environmental enhancement again

[Michael Klein]

Bayensis, which is federally threatened, has the same biology as Euphydryas
editha quino (Quino Checkerspot), federally endangered.  The third instar
enters into diapause in April or May and remains that way until late January
or February.  It emerges from diapause and we call this a post diapause
larvae.  Its primary host plant at this stage is Plantago erecta.  If rains
have not been good, the plant can dry up early and the caterpillar would
then move over to Owl's Clover as a secondary host plant to complete its
larval growth.  Plantago grows earlier than the Castilleja so this would be
the regular sequence.

Michael Klein
San Diego

-----Original Message-----
From: owner-leps-l at lists.yale.edu [mailto:owner-leps-l at lists.yale.edu]On
Behalf Of Richard Worth
Sent: Wednesday, January 16, 2002 8:27 AM
To: leps-l at lists.yale.edu
Subject: Re: environmental enhancement again

Actually bayensis, down in Santa Clara County, CA, uses two native
hosts, Owl's clover, a scroph like Castilleja, and Plantago erecta.
I believe the larva starts feeding early in the spring on one, and
then moves over to the other host a little later to finish
development (not sure the order of plants used).  I recall slope
angle and aspect as factors in this behavior, too.  Though the plants
are in different families maybe there are chemical similarities that
allow "an easy switch" or maybe one is just "lettuce" to munch on to
finish development.????  But it seems there  is certainly some recent
evolution in the host use of editha over a wide distribution.  What
do other races of editha use as hosts throughout the range in the
west?  Anyone?

Rich

Andy wrote:  snipped
>So this is a taxon that DEPENDS on early successional habitats to
>reproduce (and who knows what else it needs...).  Land management
>practices in the Coast Ranges and valleys certainly have not favored this
>butterfly.  Interestingly, the "typical" larval food plant for Euphydryas
>editha through most of its range is Castilleja (in almost all of Oregon,
>anyway); however the possible original host Castilleja species in the
>Willamette Valley is also nearly extinct, and occurs only at a few sites
>(but not at the taylori site).
>The taylori's W of Corvallis feed on Plantago lanceolata, a widespread
>introduced "weed" (that occurs as a dense ground cover in areas under this
>powerline cut).  [note, however that the BC butterfly book indicates a
>native Plantago species as the a host for taylori, so perhaps the
>host-switch to lanceolata, which has presumably occurred separately in OR
>and WA - BC is not so dramatic].

Richard A. Worth
Oregon Department of Agriculture
Plant Division
rworth at oda.state.or.us
(503) 986-6461


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