|scientific name Limenitis arthemis |
common name White Admiral
Common in shrubby and wooded areas throughout the province.
One annual brood, peak flight period from mid June to late July.
Similar to our other two species of true admirals (Limenitis). The White lacks the rust-coloured forewing tips of Lorquin's (L. lorquini), and has a row of reddish spots bordering the outside of the hindwing white band. Their ranges overlap only in the Waterton - Crowsnest region, where hybrid individuals exhibiting characters intermediate between the White and Lorquin's are sometimes found. L. arthemis also has more orange on the hindwing upperside than Weidemeyer's (L. weidemeyerii), and has a red-brown hindwing underside base rather than predominantly white. Hybrids between these two species sometimes also occur.
The western Canadian populations are subspecies rubrofasciata.
The pale green eggs are round and sculptured (Guppy &Shepard 2001). Second instar larvae construct a shelter out of a partially rolled-up leaf base with silk, and hibernate inside this structure (Guppy & Shepard 2001). Mature larvae bear a remarkable resemblance to a bird dropping when resting on a leaf, since they are splotchy white and grey brown in colour (Guppy & Shepard 2001) and have a shiny look to them. There are usually five instars, but in BC, male larvae may occasionally 'fast-track' and pupate the same season after only four instars (Guppy & Shepard 2001), forming a partial second brood in late summer and early fall. This phenomenon may also account for August and September records in Alberta (Bird et al. 1995).
Adult males perch in shrubs and trees, occasionally patrolling along forest edges, and fly out to investigate other butterflies passing by.
Not of concern.
Larvae have been recorded primarily from poplars and willows (Salicaceae) (Layberry et al. 1998), although no particular species have been noted for Alberta. Adults are more fond of carrion and scat than flowers.
Alaska east to Newfoundland, south to Florida and eastern Texas. In the range roughly south of the Canadian border, this species looks very different, and is known as the Red-spotted Purple (L. arthemis astyanax).
Joe Belicek (2014-04-23)
Limenitis arthemis rubrofasciata (Barnes & McDunnough, 1916)
Original description in the Canadian Entomologist, 48 (7): 221-222.
(a) Distribution and bio-topic association: the univoltine Western White Admiral is a permanent resident in Alberta, found through out the Province where willows, aspens and birces grow. In Alberta, the willows (Salix spp.), Trembling Aspen (Populus tremuloides) and birch (Betula spp.) are the recorded food plants for the larva. In Edmonton area, my observations indicate a preference for willows. On the prairies, it is restricted to the coulies.
(b) Overwintering: In Alberta, the Western White Admiral overwinters as the third instar larva, hidden in a hibernaculum attached to a twig of the host plant, near the ground. A hibernaculum is a tent-like structure that the young larva makes from a half eaten, rolled-up leaf, tied together with the silken threads. The petiole of each hibernaculum is securely fastened with silken thread to the stem (this prevents the hibernaculum from detaching from the stem).
(c) Life natural history notes: In early May, the solitary larva leaves the hibernaculum and resumes feeding on the new foliage. During the day, the larva rests the mid-rib, feeding at night. The larva consumes the leaf in a peculiar fashion. Starting feeding from both edges, the larva leaves the a little bit of the leaf tip intact. The larva ties-up a small packet, leaving it dangling from a silk thread at the edge of last feeding. The packet contains bits of leaves, including frass. The suspended packet (the size of a lentil), like a pendulum, constantly moves as it is propelled by the slightest air-movements. The larva moves the packet daily, alongside the edge where it fed at night. You might ask: what is the purpose of this behaviour? I surmise that the swing packet may function like a decoy. The maturing larva has two prominent, modified scoli on the second abdominal segment, and paired warty bumps on the 3 and 5 segments. A mid-dorsal, lighter coloured blotch, on the darker body uncannily resembles a bird dropping. The hanging pupa, suspend by the tail, has a prominent dorsal hump. After the pupal stage, the new generation of butterflies emerges in the early part of June. The sailing flight is typical for this species. The exquisite egg of the Western White Admiral is globular, initially silvery-white, adorned with geodesic microstructure and pattern, embossed on the chorion. The newly emerged, young larva devours the egg shell as its first meal. The larvae of the first two instars feed by skeletonizing the leaf. The egg is laid on or near the tip of the host plant leaf in July.
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