Speyeria diana

(Cramer, 1779)

Diana fritillary

diana is a threatened in the Nymphalidae, historically distributed throughout the southeastern United States. The has undergone severe range collapse, disappearing from lowland and Atlantic coastal plain sites and now persisting in two disjunct mountainous regions: the Southern Appalachian Mountains and the Interior Highlands of Oklahoma and Arkansas. Climate change poses an existential threat, with models predicting an average loss of 91% of suitable by 2050.

Speyeria diana 234233304 by Roy Cohutta. Used under a CC BY 4.0 license.

Speyeria diana by Dr. Thomas G. Barnes, University of Kentucky, U.S. Fish and Wildlife Service. Used under a Public domain license.

Pronunciation

How to pronounce Speyeria diana: //spaɪˈɪəriə ˈdaɪənə//

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Habitat

Suitable for diana is now restricted to two phylogenetically disjunct high elevation regions: the Southern Appalachian Mountains (eastern ) and the Interior Highlands of Oklahoma and Arkansas (western population). The has disappeared from lowland sites and the Atlantic coastal plain where it was originally described. Populations are shifting to higher elevations at approximately 18 meters per decade.

Distribution

Currently persists in two isolated regions: (1) the Southern Appalachian Mountains across Georgia, Tennessee, South Carolina, North Carolina, and Virginia; and (2) the Interior Highlands of Oklahoma and Arkansas. Historically ranged throughout the southeastern United States including the Atlantic coastal plain. The is no longer found in the coastal plain or interior lowland sites.

Seasonality

Females have been documented emerging and being collected 4.3 days earlier per decade, indicating a phenological shift. Males, which emerge first, have not shown significant phenological shifts.

Diet

imbibe nectar from at least five of flowering plants (>11 ), with 57% of observations on milkweed (Asclepias spp.). Adults also feed on liquids from dirt roads and horse manure.

Life Cycle

Larvae feed on Viola ; 14 species of Viola have been documented in survey sites. Larvae undergo first instar , though laboratory rearing methods have been developed to bypass this diapause. Rearing studies found no evidence of plant preference among three native violet species (Viola sororia, V. pubescens, V. pedata). Males reared in captivity emerged significantly earlier than females.

Behavior

Recapture rates in mark-recapture studies ranged from 17% to 56%, suggesting somewhat limited out of suitable .

Human Relevance

The Diana fritillary is a threatened of conservation concern. Climate change modeling indicates severe range reduction, with Southern Appalachian predicted to suffer the most severe fragmentation, threatening an important source of genetic diversity. Both eastern and western populations are considered vulnerable due to geographic and genetic isolation. Habitat restoration promoting diverse larval and plants has been identified as urgently needed for conservation.