Phenotypic variability in traits related to flight dispersal in the wing dimorphic species Triatoma guasayana

Abstract

Background Triatoma guasayana is considered an emerging vector of Chagas disease in the Southern Cone of South America. The presence of a triatomine population with brachypterous individuals, in which both wings are reduced, has recently been reported for this species. The aim of the present study was to determine if flight-related traits varied across populations, if these traits could explain differences in flight capacity across populations and if flight-related traits are associated with geographic and/or climatic variation. Methods The study involved 66 male T. guasayana specimens from 10 triatomine populations. Digital images of wing, head and pronotum were used to estimate linear and geometric morphometric variables. Variations in size and shape were analysed using one-way analysis of variance and canonical variate analysis (CVA), respectively. Mantel tests were applied to analyse the relationship between morphometric and geographic distances, and the association between size measurements was analysed using Pearson’s correlation. We explored covariation between size and shape variables using partial least square analyses (PLS). The association of geographic and climatic variables with size measurements was tested using linear regression analyses. We performed PLS analyses for shape measurements. Results Wing size differed significantly across triatomine populations. The CVA showed that wing shape of the brachypterous population is well discriminated from that of the other populations. The Mantel test showed a positive and significant association between wing shape and geographic distances. The heads of the brachypterous population were significantly larger than those of the other populations. Similar to wing shape, the head shape of the brachypterous population was well discriminated from those of the other populations. Pronotum width did not show significant differences across populations. Geographic and climatic factors were associated with size and shape of both the wing and head, but not with pronotum width. Conclusions Most of the traits related to flight dispersal varied across populations. Wing shape and head shape were found to be better markers for differentiated morphological variation across populations. Head measurements also varied in accordance with this condition. Geographic and climatic variables were associated with most of the flight-related traits. Graphical Abstract

Association between environmental gradient of anthropization and phenotypic plasticity in two species of triatomines

“…During dispersal events, heads and wings play critical roles as fundamental structures. It has been proposed that narrow heads, with the associated development of compound eyes, have been proposed to be correlated with morphotypes that allow improved flight in triatomines [ 27 – 29 ]. Furthermore, small changes in wing shape may significantly affect aerodynamic performance [ 30 ].…”

Relationship between genetic diversity and morpho-functional characteristics of flight-related traits in Triatoma garciabesi (Hemiptera: Reduviidae)

“…In several insects, changes in head phenotype have been associated with flight capacity [ 30 , 41 , 42 ]. In the triatomines Mepraia spinolai Porter, 1934 and T. guasayana , some characteristics, such as narrow head with highly developed compound eyes, are considered to be associated with flight dispersal [ 41 – 43 ]. When developed, flight muscles are located under the pronotum.…”

Association between environmental gradient of anthropization and phenotypic plasticity in two species of triatomines

“…During dispersal events, heads and wings play critical roles as fundamental structures. It has been proposed that narrow heads, with the associated development of compound eyes, have been proposed to be correlated with morphotypes that allow improved ight in triatomines [27][28][29]. Furthermore, small changes in wing shape may signi cantly affect aerodynamic performance [30].…”