with the terrestrial bug fauna of the region of
Basel. Currently most of our knowledge goes back to Frey-Gessner's catalogue (1864a, b,
1865, 1866a, b, 1871) – obsolete for a long time. A few scattered papers have been published
since (e. g. Voellmy & Egli, 1981; Meduna et al., 2001) but a thorough inventory lacks to
date. In Switzerland, in general, faunistic surveys on true bugs are scarce in contrast to other
European countries. The relatively few papers recently published on Swiss Heteroptera are
based, to a large extent, on material from traps run for ecological investigations (e. g. Otto,
1996; Di Giulio et al., 2000).
The combination of systematic revisions and faunistic investigations is necessary if we
want to know and conserve our fauna. Turnball (1979) brought this to the point: “How can we
detect change in the future if we cannot define the fauna we now have?”