Metric differences between silvatic and domestic Triatoma infestans (Heteroptera: Reduviidae) in Bolivia.

One hundred and fifty-seven specimens of Bolivian Triatoma infestans (Klug 1834), including 44 from the silvatic focus at Cochabamba (Bolivia), were compared using morphometric characters of the head capsule. From these specimens, 10 silvatic and 28 domestic adults were also compared using additional morphometric characters of the membranous part of the hemelytra. Nonparametric univariate comparisons between specimens from silvatic and domestic ecotopes indicated the importance of the postocular region as a possible diagnostic character for nymphs and adults from the different ecotopes, and they detected wing differences in males. Populations became more distinct entities when head or wing characters were considered jointly in canonical variate analysis. Regardless of whether size variation was considered, canonical variate analysis generally showed greater significance for wing than for head features. These morphological differences between silvatic and domestic bugs, particularly unrelated to size differences, are interpreted to indicate incipient separation between silvatic and domestic populations that had not been detected by previous isoenzyme analyses, and suggest a reinterpretation of the epidemiological significance of silvatic populations of T. infestans in Bolivia.