The Phylogeographic History of the New World Screwworm Fly, Inferred by Approximate Bayesian Computation Analysis

Abstract

Insect pest phylogeography might be shaped both by biogeographic events and by human influence. Here, we conducted an approximate Bayesian computation (ABC) analysis to investigate the phylogeography of the New World screwworm fly, Cochliomyia hominivorax, with the aim of understanding its population history and its order and time of divergence. Our ABC analysis supports that populations spread from North to South in the Americas, in at least two different moments. The first split occurred between the North/Central American and South American populations in the end of the Last Glacial Maximum (15,300-19,000 YBP). The second split occurred between the North and South Amazonian populations in the transition between the Pleistocene and the Holocene eras (9,100-11,000 YBP). The species also experienced population expansion. Phylogenetic analysis likewise suggests this north to south colonization and Maxent models suggest an increase in the number of suitable areas in South America from the past to present. We found that the phylogeographic patterns observed in C. hominivorax cannot be explained only by climatic oscillations and can be connected to host population histories. Interestingly we found these patterns are very coincident with general patterns of ancient human movements in the Americas, suggesting that humans might have played a crucial role in shaping the distribution and population structure of this insect pest. This work presents the first hypothesis test regarding the processes that shaped the current phylogeographic structure of C. hominivorax and represents an alternate perspective on investigating the problem of insect pests.

Incongruent Nuclear and Mitochondrial Genetic Structure of New World Screwworm Fly Populations Due to Positive Selection of Mutations Associated with Dimethyl- and Diethyl-Organophosphates Resistance

“…Another important factor to successfully implement a control program based on SIT is the adequate delimitation of the geographic areas to be targeted [ 31 ]. Many population genetic studies, based on several molecular markers, were conducted with this aim in the NWS fly, which resulted in different population structure scenarios and interpretations [ 32 – 39 ]. At least four genetic regional groups were described for the NWS fly throughout its current geographical range, including Cuba (CG), the Dominican Republic (DRG), and North and South of the Amazon Region (NAG and SAG, respectively), with island populations being derived from mainland ones [ 38 ].…”

“…In the mainland, a split between populations from North/Central America and South America, preceded by an expansion process initiated in North America, occurred after the Last Glacial Maximum. A subsequent split between the Pleistocene and Holocene epochs resulted in the NAG and SAG regions in South America [ 39 ]. Within these two areas, the NWS fly did not share mitochondrial haplotypes [ 38 ] and the genetic structure was associated with a barrier in the north of the Amazon basin, with NWS fly populations from the Amazon only sharing haplotypes with those in the SAG but not in the NAG region [ 40 ].…”

“…Within these two areas, the NWS fly did not share mitochondrial haplotypes [ 38 ] and the genetic structure was associated with a barrier in the north of the Amazon basin, with NWS fly populations from the Amazon only sharing haplotypes with those in the SAG but not in the NAG region [ 40 ]. Despite the wide area sampled, a low population differentiation was observed without a geographic correlation in the SAG group [ 38 ], probably due to the population expansion process [ 39 ].…”

Comparative phylogeography of Aedes mosquitoes and the role of past climatic change for evolution within Africa

“…Demographic signals relating to past climate change can be complex since allopatric divergence may have occurred multiple times in several different refugia, which can be further complicated by periods of secondary contact, founding events, and genetic drift (Estoup & Guillemaud, ; Guillemaud, Beaumont, Ciosi, Cornuet, & Estoup, ). Therefore in addition to a standard population genetics approach, we use Approximate Bayesian Computation (ABC) to test our hypotheses since this method has been used to successfully link historical climate change to the demographic structure retained in contemporary populations (Barrientos et al., ; Fresia, Azeredo‐Espin, & Lyra, ; Inoue, Monroe, Elderkin, & Berg, ; Logossa et al., ; Rovito, ).…”

Phylogeography of the Wheat Stem Sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae): Implications for Pest Management

“…e . population size changes, range expansions or contractions) [20]. Little is known about the population genetics of this pest, the data being restricted to a single study using RAPD markers to decipher distinct genetic units from Montana and North Dakota [21].…”