Dr Justin K Cappadonna1,2, Dr James P Hereward2, Emeritus Professor Gimme H Walter2

1The University of Tasmania, Launceston, Australia, 2The University of Queensland, St Lucia, Australia

Biography:

Dr Justin Cappadonna is an applied entomologist interested in understanding the behaviours of generalist pests and integrating novel technologies with traditional pest management approaches. He earned his PhD at the University of Queensland and was previously R&D Entomology Lead at the agtech company, RapidAIM, developing technologies to remotely forecast agricultural pest infestations. He is now a Lecturer at the Tasmanian Institute of Agriculture.

Abstract:

Green mirids (Creontiades dilutus, Miridae) are bugs endemic to Australia that frequently move back-and-forth across different host plants while feeding. In cotton (Gossypium hirsutum) growing landscapes, these insects will leave crops that support high densities, such as pigeon pea (Cajanus cajan), arrive at nearby cotton in low densities, feed, and then return to pigeon pea hosts. This is problematic for pest managers because even in low densities mirids are highly damaging to cotton, and the reasons that they move across hosts and the mechanisms responsible for their retention at specific hosts remain elusive. Also, green mirids may be nocturnal which makes collecting behavioural observations in the field challenging. This study evaluated: (1) the diel (24 h) period in which green mirids were most active, (2) whether they respond to plant volatiles immediately before landing on host substrates, and (3) if their presence on a host is in response to attraction or arrestment cues. The results suggest that green mirids are most active shortly after sunset, and they remain motionless during the day (unless disturbed). Their movement at night was arrested by hosts before touching plant tissues. There was no evidence to suggest that these bugs are attracted by plant volatiles beyond 2 cm. These outcomes demonstrate that insect behaviours need to be investigated within their typical activity periods, and that arrestment cues possibly play a central role in the host-finding process of green mirids and probably, therefore, other mirid species.