Phylogenetic analysis of the genus Laparocerus, with comments on colonisation and diversification in Macaronesia (Coleoptera, Curculionidae, Entiminae)

Abstract

The flightless Entiminae weevil genus Laparocerus is the species-richest genus, with 237 species and subspecies, inhabiting Macaronesia (Madeira archipelago, Selvagens, Canary Islands) and the continental ‘Macaronesian enclave’ in Morocco (one single polytypic species). This is the second contribution to gain insight of the genus and assist in its systematic revision with a mitochondrial phylogenetic analysis. It centres on the Canarian clade, adding the 12S rRNA gene to the combined set of COII and 16S rRNA used in our first contribution on the Madeiran clade (here re-analysed). The nuclear 28S rRNA was also used to produce an additional 4-gene tree to check coherency with the 3-gene tree.A total of 225 taxa (95%) has been sequenced, mostly one individual per taxa. Plausible explanations for incoherent data (mitochondrial introgressions, admixture, incomplete lineage sorting, etc.) are discussed for each of the monophyletic subclades that are coincident with established subgenera, or are restructured or newly described. The overall mean genetic divergence (p-distance) among species is 8.2%; the mean divergence within groups (subgenera) ranks from 2.9 to 7.0% (average 4.6%), and between groups, from 5.4% to 12.0% (average 9.2%). A trustful radiation event within a young island (1.72 Ma) was used to calibrate and produce a chronogram using the software RelTime.These results confirm the monophyly of both the Madeiran (36 species and subspecies) and the Canarian (196 species and subspecies) clades, which originated ca. 11.2 Ma ago, and started to radiate in their respective archipelagos ca. 8.5 and 7.7 Ma ago. The Madeiran clade seems to have begun in Porto Santo, and from there it jumped to the Desertas and to Madeira, with additional radiations. The Canarian clade shows a sequential star-shape radiation process generating subclades with a clear shift from East to West in coherence with the decreasing age of the islands. Laparocerus garretai from the Selvagens belongs to a Canarian subclade, and Laparocerus susicus from Morocco does not represent the ancestral continental lineage, but a back-colonisation from the Canaries to Africa. Dispersal processes, colonisation patterns, and ecological remarks are amply discussed. Diversification has been adaptive as well as non-adaptive, and the role of ’geological turbulence’ is highlighted as one of the principal drivers of intra-island allopatric speciation.Based on the phylogenetic results, morphological features and distribution, five new monophyletic subgenera are described: Aridotrox subg. n., Belicarius subg. n., Bencomius subg. n., Canariotrox subg. n., and Purpuranius subg. n., totalling twenty subgenera in Laparocerus.

Deep segregation in the open ocean: Macaronesia as an evolutionary hotspot for low dispersal marine invertebrates

“…These rates were also applied successfully by Xavier et al () and Panova, Nygren, Jonsson, and Leidenberger () in other two isopod genera ( Stenosoma and Idotea, respectively) and fit within the range of COI rates estimated for other marine arthropods (Knowlton & Weigt, ; Markow & Pfeiler, ; Sponer & Lessios ; Wares & Cunningham, ). The second and third priors were based on the hypotheses that D. edwardsi colonized La Palma (formed at around 1.7 Myr; Fernández‐Palacios et al, ; Guillou, Carracedo, & Duncan, ) and El Hierro (1.1 Myr; Carracedo, ; Fernández‐Palacios et al, ) shortly after the formation of the islands, as used by Machado, Rodríguez‐Expósito, López, and Hernández (). The corresponding clades were set to priors of 1.7 Myr (standard error of 0.17 Myr) and 1.1 Myr (standard error of 0.11 Myr).…”

“…Myr;Fernández-Palacios et al, 2011;Guillou, Carracedo, & Duncan, 2001) and El Hierro (1.1 Myr;Carracedo, 2011;Fernández- Palacios et al, 2011) shortly after the formation of the islands, as used byMachado, Rodríguez-Expósito, López, and Hernández (2017). Thecorresponding clades were set to priors of 1.7 Myr (standard error of 0.17 Myr) and 1.1 Myr (standard error of 0.11 Myr).…”

Complex inter‐island colonization and peripatric founder speciation promote diversification of flightless Pachyrhynchus weevils in the Taiwan–Luzon volcanic belt

“…Recent studies on a few flightless weevils have suggested that they have been able to colonize numerous remote archipelagos and islands likely due to their long and complex histories in the regions (Claridge et al, 2017;Machado et al, 2017;T€ anzler et al, 2016). However, the mechanism and transporting vectors of effective long-distance dispersal across oceanic barriers remain elusive for these weevils.…”

“…The P. orbifer complex represents an excellent set of organisms to test the stepping-stone hypothesis, not only because of the existence of closely related endemic species on nearly every sizable island across the archipelago, but also due to three intriguing adaptations that may facilitate their cross-ocean dispersal through rafting on floating vegetation by oceanic currents: (1) Pachyrhynchus adults are wingless and have completely fused elytra; (2) they have the ability to draw and keep air under their elytra, allowing them to float on water for at least several hours (Schultze, 1923); (3) their eggs are inserted into plant tissues, and the larvae live and feed inside the stems of the host plants. Recent studies suggested that flightless weevils were able to colonize remote archipelagos of Southeast Asia and the Pacific via stepping-stone islands (Claridge, Gillespie, Brewer, & Roderick, 2017;Machado, Rodr ıguez-Exp osito, L opez, & Hern andez, 2017;T€ anzler et al, 2016).…”

Chance and predictability in evolution: The genomic basis of convergent dietary specializations in an adaptive radiation

“…The comparative analysis of such independent events and the subsequent island radiation (both within and between islands) in different archipelagos provides new insights into the general evolutionary process generating biological diversity (Gillespie & Roderick, 2002;Losos & Ricklefs, 2009). Such approximation has been successfully applied in a number of studies on oceanic islands (Losos, Jackman, Larson, Queiroz, & Rodriguez-Schettino, 1998;Stroud & Losos, 2016), such as Hawaii (Gillespie, 2004), the Galapagos (Grant & Grant, 2008) and the Canary Islands and Madeira archipelagos (Juan, Emerson, Oromı, & Hewitt, 2000;Machado, Rodríguez-Expósito, López, & Hernández, 2017), where explicit hypotheses on the evolutionary processes underlying radiations have been tested.…”