Large blue

Appearance

Large blue caterpillars are about half an inch in length and can live as long as 9 months before they form a chrysalis to become a butterfly. Large blue butterflies have a wingspan of up to 2 inches, and will live for only a few weeks. The wings of the large blue butterfly are speckled with black dots. Compared with a large blue caterpillar, the adult's lifespan is short.

Naming

*"M. a. arion" Europe West Siberia, Altai, North-West Kazakhstan
⤷ "M. a. delphinatus" "Dauphine"
⤷ "M. a. zara Jachontov", 1935 Caucasus, Armenia
⤷ "M. a. buholzeri" Rezbanyai, 1978
⤷ "M. a. inferna" Sibatani, Saigusa & Hirowatari, 1994 Sichuan

Distribution

The large blue butterfly is found from coast to coast of the Palearctic ecozone, but is most concentrated in the areas from France to China.

Behavior

Like many members of the genus "Phengaris", large blue butterfly caterpillars exhibit a form of parasitism in which they take advantage of a host species. In this case, the hosts are specific species of the "Myrmica" ant. By being similar to "Myrmica" ants physically and chemically and possibly using other forms of mimicry, large blue caterpillars are able to trick the ants into taking them back to the ant nest. Once there, the caterpillar will either become a predator of the ant larvae or beg for food by acting like an ant larvae in what is known as a “cuckoo” strategy. Through much research, it has been well documented that large blue butterflies act as predators in the host nests. Currently, the “cuckoo” method is viewed as a more viable strategy as studies have found more larvae per nest of “cuckoo” butterflies than predator butterflies.Since the parasitic-host relationship between the large blue and the "Myrmica" is essential for the caterpillar survival, female butterflies must lay eggs in areas where the larvae can be found by ant workers of the correct species. In the past it was unclear if "Phengaris" butterflies were capable of identifying areas of specific "Myrmica" species. It was believed that the certain species of "Phengaris" could detect specific odors to identify "Myrmica" species. It was also thought that certain species of "Phengaris" were capable of avoiding overcrowding on food-plants by detecting high egg loads. New studies indicate that female egg-laying is merely attuned to the "Myrmica" species, and that females do not take other factors into consideration.

Habitat

The habitat of the large blue butterfly is largely influenced by location of its food sources. The species requires a combination of abundant amounts of its larval food plant, "Thymus drucei" and the presence of "Myrmica" ants in order to survive.

It has also been found that an underlying key factor for the survival of the large blue is site heterogeneity. The butterfly is most abundant in pastures and abandoned areas of diverse vegetation and shrubbery. This preference can be explained by examining the result of a uniform landscape. A constant landscape synchronizes many biological activities including flowering of host plants, adult emergence dates, or larval pressures on the ant colonies. If important biological functions take place at the same times, the population becomes much more susceptible to random unfortunate events such as environmental disasters. Thus traditional farming acts to desynchronize the biological system, and allows for re-colonization of patches that are temporarily untouched. The presence of differing sites and varied ecological structures provides differing microclimates that can make a huge impact on the survival of the large blue butterfly.