2025-W2 Conservation genetics of the Noble chaffer (Gnorimus nobilis)

Overview

The Three Counties (Herefordshire, Worcestershire and Gloucestershire) have a long history of, and are nationally significant for, traditional orchards and key species that utilize the orchard wood rot habitat. In particular the Three Counties traditional orchards are a stronghold for the rare Noble chafer (Gnorimus nobilis), a large, saproxylic, metallic-green beetle. Other small outlier populations occur across the South East.  While in Europe, Noble chafer is associated with veteran oak, beech and willow, in the UK, Noble chafer larvae eat the decaying wood of fruit trees, with the exception of a remnant New Forest population which is found in oak.  

The reason for this difference in the habit of UK and European Noble chafer is not known, however, traditional orchard acts like an accelerated mini wood pasture habitat, as fruit trees veteranize more rapidly that longer lived species such as oak or beech, producing rot habitat over 50-80 years rather than hundreds. Noble chafer may have made that jump to fruit trees during the mass expansion of orchards in the 19th century which coincided with the felling of large timber trees for shipbuilding during the Napoleonic wars.  

Due to post WWII losses of traditional orchard habitat,  Noble chafer is classed as “vulnerable” in the UK and is on the list of priority habitats and species in England (‘Section 41 habitats and species’). The beetle is large and unlikely to fly very far, estimates are between 200 and 700m based on similar species and a single observation of a beetle on flowers 700m from the nearest orchard. The remaining populations appear to be fragmented and isolated, though the degree to which they are isolated is unknown and is a crucial piece of missing information to inform the conservation of the species.  

This project will focus on:  

• Generation of a Noble chafer genome sequence 

• A study of the population demographics and isolation of Noble chafer in the three counties using genetic analysis from frass.  How isolated are they, how long have they been isolated for and how long can they survive as these isolated populations before local extinction occurs?  

Figure 1: Noble chafer occurrence across the three counties (data 2000- 2010).