Biogeography of Trimerotropis pallidipennis (Acrididae: Oedipodinae): deep divergence across the Americas

Abstract

Aim Trimerotropis pallidipennis represents a species complex of band-winged grasshopper distributed over North and South America. Previous studies indicated a North American origin of the species and suggested that colonization of South America occurred during the Pleistocene after the closure of the Isthmus of Panama. Here we use a phylogeographical approach in order to test different biogeographical scenarios and determine how many distinct units exist within the species complex.Location North and South America with specific emphasis on the Andes mountains of South America.Methods We sequenced two mitochondrial and two nuclear genes for multiple specimens belonging to each taxonomic unit. Using the concatenated dataset and a coalescent-based approach we estimated the phylogeny of the complex. In order to distinguish the different biogeographical and species delimitation hypotheses we constrained our dataset to different taxon sets and ran Bayesian analyses in *beast. Posterior probabilities and DensiTree plots allowed us to determine the best hypotheses. We used a molecular clock approach to correlate geological events with observed phylogenetic splits. ResultsAll analyses indicate the existence of at least three distinct genetic lineages: Trimerotropis pallidipennis from North America, Trimerotropis ochraceipennis from Chile and an undescribed Trimerotropis species from Argentina. The split between North and South American forms took place about 1.3 Ma, long after the Isthmus of Panama had been completed. Biogeographical analyses suggest a first dispersal event from North to South America. Subsequent dispersion and vicariance probably led to the differentiation of the endemics now found in Chile and Argentina. Main conclusionsWe demonstrate the existence of three distinct genetic lineages in the Trimerotropis pallidipennis species complex. These lineages are also chromosomally differentiated as previous studies have indicated. Dispersion of T. pallidipennis from North to South America probably occurred during the early Pleistocene, when climatic conditions were more suitable. Subsequent diversification in South America was the result of range expansion and vicariance, possibly in response to later Pleistocene glaciations of the Andes.

Historical biogeography of the widespread spider wasp tribe Aporini (Hymenoptera: Pompilidae)

“…Even though recently published molecular phylogenetic studies in insects suggest dispersals at the time of the Great American Biotic Interchange ( c. 3 Ma) (Ramirez et al ., ; Husemann et al ., ), our data are consistent with accumulating studies suggesting that a number of biotic groups, including plants (Carvalho & Renner, ) and vertebrates (e.g. Perini et al ., ; Colston et al ., ), dispersed through this area before 7 Ma.…”

Diversification of montane species via elevation shifts: the case of the Kaçkar cricketPhonochorion(Orthoptera)

“…; Husemann et al. ; Kaya et al. ), recent studies have highlighted much variation between mitochondrial genes for substitution rates (Mueller ; Papadopoulou et al.…”

“…Although the general substitution rate for the insect mitochondrial genome proposed by Brower 1994 (2.3% divergence per million years between sequences) is still heavily used in Orthoptera and other insect species (i.e. Allegrucci et al 2009;Voje et al 2009;Husemann et al 2013;Kaya et al 2013), recent studies have highlighted much variation between mitochondrial genes for substitution rates (Mueller 2006;Papadopoulou et al 2010;Pons et al 2010). These studies give a much higher rate of substitution for genes of the cytochrome family (cox1, cox2, cox3, Cytb) somewhere around the order of 3-4% divergence, whereas genes of the NAD family (nad1, nad2, nad3, nad4) seem to evolve closer to the general rate of 2.3% divergence per million years.…”

Trimerotropis aberasturii(Orthoptera: Acrididae: Oedipodinae), a New Species of Band-Winged Grasshopper from North Central Nevada

“…The new species described herein is a member of the band-winged grasshopper (Oedipodinae) genus Trimerotropis, a New World genus of more than 52 species Weissman 1980, Eades et al 2014) that ranges from Canada south to Argentina and Chile. The majority of species occur throughout western North America; 4 species occur in eastern North America and 7 species in South America (Eades et al 2014), although 6 of those have been referred to as synonyms of one (Husemann et al 2013). All Trimerotropis species are macropterous.…”

“…They are strong fliers and produce mate-attraction sounds (crepitation) in flight. Many species have widespread geographic ranges, and one species, T. pallidipennis (Burmeister), has been recorded from Canada to southern Mexico (Otte 1984, Husemann et al 2013, Eades et. al.…”