Metric Differences Between Silvatic and Domestic Triatoma infestans (Heteroptera: Reduviidae) in Bolivia

Abstract

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.

Variación del fenotipo antenal de poblaciones del domicilio, peridomicilio y silvestres de Triatoma dimidiata (Hemiptera: Reduviidae) en Santander, Colombia

“…Las diferencias del fenotipo antenal observado en hembras revelan una mayor plasticidad fenotípica en la diferenciación y adaptación a diferentes hábitats, como también se observó en estudios de morfometría de la cabeza de T. dimidiata y T. infestans (40,41). La rápida adaptación de las hembras a las nuevas condiciones ecológicas pone de manifiesto nuevos arreglos sensoriales característicos de ese hábitat; por otra parte, la ausencia de diferenciación en el fenotipo antenal de machos podría ser un indicador de mayor dispersión entre hábitats.…”

Morphometric changes of Triatoma flavida Neiva, 1911 (Hemiptera:Triatominae) in the transition from sylvatic to laboratory conditions

“…For instance, natural selection may favor larger phenotypes in less favorable (more unstable or "sylvatic") habitats, possibly due to a greater capacity to resist temporary food shortages, whereas smaller individuals apparently survive better under laboratory or domestic conditions where food availability is less restricted 4,11 . 6 also suggested that the size reduction could reveal the effect of population density on bug size: in laboratory colonies each individual would get less blood because of competition, smaller individuals would survive and the average size decrease.…”

“…These changes generally involved genetic drift effects 3 together with a reduction in average size and modification of sexual size dimorphism 4,6,7 . Although these observations are found in various genera (Rhodnius, Triatoma and Panstrongylus), more species have to be analyzed before accepting them as generalities for Triatominae.…”

“…Sexual dimorphism was not present at all for laboratory wings (Table 4, left part). 1,4,5,6,7,14 . It was thus also verified here for T. flavida with a significant decrease in almost all the characters measured in head, thorax and wings.…”

Evaluación de la estructura espacial de Triatoma maculata del centro-occidente de Venezuela y su viabilidad alimentado con sangre humana en condiciones de laboratorio

“…En triatominos se ha propuesto el uso de marcadores como el tamaño de las alas y las cabezas para discriminar entre poblaciones silvestres y de ambientes domiciliarios (8,(11)(12)(13)(14)(15)(16). La detección de la reducción del tamaño y del dimorfismo sexual podrían constituir marcadores de adaptación de estos insectos al domicilio (13).…”