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Back to A frica: autumn migration of the painted lady butterfly Vanessa cardui is timed to coincide with an increase in resource availability
Author(s) -
STEFANESCU CONSTANTÍ,
PUIGMONTSERRAT XAVIER,
SAMRAOUI BOUDJÉMA,
IZQUIERDO REBECA,
UBACH ANDREU,
ARRIZABALAGA ANTONI
Publication year - 2017
Publication title -
ecological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.865
H-Index - 81
eISSN - 1365-2311
pISSN - 0307-6946
DOI - 10.1111/een.12442
Subject(s) - biology , butterfly , abundance (ecology) , ruderal species , ecology , nectar , population , host (biology) , habitat , range (aeronautics) , demography , pollen , materials science , sociology , composite material
1. The painted lady Vanessa cardui is a long‐range migratory butterfly that performs an annual multi‐generational round‐trip between E urope and A frica. Each autumn it returns to northwest (NW) A frica, presumably to track changes in resources that follow a predictable climate‐related spatio‐temporal pattern. 2. Data on the abundance of adult and immature stages in the M aghreb in 2014–2016 are used to test several hypotheses regarding the autumn migration of this species. 3. A strong seasonal migratory strategy was confirmed by the all but total absence of the species in NW A frica at the end of summer and the arrival of huge numbers migrants in O ctober and N ovember. Migration was timed to coincide with an increase in host plant availability but not with any increase in nectar sources. 4. Flower abundance was the main predictor of adult abundance in autumn, with Ditrichia viscosa, Verbesina encelioides, and Medicago sativa being key resources that attracted enormous numbers of butterflies to oases, ruderal habitats, and oueds. The distribution of immature stages was strongly predicted by host plant abundance (with traditional agriculture representing the most important breeding habitat) and latitude (most breeding occurred in the south of the region). Also, both adults and immature stages were more common inland than in coastal areas. 5. Changes in age structure of the adult population were also noted. The number of fresh adults slowly increased, indicating that butterflies did not return in a single wave and that the first offspring of the first returners were already emerging when some butterflies were still arriving.