Icaricia saepiolus ssp. insulanus (Vancouver Island Blue)

[Melly]

The Island Blue, Plebejus saepiolus insulanus Blackmore, a subspecies of the Greenish Blue, Plebejus
saepiolus (Boisduval), occurred on Vancouver Island from Saratoga Beach near Campbell River south to Victoria. It
has not been seen since 1979 and may be extinct.

[sebastian]

5 ISLAND BLUE
Plebejus saepiolus insulanus Blackmore Coppers, Hairstreaks, and Blues: Lycaenidae

5.1 Taxonomic Status
Until recently, the Island Blue has been considered to be restricted to southeastern Vancouver Island. In the United States there is confusion in the application of this subspecies name. In Oregon, the name P. s. insulanus was applied to a few isolated populations that occur on the immediate coast (Hinchliff 1994). In Washington, there are no populations recorded for the immediate coast. The Olympic Mountains populations are classified as belonging to the subspecies P. s. saepiolus (Hinchliff 1996). Since subspecies are normally considered to be contiguous, similar populations (Hinchcliff 1994, 1996), usage of the name P. s. insulanus for the Oregon populations is incorrect. By contrast, Scott (1986) uses the subspecies name P. s. insulanus to apply to all P. saepiolus populations from northwest California through western Oregon and Washington and southwest British Columbia. This interpretation is much too inclusive. However, regardless of the taxonomic considerations elsewhere, the provincial and national status of this butterfly in British Columbia and Canada will not change. The Vancouver Island populations are a distinct subspecies found nowhere else in Canada.

5.2 Biology
The larvae of P. saepiolus require clovers (Trifolium spp.) as their specific larval foodplant (Emmel and Emmel 1973). One clover native to Vancouver Island, T. wormskjoldii Lehn., has been recorded as a foodplant of this butterfly species (Scott 1986). It is possible that non-native plant species have invaded disturbed sites on Vancouver Island and thus native clovers are not as common as they once were. The coastal Oregon populations of native Trifolium are known to be affected by weeds (P. Hammond, pers. comm.). Little is known about the biology of the Island Blue. Museum data indicate that the utterfly had a single generation per year with the adults flying from late May to early August, depending on elevation and the time when warm spring weather begins on Vancouver Island.

5.3 Habitat
Nothing is known about the habitat on Vancouver Island. Elsewhere, the adults and larvae of P . saepiolus are normally found near or on the host plant, clover (Trifolium spp.), along open streams and moist disturbed sites, such as old roads or campgrounds.

5.4 Distribution
The Island Blue was found only on Vancouver Island, British Columbia. Historically this has been considered its world distribution (Jones 1951). Recent application of the name P. s. insulanus to coastal Oregon populations of P. saepiolus (Hinchliff 1994) but not to coastal Washington populations (Hinchliff 1996) must be an error. Museum records indicate that P. s. insulanus occurred only on the east side of Vancouver Island from Saratoga Beach, south of Campbell River, south to Victoria (Figure 4).

5.5 Protection and Status
There are no known records of the P. s. insulanus since 1979 (Appendix 5). In 1995, this butterfly was not encountered in an extensive field survey of appropriate habitat throughout southeastern Vancouver Island north to Comox (Shepard 1996). However, there is still a possibility that it may be found in unsurveyed appropriate habitat. Thus the Conservation Data Centre status is revised to G5TH NH SH, which means that there are no recent records and extinction is a definite possibility. Since Vancouver Island north of Comox has never been surveyed at the peak flight time for the Island Blue, there is a remote possibility that the butterfly may exist there.

5.6 Population Size and Trend
Since the Island Blue has not been seen since 1979, and since the data from earlier years is not extensive, population size and trends are unknown. The subspecies may be extinct.

5.7 Limiting Factors
P. saepiolus requires clovers (Trifolium spp.) as its larval foodplant (Emmel and Emmel 1973). Other subspecies of the butterfly range widely in Canada and the United States and no other limiting factors are known.

5.8 Special Significance of the Subspecies
This subspecies is (or was) endemic to Vancouver Island. The recent rarity of this particular subspecies probably reflects the successful spread of many introduced weed species which grow in disturbed sites. This butterfly has similar requirements to the Dun Skipper, Euphyes vestris vestris, another imperiled butterfly.

