The Evolution of Pollinator-Plant Interaction Types in the Araceae

Abstract

Interactions between a plant and its pollinators exert great influence on its morphological and physiological adaptations. To the extent that such adaptations are evolutionarily conservative, they can be traced on a phylogeny at least if traits can be unambiguously coded and species are reasonably densely represented in the phylogeny. Studies using historic reconstructions have inferred the evolution of long-tubed flowers adapted to pollinators with long mouthparts (Whittall and Hodges 2007), radial or bisymmetric flowers adapted to different pollinators (Knapp 2010), or perfume-producing flowers adapted to oil-collecting bees (Renner and Schaefer 2010). In orchids, it has also been possible to infer evolutionary shifts between different types of mimicry and deception (Vereecken et al. 2012) and between deceptive and rewarding pollination systems (Johnson et al. 2013). Such shifts between antagonistic and mutualistic pollination interactions are of interest because theory predicts that mutualistic interactions are vulnerable to cheaters (Bronstein 2001). Over evolutionary time, this is expected to lead to the repeated replacement of mutualistic interactions by interactions in which plants deceive their pollinators by attracting them to consistently rewardless flowers. Yet of the 415 families of flowerings plants, only 32 have evolved pollination modes that rely on deceit (Renner 2006). Quantitatively most important among these families are the Orchidaceae, in which thousands of species are thought to rely on deceptive pollination, often involving sexual deception. The first phylogenetic studies addressing evolutionary transitions between deceptive and rewarding pollination in orchids, however, revealed unexpected results. Thus, in the Orchidinae, the ancestral state seems to have been bee-pollinated, food-deceptive flowers, with sexual deception evolving later (Inda et al. 2012),

Don’t forget the flies: dipteran diversity and its consequences for floral ecology and evolution

“…The chemical ecology of brood-site deception is best understood in fly-pollinated systems involving the mimicry of dung (oligosulfides) or carrion (cresol and indole; Jürgens et al 2013;Urru et al 2011), with recent studies elucidating brood-site mimicry of rotting fruit, sap or yeasts nurtured by these substrates (small aliphatic alcohols and esters; Martos et al 2015;Stökl et al 2010). Brood-site deceptive flowers or inflorescences often take the form of kettle traps, to which duped insects are attracted by volatile compounds, and within which they are held captive as a mechanism for ensuring pollen placement or transfer (Bernhardt 2000, Burgess et al 2004;Chartier et al 2014;Heiduk et al 2015). Furthermore, many brood-site deceptive plants are thermogenic, presumably because heat is an important cue attracting flies to dead or decaying substrates (Angioy et al 2004;Schiestl 2017).…”

A review of taxonomy and flower-breeding ecology of the Colocasiomyia toshiokai species group (Diptera: Drosophilidae), with description of a new species from Indonesia

“…Although these Homalomena species attract not only beetles but also Colocasiomyia fl ies, Kumano & Yamaoka (2006) (Wong et al, 2013;. Chartier et al (2014) categorize the genus Homalomena as plants "pollinated by fl y and beetle", and its closely related genera Philodendron as those "pollinated by beetle" and Furtadoa as those "pollinated by fl y". Mapping these pollination interaction types on a phylogenetic tree, they inferred that beetle pollination would have been the ancestral state for these related taxa.…”

Compositional changes of the floral scent volatile emissions from Asian skunk cabbage (Symplocarpus renifolius, Araceae) over flowering sex phases

“…revealed that dimethyl oligosulphides (typically dimethyl disulphide and dimethyl trisulphide) were frequent constituents . Their characteristic foul odour is thought to be a prime factor for attracting saprophagous species . The oligosulphide mixture is implicated in attracting blowflies (Diptera, Calliphoridae), which are pollinators of the Dead‐horse Arum …”

“…9 Their characteristic foul odour is thought to be a prime factor for attracting saprophagous species. 5,10,11 The oligosulphide mixture is implicated in attracting blowflies (Diptera, Calliphoridae), which are pollinators of the Dead-horse Arum. 6 Symplocarpus inflorescences also emit a characteristic smell.…”