Hawaiian caterpillars: Hyposmocoma molluscivora

[MexicoDoug at aol.com]

Hawaiian caterpillars hunt like spiders -report
Jul 22, 10:18 AM  (ET)
 
WASHINGTON (Reuters) - Tiny, snail-eating caterpillars found in Hawaiian  
rain forests tie up their prey with sticky silk and snack on them at leisure,  
surprised scientists said on Thursday.
 
It is the first time that caterpillars that eat snails or any other mollusk  
have been found, the researchers write in Friday's issue of the journal  
Science.
 
And while caterpillars of all kinds spin silk to make cocoons, this is the  
first time one has been seen to use it as spiders do to capture prey.
 
"Although all caterpillars have silk glands, this predatory caterpillar  uses 
silk in a spiderlike fashion to capture and immobilize prey," Daniel  
Rubinoff and William Haines at University of Hawaii wrote in their report.

The caterpillars of the newly described species, Hyposmocoma  molluscivora, 
are small -- about a third of an inch (8 mm) long. Wrapped in  their cocoons, 
they "lumber along" leaves, Rubinoff and Haines said.
 
"The caterpillars do not eat plant foliage, even when starving," they  wrote.
 
Instead, they hunt Tornatellides snails.
 
When they find one, "they immediately begin to spin silk webbing attaching  
the snail shell to the leaf on which it rests, apparently to prevent the snail  
from sealing itself against the leaf or dropping to the ground," the 
researchers  wrote.
 
"The larva (caterpillar) then wedges its case next to or inside the snail  
shell and stretches much of its body out of its silk case, pursuing the  
retreating snail to the end of the shell from which there is no escape. We  observed 
18 attacks by 10 different larvae following this sequence."
 
Sometimes the caterpillars decorate their silk casings with empty snail  
shells, probably as a form of camouflage, the researchers said.
 
The caterpillars eventually become small moths.
 
The researchers say they are surprised by the findings and note the  
caterpillars join a range of unusual Hawaiian fauna, including spiders that  impale 
their prey in flight.
 
"Caterpillars and terrestrial snails co-occur widely on all the continents  
where they are present, but only in Hawaii have caterpillars evolved to hunt  
snails," they wrote. 

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