on steep, well-drained, gravelly slopes. They can mostly be found 20–40 meters above the tree-line. Herbivores rarely feedon S. lanceolatum, because it produces a deterrent cyanoglycoside, sarmentosin, so there is little risk that larvae will be accidentally preyed upon as a result of the foodplant being ingested. The larvae also sequester sarmentosin from the plant in their bodies for their own defense. However, it has been found that if the S. lanceolatum plant becomes physically damaged by mechanical means, the larvae feeding on it have reduced growth rates, possibly due to an induced defense by the plant itself. While damage by insects does not cause plant defense, damage from feeding by the larvae does induce defense by the plant. Consequently, the larvae often hurry to feed, then switch to another host plant within the time window offering the highest nutritional quality. Larvae will typically feed and leave a plant in less than half an hour. From November to February, the leaves of their foodplant are fatally toxic to the larvae, but for the rest of the year, the larvae feed and develop normally. If the snow melts before March, the eggs hatch while the larval foodplant is still toxic, and the larvae perish. Reproduction and life cycle Reproduction Mate searching behavior Males of this species often have poor visual discrimination, so they investigate all flying or sitting objects of the approximate size and color of the females of their species. They primarily identify females by their light color, so they are as likely to chase small blue lycaenids as they are to chase large white butterflies, but tend to ignore darker butterflies like fritillaries. The males emerge from their pupae before females do in order to patrol for newly emerged females over a large area. They patrol by flying over large areas then investigating any resting or flying females after spotting them. Males fly long distances continuously in search of females, stopping only to bask or feed. Mate choice Males mate with young females, preferring females that have not yet expanded their wings. The females only mate once, lay eggs only once, and mature their eggs throughout their life, so the youngest females have the greatest potential fitness, and are selected for by males. There is also evidence that females emit a pheromone produced during the pupal stage, but its effect diminishes with time. The window of opportunity for a