Samea multiplicalis

Samea multiplicalis (Guenée, 1854)
Salvinia Moth
(one synonym : Isopteryx nicaeusalis)
SPILOMELINI , PYRAUSTINAE , CRAMBIDAE

Don Herbison-Evans ( donherbisonevans@yahoo.com )
&
Stella Crossley

Samea multiplicalis
(Photo: courtesy of Buck Richardson, Kuranda)

This caterpillar is yellowish with a brown head. It lives in a silk web constructed on top a foodplant leaf. The caterpillar grows to a length of about 2 cms.

It is a native of southern Brazil, but was introduced deliberately into Australia to control its foodplants :

Water Lettuce ( Pistia stratiotes, ARACEAE ),

Duckweed ( Lemna species, ARACEAE )

Kariba Weed ( Salvinia molesta, SALVINIACEAE ),

Water Hyacinth ( Eichhornia crassipes, PONTEDERIACEAE ), and

Water Fern ( Azolla pinnata, AZOLLACEAE ).

These are aquatic weeds which can block tropical waterways. It has been studied in the USA for similar purposes. The moth was released at three sites in Australia around 1987, where it became established and dispersed about 170 km in 20 months. However, control of the water weeds was not achieved, and the caterpillars did not reduce plant growth permanently at any study site.

(Photo: courtesy of Graeme Cocks, Townsville)

The adult moth is pale brown with multiple white markings outlined and transected in dark brown. It has a wingspan of about 2 cms.

The caterpillar is attacked by several parasites which may limit its population growth, incuding:

Bassus agathoides ( BRACONIDAE ).

It is also sensitive to nitrogen levels in the plant.

In Australia: the moth may now be found in :

New South Wales, and

Queensland.