Help map Crusader Bug in Tasmania
Adult male (right) and female crusader bug on young shoot tips of coast wattle growing in dune scrub at Beechford, north east Tasmania. Note distinctive cross on hemelytra, orange antennae tips and swollen hind legs particularly on the male. Adults of gum tree bug are brown and lack the pale cross. (photo Simon Fearn QVMAG)
Crusader bug is one of the largest and most widespread species in the family of coreid bugs in Australia. Adults of this distinctive species are characterised by a pale yellowish cross on the back, orange tips to the antennae and large, expanded hind legs. Males also have spines on the hind legs.
Crusader bug occurs widely across mainland Australia but was not recorded in Tasmania until 2015. It also occurs in Indonesia, New Guinea and east to Fiji.
It is a sap sucking insect – a true bug. Favoured host plants in Australia are Acacia (wattle) and Cassia but crusader bug can also be a minor pest of citrus. At least 22 species of plants in nine families have been documented as food plants including 10 wattles.
Many species of coreid bugs emit an acrid-smelling defence chemical if carelessly handled and the males have enlarged hind legs.
The most commonly encountered large coreid bug in Tasmania is the gum tree bug Amorbus obscuricornis, which can be observed feeding on the soft upper shoots of eucalypts during the summer. It is brown and lacks the pale cross.
A juvenile crusader bug on coast wattle. It has no wings and so no cross pattern on its back. Instead it has a transverse pale waistband. Juveniles of gum tree bug have an orange Y mark instead of the pale band. (photo Simon Fearn - QVMAG)
Crusader bug is now common as adults and juveniles at Beechford on the north east coast of Tasmania and east of the mouth of the Curries River for at least 1.3 km. It was not present there in the 1970s and 1980s. It gathers on low-growing, juvenile stems and foliage of coast wattle (Acacia sophorae) on the seaward fringes of large, dense and well established stands of mature specimens. Adults have also been seen close to the river mouth to the east of Greens Beach town.
Crusader bug is not known elsewhere in Tasmania. Being a large and conspicuous insect it is unlikely to have gone unnoticed for many decades. At Beechford, the bugs have been seen flying strongly over the dune scrubland at heights of up to 6 m. It could spread along the kilometres of suitable, interconnected habitat along the coastline and perhaps inland.
Crusader bug has shown a preference for softer, juvenile foliage on young specimens of coast wattle. All the dense aggregations of crusader bug at Beechford that included juveniles were confined to sheltered gullies in dune scrubland or on very low-growing coast wattle in more exposed sites.
Help Map Its Distribution
Simon Fearn at the Queen Victoria Museum and Art Gallery in Launceston and the Entomology Team in Biosecurity Tasmania (Department of Primary Industries, Parks, Water and Environment) want to map the distribution of crusader bug.
Beechford north east Tasmania with locations where crusader bug occurs marked in blue. Sites further east or west have not been surveyed. (map Simon Fearn)
For further information or to report suspect crusader bug please contact us using one of the methods set out below. If you are reporting crusader bug sightings please include location and date and if possible attaching an image.
Queen Victoria Museum
2 Invermay Road
Phone 03 6323 3777
P.O. Box 403, LAUNCESTON 7250
Department of Primary Industries, Parks, Water & Environment
1 Rundle Street
Phone 0418 379 726
P.O. Box 303, DEVONPORT 7310.