Mechanisms of flower coloring and eco-evolutionary implications of massive blooming events in the Atacama Desert

Abstract

The Atacama Desert, one of the driest places on earth, holds a rich biodiversity that becomes most appreciable in years when unusual rainfall accumulation triggers a phenomenon of explosive development of ephemeral herbaceous and woody desert species known as “desierto florido” or “blooming desert.” Despite the scientific importance of this unique phenomenon only few studies have addressed the mechanisms of flower phenotypic divergence under the fluctuating environment provided by this recurrent event. We investigated the mechanisms of floral color diversity in Cistanthe longiscapa (Montiaceae), a dominant species across the ephemeral blooming landscape of Atacama Desert. Our analyses show that the variation in colors of C. longiscapa flowers result from petals containing betalain pigments with different absorption spectra. The different pigment composition of petals causes flower color differences in the visible and ultraviolet (UV) range of the spectrum. Through color vision models we show that C. longiscapa flowers are highly polymorphic in their color appearance for insect pollinators. Our results highlight the variable nature in flower color of C. longiscapa varieties blooming simultaneously in a geographical restricted area. Given the importance of color in attracting floral visitors, the observed color variability could contribute to increased cross pollination in extreme desert conditions, while accounting for complex and fluctuating histories of plant-pollinator interactions.

Flora diversity survey and establishment of a plant DNA barcode database of Lomas ecosystems in Peru

“…This belt is typified by a tropical desert climate, with annual precipitation of less than 50 mm (arid) or 5 mm (hyper-arid), making it one of the driest areas in the world. Despite the drought, “fog oasis” like islands with lush vegetation and flowers appear in the desert and are known as “blooming deserts” 2 , 3 . There is a tenuous balance between Pacific Ocean currents, onshore winds, the height of the Andes mountains, and cyclic El Niño events that shape such particular geographic and unique climatic conditions 4 – 6 .…”