Ottoe skipper (Hesperia ottoe) COSEWIC assessment and status report: chapter 8

Hesperia ottoe lives only in dry-mesic mixed-grass (bluestem) and sand prairie habitats. It is extremely susceptible to any habitat changes that alter the floral and structural components of its preferred habitat. Key adult and larval food resources must be present in the habitat for the long-term survival of this species.

Nectar flowers

Regular access by adults to nectar is probably critical to the survival of adult H. ottoe. Nectar provides carbohydrates needed to meet the energetic needs for flight and allows females to attain maximal fecundity (Murphy et al. 1983). Without a readily available source of nectar, lifetime fecundity would likely be reduced, thereby reducing the number of potential offspring in the next generation. Nectar also provides water, which may be the most critical resource for adult H. ottoe in the prairie habitat where free water is often absent (Dana 1991). Hesperia leonardus pawnee Dodge inadvertently deprived of water while confined in field cages died within a few hours on a hot, windy day (Dana 1991).

Although H. ottoe is a relative generalist, it has preferred species of flowers for nectaring (Dana 1991). Flower preference varies regionally, in part related to the relative abundance of the flower species in the habitats where the skipper lives. Among the preferred nectar flowers in the United States are E. angustifolia and V. stricta, characteristic components of undisturbed, native, mixed-grass prairie habitats in Canada and the United States. No data are available on nectar flowers used by Canadian populations of H. ottoe.

Male H. ottoe also puddle (Dana 1991) and may be obtaining mineral salts and water (Arms et al. 1974, Adler & Pearson 1982).

Larval host plants

The larvae of H. ottoe feed on a variety of grass species in nature (Nielsen 1958, McGuire 1982, Dana 1991). The preferred host grasses of H. ottoe are bunch grasses, such as little Bluestem (A. scoparius) and B. curtipendula (Dana 1991). All host grasses are late-maturing species that have a dense cluster of erect blades and a mass of persistent basal material that remains edible throughout the summer and into the fall (Dana 1991).  These grass species are characteristic of undisturbed native prairie habitats in North America.

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