Leaf variegation in Caladium steudneriifolium (Araceae): a case of mimicry?
- 674 Downloads
The leaves of Caladium steudneriifolium (Araceae) of the understorey of a submontane rainforest in the Podocarpus National Park (South East Ecuador, 1,060 m a.s.l.) are plain green or patterned with whitish variegation. Of the 3,413 individual leaves randomly chosen and examined in April 2003, two-thirds were plain green, whereas one third were variegated (i.e., whitish due to absence of chloroplasts). Leaves of both morphs are frequently attacked by mining moth caterpillars. Our BLAST analysis based on Cytochrome-c-Oxidase-subunit-1 sequences suggests that the moth is possibly a member of the Pyraloidea or another microlepidopteran group. It was observed that the variegated leaf zones strongly resemble recent damages caused by mining larvae and therefore may mimic an attack by moth larvae. Infestation was significantly 4–12 times higher for green leaves than for variegated leaves. To test the hypothesis that variegation can be interpreted as mimicry to deter ovipositing moths, we first ruled out the possibility that variegation is a function of canopy density (i.e., that the moths might be attracted or deterred by factors unrelated to the plant). Then plain green leaves were artificially variegated and the number of mining larvae counted after 3 months. The results on infestation rate (7.88% of green leaves, 1.61% of the variegated leaves, 0.41% of white manipulated leaves and 9.12% of uncoloured manipulated leaves) suggest that ovipositing moths are deterred by the miner-infestation mimicry. Thus, variegation might be beneficial for the plants despite the implicated loss of photosynthetically active surface.
KeywordsAraceae Herbivory Mimicry Mining moths Understorey Variegation
The Ministerio del Medio Ambiente del Ecuador granted our research permits, and the Deutsche Forschungsgemeinschaft financed our studies (LI 17-1, FOR 402/1-1 TP A8). Dr. Ulrich Meve (Bayreuth) helped with the preparation of Fig. 2. We thank Dr. Mark van Kleunen (Bern) for his careful editing.
- Bogner JS, Nicolson DH (1991) A revised classification of Araceae with dichotomous keys. Willdenowia 21:35–50Google Scholar
- Croat T (1988) Ecology and life forms of Araceae. Aroideana 11:4–55Google Scholar
- Croat T (1994) Taxonomic status of neotropical Araceae. Aroideana 17:33–60Google Scholar
- Gilbert LE (1980) Ecological consequences of a coevolved mutualism between butterflies and plants. In: Gilbert LE, Raven PH (eds) Coevolution of animals and plants. University of Texas Press, Austin, pp 210–240Google Scholar
- Madison M (1981) Notes on Caladium (Araceae) and its allies. Selbyana 5:342–377Google Scholar
- Mayo SJ, Bogner J, Boyce PC (1997) The genera of Araceae. Royal Botanic Gardens, Kew, pp 67–71Google Scholar
- Simon C, Frati F, Beckenbach A, Crespi B, Liu H, Flook P (1994) Evolution, weighting, and phylogenetic utility of mitochondrial gene sequences and a compilation of conserved polymerase chain reaction primers. Ann Entomol Soc Am 87:650–701Google Scholar
- StatSoft, Inc. (2005) STATISTICA (data analysis software system), version 7.1. www.statsoft.com
- Wiens D (1978) Mimicry in plants. Evol Biol 11:365–403Google Scholar