Marine Blue Butterfly (Leptotes marina)
One of the more enjoyable aspects of gardening is watching the birds and animals that visit/live in your garden. Butterflies are among the more popular visitors, and most gardens attract a few species. But a garden filled with nectar-rich flowers and larval host plants can be alive with many species by mid-summer. To learn more about butterfly gardening see: http://mother-natures-backyard.blogspot.com/2012/06/butterfly-gardens.html
Among the common butterflies visiting native ‘butterfly plants’ are the small species known as the Blue Butterflies. There are many species of ‘Blues’ throughout the world. They all are classed as Gossamer-winged Butterflies (Family Lycaenidae), a large group that includes around 40% of all butterfly species (over 5000 species in the Family). Some of the common types of butterflies in this family are the Blue, Copper, Azure and Hairstreak butterflies. We introduced another Gossamer-wing, the Gray Hairstreak, last month: http://mother-natures-backyard.blogspot.com/2018/07/gray-hairstreak-butterfly-strymon.html
The Gossamer-winged butterflies are mostly small. They have delicate wings that appear to shine with color. In the case of the Blue Butterflies, the predominant color of the upper-side of the wings is a shimmery blue that varies with the light. Gossamer-wings live in a wide range of habitats from deserts to tropical rain forests and wetlands. And some are common visitors to home gardens.
The Blue Butterflies belong the sub-family Polyommatinae (the Blue Butterflies). This sub-family has traditionally been a sort of catch-all for species of similar appearance. So it’s difficult to tell how many species it actually contains (molecular taxonomy will one day sort this out). Southern California genera currently included in the Polyommatinae are: Brephidium (Pygmy Blues), Celastrina (Azures), Euphilotes, Glaucopsyche, Hemiargus, Leptotes, Philotes, and Plebejus.
The most widely known (and the rarest) of the local Blue Butterflies are the Palos Verdes and El Segundo Blues (Glaucopsyche lygdamus palosverdesensis and Euphilotes battoides allyni, respectively). These two species have very limited geographic ranges (in Western Los Angeles County) and larval food sources. Efforts to bring these two species back from the brink of extinction have been widely publicized. Their story has become part of the restoration ecology lore.
|Mesquite (Prosopis species): larval food for|
Marine Blue Butterfly (Leptotes marina)
The Marine Blue (Leptotes marina) is a far more common butterfly in S. California. Its range extends from California and Arizona east to Texas and south to Central America.  It’s a fairly common small butterfly in S. California, living in Mesquite and Coastal Sage scrub, city gardens and agricultural areas where alfalfa is grown. In the Sonoran Desert, it’s commonly seen along riparian corridors, which contain mesquites or other plants in the bean family. Because its larval foods are common, gardeners in S. California, Arizona, New Mexico, southern Colorado or Texas may see this butterfly in their home gardens. Individuals occasionally stray further north, but they apparently don’t over-winter.
The species was named by Tryon Reakirt (1844 – ?) in 1868. Reakirt was a businessman but was really a lepidopterist at heart.  He joined the Entomological Society of Philadelphia at the age of 19 and became an accomplished taxonomist. Reakirt's Blue butterfly also honors Tryon Reakirt.
Reakirt was particularly interested in butterflies of the tropics and the American Rockies, publishing nine articles in the Proceedings of the Entomological Society of Philadelphia. He apparently was not a field collector and never visited the American Southwest. Ultimately, his business dealings failed (there were hints of corruption), and Reakirt fled to Peru in 1871. For more on the little that’s known about this talented lepidopterist see reference 2, below.
|Marine Blue Butterfly (Leptotes marina) is small|
Like all the Blues, the Marine Blue is a rather small butterfly, with a wingspan ranging from 7/8 to 1 1/8 inches (2.2 - 2.9 cm).  It flies with a rapid, erratic flight pattern, landing to feed or search for mates. When perched, the wings are usually closed, making it difficult to see (or photograph) the upper wing surface. The upper surface is an iridescent blue-purple with a hint of brown. The males have pale brown and white markings on the upper wing surface; females are all blue-purple. For good photos, see references 3 & 4, below.
