Variation in floral morphology and individual fecundity in Erythronium dens-canis (Liliaceae)

This study investigated the extent to which the reproductive success of plants of Erythronium dens-canis (Liliaceae), a spring herb of mountain habitats, is dependent on floral morphology. To this end, a series of studies was performed in an area in northwest Spain. The results show that E. dens-canis plants in this area a) are self-compatible, b) need pollinator visits (largely Bombus terrestris and Andrena spp.) to produce seed, and c) show high fruit set under natural conditions. Only 20% of among-plant variance in floral morphology variables was explained by variation in plant size. Floral morphology variables (outer tepal length, stamen length, style length and ovule number) tend to vary in parallel, indicating the existence of an "integrated floral phenotype". Two floral morphology variables (initial number of ovules and outer tepal length) had statistically significant or near-significant effects on seed production. A more detailed experimental analysis indicated that small-flowered plants produce fewer seeds than large-flowered plants, and that this is attributable to less efficient pollination of small flowers. The results of this study thus suggest that among-plant variation in floral morphology in E. dens-canis has implications for reproductive success.     

Selecting for floral character associations in wild radish,Raphanus sativus L.

ESS models of reproductive allocation have been used extensively to explain patterns of floral diversity in angiosperms. These theoretical explorations assume that proportional allocation to pollen, ovules, and seeds, as well as to secondary features such as showy petals and nectar rewards, can evolve independently within the limits set by total resource availability. In populations of California wild radish, we have shown previously that petal size, a strong determinant of visitation by honey bee pollinators, is positively correlated with both pollen and nectar production, but not with ovule or seed number per flower. These phenotypic associations may reflect selection, environmental correlation, and/or genetic constraint. By exerting selection on the petal size : pollen number ratio over two generations, we eliminated the positive correlation between petal size and pollen production, with both characters showing significant change after a single selection episode. Once these two floral traits became uncoupled, nectar sugar production was significantly correlated only with petal size. Our results suggest that natural selection could readily alter reproductive allocation in these flowers, and that the phenotypic correlations observed in nature may be maintained by selection for effective reproductive phenotypes.     

Fruit set in a deceptive orchid: The effect of flowering phenology,display size,and local floral abundance

We investigated the effect of flowering time, display size, and local floral density on fruit set in Tolumnia variegata, a pollination-limited orchid that offers no reward to its pollinator(s). During 1990, natural variation in flowering time, display size, and fruit set were monitored in 508 plants at one locality in Puerto Rico. The following season, orchid floral abundance per host tree (Randia aculeata) was manipulated to investigate its effect on fruit set. Four floral abundance treatments were established (700, 500, 300, and 100), each replicated four times. Flowering time was the most important trait affecting fruit set. The proportion of plants setting at least one fruit was significantly high early and late in the season, but low during the flowering peak. Thus, strong disruptive selection differential on flowering phenology was found. Display size had little effect on fruit set. A weak, but significant disruptive selection differential on display size was found. Orchid floral abundance per host tree had a significant effect on fruit set. Early in the season, T. variegata flowers with intermediate number of conspecific flowers exhibited a greater probability of setting fruit than those in host trees with fewer or more flowers. Our results show that flowering phenology may be evolutionarily unstable, possibly a consequence of the deception pollination system. Furthermore, a deception strategy would be relatively unsuccessful in populations where plants are found in either very dense or sparse patches.     

Reproductive success and variation in floral traits in the Iberian Peninsula endemic white campion <Emphasis Type="Italic">Silene marizii</Emphasis> (Caryophyllaceae)

Silene marizii (Caryophyllaceae) is a schizoendemism of the west Iberian Peninsula. The correlation between the evolution of reproductive success (as measured in terms of fruit set and seed production) and five floral traits (peduncle length, calyx length, calyx width, petal limb length, and petal limb width) was investigated in five populations of S. marizii, taking into account both intra-populational and inter-populational variability. The populations studied represented the different habitats of S. marizii over its area of distribution. None of the five traits examined was significantly and positively correlated with the number of seeds produced by the flower. An analysis was also made of how floral morphology varies with the position of the flower in the inflorescence in the five populations. The populations from higher altitudes (Caramulhino, Puerto de Menga and Peña de la Cruz) had larger peduncles, calices and petal limbs than those living at lower altitudes (Sabugal and Mangualde) All five morphometric traits, plus the number of ovules per ovary, varied significantly between flower positions on the same plant and among populations.     

