Revisiting the Hybridization Processes in the Triatoma brasiliensis Complex (Hemiptera, Triatominae): Reproductive Isolation between Triatoma petrocchiae and T. b. brasiliensis and T. lenti

Abstract

Triatoma petrocchiae is a species morphologically similar to T. b. brasiliensis (which resulted in a synonymization event); despite this similarity, genetic, morphological, and experimental crossbreeding studies confirmed the specific status of T. petrocchiae. Considering that both species have been reported living in sympatry and that, for a long time, most species of the T. brasiliensis complex were considered only chromatic variants of T. b. brasiliensis, we carried out experimental crosses between T. b. brasiliensis and T. petrocchiae (to confirm whether these species are reproductively isolated) and between T. lenti and T. petrocchiae (to assess whether T. petrocchiae also presents prezygotic isolation with the other species of the T. brasiliensis complex). Reciprocal experimental crosses were conducted, and weekly, the eggs were collected, counted, and separated in new containers to assess the hatch rate. Neither cross resulted in hybrids, demonstrating that there are pre-zygotic reproductive barriers installed between T. petrocchiae and the other species of the T. brasiliensis complex. On the basis of the results above, we demonstrated that T. petrocchiae is reproductively isolated from T. b. brasiliensis and T. lenti. Furthermore, we suggest that T. petrocchiae is the species most derived from the T. brasiliensis complex.

Karyotype Evolution in Triatominae (Hemiptera, Reduviidae): The Role of Chromosomal Rearrangements in the Diversification of Chagas Disease Vectors

“…The generation of hybrids is relatively common between the species of this subfamily, with the main evolutionary events responsible for the decline of the hybrid lineage (postzygotic barriers) being inviability (offspring mortality before reaching adulthood) [ 8 ], sterility (partially or completely infertile offspring) [ 9 , 10 ] and the collapse of the hybrid (high offspring mortality from the second generation) [ 11 , 12 ]. Several studies involving experimental crosses have already been carried out among the triatomines, focusing mainly on taxonomic [ 8 , 11 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ] and epidemiological aspects [ 24 , 25 , 26 , 27 ]. On the other hand, although prezygotic barriers are less frequent and, generally, are present in only one direction of the crossings, as observed between Rhodnius colombiensis Mejia, Galvão and Jurberg, 1999 and R. pallescens Barber, 1932 [ 28 ], Triatoma pseudomaculata Corrêa and Espínola, 1964 and T. infestans (Klug, 1834) [ 29 ], T. delpontei Romaña and Abalos, 1947 and T. platensis Neiva, 1913 [ 30 ] and T. longipennis Usinger, 1939 and T. mopan Dorn et al, 2018 [ 17 ], they may be present between species that are very distant from the phylogenetic point of view [ 29 , 31 ] and between species of different genera ( Triatoma Laporte, 1832 × Panstrongylus Berg, 1879, Triatoma × Rhodnius Stål, 1859 and Rhodnius × Psammolestes Bergroth, 1911 [ 18 , 23 , 31 ]).…”