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At 9:54 AM -0300 9/23/14, Jim Wolford wrote:
>THANKS, KIRK, from Jim in Wolfville
>
>>From: Kirk Hillier <<mailto:kirk.hillier@acadiau.ca>kirk.hillier@acadiau.ca>
>>Subject: Re: complexity of mimicry examples -- was Batesian Mimic - got me
>>Date: September 22, 2014 at 8:47:48 PM ADT
>>To: Jim Wolford
>><<mailto:jimwolford@eastlink.ca>jimwolford@eastlink.ca>, naturens
>><<mailto:naturens@chebucto.ns.ca>naturens@chebucto.ns.ca>
>>Cc: Todd Smith <<mailto:todd.smith@acadiau.ca>todd.smith@acadiau.ca>
>>
>>My understanding is that all milkweed species will produce the
>>cardiac glycosides which make them (and subsequently monarchs)
>>distasteful or even toxic. The amount produced by each species is
>>undoubtedly variable. It is worth noting that monarchs will feed
>>on a Physocarpus ('nine bark') species as well - I'd wager they're
>>less toxic/non toxic under those circumstances. The queen
>>butterflies also sequester similar compounds from their food plants.
I beg to differ with this "worth noting" statement. There are no
records, that I am aware of, of Danaus plexippus feeding on any
member of the Rosaceae (see the HOSTS database at
http://www.nhm.ac.uk/research-curation/research/projects/hostplants/).
I suspect this erroneous 'record' of Physocarpus opulifolius
(ninebark) is actually an error derived from the Monarch's known use
of Gomphocarpus physocarpus, a member of the Asclepiadaceae (the
milkweed family).
On the subject of Asclepias phytochemistry, there IS variation in the
quantity, efficacy and identity of cardenolides found amongst, and
even within, species of milkweeds (see
http://onlinelibrary.wiley.com/enhanced/doi/10.1111/j.1469-8137.2011.04049.x/
for the excellent recent review by Agrawal et al., 2012). There is
also variation in the use and preference of Monarch butterflies for
these plants (only 27 of the 108 known species of milkweed in North
America are used by Monarchs, Malcolm & Brower, 1989, Experentia,
citation below).
As has been noted the common milkweeds found in NS have relatively
low cardenolide levels, however, it is important to note that these
levels are significantly higher in the young plants that are
overwhelmingly preferred by Monarchs AND that caterpillars can
bioaccumulate cardenolides to concentrations much higher than is
present in the milkweeds that they feed on (see Malcolm and Browers
1989 paper in Experentia, full text at
http://link.springer.com/article/10.1007%2FBF01951814#page-1).
Phil
--
Phil Schappert, PhD
27 Clovis Ave.
Halifax, NS, B3P 1J3
902-460-8343 (cell)
philschappert.ca
imaginaturestudio.ca
imaginaturestudio.blogspot.ca
philschappert.com
"Just let imagination lead, reality will follow through..."
(Michael Hedges)
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<html><head><style type="text/css"><!--
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--></style><title>Re: [NatureNS] re complexity of mimicry
systems</title></head><body>
<div>At 9:54 AM -0300 9/23/14, Jim Wolford wrote:</div>
<blockquote type="cite" cite>THANKS, KIRK, from Jim in Wolfville<br>
<blockquote type="cite" cite><b>From:</b> Kirk Hillier <<a
href="mailto:kirk.hillier@acadiau.ca">kirk.hillier@acadiau.ca</a
>></blockquote>
<blockquote type="cite" cite><b>Subject: Re: complexity of mimicry
examples -- was Batesian Mimic - got me</b></blockquote>
<blockquote type="cite" cite><b>Date:</b> September 22, 2014 at
8:47:48 PM ADT</blockquote>
<blockquote type="cite" cite><b>To:</b> Jim Wolford <<a
href="mailto:jimwolford@eastlink.ca">jimwolford@eastlink.ca</a>>,
naturens <<a
href="mailto:naturens@chebucto.ns.ca">naturens@chebucto.ns.ca</a
>></blockquote>
<blockquote type="cite" cite><b>Cc:</b> Todd Smith <<a
href="mailto:todd.smith@acadiau.ca">todd.smith@acadiau.ca</a>></blockquote
>
<blockquote type="cite" cite><br></blockquote>
<blockquote type="cite" cite>My understanding is that all milkweed
species will produce the cardiac glycosides which make them (and
subsequently monarchs) distasteful or even toxic. The amount
produced by each species is undoubtedly variable. It is worth
noting that monarchs will feed on a Physocarpus ('nine bark')
species as well - I'd wager they're less toxic/non toxic under those
circumstances. The queen butterflies also sequester similar
compounds from their food plants.</blockquote>
</blockquote>
<div><br></div>
<div>I beg to differ with this "worth noting" statement.
There are no records, that I am aware of, of Danaus plexippus feeding
on any member of the Rosaceae (see the HOSTS database at
http://www.nhm.ac.uk/research-curation/research/projects/hostplants/).
I suspect this erroneous 'record' of Physocarpus opulifolius
(ninebark) is actually an error derived from the Monarch's known use
of Gomphocarpus physocarpus, a member of the Asclepiadaceae (the
milkweed family).</div>
<div><br></div>
<div>On the subject of Asclepias phytochemistry, there IS variation in
the quantity, efficacy and identity of cardenolides found amongst, and
even within, species of milkweeds (see
http://onlinelibrary.wiley.com/enhanced/doi/10.1111/j.1469-8137.2011.<span
></span>04049.x/ for the excellent recent review by Agrawal et al.,
2012). There is also variation in the use and preference of Monarch
butterflies for these plants (only 27 of the 108 known species of
milkweed in North America are used by Monarchs, Malcolm & Brower,
1989, Experentia, citation below).</div>
<div><br></div>
<div>As has been noted the common milkweeds found in NS have
relatively low cardenolide levels, however, it is important to note
that these levels are significantly higher in the young plants that
are overwhelmingly preferred by Monarchs AND that caterpillars can
bioaccumulate cardenolides to concentrations much higher than is
present in the milkweeds that they feed on (see Malcolm and Browers
1989 paper in Experentia, full text at
http://link.springer.com/article/10.1007%2FBF01951814#page-1).</div>
<div><br></div>
<div>Phil</div>
<div><br></div>
<x-sigsep><pre>--
</pre></x-sigsep>
<div><font face="Courier" color="#000000"><br>
Phil Schappert, PhD</font&g