| Title: | "Divergence in floral scent and morphology, but not thermogenic traits, associated with pollinator shift in two brood-site-mimicking Typhonium (Araceae) species" |
| Author(s): | Sayers TDJ; Johnson KL; Steinbauer MJ; Farnier K; Miller RE; |
| Address: | "School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Blvd, Richmond, VIC 3121, Australia. Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, VIC 3086, Australia. Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, VIC 3086, Australia. Department of Jobs, Precincts and Regions, Agriculture Victoria, Melbourne, VIC 3083, Australia. Royal Botanic Gardens Victoria, South Yarra, VIC, 3141, Australia" |
| ISSN/ISBN: | 1095-8290 (Electronic) 0305-7364 (Print) 0305-7364 (Linking) |
| Abstract: | "BACKGROUND: Flowers which imitate insect oviposition sites probably represent the most widespread form of floral mimicry, exhibit the most diverse floral signals and are visited by two of the most speciose and advanced taxa of insect - beetles and flies. Detailed comparative studies on brood-site mimics pollinated exclusively by each of these insect orders are lacking, limiting our understanding of floral trait adaptation to different pollinator groups in these deceptive systems. METHODS: Two closely related and apparent brood-site mimics, Typhonium angustilobum and T. wilbertii (Araceae) observed to trap these distinct beetle and fly pollinator groups were used to investigate potential divergence in floral signals and traits most likely to occur under pollinator-mediated selection. Trapped pollinators were identified and their relative abundances enumerated, and thermogenic, visual and chemical signals and morphological traits were examined using thermocouples and quantitative reverse transcription-PCR, reflectance, gas chromatography-mass spectrometry, floral measurements and microscopy. KEY RESULTS: Typhonium angustilobum and T. wilbertii were functionally specialized to trap saprophagous Coleoptera and Diptera, respectively. Both species shared similar colour and thermogenic traits, and contained two highly homologous AOX genes (AOX1a and AOX1b) most expressed in the thermogenic tissue and stage (unlike pUCP). Scent during the pistillate stage differed markedly - T. angustilobum emitted a complex blend of sesquiterpenes, and T. wilbertii, a dung mimic, emitted high relative amounts of skatole, p-cresol and irregular terpenes. The species differed significantly in floral morphology related to trapping mechanisms. CONCLUSIONS: Functional specialization and pollinator divergence were not associated with differences in anthesis rhythm and floral thermogenic or visual signals between species, but with significant differences in floral scent and morphological features, suggesting that these floral traits are critical for the attraction and filtering of beetle or fly pollinators in these two brood-site mimics" |
| Keywords: | Animals *Araceae Flowers Insecta *Odorants Pollination Typhonium angustilobum Typhonium wilbertii Alternative oxidase Araceae Coleoptera Diptera brood-site mimicry cantharophily floral trap floral volatile organic compounds sapromyophily thermogenesis; |
| Notes: | "MedlineSayers, Thomas D J Johnson, Kim L Steinbauer, Martin J Farnier, Kevin Miller, Rebecca E eng Research Support, Non-U.S. Gov't England 2021/03/25 Ann Bot. 2021 Aug 26; 128(3):261-280. doi: 10.1093/aob/mcab044" |
