New York Natural Heritage Program
Frosted Elfin
Callophrys irus (Godart, [1824])

Threats [-]
Besides the destruction of habitats by development, threats that can quickly wipe out colonies. Threats include deer eating the foodplants (and eggs and larvae) and lack of appropriate habitat management, including applying herbicides to or disking utility right-of-ways. Mowing the foodplants before late June could eradicate or reduce an occurrence. Gypsy Moth (Lymantria dispar) spraying is also a potential threat, but the risk cannot be evaluated in the case of Bt (Bacillus thuringiensis - a bacterial biological control used on Gypsy Moth caterpillars). Depending on the application date, most larvae could be exposed, but their sensitivity is unknown. Habitat fragmentation may be the greatest threat in locations where potentially viable metapopulations still occur. Small isolated colonies are more likely to become extirpated because these populations sometimes fail to produce any adults in some years, due to deer browse or other variables, and subsequently are not recolonized. However, when populations are clustered, females can move between each of them and extirpations are often temporary.

Conservation Strategies and Management Practices [-]
All habitats require disturbance, such as fire or mowing, to impede succession. Where fire is used, unburned habitat patches, or refugia, are needed since Indigo (Baptisia spp.) feeders will usually have very high mortality in these areas. Although Lupine (Lupinus perennis) feeders, which pupate in the sand, may not have the same high mortality rates, they may leave the burned areas. Winter mowing is a proven management option, but the footprint of the machinery should be minimized in order to avoid crushing the pupae. Populations can be maintained for decades with mowing. Generally, management that works for the Karner Blue (Plebejus melissa samuelis) should work for the co-occurring Frosted Elfin, although the elfins might be more vulnerable to deer since the larvae feed on the lupine flowers. Shelter from wind and the proximity of trees may be important for Wild Indigo feeders, although the adjacent habitat may be brushy with few trees. Maintaining connectivity of colonies where they are clustered is important and is likely to be critical for long term persistence of populations. See Albanese et al. (2006) regarding habitat needs.

Research Needs [-]
Research into the effects of prescribed burning on populations, especially lupine (Lupinus perennis) feeders is needed. Lupine feeders, which pupate in the sand, probably do not incur much mortality, but they apparently avoid recently burned areas. Research is also needed to determine how long the post-fire effects persist and if they can be mitigated. Additional information on the situations that encourage females to move between foodplant patches is also needed.