Effects of Formalin Treatment and Dung Consistency on Hatching and Establishment of Larvae of Onthophagus taurus (Schreber), Bubas bison (L.) and Onitis belial (F.) (Coleoptera: Scarabaeidae)

ABSTRACT As part of a program concerned with the introduction of exotic dung beetles to Australia, eggs of three species of dung beetle ( Onthophagus taurus, Bubas bison and Onitis belial ) were immersed for 3 min in 1% formaldehyde ( ca 3% formalin), followed by rinsing in ammonium carbonate and/or reverse osmosis water to neutralise or remove formaldehyde‐residues. In all three species, formaldehyde treatment had no adverse effects on either egg survival or larval establishment, irrespective of the type of post‐immersion rinse. Species effects and effects associated with the nature of the dung on which the eggs were placed after treatment were the main factors determining egg and larval survival. O. taurus was the most robust species, with 82.5% of individuals reaching pupation regardless of treatment. This compared with 18.5% for B. bison and 0% for O. belial. an alternative method of satisfying requirements for release from quarantine is suggested for species such as O. belial .