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Abstract:
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Mepraia is an endemic genus found in the semiarid and arid regions of north-central Chile. Until 1998,
Mepraia spinolai was the only species of the genus, distributed in coastal and interior valleys from Chile
between 188 and 348S. However, on the basis of karyotype and morphological characters, coastal desert
populations between 188 and 268S were ranked as a new species, Mepraia gajardoi. Recently, genetic
studies using nuclear and mitochondrial markers on Mepraia populations suggest that the geographical
criterion to separate the two species should be reviewed. Mepraia species show conspicuous alary
polymorphism, unique in the Triatominae subfamily. Females of both species are invariably
micropterous, while males of M. spinolai can be micropterous, brachypterous or macropterous, and
only brachypterous in M. gajardoi. In this study, we use geometric morphometrics analyses to compare
male wings of M. spinolai and M. gajardoi from natural populations, in order to examine if these two
species have diverged in alary shape. As expected, we found that brachypterous wings of both species are
smaller than macropterous wings of M. spinolai. Additionally, we detected clear differences in shape on
wings of M. gajardoi and M. spinolai, not attributable to allometric effects. For last, a new alary phenotype,
insects with vestigial wings, was described here for the first time. In conclusion, our analyses on wings of
Mepraia species separate two distinct groups consistent with the two described species. However, our
findings of vestigial wings in some coastal areas of the north part of Chile cannot rule out the existence of
a hybrid zone. |