Biogeographic origin and phylogenetic relationships of Mepraia (Hemiptera, Reduviidae) on islands of northern Chile

Abstract

Chagas disease is one of the main zoonoses mediated by vectors in America. The etiological agent is the protozoan Trypanosoma cruzi, transmitted mainly by hematophagous insects of the subfamily Triatominae. Mepraia species are triatomines endemic to Chile that play an important role in T. cruzi transmission in the wild cycle and are potential vectors for humans. In addition to the continental distribution, populations of Mepraia genus have been reported inhabiting islands of northern Chile. The presence of individuals of Mepraia in insular areas might be explained through passive dispersion by marine birds or by vicariance of an ancestral widespread population. To clarify the biogeographic origin and phylogenetic relationships of island individuals of Mepraia, mitochondrial COI and cyt b genes were sequenced in individuals from island and continental areas. Gene sequences were used to estimate phylogenetic relationships, divergence dates and migration rates between insular and continental populations. The dates of divergence estimates are congruent with sea level and tectonic changes that originated the islands during Pleistocene. Migration rates suggest symmetric historical island-continent gene flow. We suggest that the origin of island triatomines can be explained by both vicariance and dispersion. Phylogenetic relationships show that individuals from Santa María Island and the continent clustered in a clade different from those previously reported, indicating a new lineage of Mepraia genus. This study will contribute to understand the origin of the T. cruzi infection in coastal islands of northern Chile.

Trypanosoma cruzi-infected triatomines and rodents co-occur in a coastal island of northern Chile

“…However, we sampled intensively using both a passive ( Campos-Soto, Torres-Pérez & Solari, 2015 ) and active method, and the park rangers never reported seeing triatomines (personal communication with park rangers). A study suggests that the current absence of M. spinolai in those islands may be explained by their absence when the islands were formed or that ancient allopatric populations were extinguished ( Campos-Soto et al, 2020 ). If hypothetically triatomines are not present, alternatives to explain the T. cruzi infection in rodents include: (i) Maintenance of the parasite by vertical trans-placental transmission between rodents, which has been reported in humans, bats and mice ( Delgado & Santos-Buch, 1978 ; Añez, Crisante & Soriano, 2009 ; Ortiz et al, 2012 ); (ii) Cross-reaction with other trypanosomatids (see below).…”

“…The origin of Mepraia populations on Santa María and Pan de Azúcar islands was suggested by mechanisms of vicariance and dispersal, starting about middle-upper Pleistocene. Bidirectional migration rates between these islands and continental populations was inferred ( Campos-Soto et al, 2020 ). Possible means of dispersal include passive transport by marine birds ( Schofield et al, 1998 ; Sagua et al, 2000 ) and fishermen who sail to the islands carrying infected triatomines and/or eggs in their clothes or backpacks.…”

Testing Phylogeographic Hypotheses in Mepraia (Hemiptera: Reduviidae) Suggests a Complex Spatio-Temporal Colonization in the Coastal Atacama Desert

“…sp. from now on), which inhabits between the distributions of M. parapatrica and M. gajardoi (23°25′ to 23°28′ S) [ 9 ]. The coastal species inhabit landscapes with low vegetation under stones and in rock crevices, associated with marine bird nests, rodent burrows and lizards [ 9 , 10 ].…”

“…from now on), which inhabits between the distributions of M. parapatrica and M. gajardoi (23°25′ to 23°28′ S) [ 9 ]. The coastal species inhabit landscapes with low vegetation under stones and in rock crevices, associated with marine bird nests, rodent burrows and lizards [ 9 , 10 ]. Although each of the Mepraia species forms well-supported clades, the phylogenetic relationships between these lineages are still unresolved, leading to controversy regarding the colonization routes of Mepraia species in Chile [ 7 , 9 ].…”

Do the new triatomine species pose new challenges or strategies for monitoring Chagas disease? An overview from 1979-2021

“… 82 , 83 , 84 , 85 For example, in a natural hybrid zone identified in the State of Pernambuco, Brazil, 13 phenotypes (nine of them intermediate between T. b. brasiliensis and T. juazeirensis ) were revealed for T. brasiliensis complex, based on molecular analysis. 86 On the other hand, the possibility of the existence of new species due to the detection of genetic variations in taxa that are now considered a single taxon, such as Mepraia Mazza, Gajardo & Jörg, 1940; 87 R. pallescens Barber, 1932; 88 T. patagonica Del Ponte, 1929; 89 T. costalimai Verano & Galvão, 1958; 90 and R. ecuadoriensis , 91 , 92 , 93 , 94 was demonstrated.…”