Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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Author: search.filters.author.Trewick SASubject: search.filters.subject.Animals

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    Mwhitiwhiti Aotearoa: Phylogeny and synonymy of the silent alpine grasshopper radiation of New Zealand (Orthoptera: Acrididae)
    (Magnolia Press, 2023-12-11) Trewick SA; Koot EM; Morgan-Richards M
    Aotearoa New Zealand has a fauna of endemic alpine grasshoppers, consisting of thirteen species distributed among four genera. The many re-classifications of species within this group and the presence of species complexes highlight the uncertainty that surrounds relationships within and between these genera. High-throughput Next Generation Sequencing was used to assemble the complete mitochondrial genomes, 45S ribosomal cassettes and histone sequences of New Zealands four endemic alpine genera: Alpinacris, Brachaspis, Paprides and Sigaus. Phylogenetic analysis of these molecular datasets, as individual genes, partitions and combinations returned a consistent topology that is incompatible with the current classification. The genera Sigaus, Alpinacris, and Paprides all exhibit paraphyly. A consideration of the pronotum, epiphallus and terminalia of adult specimens reveals species-specific differences, but fails to provide compelling evidence for species groups justifying distinct genera. In combination with phylogenetic, morphological and spatial evidence we propose a simplified taxonomy consisting of a single genus for the mwhitiwhiti Aotearoa species radiation.
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    A new species of large Hemiandrus ground wētā (Orthoptera: Anostostomatidae) from North Island, New Zealand
    (Magnolia Press, 2021-03-12) Trewick SA
    A new species of Hemiandrus ground wētā is described from North Island, New Zealand. Hemiandrus jacindasp. nov.is larger and more brightly coloured than other species in the region, but appears to be scarce and restricted to remnant native forest habitat.
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    Lack of assortative mating might explain reduced phenotypic differentiation where two grasshopper species meet
    (John Wiley and Sons Ltd on behalf of European Society for Evolutionary Biology, 2022-04-12) Morgan-Richards M; Vilcot M; Trewick SA
    Hybridization is an evolutionary process with wide-ranging potential outcomes, from providing populations with important genetic variation for adaptation to being a substantial fitness cost leading to extinction. Here, we focussed on putative hybridization between two morphologically distinct species of New Zealand grasshopper. We collected Phaulacridium marginale and Phaulacridium otagoense specimens from a region where mitochondrial introgression had been detected and where their habitat has been modified by introduced mammals eating the natural vegetation and by the colonization of many non-native plant species. In contrast to observations in the 1970s, our sampling of wild pairs of grasshoppers in copula provided no evidence of assortative mating with respect to species. Geometric morphometrics on pronotum shape of individuals from areas of sympatry detected phenotypically intermediate specimens (putative hybrids), and the distribution of phenotypes in most areas of sympatry was found to be unimodal. These results suggest that hybridization associated with anthropogenic habitat changes has led to these closely related species forming a hybrid swarm, with random mating. Without evidence of hybrid disadvantage, we suggest a novel hybrid lineage might eventually result from the merging of these two species.