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Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Marino, Paul [1], Piercey, Brandon [1].

Are the pollen-like clumps of spores in Splachnaceae mosses an important visual signal in attracting spore-dispersing flies?

In the absence of a nutritional reward, many plants deceive insects using visual and olfactory signals to facilitate the movement of their gametes to conspecifics or propagules to resource patches. In this study, the role of moss spores, as putative pollen mimics, in deceptive visual signaling in attracting spore-dispersing flies to the mosses, Splachnum ampullaceum and S. pensylvanicum was examined. At the study site both species are primarily restricted to growing on summer moose dung, differ in their visual and olfactory signals, coexist in the same peatland habitat and can grow either alone or intermixed on the same dropping. A previous study on S. ampullaceum and S. pensylvanicum demonstrated that olfactory signals determined the taxa of flies associated with each species of moss whereas visual signals magnified the number of flies attracted to each species of moss. However, S. ampullaceum has a strong visual signal; its 15-65 mm tall sporophytes and a bright yellow, highly inflated swelling (hypophysis) just below the capsule. Whereas S. pensylvanicum has short 2-10 mm sporophytes with a small basally green and distally red/brown hypophysis. Both species have clumped bright yellow sticky pollen-sized spores that, because of the background colour of the hypophysis are visually distinct in S. pensylvanicum but not in S. ampullaceum. The spores are the same size as pollen and, given their bright yellow colour and clumping, look like pollen and, hence, are reminiscent of pollen mimicry in Angiosperms and Fungi. Flies were trapped on single-species populations of both species of moss with the following treatments: 1) populations of S. ampullaceum with mature sporophytes (visual signal present), 2) populations of S. ampullaceum with mature sporophytes stained with malachite green (visual signal absent), 3) populations of S. pensylvanicum with mature sporophytes (visual signal present), 4) populations of S. pensylvanicum with mature sporophytes stained with malachite green (visual signal absent), and 5) fresh moose dung. Removal of the visual signal produced by spores resulted in a significant decrease in the number of flies visiting S. pensylvanicum but not S ampullaceum and it had no effect on the faunal composition of flies that visited each species of moss. The results confirm the that visual signals affect the number of visiting flies whereas odour determines the taxa of visiting flies and, they support that, for S. pensylvanicum, the pollen-like mass of spores are the primary visual single.

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1 - Memorial University, Biology, St. John's , NL, A1B 3X9, Canada

visual signaling
Splachnaceae mosses
pollen mimicry.

Presentation Type: Oral Paper
Session: SYMB1, Symbioses: Plant, Animal, and Microbe Interactions
Location: Tucson J/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 10:15 AM
Number: SYMB1009
Abstract ID:152
Candidate for Awards:None

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