Effects of floral sexual investment and dichogamy on floral longevity

Aims Floral longevity, the duration that a flower remains open and functional, varies greatly among species. Variation in floral longevity has been considered to be optimal strategy for resource allocation under different ecological conditions, mainly determined by the rates of pollination and cost of flower maintenance. However, it is unclear whether an intrinsic factor, floral sexual investment, constrains evolution of floral longevity. The theoretical model also predicts that dichogamy favors long-lived flowers, but empirical studies to test this prediction remain unexplored.Methods To examine the effect of floral sexual investment on floral longevity, we measured flower size together with pollen and ovule production in 37 sympatric flowering plants in a natural community. The duration of the female and male phase in 21 protandrous species and floral longevity of the other 16 adichogamous species were documented in the field.Important findings Floral longevity varied from 1 day to 15 days, while pollen number per flower varied from 643 to 710880 and ovule number per flower from 1 to 426 in the 37 species. Flower size was correlated with pollen production as well as ovule production. Floral longevity was positively related to pollen production but not to ovule production. Consistent with the prediction that dichogamy favors long-lived flowers, we found the floral longevity of protandrous species was significantly longer than that of adichogamous species. In the protandrous species, pollen production per flower was observed to be positively related to male duration, while ovule production was not related to female duration. Our analyses of variation in floral longevity and sexual investment among different species suggest that the floral sexual investment could be an intrinsic factor contributing to the selected floral longevity, particularly the male phase, and that high pollen production could potentially increase pollen removal, i.e. male productive success.     

基于同质园栽培的21种淫羊藿属植物花部特征的分类学意义

以采自中国多地并同质园栽培于吉首大学种质资源圃的21种淫羊藿为研究材料,通过观测这些物种的花梗长、花直径、内萼片长宽、蜜距长、雌雄蕊长、花药长、花柱长、胚珠数、花粉大小及花粉量等16个花部特征数量性状和花序类型、有无蜜距、花瓣颜色、内萼片颜色、内萼片与花瓣相对长度及花粉颜色6个质量性状,并对其分类学意义进行探讨。结果表明,(1)21种淫羊藿内轮萼片花瓣状,4枚花瓣除无距淫羊藿外均特化成蜜距,但花部形态种间存在显著差异,尤其体现于花直径、内萼片长宽、蜜距长、雌蕊长、胚珠数、花粉量、花粉直径等特征。(2)主成分分析显示花直径、内萼片长、花药长、胚珠数和花粉直径等性状信息负荷量较大,在该属分类中起主要作用。(3)根据花部特征聚类分析,物种间区分良好,21物种可分为4支:第1支花小,花瓣短于内轮萼片,囊状距或兜状距;第2支花较大,花瓣远长于内轮萼片,长距状;第3支花小,花瓣没有特化形成蜜距;第4支花较小,花丝伸长明显,可达10 mm,花蜜距呈钻状。(4)依据所观察到的花部形态特征编写了淫羊藿属21种植物花部特征分种检索表。研究认为,基于同质园栽培下的淫羊藿属物种的花部特征具有分类学意义,可以为该属分类提供一定依据。     

Selection for floral integration and trait variation in zygomorphic flowers of Aconitum japonicum ssp. subcuneatum (Ranunculaceae)

Pollinator-mediated selection might lead to among-trait differences in the degree and pattern of floral integration and intra-flower variation. To examine the patterns of intra-flower variation in floral traits, including nectar volume, we performed a field study using the zygomorphic flowers of Aconitum japonicum ssp. subcuneatum. We investigated (1) correlations between the sizes of the left and right sepals and petals, (2) variation in floral traits among plants, within plants and within flowers, (3) effects of sexual phases on floral integration variation in floral and nectar traits, and (4) the effect of size and intra-flower variation in traits of the left and right sepals and petals on pollen removal by pollinators. Lateral sepal area, but not lower sepal area, was highly correlated between the left and right sepals. Floral traits were more integrated during the male phase than during the female phase. Nectar standing crop in male-phase flowers correlated with helmet height and lateral and lower sepal area, but in female-phase flowers it only correlated with spur length. While intra-flower variance in lateral sepal area accounted for approximately 10% of the overall variance in these traits, the variance in lower sepal area accounted for 70% of the overall variance. Lateral sepal area had a negative effect on the number of pollen grains remaining after pollinator visits. Low variance in lateral sepals within flowers and measurements of pollen removal suggest that lateral sepals play a more important role in pollen export than the other traits. Left and right sepals may be the targets of selection for symmetry in zygomorphic flowers.

