environmental enhancement again

[Richard Worth]

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

 
 ------------------------------------------------------------ 

   For subscription and related information about LEPS-L visit:

   http://www.peabody.yale.edu/other/lepsl