The ecological role of orientation in tropical convolvulaceous flowers

Patiño, S.; Jeffree, C. E.; Grace, John

doi:10.1007/s00442-001-0824-1

Cited by 44 publications

(63 citation statements)

References 14 publications

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“…The adaptive signiWcance of Xower orientation has been investigated in terms of pollinator attraction (Kevan 1975;Kudo 1995;Huang et al 2002;Patino et al 2002;Ushimaru et al 2006), but few studies have focused on the eYciency of pollen transfer (e.g., Tadey and Aizen 2001;Ushimaru et al 2006). We found that Xower angle strongly inXuenced pollinator behaviors and consequent pollen transfer in a zygomorphic species, suggesting the importance of Xower orientation in specialized pollination systems.…”

Section: Discussionmentioning

confidence: 85%

Flower orientation enhances pollen transfer in bilaterally symmetrical flowers

et al. 2009

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Zygomorphic flowers are usually more complex than actinomorphic flowers and are more likely to be visited by specialized pollinators. Complex zygomorphic flowers tend to be oriented horizontally. It is hypothesized that a horizontal flower orientation ensures effective pollen transfer by facilitating pollinator recognition (the recognition-facilitation hypothesis) and/or pollinator landing (the landing-control hypothesis). To examine these two hypotheses, we altered the angle of Commelina communis flowers and examined the efficiency of pollen transfer, as well as the behavior of their visitors. We exposed unmanipulated (horizontal-), upward-, and downward-facing flowers to syrphid flies (mostly Episyrphus balteatus), which are natural visitors to C. communis. The frequency of pollinator approaches and landings, as well as the amount of pollen deposited by E. balteatus, decreased for the downward-facing flowers, supporting both hypotheses. The upward-facing flowers received the same numbers of approaches and landings as the unmanipulated flowers, but experienced more illegitimate landings. In addition, the visitors failed to touch the stigmas or anthers on the upward-facing flowers, leading to reduced pollen export and receipt, and supporting the landing-control hypothesis. Collectively, our data suggested that the horizontal orientation of zygomorphic flowers enhances pollen transfer by both facilitating pollinator recognition and controlling pollinator landing position. These findings suggest that zygomorphic flowers which deviate from a horizontal orientation may have lower fitness because of decreased pollen transfer.

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Section: Discussionmentioning

confidence: 85%

Flower orientation enhances pollen transfer in bilaterally symmetrical flowers

et al. 2009

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“…For example, in a rainy environment, it may be optimal for a plant to have its flowers pointing downwards in order to avoid flooding out the nectar (Aizen 2003;Tadey & Aizen 2001). Similarly, heliotropic plants move their flowers to face towards the sun throughout the day, which may be an important strategy for pollinator attraction or floral development in cold climates (Kevan 1975;Kudo 1995;Patiño et al 2002). Furthermore, field experiments have demonstrated that unusual floral orientation may have an effect upon pollinator landing behaviour (Ushimaru & Hyodo 2005) and pollination success (Ushimaru et al 2009), and it is known that floral orientation can be used as a cue by honeybees (Lamb & Wells 1995) and beetles (Dafni & Potts 2004).…”

Section: Discussionmentioning

confidence: 99%

Floral epidermal structure and flower orientation: getting to grips with awkward flowers

Rands

Glover

Whitney

2011

Arthropod-Plant Interactions

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This is a copy of the author's accepted version of this manuscript, and the definitive published version in Arthropod-Plant Interactions may have changed slightly in response to editing. This version is made available on the University of Bristol's repository, complying with Springer's policy on self-archiving (7 th April 2008). The original article, with full details of citation, is available at springerlink.com, at http://www.springerlink.com/content/v81t25t4421126n2/ .-2 - AbstractThe petal epidermis has been found to be important in mediating flower-pollinator interactions. Structures produced on the petal surface, in particular cone-shaped papillate (or conical) cells, have been shown to enhance bumblebee preference for flowers. One reason for this increase in preference is that the conical cells facilitate efficient handling of flowers. This is particularly clear when flower architecture requires bees to land on a vertical surface. We therefore tested the hypothesis that flowers that are held vertically show a greater tendency to produce conical cells. Analysis of 183 species finds that there is no significant relationship between the structures on the petal surface and flower orientation. We discuss the multifunctional properties of conical cells and other floral surface structures that may mean that other factors are of equal or greater importance in the relationship between pollinators and petal epidermal form.

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“…Insects may warm up passively by basking in the sun but large bees can also warm up actively through shivering thermogenesis, contracting the flight muscles to produce metabolic heat (Heinrich 1979). Insects may also profit from flowers whose temperature is higher than that of the ambient air (Herrera 1995;Lack 1976;Patino et al 2002;Totland 1996). Above-ambient floral temperature may result from heliotropic movement of concave flowers (Galen and Stanton 2003;Kevan 1975;Orueta 2002;Patino et al 2002;Totland 1996) or floral metabolic thermogenesis (Dieringer et al 1999;Jewell et al 1994;Patino et al 2000;Seymour et al 2003).…”

Section: Introductionmentioning

confidence: 98%

Morning floral heat as a reward to the pollinators of the Oncocyclus irises

2005

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Relationships between flowering plants and their pollinators are usually affected by the amount of reward, mainly pollen or nectar, offered to pollinators by flowers, with these amounts usually positively correlated with floral display. The large Oncocyclus iris flowers, despite being the largest flowers in the East Mediterranean flora, are nectarless and have hidden pollen. No pollinators visit the flowers during daytime, and these flowers are pollinated only by night-sheltering solitary male bees. These iris flowers are partially or fully dark-colored, suggesting that they gather heat by absorbing solar radiation. Here we test the hypothesis that the dark-colored flowers of the Oncocyclus irises offer heat reward to their male solitary bee pollinators. Floral temperature was higher by 2.5 degrees C than ambient air after sunrise. Solitary male bees emerged earlier after sheltering in Oncocyclus flowers than from other experimental shelter types. Pollination tunnels facing east towards the rising sun hosted more male bees than other aspects. We suggest that floral heat reward can explain the evolution of dark floral colors in Oncocyclus irises, mediated by the pollinators' behavior.

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The ecological role of orientation in tropical convolvulaceous flowers

Cited by 44 publications

References 14 publications

Flower orientation enhances pollen transfer in bilaterally symmetrical flowers

Flower orientation enhances pollen transfer in bilaterally symmetrical flowers

Floral epidermal structure and flower orientation: getting to grips with awkward flowers

Morning floral heat as a reward to the pollinators of the Oncocyclus irises

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