The benefits of bathing buds: water calyces protect flowers from a microlepidopteran herbivore

• Published in: Biology letters (2005) Vol. 3; no. 4; pp. 405 - 407
• Main Authors: Carlson, Jane E, Harms, Kyle E
• Format: Journal Article
• Language: English
• Published: London The Royal Society 22.08.2007
• Subjects: Adaptation, Biological; Alucitidae; Animals; Chrysothemis friedrichsthaliana; Evolutionary Biology; Feeding Behavior; Floral Evolution; Floral Herbivory; Flowers - anatomy & histology; Flowers - chemistry; Gesneriaceae; Larva - physiology; Magnoliopsida - anatomy & histology; Moths - physiology; Oviposition; Selection; Water
• ISSN: 1744-9561; 1744-957X
• DOI: 10.1098/rsbl.2007.0095

Protective floral structures may evolve in response to the negative effects of floral herbivores. For example, water calyces-liquid-filled, cup-like structures resulting from the fusion of sepals-may reduce floral herbivory by submerging buds during their development. Our observations of a water-calyx plant, Chrysothemis friedrichsthaliana (Gesneriaceae), revealed that buds were frequently attacked by ovipositing moths (Alucitidae), whose larvae consumed anthers and stigmas before corollas opened. Almost 25% of per-plant flower production was destroyed by alucitid larvae over two seasons, far exceeding the losses to all other floral herbivores combined. Experimental manipulation of water levels in calyces showed that a liquid barrier over buds halved per-flower alucitid egg deposition and subsequent herbivory, relative to buds in calyces without water. Thus, C. friedrichsthaliana's water calyx helps protect buds from a highly detrimental floral herbivore. Our findings support claims that sepal morphology is largely influenced by selection to reduce floral herbivory, and that these pressures can result in novel morphological adaptations.