     

Pollination biology and the impact of floral display, pollen donors, and distyly on seed production in Arcytophyllum lavarum (Rubiaceae)

In animal-pollinated plants, two factors affecting pollen flow and seed production are changes in floral display and the availability of compatible mates. Changes in floral display may affect the number of pollinator visits and the availability of compatible mates will affect the probability of legitimate pollination and seed production. Distyly is a floral polymorphism where long-styled (pin) and short-styled (thrum) floral morphs occur among different individuals. Distylous plants frequently exhibit self and intra-morph incompatibility. Therefore changes in morph abundance directly affect the arrival of compatible pollen to the stigmas. Floral morph by itself may also affect female reproductive success because floral morphs may display differences in seed production. We explored the effects of floral display, availability of neighboring compatible mates, and floral morph on seed production in the distylous herb ARCYTOPHYLLUM LAVARUM. We found that floral display does not affect the mean number of seeds produced per flower. There is also no effect of the proportion of neighboring legitimate pollen donors on seed production in pin or thrum flowers. However, floral morphs differed in their female reproductive success and the thrum morph produced more seeds. Hand pollination experiments suggest that differences in seed production between morphs are the result of pollen limitation. Future research will elucidate if the higher seed production in thrum flowers is a consequence of higher availability of pollen donors in the population, or higher efficiency of the pin morph as pollen donor.     

Comparison of floral properties and breeding system in dimorphic Buddleja delavayi (Scrophulariaceae)

In this study, floral color, scent composition and emission rate, nectar property, pollinators, and breeding system of dimorphic Buddleja delavayi Gagnep. were investigated. Flower color of B. delavayi was determined using a standard color chart and spectrophotometer, and two distinct color polymorphisms were observed having purple or white flowers. Floral scents of B. delavayi were collected using dynamic headspace adsorption and identified with coupled gas chromatography and mass spectrometry. In total, 28 compounds were identified from the flowers of B. delavayi. The identified scents were divided into three chemical classes based on their biosynthetic origin: terpenes, fatty acid derivatives, and benzenoids. The scent profiles in all individuals were dominated by a few components, such as lilac aldehyde and alcohol, 4-oxoisophorone, benaldehyde, and oxoisophorone oxide. Floral scent composition (benzenoids and terpenes) showed a significant difference between white and purple flower morphs. Flower color–flower scent associations in B. delavayi were identified with two distinct scent profiles in the two color phenotypes. The studies of other floral characteristics (nectar, floral visitors, breeding system, and fruit set) indicated that floral scent emission rate, nectar volume, visitor visitation frequency, and natural fruit set were not significantly different between the two flower color morphs. Bagging experiments revealed that seed production of B. delavayi is dependent mainly on honeybee Apis cerana. Lastly, this study implies that dimorphic floral color in B. delavayi may have been maintained by floral visitors and nectar guide color.     

Floral closure induced by pollination in gynodioecious Cyananthus delavayi (Campanulaceae): effects of pollen load and type, floral morph and fitness consequences

Background and aims

Pollination-induced floral changes, which have been widely documented in flowering plants, have been assumed to enhance the plant''s reproductive success. However, our understanding of the causes and consequences of these changes is still limited. Using an alpine gynodioecious species, Cyananthus delavayi, we investigated the factors affecting floral closure and estimated the fitness consequences of floral closure.

Methods

The timings of floral closure and fertilization were determined. The effects of pollen load, pollen type (cross- or self-pollen) and floral morph (female or perfect flower) on the occurrence of floral closure were examined. Ovule fertilization and seed production were examined to investigate the causes and consequences of floral closure. Flowers were manipulated to prevent closing to detect potential benefits for female fitness.

Key Results

Floral closure, which could be induced by a very low pollen load, occurred within 4–7 h after pollination, immediately following fertilization. The proportion of closed flowers was influenced by pollen load and floral morph, but not by pollen type. Floral closure was more likely to occur in flowers with a higher proportion of fertilized ovules, but there was no significant difference in seed production between closed and open flowers. Those flowers in which closure was induced by natural pollination had low fruit set and seed production. Additionally, seed production was not influenced by closing-prevented manipulation when sufficient pollen deposition was received.

Conclusions

The occurrence of floral closure may be determined by the proportion of fertilized ovules, but this response can be too sensitive to ensure sufficient pollen deposition and can, to some extent, lead to a cost in female fitness. These results implied that the control of floral receptivity by the recipient flowers does not lead to an optimal fitness gain in C. delavayi.     

