Manual for Diagnosis of Screw-worm Fly - xcs consulting

A Manual for the Diagnosis of Screw-Worm Fly
7.2 Geographical races of Chrysomya bezziana
Collections of the Old World screw-worm fly, Chrysomya bezziana, from different parts of its
geographical range have shown morphological differences between populations from southeast
Asia, Arabia and Africa (D.H. Colless, personal communication) (Figs 30, 31).
Figure 30: Wings of Chrysomya bezziana
from different geographical regions.
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• body colour is mainly blue/black in SE
Asia specimens; blue/green in Arabian and
green/blue in African with the black
abdominal bands more obscure in SE Asian
and more obvious in African flies.
• wing base (A) of SE Asian flies is slightly
blackened with cell R clear, almost
completely clear in Arabian but strongly
blackened, especially cell R, in African flies.
• soft hairs of the thorax (pleura) (B) are
predominantly black in SE Asian, pale in
Arabian and mixed in African flies.
• lower (posterior) squamae (C) of SE
Asian flies darker waxy white and covered
in long black hairs; African and Arabian flies
with more brilliantly white lower squamae
and long white hairs.
• frontal setulae (bristles) (D) in SE Asian
flies black; pale except for dorsal patch in
Arabian flies and lower 2/3 mixed black and
pale (gingery) in African flies.
• setulae around vibrissa (E) in SE Asian
flies, a few black below vibrissae in Arabian
flies and all pale in African flies.
• genal groove below compound eye (F)
heavily indented in SE Asian flies, less so in
Arabian and only slight indentation in
African flies.