Muscle attachment site patterns for species determination in West Palaearctic Wohlfahrtia (Diptera: Sarcophagidae) of medical and veterinary importance

Abstract

The flesh fly genus Wohlfahrtia Brauer & Bergenstamm contains at least six species of medical and veterinary importance. Traditional methods of species identification in specimens of Wohlfahrtia, however, are restricted mostly to adult forms. Muscle attachment site (MAS) patterns allow for species determination in larval forms. MAS patterns in third instar larvae of six common West Palearctic species of Wohlfahrtia have been analyzed for this study. As in previously investigated Calliphoridae and Sarcophagidae, MAS patterns were found to be species specific. A genus pattern was established to be used as base for comparison in further species determination. For the first time a tool is provided for species identification of such broad range in larvae of Wohlfahrtia species. Wohlfahrtia patterns are composed of a significantly higher number of MAS than patterns found in Sarcophaga. Specifics of the six species analyzed are explained in detail. The larvae of the well-known species W. magnifica, an obligate traumatic myiasis agent, had to be excluded from the analysis as a great number of spines on the outside obscure muscle attachment sites on the inside of the cuticle.

Figure 1

Habitus of Wohlfahrtia larvae studied: (A) - W. magnifica, (B) - W. bella, (C) - W. indigens, (D) - W. nuba, (E) - W. trina, (F) - W. villeneuvi.

Figure 2

Segments 2–5 of Wohlfahrtia third instar larvae, cuticula only, dyed with Coomassie-brillant blue solution 1%: (A) - W. trina, MAS pattern clearly visible, (B) – W. magnifica, MAS pattern obscured by sclerotized spines, t = thoracic segment, a = abdominal segment and numbers for plain designation.

Figure 3

Genus pattern for Wohlfahrtia composed of 56 individual MAS patterns of W. bella, W. indigens, W. nuba, W. trina, W. villeneuvi. Rows are labeled according to their location on and affiliation with a segment (e.g. 2.1 = central row in segment 2, 4.5 = most peripheral row in segment 4), dashed line = step-like appearance of pattern.

Figure 4

Condensed MAS pattern for Wohlfarthia bella (solid structures) superimposed with outlines of the genus pattern (dotted lines). Numbers indicate rows of transversal muscle attachment site patterns according to their location on and affiliation with a segment. Arrows indicate important differences compared to genus pattern.

Figure 5

Condensed MAS pattern for Wohlfarthia indigens (solid structures) superimposed with outlines of the genus pattern (dotted lines). Numbers indicate rows of transversal muscle attachment site patterns according to their location on and affiliation with a segment. Arrows indicate important differences compared to genus pattern.

Figure 6

Condensed MAS pattern for Wohlfarthia nuba (solid structures) superimposed with outlines of the genus pattern (dotted lines). Numbers indicate rows of transversal muscle attachment site patterns according to their location on and affiliation with a segment. Arrows indicate important differences compared to genus pattern.

Figure 7

Condensed MAS pattern for Wohlfarthia trina (solid structures) superimposed with outlines of the genus pattern (dotted lines). Numbers indicate rows of transversal muscle attachment site patterns according to their location on and affiliation with a segment. Arrows indicate important differences compared to genus pattern.

Figure 8

Condensed MAS pattern for Wohlfarthia villeneuvi (solid structures) superimposed with outlines of the genus pattern (dotted lines). Numbers indicate rows of transversal muscle attachment site patterns according to their location on and affiliation with a segment. Arrows indicate important differences compared to genus pattern.

Figure 9

Genus pattern of Wohlfarthia (solid structures) superimposed with outlines of the genus pattern of Sarcophaga (dotted lines). Numbers indicate rows of transversal muscle attachment site patterns according to their location on and affiliation with a segment.