Greg Dalton2, Kate Joseph3, Dr Bernard Doube1

1Dung Beetle Solutions International, Bridgewater, Australia, 2Creation Care, Strathalbyn, Australia, 3South West Prime Lamb Group, Portland, Australia

Biography:

Dr Bernard Doube OAM worked with CSIRO for 29 years, including 7 years as OIC of the CSIRO Dung Beetle Research Unit in Pretoria, South Africa. Since 2003 he has been the lead researcher and director of Dung Beetle Solutions International (DBSI), where he is strongly involved in research and farmer education. Bernard works in association with many research partners including water authorities, federal agencies (e.g. Meat and Livestock Australia), universities, and Landcare and other landholder groups. He has published many research papers on dung beetles, earthworms and the biological basis of soil health. In 2021 he was invited by the FAO Global Soil Partnership to be lead author in producing a practices overview and a case study on the role of dung beetles in recarbonising global soils.

Bernard is an adjunct researcher at Charles Sturt University and was a theme leader in the Dung Beetle Ecosystem Engineers project. A major part of this work was the development and management of on-farm producer-managed field nurseries for mass rearing new species for wide distribution.

Abstract:

We discuss three serious challenges to establishing the introduced dung beetle Onthophagus vacca in southern Australia. In Europe and North Africa, it coexists with 30+ other species. In Australia it would coexist with 2–4 species but would face severe competition from the enormously abundant Onthophagus taurus. O. vacca was introduced to Australia in 2012 and was reared through several generations in the laboratory and then in field-cages at Strathalbyn SA, reaching 15,000+ adults by 2018. About 10,000 were provided to the national project Dung Beetle Ecosystem Engineers (DBEE) but, while some progeny emerged in the laboratory, none survived from mass-rearing-cages. In 2019 a further 20,000 beetles were provided from Strathalbyn. !5,000 were released to the field in December 2019 with no progeny recovered. 1500 failed to breed in DBEE mass-rearing-cages but successful rearing continued in the laboratories. The remaining 3500 were allocated to a successful national field trial which involved field cages (1x1m) in five states and bred successfully in sheep and cattle dung. Cages were inoculated with 50 adult beetles and emergence of progeny was monitored over time. Egg-to-emerged adult took 8–12 weeks in warm-moist environments and 30+ weeks in cool-moist environments. There was no survival in hot-dry environments.

The challenges to establishment include:

– Providing a suitable environment in the laboratory and field cages

– Choosing the appropriate temperature and moisture regimes for field releases

– Severe competition with O. taurus.

We recommend the species be introduced into cool-moist environments with low numbers of O. taurus.