anise swallowtail & purplish copper

Cris Guppy or Aud Fischer cguppy at quesnelbc.com
Sun Feb 18 23:46:07 EST 2001


Hi from Quesnel, BC,

For those who do not know the area, the Boundary Bay dike (Delta, BC)and the
Terra Nova site (Richmond, BC) are fairly close together, and have the same
basic climate. Both are south of Vancouver, BC (which appears on most maps).
The foodplants should grow just fine at Terra Nova, keeping in mind that cow
parsnip and angelika prefer wet, rich soil, lots of sunshine and not too
much competition from other tall vegetation.

Most British butterfly introductions have been successful, with most of the
failures resulting from the habitat becoming unsuitable due to vegetation
succession eliminating the larval foodplants. At least one introduction
failed because the caterpillars destroyed all the foodplant, due to lack of
predators or parasites to control the butterfly population.

The Purplish Copper should be relatively easy to successfully introduce,
providing the correct foodplants are abundant there (Polygonum species are
best, Rumex species are also used). The foodplant should be as widespread as
possible within the release area, so that when females stray from one part
of the area they will find foodplants in another part. I suspect that 10-20
females would be sufficient, but more is better. If you can only get a few
females, plan to cage them over a patch of foodplant, and then move the cage
every 2-3 days (ensure that nectar sources are available, or hand feed).
This will help to maximize the number of eggs laid during the life of the
female. I know of one high-density population near Victoria, BC that exists
in about 1/2 hectare of ditchline, so 14 hectares should be ample to
maintain a population.

The Anise Swallowtail is more problematic. Females roam large areas while
laying eggs, so foodplants should be scattered as widely as possible. At
Boundary Bay, the ocean prevents females from straying to the west. The dike
is long enough so that females constantly find new foodplants as they move
back and forth along the dike. Probably many females are lost to the
population by straying out over the farmland to the east. The critical
factor for the establishment of an Anise Swallowtail population at Terra
Nova will be what proportion of the population is lost through straying
outside the area of suitable habitat. I cannot predict what will happen, all
you can do is try. Near Victoria there is a healthy population in Uplands
Park, which at a guess is about the size of Terra Nova. Caterpillar
collection at Boundary Bay is definitely the best way to introduce Anise
Swallowtails, rather than using females. You could also cage a few females
over foodplants at either Boundary Bay or Terra Nova for a few sunny days,
and then disperse the eggs over as many individual foodplants as possible. I
would try for at least 100 caterpillars/eggs, and preferably more.

You could also consider introducing Margined Whites (Pieris marginalis).
They are also present at Boundary Bay, but I do not know how common they
are. The foodplant is wild mustard (usually native Arabis species), which is
a biannual and could be seeded in disturbed soil at Terra Nova (loosen
compacted soil with a rake, then scatter seed). Probably 5-10 females would
be sufficient to establish a population. [all my estimates of number of
females or caterpillars are based on "gut feeling" derived from knowledge of
wild populations, and so are little better than guesses]

Please be sure to keep notes on exactly what you do, and publish the methods
and results in Discovery (Vancouver Natural History Society) or the BC
Naturalist (Federation of BC Naturalists newsletter), as well as progress
reports on leps-l. Whether you succeed or fail, what you do will provide
information for future introduction attempts.

Cris Guppy
Quesnel, BC

----- Original Message -----
From: "Don Benson" <don.benson at attcanada.net>
To: <leps-l at lists.yale.edu>
Sent: Sunday, February 18, 2001 12:00 PM
Subject: anise swallowtail & purplish copper


> As part of a habitat enhancement project in Richmond BC, we are planning
> to introduce anise swallowtail and purplish copper butterflies to a 14
> hectare
> site.  We will plant larval foodplants for the anise swallowtail and then
> take
> caterpillars from Boundary Bay where these butterflies are common and put
> them on the larval foodplants.  To introduce the purplish coppers we plan
to
> capture females and release them in the new site.
>
> We will plant cow parsnip (Heracleum lanatum) and seaside angelica
(Angelica
> lucida)
> for the anise swallowtail.  Laral foodplants for the purplish coppers are
> already present
> at the site.  The 14 hecatare site called Terra Nova is located on the
west
> side of Richmond,
> next to the dyke.
>
> We are not very knowledgeable about butterflies and would appreaciate any
> suggestions
> or comments that might help us.
>
> Don Benson
> don.benson at attcanada.net
>
>
>
>
>
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