Herbivory Increases Fruit Set in Silene latifolia: A Consequence of Induced Pollinator-Attracting Floral Volatiles?
- 537 Downloads
Although the effect of herbivory on plant reproduction has been investigated in some detail, little is known about how herbivores affect floral signalling. Here, we investigated the effect of foliar herbivory by the African Cotton Leafworm (Spodoptera littoralis) on floral signalling and fruit set in the White Campion (Silene latifolia). We found no effects of herbivory on floral traits involved in visual signalling (flower number, corolla diameter, calyx length, petal length) or in amount of nectar produced. However, Spodoptera-infested plants emitted higher amounts of the two floral volatiles, (Z)-3-hexenyl acetate and β-ocimene, than control plants. Open pollinated, infested plants also were found to produce more fruits than control plants, but only with nocturnal pollinators. Experimental addition of the two induced floral volatiles to non-infested Silene flowers also led to the production of more fruits with nocturnal pollination. This suggests that higher fruit production in herbivore-infested plants was caused by increased nocturnal pollinator attraction, mediated by the induced floral emission of these two volatiles. Our results show that the effects of herbivory on plant reproductive success are not necessarily detrimental, as plants can compensate herbivory with increased investment in pollinator attraction.
KeywordsPollination Herbivory Flower scent Volatiles
The authors thank Anna Salatiello and Giovanna Dati for help with conducting experiments. David Carrasco from Swedish University of Agricultural Science provided the Spodoptera larvae used in this study. This research was funded by the CRN-InvaVol grant and POR-Campania BIP to SC and SF and by Swiss National Science Funds (SNF/ESF grant no. 31VL30_134416 to FPS, embedded in the Eurocores Invavol program).
- CABI/EPPO (1997) Quarantine pests for Europe, 2nd edn. CAB International, WallingfordGoogle Scholar
- Elzinga JA, Biere A, Harvey JA (2002) The rearing of the gregarious koinobiont endoparasitoid Microplitis tristis (Hymenoptera: Braconidae) on its natural host Hadena bicruris (Lepidoptera: Noctuidae). Proc Exp Appl Entomol 13:109–115Google Scholar
- Marquis RJ (1992) The selective impact of herbivores. In: Fritz RS, Simms EL (eds) Plant resistance to herbivores and pathogens: ecology, evolution and genetics. University of Chicago Press, Illinois, pp 301–325Google Scholar
- Reekie E, Bazzaz F (2005) Reproductive allocation in plants. Elsevier Academic Press, San DiegoGoogle Scholar
- Seybold S (1990) Caryophyllaceae. In: Sebald O, Seybold S, Philippi G (eds) Die Farn- und Blütenpflanzen Baden-Württembergs. Band 1. Verlag Eugen Ulmer, Stuttgart, pp 368–466Google Scholar