L'hespérie tachetée

Erynnis martialis
Statut de l'espèce : En voie de disparition au Canada (évaluation du COSEPAC) ; En voie de disparition en Ontario
Action requise : Augmentation de la population, réintroduction et/ou colonisation assistée

L'hespérie tachetée (Erynnis martialis)

Les plantes dont se nourrissent les larves de l'hespérie tachetée poussent dans des zones sablonneuses et sèches ou des alvars calcaires que l'on trouve dans très peu d'endroits dans l'Est du Canada. Malheureusement, ces milieux fragiles sont aussi des sites privilégiés pour le développement humain.

Characteristics

The mottled duskywing (Erynnis martialis) is a small to medium skipper butterfly, measuring 23 to 33 mm across the wings. It earned its common name from its wings which display a strongly mottled pattern of light and dark brown with yellowish-brown spots. It can be spotted in dry, open habitats like barrens, sandy patches in woodlands, oak savannas, tallgrass prairies, and alvars (limestone areas with sparse vegetation).

The male and female look almost identical. What sets them apart is the males possess a fold along the leading edge of the forewing that contains yellow scent scales used during mating. Females lack this specialized fold but overall have heavier mottling patterns than males, making them appear more distinctly patterned.

Similar looking species

  • Horace’s duskywing (Erynnis horatius)
  • Juvenal’s duskywing (Erynnis juvenalis)
  • Zarucco duskywing (Erynnis zarucco)

Habitat

Contrairement à de nombreux autres papillons qui préfèrent les prairies luxuriantes, les hespéries tachetées habitent généralement des zones sèches et partiellement ombragées. Celles-ci comprennent des zones sableuses dans les bois, des landes ouvertes et des endroits avec un sol peu profond et une végétation clairsemée.

Aire de répartition

Historiquement, les hespéries tachetées se trouvaient dans l'est et le centre des États-Unis et dans certaines parties du centre-sud du Canada. Malheureusement, leurs populations ont tellement chuté qu'elles ont peut-être disparu de nombreux États américains dans leur aire de répartition principale. Au Canada, ces papillons s'étendaient autrefois dans le sud-ouest du Québec, au sud de l'Ontario et au sud-est du Manitoba. Cependant, les hespéries tachetées n'ont pas été vues au Québec depuis les années 1950, et en Ontario, on ne les trouve que dans de petites populations isolées. Au Manitoba, elles sont limitées à une petite zone de forêt de pins dans le sud-est.

Biology

The mottled duskywing follows two distinct life patterns depending on location. In central Ontario, the butterfly produces just one generation per year. In warmer southern areas like Pinery Provincial Park and Norfolk County, two generations emerge annually, one in May, another in July. Females deposit single eggs directly onto New Jersey tea (Ceanothus americanus) or prairie redroot (Ceanothus herbaceus) plants, typically on new growth or flower buds. The eggs hatch within a few days and, once hatched, the caterpillars are independent and immediately begin constructing shelters from woven silk around leaves. They grow for about 2 months and if it is warm enough they will pupate in a cocoon for 2 to 4 weeks (if too cold, they overwinter as mature larvae before pupating) then emerge as an adult. Adult mottled duskywings live for about 2 to 3 weeks in the wild.

Males and females carry “scent scales,” which contain pheromones for attracting the opposite sex. Males are often found “puddling” — sipping water from moist soil to get salt and essential minerals. During mating, those nutrients are transferred to the female through the male’s sperm, which in turn improve the health of the female’s eggs.

Menaces

Habitat destruction and fragmentation caused by human development ranks as a primary threat to the mottled duskywing. Meanwhile, the plants these butterflies depend on are being eaten by deer and crowded out by invasive species. Spraying to control spongy moth populations is also taking a toll on the mottled duskywing.

Rétablissement

Actions de rétablissement recommandées

La stratégie de rétablissement de l'Ontario pour l'hespérie tachetée prévoit un certain nombre de mesures de conservation. Celles-ci comprennent la cartographie de l'habitat convenable, la protection et la gestion de l'habitat, l'analyse de la viabilité des populations actuelles et l'identification du potentiel d'augmentation des populations existantes, de réintroduction des populations dans des sites historiques ou d'aide à la colonisation de nouveaux sites.

Ce que nous faisons

Découvrez comment nous sauvons actuellement d'autres pollinisateurs indigènes, y compris l'hespérie tachetée, et comment vous pouvez faire une différence.

Visitez la page du projet

What you can do

Anyone with land in suitable oak savanna, pine woodland, or prairie habitat can plant New Jersey tea. Supporting organizations working on habitat restoration directly aids the butterfly. If you encounter a mottled duskywing, photograph and report it to your provincial wildlife agency. Every sighting contributes to monitoring efforts.

FAQs

A: Habitat loss is the dominant driver. Mottled duskywings depend on disturbance-maintained ecosystems; landscapes that historically burned periodically and stayed open and sunny. When European settlement suppressed wildfires, forests began closing over oak savannas and prairies. Without regular disturbance, New Jersey tea cannot compete with shade-tolerant trees, and the butterflies disappear. Agricultural conversion and urban development have accelerated the decline, fragmenting populations into isolated pockets.

A: Getting captive females to lay eggs can be challenging. Females sometimes lack sufficient motivation or encounter conditions that don’t trigger oviposition behaviour. 

A: The Ontario Butterfly Species at Risk Recovery Team tests different approaches. They’ve released caterpillars, pupae, and adult butterflies at different sites within Pinery to determine which life stage works best. Early-stage releases (caterpillars and pupae) have the advantage of allowing butterflies to acclimate, select their own pupation sites, and choose preferred feeding and laying areas. Adult releases establish breeding populations quickly. Results show that all three approaches can work, depending on conditions.

A: The Pinery monitoring team uses “distance sampling” surveys. They walk a series of parallel lines through habitat where host plants are abundant, counting and recording the distance at which they first spot each duskywing. This technique provides population estimates without the intensive effort of marking and recapturing individual butterflies. They also note whether they observe mating, egg-laying, and presence of caterpillars; all signs of reproductive success.