不同生境与花部特征对巫山淫羊藿结实特性的影响

对不同生境中巫山淫羊藿结实特性进行比较研究。结果表明:(1)三个种群在繁殖时期中不同花部特征的植株繁殖投资差异不大,如每株分枝数、每株花序数和每株开花数差异均不显著;(2)三个种群中每株结实数、每株结实率、每花序结实数在不同花部特征中差异显著,PLS和SAA要显著大于PESS;(3)三种花部特征在不同生境中单株分枝数和单株花序数均无显著差异。在不同花部特征中种群1开花数量相较少,因而在结实方面均值均要小于种群2和种群3;(4)不同花部特征的果实饱满种子数、败育数和败育率均具有显著差异,而种子数差异不大,但在种群间均无显著的差异。说明种子的多少更多地受到花部特征的影响。总之,巫山淫羊藿的结实特性受到生境和花部特征的双重影响,其中花型比生境对巫山淫羊藿结实特性的影响更为明显。     

Pollen limitation and natural selection on floral characters in the yellow monkeyflower, Mimulus guttatus

In flowering plants, pollen limitation has been proposed to intensify selection on floral characters important in pollinator attraction, but may also select for traits that increase seed set through autonomous selfing. Here, a factorial design (+/- pollen addition, +/- pollinator removal) was used to investigate how the pollination environment affects selection on floral morphology via female fitness in a mixed-mating population of the yellow monkeyflower, Mimulus guttatus (Phrymaceae). Female fitness was strongly pollen-limited, with supplementally pollinated plants setting 37% more seeds than open-pollinated individuals. Strong positive selection was found on flower length, weak positive selection on flower width : length ratio and no selection on stigma-anther distance in both open-pollinated and supplementally pollinated treatments. By contrast, flowers with relatively narrow corollas and low stigma-anther distances were favored in the pollinator exclusion treatment. These results provide mixed support for the idea that pollen limitation intensifies selection on floral characters. Despite strong phenotypic selection, natural pollen limitation did not mediate selection on characters associated with either pollinator attraction or self-fertilization. However, the novel pattern of selection on severely pollen-limited plants suggests that reproductive assurance against pollinator loss may have been directly involved in the floral evolution of closely related selfing taxa.     

The mechanism of floral heliotropism in the snow buttercup, Ranunculus adoneus

We designed field experiments using solar-tracking Ranunculus adoneus flowers to determine where photoreception occurred, which organs responded, and how movement was achieved. Flower peduncles bend eastward in the morning and gradually unbend over the course of the day. Peduncles were found to bend significantly more frequently in the middle region near the floral bracts, 1–3 cm below the flower, than elsewhere on the peduncle. Because the peduncle tip continued to track the sun even after the flower itself was removed, our experiments concentrated on shielding (or conversely, exposing) various portions of peduncles from (or to) sunlight. Photoreception occurred primarily in the portion of the stem just beneath the floral receptacle. By following the position of landmarks applied to the stem, we found that 40% more growth occurred on the shaded side of bent peduncles, compared to the sunlit side. In contrast, top-shielded peduncles did not solar track well and grew only 25% more on the shaded side than on the sunlit side. This growth differential corresponded to differences in cell length on the two sides of bent peduncles, with significantly longer epidermal cells occurring on the shaded side than on the sunlit side.     

The cost of floral longevity in Clarkia tembloriensis: An experimental investigation

The hypothesis that flower maintenance requires resources that would be used to support other plant functions (i.e. a cost of floral maintenance) was tested by experimentally manipulating floral longevity. Plants of Clarkia tembloriensis, a species with pollination-induced flower senescence, received either early or late pollinations (long and short longevities, respectively). We examined the effect of this manipulation on (1) per-flower allocation to nectar production and (2) flower, fruit and seed production per plant under two levels of resource availability. The direct costs of floral longevity measured in terms of nectar sugar were high: flowers that were maintained 35% longer invested proportionately more in nectar sugar (30%). At the whole-plant level, a cost of floral longevity was manifested as reduced seed production, but the magnitude of this cost varied with resource level. While plants with longer-lived flowers showed a 12% reduction in seed production, those that experienced reduced resource levels via partial defoliation, showed a decrement in seed production that was almost three times larger (34%). These differences were not brought about by changes in the number of flowers and fruits, but by significant alterations in their sizes. A model that expresses the cost of flower maintenance as a trade-off between floral longevity and seed production shows that an optimal flower longevity is determined by both the rate of fitness accrual and the cost of floral maintenance.     

