Papillons des prairies

Statut de l'espèce :
Hespérie ottoé (Hesperia ottoe): En voie de disparition au Canada
Hespérie du Dakota (Hesperia dacotae): Menacée au Canada
Hespérie de Poweshiek (Oarisma poweshiek): Menacée au Canada
Action requise : Réintroduction

Papillons des prairies

Depuis les années 1850, plus de 99 % des prairies indigènes d'Amérique du Nord ont été perdues au profit de l'agriculture et du surpâturage, mettant en grave péril la survie de nombreuses espèces des prairies, dont plusieurs papillons.

Characteristics

All three butterflies belong to the skipper family (Hesperiidae), sharing the family’s characteristic features: hooked antennae, short stout bodies, heavily muscled thoraxes that give them swift, powerful flight, and a preference for resting with wings held in a characteristic “spread-wing” posture. Their wingspans range from roughly 21 to 35 mm which is about the width of a toonie. They’re small and are brown to orange in colour which makes them difficult to distinguish in the field. The Ottoe skipper is the largest of the three, with males displaying bright yellowish-orange upper wings with a dark border and an elongated black mark (the “brand”) on the forewing. Females are dull brown with buff markings. The Dakota skipper is slightly smaller and more delicate, with males showing tawny-orange to brown coloration and females displaying darker brown with tawny spots and white spots on the forewing margin. The Poweshiek skipperling is the smallest and darkest, with males showing dark brown upper wings and a distinctive golden-orange edge along the forewing, while the hindwing undersides are marked by white veins creating a striking white appearance.

Habitat

The Dakota skipper is found in native tallgrass prairies and dry, upland mixed-grass prairies. Similarly, the Ottoe skipper prefers sand prairies and mixed-grass prairies with bluestem and other medium-height grasses. The Poweshiek skipperling is also found in native tallgrass prairie, but needs both wet and dry habitats at different life stages. As caterpillars, Poweshiek skipperlings feed on plants found in the wetter areas, whereas the adults rely on plants like black-eyed Susan that grow in drier areas.

Aire de répartition

Historically, the Ottoe skipper could be found from southern Manitoba south to Texas and west to Colorado. However, they now only occur in very isolated populations, with the last recorded sighting in Canada in 1986.

Aux États-Unis, l'hespérie du Dakota se trouve dans des populations isolées dans le Dakota du Nord et du Sud jusqu'à l'ouest du Minnesota. Au Canada, ces papillons ne se trouvent que dans le sud du Manitoba et le sud-est de la Saskatchewan.

L'hespérie de Poweshiek se trouve dans des zones isolées dans le nord des États-Unis. Au Canada, cette espèce n'a été trouvée que dans la Réserve de la prairie à herbes hautes du Manitoba.

Biology

All three butterflies complete exactly one generation per year. Adults emerge in mid to late June, peak in early-to-mid July, and disappear by early August. Adults live on average 1-3 weeks in the wild. Mating occurs almost immediately once emerged and the females typically mate once, while males mate repeatedly. Females lay eggs singly on host plants over a period of days to weeks and they hatch within 8 to 14 days depending on temperature and species. The caterpillars that emerge are slender and feed on grass leaves at night, constructing protective shelters from silk and grass during the day. Overwintering in caterpillar form, they pass through multiple developmental stages (instars) and when ready will pupate in their cocoon for 2 to 4 weeks before emerging as a butterfly.

Menaces

Habitat loss, degradation and fragmentation are the main threats to prairie butterflies. Since the arrival of Europeans to North America, over 99 per cent of native prairies have been converted to grow crops and graze farm animals. The plants that adults and larvae depend on are scarce in agricultural areas, and those butterflies that remain are at increased risk of being trampled by livestock. Fires, invasive species — and the chemical spraying to control those species — also pose serious risks to prairie butterflies, while climate change and inclement weather may add further pressure.

Rétablissement

Actions de rétablissement recommandées

Les stratégies fédérales de rétablissement pour ces papillons prévoient un certain nombre de mesures de conservation, notamment la réalisation de recensements des populations sur les sites historiquement occupés, la gestion de l'habitat, l'identification des plantes hôtes, l'identification des habitats inoccupés qui pourraient convenir à des réintroductions et l'évaluation de la faisabilité du rétablissement de certaines populations.

Ce que nous faisons

Ces papillons des prairies figurent sur la liste de priorités de Conservation de la faune au Canada pour d'éventuelles actions futures. Découvrez comment nous sauvons actuellement d'autres papillons canadiens comme le damier de Taylor et le bleu mélissa, et comment vous pouvez faire une différence.

What you can do

About 50% of all known Dakota skipper populations occur on private lands. Landowners interested in prairie conservation have multiple options: establishing conservation easements, implementing light to moderate grazing regimes that maintain prairie structure, removing invasive species, and avoiding pesticide applications.

FAQs

A: Size is your first clue. If it’s noticeably larger (29 to 35 mm), it’s likely an Ottoe skipper. Between the smaller two, look at the Poweshiek skipperling’s distinctive white-veined hindwing undersides as it is unique among the three. Flight timing also helps: all three fly in June-July, but their exact peak varies slightly by location. The Poweshiek typically emerges slightly later (late June/early July) than the Dakota skipper (mid-June to early August).

A: These butterflies evolved with natural fires that maintained prairie structure. However, their caterpillars are vulnerable to fire: they overwinter on or below ground, and strong spring fires kill most larvae. Late-season fires are particularly deadly. Yet without any fire, forests close in and the prairie collapses.

A: Because they’re indicators. When prairie specialist butterflies decline, it signals that the entire prairie ecosystem is in trouble, and dozens of other species (birds, insects, mammals, plants) share that habitat. Saving these skippers means saving prairie, which benefits everything that depends on it.