Linking Self-Incompatibility, Dichogamy, and Flowering Synchrony in Two Euphorbia Species: Alternative Mechanisms for Avoiding Self-Fertilization?

Background: Plant species have several mechanisms to avoid selfing such as dichogamy or a self-incompatibility response. Dichogamy in a single flower may reduce autogamy but, to avoid geitonogamy, plants must show flowering synchronization among all their flowers (i.e. synchronous dichogamy). It is hypothesized that one species would not simultaneously show synchronous dichogamy and self-incompatibility because they are redundant mechanisms to reduce selfing; however, this has not been accurately assessed. Methodology/Principal Findings: This expectation was tested over two years in two natural populations of the closely related Mediterranean spurges Euphorbia boetica and E. nicaeensis, which completely avoid autogamy by protogyny at the cyathia level. Both spurges showed a high population synchrony (Z,79), and their inflorescences flower synchronously. In E. nicaeensis, there was no overlap among the cyathia in anthesis of successive inflorescence levels and the overlap between sexual phases of cyathia of the same inflorescence level was uncommon (4–16%). In contrast, E. boetica showed a high overlap among consecutive inflorescence levels (74–93%) and between sexual phases of cyathia of the same inflorescence level (48–80%). The flowering pattern of both spurges was consistent in the two populations and over the two successive years. A hand-pollination experiment demonstrated that E. nicaeensis was strictly self-compatible whereas E. boetica was partially self-incompatible. Conclusions/Significance: We propose that the complex pattern of synchronized protogyny in E. nicaeensis prevents geitonogamous crosses and, consequently, avoids selfing and inbreeding depression. In E. boetica, a high probability of geitonogamous crosses may occur but, alternatively, this plant escapes selfing through a self-incompatibility response. We posit that synchronous dichogamy and physiological self-incompatibility do not co-occur in the same species because each process is sufficiently effective in avoiding self-fertilization.España Ministerio de Ciencia y Tecnología PLO CGL2005-03731; CGL2008-02533-EEspaña Ministerio de Ciencia y Tecnología MA CGL2009-0825

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Virtual Reality (VR) has been widely applied to cultural heritage such as the reconstruction of ancient sites and artifacts. It has hardly been applied to the reprise of specific important moments in history. On the other hand immersive journalism does attempt to recreate current events in VR, but such applications typically give the viewer a disembodied non-participatory role in the scene of interest. Here we show how VR was used to reconstruct a specific historical event, where a famous photograph was brought to life, showing Lenin, the leader of the 1917 October Russian Revolution, giving a speech to Red Army recruits in Moscow 1920. We carried out a between groups experimental study with three conditions: Embodied—where the participant was first embodied as Lenin and then later in the audience watching Lenin; Included—where the participant was not embodied as Lenin but was embodied as part of the audience; and Observing—where the participant mainly viewed the scene from a disembodied third person point of view. Twenty participants were assigned to each of the three conditions in a between-groups design. We found that the level of presence was greatest in the Embodied and Included conditions, and that participants were least likely to later follow up information about the Russian Revolution in the Observing condition. Our conclusion is that if the VR setup allows for a period of embodiment as a character in the scenario then this should be employed in order to maximize the chance of participant presence and engagement with the story.</p

The Ability of Spontaneous Autogamy in Four Orchid Species: Cephalanthera Rubra, Neottia Ovata, Gymnadenia Conopsea, and Platanthera Bifolia

The breeding system in Orchidaceae generates many questions about the selfing potential of its representatives. We investigated the ability of spontaneous autogamy of four orchid species: Cephalanthera rubra and Neottia ovata of the Neottieae tribe and Gymnadenia conopsea and Platanthera bifolia of the Orchideae tribe. These species represent diverse specializations of the gynostemium architecture. The self-compatibility and properties of autogamous seeds were determined in a bagging experiment and seed development analysis. After induced autogamy, a high level of fruiting (80-100%) was noted in all of the four study species. C. rubra, N. ovata, and G. conopsea are completely self-compatible, and P. bifolia is suggested to be partially self-compatible. If autogamy occurred, inbreeding depression and resource limitation on seed development appeared only in the two Orchideae species. Independent of flower specialization, both Neottieae species and P. bifolia were completely allogamous, whereas G. conopsea could be facultatively autogamous

Pink flower preference in sunbirds does not translate into plant fitness differences in a polymorphic Erica species

Bird-pollinated plants typically have reddish flowers, but it is not clear whether this trait can be attributed to selection by birds. Here we experimentally test for the first time the foraging behaviour of sunbirds in relation to flower colour, using the Orangebreasted Sunbird Anthobaphes violacea (Nectariniidae) and the colour dimorphic Erica perspicua (Ericaceae). Pink and white flower morphotypes co-flower in intermixed populations and have similar nectar volumes and concentrations. Using floral arrays in a field aviary, we found that sunbirds preferred pink flowers; 95 % of their first choices were to pink inflorescences and they visited and probed more pink inflorescences and flowers, respectively. We also tested for flower constancy (the tendency to move between same colour rather than different colour morphotypes), but found no evidence for this in the sequence of their foraging choices, indicating that this mechanism did not maintain flower colour differences in sympatry. There was evidence for optimal foraging: 80 % of moves were to adjacent inflorescences. Unexpectedly, the preference for pink flowers observed in the aviary did not translate into a female fitness advantage for this morphotype in the field,since no difference is found in natural pollination rate, fruit or seed set.Harry Crossley Fun