Reproductive isolation revealed in preliminary crossbreeding experiments using field collected Triatoma dimidiata (Hemiptera: Reduviidae) from three ITS-2 defined groups

Abstract

Triatoma dimidiata, a Chagas disease vector distributed in Mexico, Central America, Colombia, Venezuela, Peru and Ecuador, has been studied using genetic markers and four groups have been defined by ITS–2 sequences: 1A, 1B, 2 and 3. To gather evidence on the divergence and reproductive isolation among T. dimidiata ITS–2 groups, we carried out 15 crossbreeding experiments with field–collected sylvan and domestic T. dimidiata from Guatemala where three groups are found: 1A, 2 and 3. Reciprocal crosses between individuals from groups 1A and 2, and a cross between group 2 individuals from different habitats, produced an average 129.78±42.29 eggs with hatching success ranging from 31.6% to 90.1%. The offspring of these crosses reached the adult stage, and crosses between F1 insects produced eggs. These results suggest that there are no pre– or post– zygotic reproductive barriers between groups 1A and 2, or within group 2. Crosses between group 3 females and males from groups 1A or 2 produced on average 85.67±30.26 eggs and none of them hatched. These results support the existence of pre– zygotic barriers between T. dimidiata group 3 and groups 1A and 2. The group 3 individuals were collected in sylvatic environments in Yaxha, Peten, Guatemala. Previously, distinct chromosomal characteristics (cytotype 3) were described in individuals from this population. Based on this evidence we suggest that this population is divergent at the species level from other T. dimidiata populations.

Hypothesis testing clarifies the systematics of the main Central American Chagas disease vector, Triatoma dimidiata (Latreille, 1811), across its geographic range

“…aff. dimidiata as a cryptic species is consistent with our previous cross-breeding experiments (Garcia et al, 2013) where no offspring were produced from crosses between T. spp. aff.…”

“…This hypervariation likely over-estimates genome-wide genetic distance within T. dimidiata s.s. and the clades revealed by this gene do not correlate with reproductive isolation, i.e. are not biological species (Garcia et al, 2013). More slowly evolving genes like ITS-2 lack the resolution needed to resolve relationships within T. dimidiata s.s. further supporting the need to study multiple genes when proposing systematic hypothesis.…”

Geological Changes of the Americas and their Influence on the Diversification of the Neotropical Kissing Bugs (Hemiptera: Reduviidae: Triatominae)

“…The fact that T . dimidiata is composed of more than one lineage is clear now [ 63 , 64 ], and the fact that this lineage is not monophyletic is supported by reproductive isolation in breeding experiments [ 65 ].…”

Implementation science: Epidemiology and feeding profiles of the Chagas vector Triatoma dimidiata prior to Ecohealth intervention for three locations in Central America

“…For Central America, Triatoma dimidiata became the most important vector in the human Chagas transmission cycle after vector control strategies successfully eliminated Rhodnius prolixus, a vector indigenous to South America that had been introduced into Central America [8][9][10]. In its introduced range, R. prolixus was exclusively domestic, whereas T. dimidiata, a vector native from southern Mexico through Central America and into northern South America, is a complex of subspecies found in sylvatic and domestic habitats [11][12][13][14][15][16].…”