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This April, the Vanessa thistle butterfly (Vanessa cardui) arrived at the Pedralbes monastery in Barcelona, which I was able to photograph for La Vanguardia's Readers' Photos while it was sipping nectar from thyme flowers.
To make this photographic report I stretched out on the ground and, with a little patience, it was worth capturing these images, given the beauty of this migratory butterfly.
It turns out that a research team from the Institute of Evolutionary Biology (IBE) verified how this butterfly modifies its migratory routes in search of the best survival conditions, as was found in the study published in the journal Proceeding of the Royal Society. b.
Using a model, they were able to predict the migratory movements of Vanessa cardui, which is very useful for studying the possible effects of climate change on migratory species, since it readjusts its route to better guarantee its survival according to climatic conditions and their variations over time.
The researchers used environmental variables divided over time (by months and years) and breeding records to model breeding habitat. We applied this methodology "to model the Palearctic-African migratory cycle of the butterfly Vanessa cardui, based on data spanning 36 years (646 breeding sites from 30 countries)."
Each reproductive record was linked to a particular time (month and year) and the associated values of the bioclimatic variables are used "for a joint modeling strategy to ultimately obtain monthly projections."
The results showed obligate, mostly latitudinal, movements for successive generations of this butterfly species throughout the range, with only scattered locations showing high probabilities of reproduction throughout the year.
The southernmost breeding areas estimated for the Palearctic-African migratory reserve reach equatorial latitudes from December to February. In summer, Europe represents the main seasonal resource for Vanessa cardui, while January and February show the lowest overall suitability values and are potentially the most vulnerable period for the species.
In short, thanks to this butterfly they demonstrated "the potential of the niche modeling strategy to investigate the migratory movements of insects."
Previously, in 2016, researchers had already confirmed that Vanessa cardui migrates from Europe to tropical Africa during the autumn.
Subsequently, other research revealed that the offspring of these migratory butterflies reverse their migrations again in the direction of Europe throughout the spring, covering routes of up to 15,000 kilometers. This is how this April we have had this butterfly again in Barcelona.
