First Record of Flower Bud Galls in Senega (Fabales: Polygalaceae): The Case of S. salasiana and Their Effect on Plant Reproduction.

Abstract

We report the first case of flower bud galls in a species of the mainly American genus Senega (Polygalaceae), specifically in the South Andean Patagonian plant species S. salasiana. The galls were found to be induced by gall midges (Diptera, Cecidomyiidae) and mites (Acari). We also assessed their impact on plant reproduction by measuring the relationship between inflorescence density (number of inflorescences/plant cover) and gall abundance in two populations next to San Carlos de Bariloche, Patagonia, Argentina. Plant reproduction was negatively related to the number of galled inflorescences, suggesting that high levels of gall abundance strongly reduced plant reproductive success. Our study illustrates a novel case of flower galls in the genus Senega and highlights the negative impact of this type of herbivory on plant fitness.