Glacial refugia in a maritime temperate climate: Cicada (Kikihia subalpina) mtDNA phylogeography in New Zealand

Abstract

Understanding the biological significance of Pleistocene glaciations requires knowledge of the nature and extent of habitat refugia during glacial maxima. An opportunity to examine evidence of glacial forest refugia in a maritime, Southern Hemisphere setting is found in New Zealand, where the extent of Pleistocene forests remains controversial. We used the mitochondrial phylogeography of a forest-edge cicada (Kikihia subalpina) to test the hypothesis that populations of this species survived throughout South Island during the Last Glacial Maximum. We also compared mitochondrial DNA phylogeographic patterns with male song patterns that suggest allopatric divergence across Cook Strait. Cytochrome oxidase I and II sequences were analyzed using network analysis, maximum-likelihood phylogenetic estimation, Bayesian dating and Bayesian skyline plots. K. subalpina haplotypes from North Island and South Island form monophyletic clades that are concordant with song patterns. Song divergence corresponds to approximately 2% genetic divergence, and Bayesian dating suggests that the North Island and South Island population-lineages became isolated around 761,000 years BP. Almost all South Island genetic variation is found in the north of the island, consistent with refugia in Marlborough Sounds, central Nelson and northwest Nelson. All central and southern South Island and Stewart Island haplotypes are extremely similar to northern South Island haplotypes, a 'northern richness/southern purity' pattern that mirrors genetic patterns observed in many Northern Hemisphere taxa. Proposed southern South Island forest habitat fragments may have been too small to sustain populations of K. subalpina, and/or they may have harboured ecological communities with no modern-day analogues.

Fire and slice: palaeogeography for biogeography at New Zealand's North Island/South Island juncture

“…Furthermore, observations from intraspecific animal phylogeography support the inference of recent occupation of the region (e.g. stick insects, Buckley et al 2009;Morgan-Richards et al 2010), and recent bridging of Cook Strait (e.g. Hemideina tree weta, Galaxiid fish, Paranephrops freshwater crayfish; see Wallis & Trewick 2009) is also consistent with young landscape formation and connection (Fig.…”

Persistence of New Zealand Quaternary beetles

“…Marske et al 2009Marske et al , 2011, and the mainly unglaciated North Island has been a source area for insects that were previously extirpated in the South Island and recolonised later (e.g. Marshall et al 2009;Buckley et al 2009Buckley et al , 2010. Our finding that there has been morphological stasis in the Auckland area is consistent with the presence of long-term refugia in the North Island and we would predict other sites in northern New Zealand to contain stable, long-term communities of beetles.…”

Climate Change and Evolutionary Adaptations at Species' Range Margins

“…This has been demonstrated in a wide variety of insect taxa, including Lepidoptera, phasmids, weevils, pitcher-plant mosquitoes, grasshoppers, caddis flies, bees, Megaloptera, and cicadas (3,4,11,17,30,45,54,55,79,83,94,117). The patterns are indicative of rapid postglacial range expansion in many regions of the globe including Europe (11), North America (36), New Zealand (16,79), and Asia (3). However, in some studies these latitudinal cline effects are relatively minor (98) or not evident at all (75,99,112).…”

“…Nonetheless, a commonly observed consequence of rapid postglacial expansions is the genetic impoverishment of populations inhabiting newly colonized areas compared to those residing in areas of persistently suitable habitat (55). This has been demonstrated in a wide variety of insect taxa, including Lepidoptera, phasmids, weevils, pitcher-plant mosquitoes, grasshoppers, caddis flies, bees, Megaloptera, and cicadas (3,4,11,17,30,45,54,55,79,83,94,117). The patterns are indicative of rapid postglacial range expansion in many regions of the globe including Europe (11), North America (36), New Zealand (16,79), and Asia (3).…”