Population morphometric analysis of the tropicopolitan bug Triatoma rubrofasciata and relationships with Old World species of Triatoma: evidence of New World ancestry

Abstract

Quantitative analysis of morphological characters of the head was used to reconstruct the evolutionary history of the tropicopolitan bug Triatoma rubrofasciata (De Geer) (Hemiptera: Reduviidae) and seven species of Old World Triatoma. Multivariate analysis demonstrates that T. rubrofasciata and the Old World species have a high degree of similarity with Nearctic Triatoma species, particularly T. rubida (Uhler). We interpret this to imply a common ancestry for these groups. Dissemination of T. rubrofasciata and subsequent derivation of the Old World species of Triatoma is deduced to have occurred over a period of not more than 350 years.

Triatominae (Hemiptera: Reduviidae): Systematic questions and some others

“…Or, might some Old World Triatoma species have arisen from some other species, whether another Triatoma or an unrelated reduviid? Patterson et al (2001) suggest the intriguing possibility that another Triatoma species, T. lectularia Stål, also invaded the Old World.…”

“…Nevertheless, attempts are being made to work out phylogenies from morphometric data (Sorensen & Foottit 1992b), and these attempts have been applied (Roskam & Zandee 1992, Wood & Pesek 1992, Patterson et al 2001. However, as Roskam & Zandee write, "because phylogenetic arguments emerge from a more sound theoretical base than phenetics, we feel they should play the prevailing role in determining past evolutionary scenarios" (1992, p. 345).…”

“…More than one invasion may also explain why some places in the Old World have populations of the species, and other places have species descended from it (see 2a, above). Old World T. rubrofasciata populations often occur near ports (Gorla et al 1997, Patterson et al 2001and see Cariaso 1968). Do Old World Triatoma species also occur near ports?…”

“…What are the relationships inter se of the derivatives of the tropicopolitan T. rubrofasciata? 2a) If, as seems likely (Patterson et al 2001), the several Old World species of Triatoma are each derived from a different population of T. rubrofasciata, and if these speciations all occurred within the past 200 (Schofield 2000) or 350 years (Patterson et al 2001), why have not other populations of T. rubrofasciata also speciated? That is, selection pressures on some populations of T. rubrofasciata must have been far greater than pressures on other populations, so that the former have become sufficiently distinct as to be accorded species status.…”

Trypanosoma cruzi -- the vector-parasite paradox

“…Similarly, comparison of domestic T. infestans from Uruguay, with their original silvatic populations in Bolivia, again shows clear morphometric and genetic differentiation over a time scale that appears to be little more than 100 years (Dujardin et al 1998a,b). A further well-studied example is that of T. rubrofasciata, exported from a New World origin on sailing ships to port areas throughout the tropics, but speciating in eastern Asia -to give seven species defined by morphological characteristics -over a period that cannot have been much more than about 200 years (Gorla et al 1997, Patterson 1999. Even in the space of a few generations in laboratory colony, morphological changes leading to apparent differentiation can be demonstrated (eg.…”