Based on the sensitivity of species to ongoing climate change, and numerous challenges they face tracking suitable conditions, there is growing interest in species' capacity to adapt to climatic stress. Here, we develop and apply a new generic modelling approach (AdaptR) that incorporates adaptive capacity through physiological limits, phenotypic plasticity, evolutionary adaptation and dispersal into a species distribution modelling framework. Using AdaptR to predict change in the distribution of 17 species of Australian fruit flies (Drosophilidae), we show that accounting for adaptive capacity reduces projected range losses by up to 33% by 2105. We identify where local adaptation is likely to occur and apply sensitivity analyses to identify the critical factors of interest when parameters are uncertain. Our study suggests some species could be less vulnerable than previously thought, and indicates that spatiotemporal adaptive models could help improve management interventions that support increased species' resilience to climate change.

Information about genetic structure and historical demography of natural populations is central to understanding how natural selection changes genomes. Drosophila ananassae is a widespread species occurring in geographically isolated or partially isolated populations and provides a unique opportunity to investigate population structure and molecular variation. We assayed microsatellite repeat-length variation among 13 populations of D. ananassae to assess the level of structure among the populations and to make inferences about their ancestry and historic biogeography. High levels of genetic structure are apparent among all populations, particularly in Australasia and the South Pacific, and patterns are consistent with the hypothesis that the ancestral populations are from Southeast Asia. Analysis of population structure and use of F-statistics and Bayesian analysis suggest that the range expansion of the species into the Pacific is complex, with multiple colonization events evident in some populations represented by lineages that show no evidence of recent admixture. The demographic patterns show isolation by distance among populations and population expansion within all populations. A morphologically distinct sister species, D. pallidosa, collected in Malololelei, Samoa, appears to be more closely related to some of the D. ananassae populations than many of the D. ananassae populations are to one another. The patterns of genotypic diversity suggest that many of the individuals that we sampled may be morphologically indistinguishable nascent species.

No abstract

Prezygotic mating isolation has been a major interest of evolutionary biologists during the past several decades because it is likely to represent one of the first stages in the transition from populations to species. Mate discrimination is one of the most commonly measured forms of prezygotic isolation and appears to be relatively common among closely related species. In some cases, it has been used as a measure to distinguish populations from subspecies, races, and sister species, yet the influences of various evolutionary mechanisms that may generate mate discrimination are largely unknown. In this study, we measured the level and pattern of mate discrimination among 18 populations of a cosmopolitan drosophilid species, Drosophila ananassae, from throughout its geographical range and its sister species, Drosophila pallidosa, which has a restricted geographical distribution in the South Pacific Islands. In addition, we measured genetic differentiation between all 18 populations using mitochondrial DNA polymorphism data. Mate discrimination varies considerably throughout the species range, being higher among populations outside the ancestral Indonesian range, and highest in the South Pacific. Our results suggest that colonization and genetic differentiation may have an influence on the evolutionary origin of mate discrimination. Our phylogeographical approach clarifies the ancestral relationships of several populations from the South Pacific that show particularly strong mate discrimination and suggests that they may be in the early stages of speciation. Furthermore, both the genetic and behavioral results cast doubt on the status of D. pallidosa as a good species.

An unknown Drosophila montium subgroup species was collected on Cape York Peninsula in 1992, a live culture of the same species was established from flies collected in the vicinity of Lake Placid near Cairns in 2001. From these specimens we now have sufficient information to describe a new species—Drosophila bunnanda. It differs morphologically from the four other montium subgroup species already known from northern Queensland—D. serrata, D. birchii, D. kikkawai, and D. sp. cf. jambulina, and from one very similar species—D. dominicana—known from Papua New Guinea. Molecular data support the taxonomic findings. Additional information and a key for all Australian montium subgroup species is provided to allow clear differentiation between them and D. bunnanda.