Phylogeny and Historical Biogeography of New Zealand Indigenous Aphidini Aphids (Hemiptera, Aphididae): An Hypothesis

Abstract

Aphids (Hemiptera: Sternorrhyncha: Aphididae) are most diverse in the temperate northern hemisphere, with only a few lineages native to the southern hemisphere. The highly diverse subfamily Aphidinae probably gained its dominance from a successful northern hemisphere radiation in the Tertiary. A few species in the tribe Aphidini, however, are indigenous to Gondwanan regions, including New Zealand and Australia. The conventional view is that these species dispersed to the south from the northern hemisphere after the main Tertiary radiation. We tested this hypothesis in a phylogenetic context by reconstructing relationships among New Zealand indigenous Aphidini, as well as their relationships to several northern taxa. Phylogenies were reconstructed from molecular data using independent and combined analyses of mitochondrial tRNA leucine cytochrome oxidase II and nuclear elongation factor-1 (EF1) sequences, with both parsimony and maximum likelihood methods. These analyses recovered a highly supported clade of four New Zealand species in the subtribe Aphidina. On the basis of previous fossil estimates of the age of Aphidini, the New Zealand clade was calculated to date to the middle Tertiary period. A second clade of two indigenous Rhopalosiphina may be similarly ancient. In EF1 and combined analyses, New Zealand indigenous species formed the two basal lineages of Aphidina, although their positions were not supported in 50% of bootstrap pseudoreplicates. These results imply that members of Aphidinae were present in the southern hemisphere during the Tertiary radiation, and suggest a new hypothesis that at least some northern lineages were derived from southern ancestors.