The El Segundo Blue butterfly (Euphilotes battoides allyni) in Los Angeles County, California.
This subspecies is part of the western square-dotted blue species complex found throughout the Western United States, except in desert habitats.
Study area
Our study focuses on the only existing populations, ranging from Santa Monica to Rancho Palos Verdes.
Natural History
Species interactions
Host Plant
Sea cliff buckwheat (Eriogonum parviflorum) hosts El Segundo caterpillars.
A large coastal buckwheat (Eriogonum parviflorum) plant set against a blue sky.
Nectar Plants
Adults nectar almost exclusively on sea cliff buckwheat. Nectaring almost exclusively on the host plant is common for buckwheat blues (Euphilotes spp.)
Symbiosis
Caterpillars are tended by ants (Linepithema and Dorymyrmex spp.). After the third instar, larvae produce sugary secretions for the ants, who protect the larvae from predators.
Other species
Sea fig (Carpobrotus chilensis) is an invasive species that threatens the success of the hostplant.
Habitat
El Segundo blueresides in coastal dunes, which are home to several other endemic native species (species not found elsewhere). This type of ecosystem is distinguished by continually moving sand and very arid conditions. "Sand obligate" species, such as the hostplant, decrease in abundance accordingly with the invasion of non-native plants, which has been widespread here.
Formerly, the El Segundo Sand Dunes covered a region of about 4.5 square miles: about one-half mile inland from the Pacific Ocean and stretching from Westchester south to the base of the Palos Verdes peninsula.
Coastal areas west of Los Angeles County, showing the dune ecosystem where E. allyni resides.
El Segundo blue and habitat.
Population Dynamics
There are three populations of the butterfly, with little possibility of butterflies traveling between them.
In 2014, the total estimate for the butterfly was ~26,000, indicating precipitous declines from 2010 estimates of over 100,000.
However, due to conservation efforts, abundance is improving from the all-time low of 400-700 individuals in the early 1980's.
The El Segundo blue is considered a sedentaryspecies, and the habitat is surrounded by development.
The El Segundo blue is one subspecies in the western square-dotted blue (Euphilotes battoides) species complex, and the development of the city of Los Angeles has cut off the El Segundo blue from other subspecies.
Life Cycle
Life Cycle
Butterflies fly from June to August. El Segundo blues produce one brood a year (univoltine).
Adults
Female butterflies are generally found on host plants; males patrol for mates. After mating, females begin laying eggs on host flowers.
An El Segundo blue butterfly closes its wings while perched on a sea cliff buckwheat flower.
Caterpillars
Caterpillars are camouflaged in buckwheat flowerheads, and may interact with ants by providing them with honeydew for protection.
Chrysalis
This butterfly overwinters in its' chrysalis, hiding in the leaves or flowerheads of the host plant.
Partnerships exist with many agencies to restore habitat, including the City of Los Angeles, the Board of Airport Commissioners and Los Angeles World Airports and the United States Fish and Wildlife Service (USFWS).
In 1986, Los Angeles World Airports (LAWA) dedicated 307 acres of its land west of the airport for preservation of the butterfly.
We had data for one site for the El Segundo blue, but we did not have consistent data for recent years. During this time period (1984-2002) we saw no change in activity or phenology, but recent trends reported by U.S. Fish and Wildlife Service are that populations are increasing or stable (last 10 years).
Example of activity trends through time each year for the El Segundo blue site.
Example of activity trends through time each year for the El Segundo blue site.
