Floral Biology of North American Oenothera Sect. Lavauxia (onagraceae): Advertisements, Rewards, and Extreme Variation in Floral Depth

نویسندگان

  • Robert A. Raguso
  • Almut Kelber
  • Michael Pfaff
  • Rachel A. Levin
  • Lucinda A. McDade
چکیده

We studied the floral biology of five North American members of Oenothera L. sect. Lavauxia (Spach) Endl. (Onagraceae L.) in field and common greenhouse settings. Oenothera sect. Lavauxia floral morphology ranges from small, cleistogamous flowers (O. flava subsp. flava (A. Nels.) Garrett in Garrett) to some of the longest-tubed flowers in North America (O. flava subsp. taraxacoides (Wooton & Standl.) W. L. Wagner). Our goal was to compare qualitative and quantitative aspects of floral advertisement and reward among taxa in section Lavauxia. All taxa are night-blooming and self-compatible, have yellow petals with ultraviolet reflectance, and produce floral scents dominated by nitrogenous compounds and monoterpenes. Methyl nicotinate is present in the fragrances of all taxa of section Lavauxia regardless of flower size or putative mating system. Because this floral volatile is largely absent from other Oenothera species, we hypothesize that it is a synapomorphy for section Lavauxia. The rare O. acutissima W. L. Wagner, which is endemic to the Uintah Mountains, is polymorphic for odors dominated by linaloolor ocimene-derived compounds. Field observations in its type locality in northeastern Utah, U.S.A., revealed frequent floral visitation by crepuscular hawkmoths during the first 1.5 hours after anthesis, a pattern common to O. flava subsp. taraxacoides and other large-flowered Oenothera throughout western North America. Quantitative aspects of floral advertisement (flower size, scent emission) and reward (nectar volume) are dramatically reduced in putatively autogamous taxa (O. flava subsp. flava, O. triloba Nutt.), whereas qualitative aspects (flower color, scent, and nectar chemistry) remain comparable. All taxa could be distinguished through ordination of characters related to flower size, herkogamy, and scent chemistry. Extreme nectar tube length variation across the range of O. flava renders this an excellent model system for measuring the costs and mechanisms of shifts between outcrossing and autogamy.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Floral humidity and other indicators of energy rewards in pollination biology

Floral traits that correlate with nectar availability or are linked functionally to nectar production carry the potential to enable remote assessment of energy rewards by pollinators. Such floral traits can be considered "honest" in the sense that they convey information about the quality or profitability of a flower to a pollinator. Recently a new sensory channel used in plant-pollinator inter...

متن کامل

Floral humidity as a reliable sensory cue for profitability assessment by nectar-foraging hawkmoths.

Most research on plant-pollinator communication has focused on sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, and foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document such a cue--transient humidity gradients--using the night b...

متن کامل

Herbivory as an important selective force in the evolution of floral traits and pollinator shifts

Floral trait evolution is frequently attributed to pollinator-mediated selection but herbivores can play a key role in shaping plant reproductive biology. Here we examine the role of florivores in driving floral trait evolution and pollinator shifts in a recently radiated clade of flowering plants, Oenothera sect. Calylophus We compare florivory by a specialist, internal feeder, Mompha, on clos...

متن کامل

Taxonomic changes in Oenothera sections Gaura and Calylophus (Onagraceae)

The long-recognized genus Gaura was shown recently to be deeply nested within one of two major clades of Oenothera. New molecular data indicate further taxonomic changes are necessary in Oenothera sect. Gaura. We make these changes here, including three new combinations, in advance of the Onagraceae treatment for the Flora of North America. The new phylogenetic studies show that several pairs o...

متن کامل

Effects of plant sex on range distributions and allocation to reproduction.

Despite an abundance of theory, few empirical studies have explored the ecological and evolutionary consequences of sex. We used a comparative phylogenetic approach to examine whether transitions between sexual and asexual reproduction are associated with changes in the size and distribution of species' geographical ranges, and their investment in reproduction. Here, we reconstructed the phylog...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2009