My research project is on hybridization between tree weta species in the North Island, New Zealand. The Auckland tree weta (Hemideina thoracica) occupies most of the north island down to the Manawatu and Hawkes Bay region. It meets the Wellington tree weta (Hemideina crassidens) in the Manawatu region and hybrids between the species have been found where their habitat overlaps. In Hawkes Bay the Auckland tree weta meets the Hawkes Bay weta (Hemideina trewicki), and in this region some hybrids have also been found. As yet it is not known whether these hybrids are fertile, and what introgression of alleles between species occurs. Any level of gene flow would have implications for species integrity and potentially give insights into these species’ evolutionary history.

My project will use morphology, karyolgy, mitochondrial haplotyping, nuclear sequences and microsatellites to find out degree of gene flow there is between the Auckland tree weta and the two species it contacts. I am also using captive breeding experiments to assess the rates of hybridization and to see if there are any post-mating barriers to hybridization. Hybrid weta will also be used to determine whether viable F2 progeny can be produced. The bacteria Wolbachia has been shown to cause hybrid inviability so its presence will also be tested for

Distribution of three species of tree weta (colours) and their chromosome races (dotted lines) in New Zealand.