SOUTH AUSTRALIAN SUN-MOTHS

Synemon 'Flinders Ranges'  (Flinders Ranges Sun-moth)

flinders_Wilpena_m_Yunta_f.jpg (126306 bytes)

Male 38mm from Wilpena (left), female 38mm from Yunta

map_S_flinders.gif (10359 bytes)

Another un-studied species, belonging in the Chrysopogon/Cymbopogon (Poaceae) feeding complex of Synemon species, particularly Synemon austera and S. brontias, and may even be a form of the latter species. This complex is more commonly found in tropical and sub-tropical latitudes. It is a pretty moth, characterised by having a hindwing that is nearly all yellow-orange coloured, and is presently documented from S.A. in only the Frome Basin along ephemeral creeks containing its tussock host-grass Cymbopogon ambiguus (Lemon-scented or Kerosene Grass). It requires its hostplant to grow in the open and to not be congested by other plants, particularly feral weeds and grasses that tend to grow in the creeks that have a more reliable supply of water. Hence, this sun-moth does not occur in the temperate areas of SA even though its Cymbopogon hostplants may occur. It is not known what the consequences are for the early stages when there is an extended wet period in the habitat area and the creeks are flowing water.

It has a wing expanse of 30-40mm and flies in spring during October-early November. The range of this species may be more extensive than presently recorded as the larval host Cymbopogon also occurs in the Southern Flinders and Gawler Ranges, and the Far North-west Regions, or perhaps there may even be another new species to be discovered in S.A. as other sun-moths are known to utilise this grass in neighbouring Australian states.

It flies during the heat of the day, but by 3.00pm starts to look for a place to hide for the night. It often uses large cracks in the creek cliffs to hide in, which would seem to be an inhospitable environment as such places also tend to contain spiders and lizards and other nasties. Males often remain inactive on the ground during the day, possibly tending their territorial areas (leks).

Females spend their time laying eggs. The eggs are laid on the stems of the hostplant near its base, which the female accesses by landing on the ground near the plant then walking in under its tussocky leaves to its base. After each egg is laid, the females rest nearby on the ground in an open wing position. They do not feed from flowers as they do not possess a functional proboscis. They carry a lot of fat in their bodies to survive on, derived from their earlier larva and pupa stages, and in museum specimens this fat tends to seep into the wings discolouring them. Newly laid eggs are about 2.3x1.0mm, white coloured and have six longitudinal ridges. Other early stage details have yet to be documented.

It is threatened by over-grazing pastoral practices and locust spraying.

HPIM8508 S flinders 72047 bytesHPIM8507 S flinders (60924 bytes)

Resting female (after laying egg); 'tent' position left; open wing position right,
showing the exaggerated hindwing flash colours.

Cymbopogon ambiguus Wilpena HPIM8466

Ungrazed Cymbopogon ambiguus in an ephemeral creek at Wilpena.
The moths retire to cracks in the cliff by late afternoon, then emerge again the following late morning.

Cymbopogon ambiguus_ Wilpena HPIM8482 (155227 bytes)

Cymbopogon ambiguus (Lemon-scented or Kerosene grass) (Poaceae) at Wilpena.

Cymbopogon ambiguus Yunta HPIM8555

Cymbopogon ambiguus in Yunta Ck.

Cymbopogon_ambiguus_Olary_8304.jpg (307994 bytes)Cymbopogon_ambiguus_Olary_8303.jpg (306646 bytes)

Cymbopogon ambiguus in a small ephemeral creek near Olary.

flinders egg side Wilpena N273-25 (80498 bytes)flinders egg end Wilpena N273-31 (34819 bytes)

Egg of Synemon 'Flinders' having 6 longitudinal ridges. Egg on left is partially dehydrated.

Photography by R. Grund

 

b_end.gif (166 bytes)b_index.gif (486 bytes)b_next.gif (460 bytes)b_end2.gif (244 bytes)

Author:  R. GRUND, copyright 12 April 2011, all rights reserved.
Last update 19 February 2013.