|Marine Blue Butterfly (Leptotes marina): underside|
The undersurface is often the best distinguishing characteristic between the different Blues. In the case of the Marine Blue, the underside has distinctive, wavy, tan and white bands that are reminiscent of ocean waves coming in to shore. I’m not sure why the Marine Blue is called ‘Marine’, but suspect it’s because of the ‘waves’. The underside also has a line of tan and white circles on the wing margins, and two larger, darker spots on the lower dorsal wing (see above).
|Marine Blue Butterfly (Leptotes marina): nectaring on |
Dune Buckwheat (Eriogonum parvifolium)
Adults nectar on whatever small flowers are blooming. In our gardens, we most often see them on the native Buckwheats or plants in the Sunflower family. They are also commonly seen around their larval food plants – the legumes (members of the Pea Family – Fagaceae). So you may see them near the peas in your vegetable garden as well. Common larval foods in S. California include the native Milkvetches (Astragalus species), Amorpha californica and fruticosa, Glycyrrhiza lepidota, native Lathyrus (wild pea) and Lotus species, and the non-native Wisterias, Plumbagos, Acacias, alfalfa and garden peas. In the desert, common host plants are the tree and shrubby legumes, including Mesquites (Prosopis species), Acacia greggii, Dalea purpurea and Lysiloma thornberi.
|Amorpha fruticosa: larval food source for|
Marine Blue Butterfly (Leptotes marina)
Females lay their eggs on the flower buds of host plants. The eggs and young larvae are small and well camouflaged; you’ll have to really look for them. The larvae eat mainly the flowers and the seedpods. For good photos of eggs, larval stages [4, 5]. For good advice on raising this butterfly see reference 5, below.
Marine Blues can be seen year-round in S. California and other warm places. We see them most often in summer and fall in Mother Nature’s Backyard. They are fun to observe and add to the interest of a garden. But what role do they play in the garden ecosystem – and why should we be interested in attracting them?
All butterflies and their larvae provide protein for birds, wasps and other insect-eating species. So Marine Blues certainly function as prey. But do they also play a role as pollinators, particularly of the small-flowered species they seem to prefer? In fact, the answer has yet to be discovered.
|Marine Blue Butterfly (Leptotes marina): note how hairy this species is.|
Butterflies are thought to be minor pollinators for most plants. Perhaps that’s why relatively little research has been done, except in the case of a few flowering plants. But a good look at the smaller butterflies, like the Gossamer Wings and Skippers, makes us wonder. These butterflies have relatively short legs (for butterflies), visit many flowers, and can be seen in large (aggregate) numbers, particularly in areas of the arid Southwest. These butterflies are also conspicuously hairy, particularly on the underbody and around the face. All these factors make us wonder if they are more important alternate pollinators than is often thought.
Good studies of pollinator activity are difficult to carry out. They require time, patience, hard fieldwork and observation. Probably the best studies document that pollen is actually carried by a pollinator. Such studies require extreme magnification – at the level of the electron microscope. As far as we can determine, few studies have focused on the Blues as pollinators. We hope that some up-and-coming Southwestern lepidopterist will seize the opportunity, enlightening us on the role of the Blue butterflies as pollinators. That would make a fantastic doctoral dissertation!
The Blue Butterflies also remind us that specialization – whether in nature, agriculture or business – carries with it a substantial risk. The highly specialized El Segundo and Palos Verdes Blue Butterflies, with their limited larval food sources, are extremely vulnerable to habitat loss. The more generalist Marine Blues, with their ability to utilize a range of native and non-native legumes, have lots more options. The Marine Blue serves to remind us that flexibility can be a reasonable survival strategy in times of rapid change – like now.
|Marine Blue Butterfly (Leptotes marina): |
Madrona Marsh Preserve, Torrance CA
See our other insect postings for more on common insect visitors to S. California gardens: http://mother-natures-backyard.blogspot.com/2016/07/insect-postings-mother-natures-backyard.html
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