Geographic patterns of phenotypic diversity in incipient species of North American blister beetles (Coleoptera: Meloidae) are not determined by species niches, but driven by demography along the speciation process

Abstract

The Epicauta stigmata complex is a group of blister beetles composed of three parapatric or sympatric species that occur in central Mexico to southern USA: E. stigmata, E. uniforma and E. melanochroa. These species are morphologically very similar, and are mainly distinguished by body colour differences. Here we assessed whether phenotypic divergence in coloration patterns define evolutionary units within the complex. We studied the phylogenetic relationships, demographic history and concordances between morphological and ecological traits in the group. The complex apparently had a demographic history of recent population expansion during the last glaciation period 75000 to 9500 years ago. The three species show no reciprocal monophyly, and thus their allospecificity was not confirmed. The current distribution of haplotypes and the genetic divergences in these taxa can be explained by either recent mitochondrial introgression events caused by hybridisation or by incomplete lineage sorting. Colour pattern differences in the complex are not likely a product of local selection acting over a common genetic background. We suggest that phenotypic divergence in colour patterns during an incipient speciation process might be seen as an enhancing factor of cohesion within each of the three evolutionary units.

Quantitative imagery analysis of spot patterns for the three-haplogroup classification of Triatoma dimidiata (Latreille, 1811) (Hemiptera: Reduviidae), an important vector of Chagas disease

“…Author details 1 Centro de Investigación en Biodiversidad y Conservación (CIByC), Universidad Autónoma del Estado de Morelos (UAEM), Cuernavaca, Morelos, México. 2 Departamento de Biología Animal y Humana, Facultad de Biología, Universidad de La Habana, Havana, Cuba.…”

“…Genetic and morphological divergences associated with speciation processes may not appear at the same time or progress at the same rate [ 1 ]. The emergence of new species usually results from the isolation of populations due to geographic, ecological or behavioral barriers that can act individually or synergistically [ 2 ].…”

Dissecting natural hybridisation in longhorned beetles through an integrative approach: Further proof of reticulate evolution in Dorcadionini (Cerambycidae, Lamiinae)

“…Most recent studies on hybridisation in Coleoptera, however, are dealing with cases of introgression detected based on discordance between phenotypic traits and genetic (mitochondrial and/or nuclear) markers. Thus, inferences of current or past introgressive hybridisation in areas of sympatric occurrence have been reported in species of Lucanidae (Cox et al., 2013; Kubota et al., 2011; Solano et al., 2016), Scarabaeidae (Wirta, 2009), Geotrupidae (Tóth et al., 2019), Chrysomelidae (Campbell et al., 2011; Kastally et al., 2019; Quinzin & Mardulyn, 2014), Carabidae (Kosuda et al., 2016) and Meloidae (Salvador de Jesús‐Bonilla et al., 2018). Natural hybrids have been identified in a wide hybrid zone in Chrysochus , Chrysomelidae (Monsen et al., 2007; Peterson et al., 2001, 2005) and Propylea , Coccinelidae (Suga et al., 2016), but without clear evidence of introgression, while in two species of Gonioctena (Chrysomelidae), nuclear introgression was detected by whole genome sequencing (Lukicheva & Mardulyn, 2021).…”

Quantitative Imagery Analysis of Spot Patterns for Haplogroup Classification of Triatoma Dimidiata (Latreille, 1811) (Hemiptera: Reduviidae) an Important Vector of Chagas Disease

“…Genetic and morphological divergences associated with speciation processes may not appear at the same time or progress at the same rate [1]. The emergence of new species usually results from the isolation of populations due to geographic, ecological, or behavioral barriers, which act individually or synergistically [2].…”