Canterbury Knobbled Weevil (Hadramphus tuberculatus)

Mohamed bin Zayed Species project number 11052747

 New Zealand is home to many endemic invertebrates (typically over 90% of species in any order) that have experienced range and population declines over the past 150 years with the arrival of humans and their pest species, and habitat modification (Winterbourn et al., 2008). On an oceanic island, the evolutionary divergences of insects isolated from neighboring continents are unique and contribute to a high level of endemic biodiversity (Caldecott et al., 1996; Cooper & Millener, 1993; Gillespie & Roderick, 2002). Perhaps the rarest weevil in New Zealand, the grassland weevil, Hadramphus tuberculatus, is a key example of a critically endangered, endemic invertebrate. It has only one known population at Burkes Pass Scenic Reserve, an area of lowland tussock grassland (690m altitude). The weevil is host plant specific to Aciphylla, a plant which is targeted for burning and removal by farmers when converting grassland areas to paddocks. Museum specimens from 150 years ago and Holocene fossils confirm the weevil was once found throughout the Canterbury Plains (Crawl, 1999; Kushel & Worthy, 1996).

 

In this study we aim to:

1) Analyze gene flow in Hadramphus tuberculatus throughout time by comparing DNA from museum specimens and DNA samples from the current population.   

2) Estimate the effective population (Ne) for past and present populations and the survival of H. tuberculatus.

3) Using phylogenetics, resolve the phylogenetic relationships among the four species in the genus Hadramphus and other genera of endemic speargrass weevils including Lyperobius.

4) Determine if H. tuberculatus has undergone a bottleneck or inbreeding depression.