We’ve dung it again! Our exotic solution to the dung problem in Australia continues
The new species - Bubas bubalus
- Bubas bubalus is a night flying, univoltine species adapted to the Mediterranean climate areas of southern Europe
- It is typically a species of grassy pastures, but is also found in open woodland.
- It readily colonises fresh dung and, in its native habitat, is one of the main species responsible for the degradation of cattle dung.
- Although it exhibits no clear preference for particular types of dung, its need for large quantities of dung when egg-laying means that it is likely to become established in areas only where ample cattle dung is available
- Eggs are laid into dung masses up to 30 cm below the surface and each female is thought to lay more than 60 eggs in its lifetime. Population densities of 20 beetles per pad are commonplace and such densities result in very rapid dung dispersal.
- Previous work with Bubas bubalus in the quarantine laboratory of the Australian Animal Health Laboratory (AAHL) showed that beetles collected in Spain in April (northern hemisphere spring), laid an average of 15 eggs per female, with the majority of the eggs being laid between mid-July and mid-September. The mean time from egg to adult was 110 days. Under laboratory conditions (23°C and 14L: 10D), there was no evidence of any interruption of juvenile development.
- In Languedoc in southern France, Bubas bubalus emerges in late winter-early spring and begins oviposition after a brief period of intensive feeding. Oviposition continues through early summer, with emergence of the next generation delayed until the following spring.
- In the cooler areas of continental Spain (e.g. Salamanca province), the seasonal phenology of Bubas bubalus is rather different, with beetles being present in all seasons except summer. First emergence occurs in late autumn, but there is little activity or ovarian development until late winter-early spring, when oviposition increases sharply.
- Bubas bubalus exhibits a similar pattern of seasonal activity in the dairying areas of northern Andalucia. It is thought that autumn and spring peaks of abundance in northern Spain are, in part, a direct response to low winter temperatures; and in part the result of two discrete periods of emergence (Lumbreras et al 1991).
- Bubas bubalus is found mainly in the Mediterranean climate areas of southern Europe, where its distribution closely parallels that of Bubas bison (Fig. 3).
Previous time in Australia
Two previous attempts to rear and release Bubas bubalus in Australia were unsuccessful, mainly because numbers reaching the adult stage were too small to make releases.
Bubas bubalus is closely related to Bubas bison, which was first released in Australia at Dardanup, WA, in 1983.
Since then, Bubas bison has been successfully re-distributed to South Australia, Victoria, southern NSW and the ACT.
Bubas bubalus is expected to attain a similar distribution to Bubas bison, but because it is a more cool-hardy species and the two species occupy somewhat different seasonal niches, inter-specific competition is unlikely to affect the establishment of Bubas bubalus or the persistence of populations of Bubas bison.
In Europe, Bubas bison begins laying soon after emergence in autumn.
Laying continues through winter and peaks in spring.
In the case of Bubas bubalus, some individuals may emerge in autumn, but the start of laying is usually delayed until early spring and continues into summer.
Both species utilise a range of dung types but are usually most abundant in cattle dung.