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Juvenile adder diet |
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Peter
Senior Member Joined: 17 Jan 2008 Location: United Kingdom Status: Offline Points: 310 |
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Posted: 01 Aug 2008 at 4:08am |
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I just wondered whether any research has been done regarding juvenile adder diet? I imagine that it would be quite some task to consistantly find mammalian and reptillian prey of a suitable size. Is there any evidence to support the theory of predation of invertebrates?
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BLF Dragonscapes Habitats officer
Amphibian and Reptile Conservation e: peter.hill@arc-trust.org |
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axel
Member Joined: 16 May 2006 Status: Offline Points: 31 |
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Last year a paper was published which conducted feeding trials with captive neonate V. berus, and found no instances of feeding on insects. In contrast the related Vipera renardi consumed inverts 98% of the time. The authors concluded that V. berus is a purely vertebrate feeder. Additionally, the venom of V. berus was found to not very toxic to crickets, in contrast to the frequent insect feeding species (such as V. renardi) have a venom which is highly toxic to crickets. The reference is Starkov et al. (2007) Toxicity of venoms from vipers of Pelias group to crickets (Gryllus assimilis) and its relation to snake entomophagy. Toxicon 49: 995-1001. You can get the abstract on google scholar, or if anyone wants the full PDF pm me your email and I can send it as an attachment cheers. |
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Vicar
Senior Member Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
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Hi Peter,
I don't know of any references, but I've often been told that young Vb are very fond of juvenile Common lizards. You certainly do find an increased presence of juv Vb at Zv sites, so observation supports this info, but I've never seen one eating. |
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Peter
Senior Member Joined: 17 Jan 2008 Location: United Kingdom Status: Offline Points: 310 |
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Hi Steve,
There certainly is a plentiful supply of juvenile commons at some of the sites that I visit, but not all. |
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BLF Dragonscapes Habitats officer
Amphibian and Reptile Conservation e: peter.hill@arc-trust.org |
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Vicar
Senior Member Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
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Appleby, 'British Snakes'.
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calumma
Senior Member Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
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I am also quite interested in this subject and have recently interrogated
the KRAG database to identify possible trends. 125 sites have records of adder. Of those, 41 sites have records of adder, slow-worm and viviparous lizard (and sometimes grass snake). 12 sites have records of adder and slow-worm but no lizard. 8 of the 12 sites only have ad hoc records (i.e. no detailed survey work has been undertaken) so the absence of lizards is by no means certain. A further 2 sites have been thoroughly surveyed and lizards not recorded - but adder could not be confirmed either. The original adder records at these two sites are either incorrect or perhaps represent vagrants, but probably do not represent a population. That leaves 2 sites where reasonably detailed survey work has been undertaken. At these last 2 sites, only adult adder have been recorded. Interestingly at one site, adult male and female adder were observed close to a suspected hibernacula. I'm keen on collecting more data to try to determine what the fate of these two populations will be. I also examined the adder data and found 13 sites with both adder and viviparous lizard, but no slow-worm. Of these, 12 sites represented ad hoc records where no detailed survey work had been undertaken. However, one site had been thoroughly surveyed and slow-worm not recorded. This site was found to support both adult and juvenile adder. Not conclusive data by any means, but hopefully of interest. Does anybody else have data on species assemblages and lifestage structure for other areas? Lee |
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Vicar
Senior Member Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
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Here's a partial cut of the data from some of our 2008 monitoring sites (still on-going).
Non-presence does not necessarily imply absence, just that no sighting has been reported.
Edited by Vicar |
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calumma
Senior Member Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
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Steve
So it looks like you also have at least one site (GNH) with adder and slow-worm that may lack lizard. Interestingly, your data also suggests that only adult adder have been recorded at this site. Is there any historical information to suggest that lizards used to occur? Is the site an area where adult adder hunt, perhaps situated close to other areas that may also support breeding adder and lizard? I can quite imagine the scenario where low numbers of adult adder are recorded at sites where lizards are absent (or present in such low numbers they are very difficult to record). The areas where females give birth are often close to hibernacula and it is perhaps these sites where the absence of lizards may become a critical factor. What I find interesting about the Kent records is that at one of the sites where lizards have not been recently observed, adult adder have been recorded close to hibernacula. Of course there is an issue with reptile recording about what actually constitutes a site. In attempting to identify key sites, KRAG are focussing on those areas where breeding and/or hibernating has been recorded. Different sites (or areas within a site) may offer different opportunities for different species. With adder, piecing this jigsaw together is obviously very important. There just aren't enough hours in the day! Lee |
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Vicar
Senior Member Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
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Hi Lee,
The GNH site is fairly isolated and not large. I doubt that there is very much opportunity for migration from the site, and fully expect to identify hibernacula in time. It is a new core site, and only added to the long-term monitoring sites from June this year. I would expect to find juvenile adders there (eventually), as we know adult adders are seen more frequently than juveniles. I would not be surprised to find Common lizards at the site, Sand lizards are present; whose juveniles are likely to be predated. ---------- Just checked historical records, and Zv has been found on (GNH) site from 1990-2005. (The table was 2008 survey data only). There are also legacy records for immature Vb as recently as 2002. Edited by Vicar |
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calumma
Senior Member Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
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Bill W has now emailed to let me know that the two Kent sites with adder but
no lizards did in fact used to support lizards during the 80's and 90's (I've asked for the records!). Survey work is continuing at the two sites and it will be interesting to see whether lizards do in fact turn up (along with juvenile Vb) - I don't yet have the 2008 data. If lizards still remain elusive, we will have to broaden our survey area and identify other nearby lizard sites that may offer better potential for breeding adder. Edited by calumma |
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