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 Function of spikes on Tachinids?
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| Tony T |
Posted on 08-09-2007 00:38
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 Member Location: New Brunswick, Canada Posts: 664 Joined: 08.02.07 |
Does anyone know why many tachinids have large spines on the abdomen? I caught one today with relatively massive spines. Seems like such spines may be defensive but against what? 7 September 2007, NB, Canada. Length: 14mm Tony T attached the following image:  [43.5Kb] |
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| cosmln |
Posted on 08-09-2007 01:22
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 Member Location: Romania Posts: 956 Joined: 18.03.07 |
Hi Tony, this is really impresive. cosmln Cosmin-Ovidiu Manci biology & photography ********************** http://cosmln.nature4stock.com - cosmln's place http://dragonfly.nature4stock.com - Dragonflies of Romania http://insects.nature4stock.com - just insects http://mybiosis.org/nature/portal.php?pagename=firstpage - a romanian flora & fauna database and not only ********************** DSLR Collecting Saves Lives! ********************** " Only after the last tree has been cut down, only after the last river has been poisoned, only after the last fish has been caught, only then will you find that money can not be eaten. " an old indian saying |
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| jorgemotalmeida |
Posted on 08-09-2007 01:47
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 Member Location: Viseu - PORTUGAL Posts: 9296 Joined: 05.06.06 |
this seems to be Tachininae > Histricia Theo said before about the bristles on tachinids: "I suppose the bristles have a sensory function. This makes sense when you are operation in thick vegetation, like canopies for instance. In grasslands, it might be less functional. That's where most of the Phasiinae are found." One of the most impressive tachinid flies with bristles I've ever seen - Paradejeania , or it could be called "cactus fly" --- http://tinyurl.co... --- I would like, just for curiosity, if anybody knows a fly with much more brisltes than this one! Edited by jorgemotalmeida on 08-09-2007 01:49 |
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| ChrisR |
Posted on 08-09-2007 09:37
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 Administrator Location: Reading, England Posts: 7700 Joined: 12.07.04 |
I have always understood that the spines are sensory - being articulated and having nerve endings in the basal socket. But I can only guess they would need extra senses to find their hosts and I can't think how the bristles would help in this. Having vibration detectors would seem a rather low-tech and less accurate idea than, say, having larger and more sensitive antennae. I think most hymenopteran parasitoids rely mainly on their antennae to detect the presence of key detector chemicals in the environment. These can be the 'smell' of the host itself or the chemicals released from the host's foodplant when the plant has been eaten by the host. Sorry, not a very comprehensive answer!  |
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| Tony T |
Posted on 08-09-2007 14:01
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Member Location: New Brunswick, Canada Posts: 664 Joined: 08.02.07 |
Thanks Cosmin, Jorge, Chris. Sensory seems to be one function but I can't see why they would need such large spines. There has to be a 'more exciting' explanation. This species is a parasitoid of Arctiid caterpillars which in many species are excessively hairy. Fly is probably Hystricia abrupta In line with my earlier posts could I venture to say "Our Tachinids may not be bigger than your Tachinids, but they are a lot more spikey"  |
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