2020 will be a year to remember. For DBEE, the importation of a new dung beetle species has been particularly challenging with Morocco, France and Australia in numerous lockdowns, rendering international transport near impossible.
While Onthophagus andalusicus (the second species to be imported as part of DBEE project) arrived in Australia in September, the third species, a dung ball roller, Gymnopleurus sturmi could not be collected from the field during the COVID 19 outbreak. Unfortunately this also meant that several experiments with G. sturmi planned by the French and Moroccan team to better understand its behaviour and optimise rearing conditions in the laboratory were not completed.
The French team thus turned to other local dung beetle species to test different protocols and learn more about roller species, which are known to be more challenging to rear than tunnelers.
Three species were collected and maintained in the laboratory: Scarabeus laticollis, Sisyphus schaefferi and Gymnopleurus geoffroyi. Each species was shown to have very different rearing requirements, with Scarabeus laticollis giving the best results overall. Scarabeus laticollis remained active at 5°C, continually feeding on dung even after two months. Further research into this species is warranted to see if it could be useful for burying dung in winter months across in southern Australia, where we observe a major gap in dung beetle activity. Interestingly, females that were kept alone in small cups successfully used handmade brood balls on offer to lay their eggs.
The use of simulated brood balls could simplify and speed the rearing process of other roller species and has previously been used on other Copris species. Sisyphus schaefferi was reared successfully under various conditions but did not use the handmade broodballs to lay eggs. Gymnopleurus geoffroyi was collected too late in the season and did not reproduce, as it has an overwintering requirement. These results further highlight the need for carefully conducted research on each species before importation.
Everything so far points towards a better 2021 season for the DBEE importation program. As soon as O. andalusicus and G. sturmi are successfully collected in Morocco in April - May, they will be shipped to France and then Australia. The Moroccan and French teams will hopefully soon be resuming their research program by testing behaviour and dung burying efficiency of G. sturmi in the laboratory and in mesocosms in the field.