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. © 2007 The Royal Society.
Publication Source (Journal or Book title)
Carlson, J., & Harms, K. (2007). The benefits of bathing buds: Water calyces protect flowers from a microlepidopteran herbivore. Biology Letters, 3 (4), 405-407. https://doi.org/10.1098/rsbl.2007.0095