Evidence of short-term shifts in floral traits in response to nectar robbing

ABSTRACT Background Nectar robbing has multiple effects on plants and pollinators, depending on the traits of a plant and its reproductive system, the behaviour of its pollinators, and the identity of the robber. Aims We aimed to evaluate temporal variation in morphological traits of robbed and intact flowers of the ornithophilous Asian basket plant, Aeschynanthus speciosus (Gesneriaceae). Methods We measured the length of the style and corolla, and the width of the stigma of the flowers of potted A. speciosus plants on three different days. We also recorded whether nectar robbing influenced the position of the androecium in relation to the gynoecium between robbed and intact flowers. Results Nectar robbing by the bananaquit, Coereba flaveola, had a negative effect on the development of floral traits of A. speciosus, resulting in flowers with smaller styles and stigmas, and reduced herkogamy. Conclusion We discuss these findings from the perspective of plant-nectar robber interactions, offering insights into the strategies adopted by plants to counteract the negative effects of nectar robbing.