Phylogeography of Bufo marinus from its natural and introduced ranges

Abstract

The marine toad, Bufo marinus, has a broad natural distribution extending from the south-west of the USA to southern Peru and the central Amazon. It was introduced to several localities in the Caribbean and Paci¢c Oceans to control sugar cane pests. We sequenced 468 bp of mitochondrial DNA (mtDNA) containing the ND3 gene, and £anking tRNA genes from toads spanning the broad natural and introduced ranges. Consistent with the known history of introductions and expected e¡ects of serial bottlenecks, mtDNA within introduced populations in Hawaii and Australia was uniform and most closely related to samples from eastern Venezuela and French Guiana. However, mtDNA nucleotide diversity in the geographic region spanning the source areas is also relatively low (0.18^0.46%) and the absence of variation in the introduced populations precludes quantitative assessment of the reduction in genetic diversity. Unexpectedly, there was a large phylogeographic break (5.4% sequence divergence) within the natural range separating populations east and west of the Venezuelan Andes. We hypothesize that the two major lineages of B. marinus were isolated by the uplift of the eastern Andean cordillera which was completed approximately 2.7 Ma. Another species of the marinus group, B. paracnemis, had mtDNA paraphyletic, with marinus, being nested within the eastern lineage. Thus, at least one speciation event within the marinus group postdates the split within marinus. These ¢ndings suggest that the taxonomy of B. marinus should be re-evaluated and that the search for pathogens to control Australian populations should be conducted in populations from both lineages in the natural range.

Molecular population genetics of the malaria vector Anopheles darlingi in Central and South America

“…Anopheles albimanus data suggest that a single barrier exists within Central America, which may be the mountain range that crosses Costa Rica and Western Panama (Molina-Cruz et al, 2004). The phylogeographic break between Central American plus NW Colombia and South American A. darlingi is consistent with studies of other Neotropical taxa, such as Neotropical butterflies (Brower 1994), toads (Slade and Moritz, 1998), bats (Hoffmann and Baker, 2003) and trees (Dick et al, 2003). However, Manguin et al (1999) observed substantial gene flow among populations of A. darlingi throughout its geographic range using four nonmitochondrial markers (isozyme, RAPD-PCR, ITS2, and morphology).…”

Phylogenetic Relationships of World Populations of Bemisia tabaci (Gennadius) Using Ribosomal ITS1

“…A similar situation was recently hypothesized to exist regarding the cane toad, Bufo marinus. Where a pest organism exists in its natural range as two or more distinct populations, control organisms may be potentially more effective if selected from population clusters other than the one from which the pest has dispersed (Slade and Moritz, 1998).…”

Amphibian molecular ecology and how it has informed conservation

“…Understanding the history of cane toads in their native habitats and their natural biological control should help decision-makers limit their impacts across their invasive range. Slade & Moritz (1998) investigated the rangewide phylogeography (from both native and introduced locations) of cane toads using 468 bp of mitochondrial DNA, confirming that introduced populations in Australia and Hawaii are most closely related to the toads from the eastern parts of Venezuela and French Guiana. They also discovered a high degree of divergence between populations on the east and west sides of the Andes.…”