Hopping out of Mindanao: Miocene‐Pliocene geological processes and cross‐island dispersal as major drivers of diversity for Philippine treehoppers

Abstract

Aim We investigated the biogeographical history of an endemic Philippine treehopper, Pyrgonota bifoliata (Membracidae), to test the effect of Neogene geological events and Pleistocene climate change in generating speciation within the Philippines.Location The Philippine archipelago.Methods Phylogenies were reconstructed based on the mitochondrial cytochrome c oxidase I subunit (cox1) and nuclear wingless (wg) genes using maximum parsimony, maximum likelihood and Bayesian criteria. Divergence times were estimated in beast based on a range of mutation rates. Ancestral ranges were reconstructed using rasp (Reconstruct Ancestral State in Phylogenies) and Bayesian stochastic search variable selection (BSSVS). Species boundaries were tested using the Bayesian general mixed Yule coalescent (bGMYC) and Bayesian phylogenetic and phylogeography (BPP) methods.Results Pyrgonota bifoliata showed one of the lowest levels of between-Pleistocene island genetic variation among all the taxa examined. Most Pleistocene aggregate island complex (PAIC) lineages and extant P. bifoliata originated before the onset of the first extensive Pleistocene glacial cycle. Ancestral P. bifoliata originated in the late Miocene from Mindanao, followed by a sequential northwards colonization of the Visayan Islands and Luzon in the Pliocene-early Pleistocene, which coincided with the spatial reorganization of the Philippines. The statistically delimited nine provisional species of what we now view as the P. bifoliata species complex correspond to current island boundaries and specialized host plants. Main conclusionsThe temporally calibrated phylogeny of P. bifoliata represents the first invertebrate study to support the hypothesis that Miocene-Pliocene geological events and consequent cross-island dispersal were pivotal promoters of species diversity in the Philippines. We hypothesize that ecological adaptation to specialized host plants, together with either local selection or genetic drift through within-island allopatric isolation, present a plausible in situ speciation mechanism for the origin of these herbivorous insects.

Phylogenetic analysis of the Oriental genera of Orthopagini Emeljanov, 1983 (Hemiptera: Fulgoromorpha: Dictyopharidae: Dictyopharinae), with a systematic revision of the genusCentromeriaStål, 1870

“…These changes could provide many chances to make the ancestors of Philippine Centromeria disperse to the Philippine Islands, although the dictyopharid species are not supposed to possess the ability of long‐distance dispersal. In addition, the historical dispersal of Centromeria species to adjacent islands might also have been promoted by drifting floating vegetation of host plants along oceanic currents, resulting in the passive transport of adults, nymphs, and/or eggs inserted in the tissues of host plants, like the Philippine treehoppers (Su et al ., ), or by wind‐assisted migration, as has been observed in the migratory planthoppers (Anderson et al ., ).…”

Parallel evolution of an alpine type ecomorph in a scorpionfly: Independent adaptation to high‐altitude environments in multiple mountain locations

“…The identification of factors leading to speciation and elucidation of the associated mechanisms generating biodiversity are considered to be important tasks by evolutionary biologists (Schluter & Pennell, ). Previous studies targeting various taxa demonstrated that the origins of genetic diversity, evolution and speciation are the results of complex interactions among geographical history, random genetic drift, the environment, biological factors, and stochastic processes (Hoskin, Higgie, Mcdonald, & Moritz, ; Kano, Nishida, & Nakajima, ; Komaki et al, ; Saito & Tojo, ; Schoville, Uchifune, & Machida, ; Su, Wang, & Villanueva, ; Suzuki, Kitano, & Tojo, ). In particular, the fragmentation of populations is one of the major factors driving diversification and speciation often as the result of (a) climate changes within habitats and (b) changes in the environmental conditions between habitats thereby promoting divergent adaptation (Cole et al, ; Jensen et al, ; Schoville & Roderick, ; Shi, Ji, Liu, Wang, & Zhang, ; Stewart, Lister, Barnes, & Dalén, ; Tojo et al, ).…”

Dynamics of genetic and morphological diversification in an incipient intra‐island radiation of Philippine rodents (Muridae: Bullimus)

“…The complex and dynamic geological history of the Philippines, characterized by extensive tectonic movement and volcanic activity gradually shaping the archipelago over the last c . 30 Myr (Hall, ; Yumul, Dimalanta, Maglambayan, & Marquez, ), has been cited as an important driver of diversification in the archipelago (Brown et al., ; Esselstyn, Timm, & Brown, ; Heaney, ; Heaney, Balete, & Rickart, ; Jansa, Barker, & Heaney, ; Su, Wang, Villanueva, Nuñeza, & Lin, ). More recently, Pleistocene climate cycles may have played a prominent role in promoting speciation in the Philippines, with numerous studies citing the effects of sea level fluctuations in fostering the dispersal and diversification of terrestrial organisms across the archipelago (Brown et al., ; Esselstyn & Brown, ; Heaney, , ; Roberts, ).…”

“…By contrast, fewer studies have examined the importance of intra‐island diversification, which could have played a significant role in generating diversity on the larger and more topographically complex islands in the Philippines (Heaney, ; Kisel & Barraclough, ; Whittaker et al., ). Evidence indicating the potential importance of intra‐island speciation in the Philippines has emerged from research on birds (Hosner, Nyari, & Moyle, ; Hosner, Boggess, et al., ), skinks (Linkem, Diesmos, & Brown, ), treehoppers (Su et al., ), shrews (Esselstyn et al., ), and murid rodents (Balete, Rickart, Heaney, & Jansa, ; Balete et al., ; Heaney, Balete, Rickart, & Jansa, ; Heaney et al., ; Justiniano et al., ; Steppan, Zawadski, & Heaney, ), with many of these studies implicating the numerous ‘sky islands’ on Luzon and Mindanao as important drivers of diversification. The extent to which such intra‐island processes represent the rule or exceptions in the Philippines, however, remains inadequately assessed.…”