Phthitia (Collimosina) spinosa (Collin, 1930)

Roháček, Jindřich, 2012, Wing polymorphism in European species of Sphaeroceridae (Diptera), Acta Entomologica Musei Nationalis Pragae 52 (2), pp. 535-558 : 539

2. Phthitia (Collimosina) spinosa (Collin, 1930)

( Figs. 12–14 )

Material examined. Almost 80 specimens (34 JJ 45 ♀♀, with 15 JJ 18 ♀♀ slightly brachypterous, rest macropterous) from Great Britain ( England), Czech Republic, Finland and Russia (North European Territory) – localities listed by ROHÁČEK (1983, 1996a), ROHÁČEK & BARTÁK (2001) and ROHÁČEK et al. (2005).

This species forms a fine example of a very initial stage of the development of wing polymorphism. The slightly brachypterous specimens were found in only two populations where they hardly predominated over fully winged ones. The wings of brachypterous specimens do not reach beyond the tip of the abdomen and their venation is usually only slightly modified ( Fig. 14 ), having a shortened 2 nd costal sector and discal (dm) cell which represents the 2 nd stage of reduction of the venation. However, also a vein mutant with lost terminal part of R 2+3 was found ( Fig. 13 ). This uncommon species is apparently associated with mosses in boggy and peat-bog meadows (ROHÁČEK 1983).

Figures

Figs. 12–14. Phthitia (Collimosina) spinosa (Collin, 1930), female wings. 12 – macropterous (Czech Republic: Řásná nr. Telč); 13 – slightly brachypterous, with apical part of R2+3 lost; 14 – distinctly brachypterous (both Czech Republic: Úvalenské louky res. nr. Krnov). Scale: 0.5 mm. Photo by J. Roháček.