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Concept
Timarcha lugens
Résumé
Timarcha lugens (Chrysomelidae) is a wingless leaf beetle endemic to the high mountains of the Sierra Nevada (Spain). The genus Timarcha comprises a group of herbivorous species, widely distributed in Europe, Turkey, North Africa and Western North America, which inhabit a broad range of habitats, including high mountains, humid forests and sandy coastal areas. In the Iberian Peninsula, Timarcha is represented by more than 25 species, some of them inhabiting montane regions. In the Sierra Nevada, this genus is represented by four species, although only three of them, T. lugens, T. insparsa Rosenh., and T. marginicollis Rosenh., occur over altitude. While T. lugens and T. insparsa are endemic species of the Sierra Nevada mountains, T. marginicollis is also present in other mountain ranges in southern Spain. T. lugens distribution area spans from above sea level, being the most abundant chrysomelid at these high-altitudes.
Timarcha lugens is strictly monophagous on Hormathophylla spinosa (Brassicaceae), a stunted shrub abundant in many West Mediterranean high mountains. This beetle feeds on leaves, flower buds, flowers and fruits.
The life cycle of T. lugens is completed in two years. Adults start their activity soon after snowmelt and are active until the beginning of autumn (end of September in the Sierra Nevada). Most adults that are active at the beginning of the season are the individuals that emerged the preceding year and have survived the winter in diapause. Mating and egg laying occur along the whole period of adult activity. At the end of the summer, approximately 15 days to one month before the snow has completely covered the study area, individuals start overwintering under large plants or stones. Overwintering is common in species of Timarcha, as well as other chrysomelids, and it occurs in most high mountain species, which are active only during the warmest period of the year. The short periods of activity (usually restricted to summertime) limits the breeding season to a few months in which these species have to maturate reproductive organs, mate, breed, and develop.
Source officielle
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