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Home » Guide » Arthropods (Arthropoda) » Hexapods (Hexapoda) » Insects (Insecta) » Ants, Bees, Wasps and Sawflies (Hymenoptera) » "Symphyta" - Sawflies, Horntails, and Wood Wasps » Common Sawflies (Tenthredinidae) » Nematinae » Willow Sawflies and allies (Nematini) » Nematus » septentrionalis group (Nematus septentrionalis group) » Dusky Birch Sawfly (Nematus latitarsus)
Photo#307747
's' shaped caterpillars, one swinging - Nematus latitarsus
Copyright © 2009 squidpillow

's' shaped caterpillars, one swinging - Nematus latitarsus
Susquehanna River, lancaster County, Pennsylvania, USA
July 20, 2009
Hi everyone... I have a few questions about these caterpillars.
1) why are they in this 's' position?
2) as you can see the caterpillar on the left is swinging itself in a circular motion. It seemed to be a defense strategy to deter predators.
3) there were a couple red eyed flies that stayed by the caterpillar's for at least an hour. does this mean anything? i have photographs of this behavior if anyone wants to see.

thank you!

Images of this individual: tag all
's' shaped caterpillars, one swinging - Nematus latitarsus 's' shaped caterpillars, one swinging - Nematus latitarsus
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Contributed by squidpillow on 21 July, 2009 - 10:08am
Last updated 8 August, 2019 - 2:28pm

Moved
Moved from Nematinae.
… v belov, 8 August, 2019 - 2:28pm login or register to post comments

Craesus latitarsus
(I hope they are on a birch)
… Alexander Boldyrev, 8 August, 2019 - 2:24pm login or register to post comments

Moved
Moved from Unidentified Sawfly Larvae.
… v belov, 9 November, 2009 - 8:50pm login or register to post comments

Tenthredinidae
Nematinae. A defensive position, when alarmed. Glands between the prolegs may emit a repelling liquid.
… Dave Smith, 9 November, 2009 - 8:29pm login or register to post comments

Moved
Moved from Sawflies, Horntails, and Wood Wasps.
… Beatriz Moisset, 19 August, 2009 - 1:16pm login or register to post comments

Moved
Moved from ID Request.
… Beatriz Moisset, 19 August, 2009 - 1:13pm login or register to post comments

Sawfly larvae
Not caterpillars--Flies may have been parasitic and waiting to lay eggs on the larvae at an opportune time -- or they may have been just chillin'. The S position is characteristic of sawfly larvae partly because of the odd configuration of their prolegs. Thrashing about could be defensive behavior--maybe it saw the same flies you did.
… Harry Zirlin, 21 July, 2009 - 10:43am login or register to post comments

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