Analysis of the geographical variation of elytral color polymorphisms in three species of soldier beetles, Chauliognathus Hentz (Cantharidae) in southern Brazil

Abstract

In the present report, we investigate polymorphism in three of the Brazilian species of Chauliognathus Hentz, 1930 (Coleoptera, Cantharidae), by analyzing the geographical color pattern variation of the elytra in C. flavipes, C. fallax and C. octomaculatus. These species belong to the mullerian complex called the "yellow-black". They are usually found in clusters on their host plants at various locations and present similarities in the external body morphology and in the color pattern of the elytra and the pronotum. Chauliognathus flavipes is the most common species with eight phenotypic classes followed by of C. fallax and C. octomaculatus with six and two phenotypic classes respectively. The analyses indicate a statistically significant difference in the frequencies of colour patterns of the three species over the entire area sampled. In general, the significant differences were observed between the regions of the State of Rio Grande do Sul (p < 0.05) but were not found within the individual regions except in the case of the Metropolitan region. That region and its three microregions demonstrated a positive co-relationship between an increase in altitude and the occurrence of diversity in C. flavipes and C. fallax (r = 0.860, p < 0.01; r = 0.974, p < 0.01, respectively).