Neotropical endemism and dispersal events between tropical and extra‐tropical regions underlay the reticulate assemblages of muscid flies

Abstract

AbstractAimThe housefly family Muscidae originated during the Paleocene–Eocene and is currently distributed worldwide. We investigated how muscid genera have assembled in the continents by historical dispersal events.LocationGlobal (except Antarctica).TaxonMuscidae, Diptera, Insecta.MethodsWe compiled a dataset of 181 species, which provided geographic information for 67 genera as terminals. Phylogenetic and geographic data were fitted by five dispersal–extinction–cladogenesis models based on dispersal constraints. Based on the event inferences of the best‐fit model, we quantified the direction and frequency of dispersals through time in absolute numbers and in relation to the number of lineages.ResultsThe best‐fit model was ‘unrestricted routes’, which inferred 48 events of dispersals: 66% were trans‐climatic events and 81% were transoceanic events. The direction of the dispersals was strongly asymmetric: the Neotropical (NEO) region was the primary source of lineages for all other regions and the Palearctic (PAL) was the secondary source. The relative frequency of dispersal events through time plot was marked by three phases: the early peak of the frequency (40–35 million years ago [Ma]), a valley of low frequencies (30–20 Ma), and the recent peak (15–5 Ma). Trans‐climatic dispersals from the NEO to the PAL region occurred in all phases. Lineages of the Cyrtoneurininae showed a low frequency of dispersal events and most of the terminals (11 of 15) were endemic to the NEO region.ConclusionThe Muscidae family originated in the Neotropical region and more recent dispersal events to the Palearctic region established the scenario for lineages to diversify and spread worldwide. Trans‐climatic dispersals were more frequent than cis‐events and tropical niche conservatism was not the underlying mechanism for the whole clade. We showed that dispersal events between biogeographic regions of the same and different climatic zones were required to achieve the current distribution of extant genera of muscids across the globe.