Brown blues greatly expanded their habitat in the UK due to the fact that climate change has extended growing season caterpillars of these butterflies and allowed them to move to a new kind of food — widespread in the wild geranium, British environmentalists claim in an article published in the journal Science.
Brown blues (Aricia agestis) are among some of the rarest butterflies in the temperate climate zone. They are found in central and southern Europe, and are also found in some parts of the south of England and Russia. Small habitat of this insect is due to its "gourmandise" — Tracks blues feed only on the leaves solntsesveta monetolistnogo (Helianthemum nummularium) — a small herbaceous plant that inhabits the rocky and dry areas of soil.
Team of biologists led Peytman Rachel (Rachel Pateman) from the University of York (UK) track changes in the life cycle and habitat of the butterflies in the UK over the past 20 years. Abundance and habitat of these insects have continued to decline in the 80 years of the last century, and therefore for them to continually observe the ecology and biology.
Scientists have noticed that brown blues and caterpillars started dating 80 kilometers north of the border they live in the early 90's. According to the researchers, this rate of migration is 2.3 times higher than the typical rate of migration of insects, which in the decade to expand their turf by only 17 miles in either direction of colonization.
In addition, the new boundaries of a habitat blues beyond the part of the United Kingdom, where there are bushes solntsesveta. This behavior puzzled Peytman butterflies and her colleagues. Biologists have connected to the study of a few volunteers amateur butterflies that monitors the behavior of local populations and the blues, inhabited caterpillars of this species of insects in a few decades, before the start of the study.
It turned out that butterflies are laying eggs on the leaves with a soft geranium (Geranium molle) — one of the most common species in the southern and central Britain. Peytman and her colleagues suggest that the transition to a new food source was due to climate change. Increasing the number of hot days in the summer allows caterpillars grow longer and eat not solntsesvetom and other less nutritious plants.
The researchers tested their hypothesis by comparing the average summer temperature during the observation period with the amount of caterpillars lived on the leaves of geranium. According to scientists, the comparison proved their hypothesis — the warmer it was summer, the greater the blues larvae on leaves Geranium molle.
"It is important that we now understand how and why this species respond to climate change. Such a study would not have been possible without the thousands of pages of data that our volunteers are prepared for decades of observation, that in the end and allowed to track these long-term changes," — enters one of the authors, Richard Fox (Richard Fox) from the Society of butterflies in Uorhem (UK).