Dracula orchids exploit guilds of fungus visiting flies: new perspectives on a mushroom mimic. (27th February 2019)

• Record Type: Journal Article
• Authors: Policha, Tobias; Grimaldi, David A.; Manobanda, Rocío; Troya, Adrian; Ludden, Ashley; Dentinger, Bryn T. M.; Roy, Bitty A.
• Is Part Of: Ecological entomology. Volume 44:Number 4(2019)
• Page Start: 457
• Page End: 470
• Publication Date: 2019-02-27
• Subjects: Brood‐site mimicry -- fly pollination -- Hirtodrosophila -- mushrooms -- orchid pollination -- Zygothrica; Insects -- Ecology -- Periodicals; Entomology -- Periodicals; 595.7
• DOI: 10.1111/een.12720
• Languages: English
• ISSNs: 0307-6946

Abstract

Abstract : 1. Dracula orchids mimic mushrooms in appearance and scent, and are pollinated by mushroom flies. This study examined the guilds of insect visitors to Dracula species and to co‐occurring mushrooms in an Ecuadorean cloud forest. Significant visitor overlap was documented (mostly in the genera Zygothrica and Hirtodrosophila ; Drosophilidae). To test the brood‐site mimicry hypothesis, behavioural observations were also performed and rearing success was examined. 2. Many fly species that visit Dracula are also found on mushrooms. Furthermore, the presence of pollinia enabled us to document the fact that particular individuals visiting mushrooms also visit Dracula . Roughly two‐thirds of the visitors to these unusual flowers are fungal‐associated, and the rest appear to be Dracula specialists. 3. A variety of behaviours common on both host groups were observed, including courtship semaphoring, feeding, sheltering, defending territory, and mating. Given this suite of shared reproductive behaviour, it was hypothesised that flies may also oviposit in both substrates. Flies were reared from mushrooms, Dracula spp., and other flowers (controls) to determine which substrate led to the highest fitness for the flies. Very few flies emerged from the Dracula flowers and there was no species overlap between the emergent insects and the known pollinators. 4. Despite the fact that there is evidence for brood‐site mimicry, the Dracula situation is complex. All the flies could derive many of the same fitness benefits from the flowers as they do from mushrooms (shelter, food, mating), but they are clearly not gaining the same fitness benefit, in terms of progeny, on flowers compared with mushrooms. Abstract : Dracula orchids mimic mushrooms in appearance and scent, and are pollinated by mushroom flies. To test the brood‐site mimicry hypothesis, this study documented visitor overlap and examined rearing success. Although behaviour was similar on flowers and mushrooms, very few flies emerged from the Dracula flowers, and there was no species overlap between the hatchlings and the known pollinators. Although there is thus evidence for brood‐site mimicry, the flies derive many of the same fitness benefits from the flowers as they do from mushrooms (shelter, food, mating).