Contrasting genetic structuring between colonies of the World’s smallest penguin, Eudyptula minor (Aves: Spheniscidae)

Abstract

The Little Penguin, Eudyptula minor, is a seabird that nests in colonies throughout New Zealand and southern Australia. Individuals from different colonies in southeast Australia differ significantly in morphology and ecology, suggesting that some genetic structuring may exist among colonies. In contrast, the marking of individuals with flipper bands has revealed some, albeit infrequent, movement between colonies. To determine the extent of genetic structuring, we tested the null hypothesis of substantial gene flow within southeast Australia by examining patterns of genetic variation across seven colonies separated by up to 1,500 km. Phylogeographic structuring was absent for mitochondrial control region sequences (2-3 individuals per colony). Microsatellite allele frequencies at five loci and mitochondrial haplotype frequencies (50 individuals per colony) were also homogenous among the majority of colonies sampled, although two colonies at the western periphery of the sampling range were distinct from those to the east. The genetic homogeneity among the majority of colonies can be explained by low but consistent contemporary gene flow among them, or a recent founder event in Bass Strait following the last marine transgression. The genetic break towards the western end of the sampling distribution appears best explained by differences in sea surface temperature and, consequentially breeding phenology, the latter hindering genetically effective migration.

Population structure in the South American tern Sterna hirundinacea in the South Atlantic: two populations with distinct breeding phenologies

“…In band‐rumped storm petrels Oceanodroma castro sympatric seasonal populations from two of the archipelagos studied (the Azores and Cape Verde) have ceased to exchange genes, providing the first example of sympatric speciation by allochrony in a tetrapod (Monteiro and Furness 1998, Friesen et al 2007b). In penguins, sea surface temperatures seem to be primarily related to differences in breeding phenology which seems to have an effect on the diversification among populations of the little penguin Eudyptula minor (Overeem et al 2008) and speciation of the rockhopper penguin Eudyptes chrysocome (Jouventin et al 2006). Furthermore, rockhopper penguins are separated by the sub‐tropical convergence, which also separates the Brazilian and Patagonian populations of the South American tern.…”

“…However, in seabirds non‐physical barriers and behavioural processes such as non‐breeding distribution and phylopatry, also play an important role in promoting genetic differentiation (reviewed by Friesen et al 2007a). More recently, isolation by time has also been described as a key mechanism preventing gene flow in seabirds (Friesen et al 2007b, Overeem et al 2008).…”

Limited genetic differentiation among chinstrap penguin (Pygoscelis antarctica) colonies in the Scotia Arc and Western Antarctic Peninsula

“…These are inherited from both parents and have higher rates of substitution relative to mitochondrial DNA, making them more sensitive to weak or recent population structure. Most of these studies have found high genetic diversity and a lack of genetic differentiation between colonies (Adélie, Roeder et al 2001;Magellanic, Spheniscus magellanicus, Bouzat et al 2009;Humboldt, Spheniscus humboldti, Schlosser et al 2009), though breaks in genetic connectivity with distance have also been recorded (little penguin, Eudyptula minor, Overeem et al 2008;yellow-eyed penguin, Megadyptes antipodes, Boessenkool et al 2009). For chinstrap penguins, there has not been a region-wide investigation using microsatellite markers.…”

Greater flamingo colonies around the Mediterranean form a single interbreeding population and share a common history

“…Predicting the genetic structure of colonial bird populations is not straightforward, as it depends both on contemporary ecological and/or behavioural features (such as the degree of natal philoptary and breeding dispersal, population size, and mating system) and on phylogeographic history (Tiedemann et al 2004, Matthiopoulos et al 2005, Milot et al 2008, Overeem et al 2008). For instance, stronger or weaker genetic structure than expected from ecological data (Milot et al 2008) or from population history (Boessenkool et al 2009) has been reported in seabirds.…”