5.9 Recommendations
Until an extant population is located, there are no specific management recommendations. If future field work discovers a population, the habitat of that population should be immediately protected. If any United States populations can be assigned to the Island Blue subspecies, it would be possible to attempt to re-establish populations of the butterfly on Vancouver Island. It is the opinion of the author, however, that none of the populations in the United States belong to the same subspecies as the Island Blue.

[sebastian]

wlapwww.gov.bc.ca/wld/documents/statusrpts/wr101.pdf

[Deleted]

The correct status of this subspecies seems to be unclear, especially the fact if it occures on Vancouver Island only, and is now extinct, or if it is found also in the USA, then it would be only a local extinction.

source:

www.env.gov.bc.ca/wld/documents/recovery/rcvrystrat/plebejus_saep_ins_rcvry_strat_010807.pdf

Is this question now answered, does someone know that ?

[Melanie]

According to Naturserve this subspecies should be renamed as Vancouver Island Blue following Guppy, C.S., and J.H. Shepard. 2001. Butterflies of British Columbia. UBC Press in collaboration with Royal B.C. Mus. 414pp.

www.natureserve.org/explorer/servlet/NatureServe?searchName=Plebejus%20saepiolus%20insulanus

[Deleted]

Mar 8, 2010 21:37:39 GMT Melanie said:

According to Naturserve this subspecies should be renamed as Vancouver Island Blue following Guppy, C.S., and J.H. Shepard. 2001. Butterflies of British Columbia. UBC Press in collaboration with Royal B.C. Mus. 414pp.

www.natureserve.org/explorer/servlet/NatureServe?searchName=Plebejus%20saepiolus%20insulanus

So it is or was really endemic to this island, right ?

The nomenclature for the Lycaenidae is indeed very, very complicated ....

[Melanie]

Well, it seems to be. But it would be interesting to see detailed illustratrions of all subspecies of Plebejus saepiolus for comparism.

Mar 9, 2010 11:33:25 GMT @noisi said:

So it is or was really endemic to this island, right ?

The nomenclature for the Lycaenidae is indeed very, very complicated ....

[Deleted]

Mar 9, 2010 14:30:00 GMT Melanie said:

But it would be interesting to see detailed illustratrions of all subspecies of Plebejus saepiolus for comparism.

... something like this ?

butterfliesofamerica.com/t/Plebejus_saepiolus_a.htm

[Melanie]

Yes, thank you very much for finding this page. It shows cleary the differences between this subspecies and the subspecies amica which is the nearest relative and which occur at the west coast of British Columbia but not on Vancouver Island. The five other subspecies are not sympatric (that means they not occur in the same distribution area). Yes, the insulanus subspecies was endemic to Vancouver Island

dsp-psd.pwgsc.gc.ca/collection_2008/ec/En3-4-60-2008E.pdf

Mar 9, 2010 17:25:28 GMT @noisi said:

Mar 9, 2010 14:30:00 GMT Melanie said:

But it would be interesting to see detailed illustratrions of all subspecies of Plebejus saepiolus for comparism.

... something like this ?

butterfliesofamerica.com/t/Plebejus_saepiolus_a.htm

[Sebbe]

Vancouver Island Blue (Icaricia saepiolus insulanus) is endemic to British Columbia and has not been documented in the field since 1979. However, search effort is insufficient to conclude that the species is extinct. Any remaining populations in its historical range must occur within a very small distributional range and are likely in decline due to declining habitat quality from invasive plants.

Reason for designation: This species has not been documented in the wild since 1979 but search effort is insufficient to conclude that it is extinct. Any remaining subpopulations in its historical range must occur within a very small distributional range and are likely in decline due to declining habitat quality from invasive plants that out-compete native host plants.

Status history: Designated Endangered in November 2000. Status re-examined and confirmed in May 2012 and December 2022.

explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.115706/Icaricia_saepiolus_insulanus
butterfliesofamerica.com/L/t/Icaricia_saepiolus_insulanus_a.htm