Hunting for ghost moth larvae

[John Grehan]

A week ago Scott Griggs and I did a search for larvae of the wood-boring 
ghost moth Sthenopis argentiomaculatus in Vermont (USA). Larvae of this 
moth bore into the root stock of swamp alder (sorry I do not have the 
genus/species to hand at this time). This species is quite common in some 
areas of its range in North America, but in much of the north-western part 
of Vermont it takes some looking for. Several years ago I found a cluster 
of alders where larvae appeared to be quite common and as I wanted to find 
some fresh material we took another look. Unfortunately this time it was 
not to be so simple as we bushwacked our way through the undergrowth 
looking for pupal exit holes from the June emergence without success. We 
then took to bending a few stems (about 2 - 4 cm diameter) and cutting a 
few to find active tunnels. After about an hour and a half of fruitless 
searching we finally found one stem with larval activity. The larva was 
well grown, so presumably it at least represents the generation from last 
year. I had hoped to take a look at what larvae were doing two months after 
the June emergence, but it was not to be.

Probably because of the secluded larval habit, very little is documented 
about the feeding behavior of this species, or many ghost moths in general. 
The larval tunnel begins in the roots and extends into the basal region of 
the stem where the larva eventually emerges. In the root stock the larval 
tunnel is open to the surface and may suggest that the larva actually feeds 
on material outside the alder stem itself. The early stages of many ghost 
moths feed on leave and soil detritus, and even fungi in some cases. 
Whether this is the case with Sthenopis remains to be seen.

John Grehan

   


 
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