Laguna Mountains Skipper

Found in the mountains near San Diego, California.

WSU Vancouver

March 19, 2022

Geography

Range Map

Laguna Mountains skipper (Pyrgus ruralis lagunae) is endemic to San Diego County and parts of Riverside County California.

The range is only where the rare hostplant is found, which is montane meadows.

Current Range and Study Area

Now, Laguna Mountains skipper is restricted to Palomar Mountain in Southern California. It is believed to be extirpated from Laguna Mountain since 2000.

Natural History

Species interactions

Host Plant

Cleveland's horkelia (Horkelia clevelandii) is Laguna Mountains skipper's only host plant. The range of the butterfly is limited to the two counties in which the plant occurs.

Nectar Plants

The host plant is the dominant nectar source. The skippers are often found puddling near water sources.

Disease

Like many butterflies, these skippers can be infected with Wolbachia spp., a protobacteria that can cause infertility in adult butterflies. However, this is not considered a current threat to the species.

Other host plants

The other subspecies of two-banded checkered skipper has a variety of host plants in the rose and mallow families. There is potential to host switch if appropriate species are in the habitat.

Habitat

The Laguna Mountains skipper is found in wet meadows at higher elevations where the host plant is present. This is usually forest edges with bare ground or other areas with high soil moisture.

Population Dynamics

The entire subspecies is now restricted to one mountain.
Population dynamics may be tied closely with annual rainfall.
Climate change may eliminate their current microclimate, as they reside in high elevation wet meadows.
Butterflies are typically moving between forest edges where hostplants are to stream banks as they frequently visit mud to drink water.
The other subspecies of two-banded checkered skipper (Pyrgus ruralis ruralis) is secure and more widespread.

Life Cycle

Adults

Butterflies are present beginning in April through July, producing two broods each year (bivoltine). About 5% of the spring brood (April and May) emerge as adults in June-July.

Eggs

Eggs are laid singly on the underside of leaves.

Caterpillars

Caterpillars hatch and immediately begin consuming their host plant. They spend their time in silk and leaf nests, like this silver-spotted skipper.

Chrysalis

The skippers survive the fall and winter in their chrysalises, then emerge in April and dry their wings.

Conservation

Listing Status

The Laguna Mountains skipper was listed as endangered under the Endangered Species Act in 1997. The species is thought to have low recovery potential.

A recovery plan is currently in review by the Fish and Wildlife Service to map out the activities needed for de-listing. The major threat to the population is climate change. The driest conditions predicted would be detrimental to the skipper. However, the wettest prediction would improve conditions for 30 years until returning to the current conditions.

Recovery Efforts

Habitat Management

Management and plans to moderate the grazing activities in habitat could improve the survival of caterpillars by protecting them from trampling, accidental consumption, or starvation from the hostplant being consumed.

Research

Study and monitoring of the skipper populations has been a major focus of the conservation efforts. Additionally, captive rearing has been used to some extent.

In fall of 2021, caterpillars were released to habitat in the Laguna Mountains. Further monitoring and research is needed to assess how successful these efforts will be.

Population Trends

We have two sites we analyzed (2007-2013) for Laguna Mountains skipper. We saw variable trends in phenolgoy and abundance. However, we only have data for a handful of years, so the trends may not be consistent with the long-term patterns.