Comparative floral structure and systematics in Ochnaceae s.l. (Ochnaceae,Quiinaceae and Medusagynaceae; Malpighiales)

Ochnaceae s.l. (Ochnaceae, Quiinaceae and Medusagynaceae), one of the well‐supported subclades of the large order Malpighiales retrieved so far in molecular phylogenetic studies, were comparatively studied with regard to floral structure using microtome section series and scanning electron microscopy (SEM). Floral morphology, anatomy and histology also strongly reflect this close relationship. Potential synapomorphies of the subclade include: flowers nectarless, sepals of different sizes within a flower, petals not retarded in development and forming the protective organs of advanced floral buds, petal aestivation contort, petals with three vascular traces, petals reflexed over the sepals and directed toward the pedicel, polystemony, anthers almost or completely basifixed, gynoecium often with more than five carpels, short gynophore present, styles separate for at least their uppermost part and radiating outwards, suction‐cup‐shaped stigmas, vasculature forming a dorsal band of bundles in the upper stylar region, gynoecium epidermis with large, radially elongate cells, ovules either weakly crassinucellar or incompletely tenuinucellar with an endothelium, abundance of tanniferous tissues and sclerenchyma in floral organs. The most strongly supported subclade of two of the three families in molecular analyses, Quiinaceae and Medusagynaceae, is also particularly well supported by floral structural features, including the presence of functionally and morphologically unisexual flowers, a massive thecal septum that persists after anther dehiscence, styles radiating outward from the ovary, two lateral ovules per carpel, positioned one above the other, conspicuous longitudinal ribs on the ovary wall at anthesis, and a ‘false endothelium’ on the nucellus at anthesis. Additionally, the group fits well in Malpighiales and further emphasizes the relationship of Malpighiales with Celastrales and Oxalidales, and thus the unity of the COM clade. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 299–392.     

Morph‐specific selection on floral traits in a polymorphic plant

Correlations between phenotypic traits are common in many organisms, but the relative importance of nonadaptive mechanisms and selection for the evolution and maintenance of such correlations are poorly understood. In polymorphic species, morphs may evolve quantitative differences in additional characters as a result of morph‐specific selection. The perennial rosette herb Primula farinosa is polymorphic for scape length. The short‐scaped morph is less damaged by grazers and seed predators but is more strongly pollen limited than the long‐scaped morph. We examined whether morph‐specific differences in biotic interactions are associated with differences in selection on two other traits affecting floral display (number of flowers and petal size) and on one trait likely to affect pollination efficiency (corolla tube width) in three P. farinosa populations. Differences in selection between morphs were detected in one population. In this population, selection for more flowers and larger petals was stronger in the short‐scaped than in the long‐scaped morph, and although there was selection for narrower corolla tubes in the short‐scaped morph, no statistically significant selection on corolla tube width could be detected in the long‐scaped morph. In the study populations, the short‐scaped morph produced more and larger flowers and wider corolla tubes. Current morph‐specific selection was thus only partly consistent with trait differences between morphs. The results provide evidence of morph‐specific selection on traits associated with floral display and pollination efficiency, respectively.     

开花式样对传粉者行为及花粉散布的影响

理解植物花的特征可以从单花特征和群体特征两个层次入手。开花式样是植物的花在群体上的特征体现, 通过在开花数目、开花类型以及花的排列上的变化, 不同的开花式样对传粉者具有不同的吸引力, 影响昆虫在植株上的活动, 使花粉运动的方向发生相应变化, 从而影响着植物最终的交配结果。此外开花式样随环境改变也会发生一些变化。本文介绍了开花式样研究的进展, 对开花数目、开花类型以及花的排列等3个方面的已有研究进行了分别阐述, 并提出开花式样研究应更多地考虑影响传粉的各种因素。     

A tomato HD-Zip homeobox protein, LeHB-1, plays an important role in floral organogenesis and ripening

Ethylene is required for climacteric fruit ripening. Inhibition of ethylene biosynthesis genes, 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase, prevents or delays ripening, but it is not known how these genes are modulated during normal development. LeHB-1, a previously uncharacterized tomato homeobox protein, was shown by gel retardation assay to interact with the promoter of LeACO1 , an ACC oxidase gene expressed during ripening. Inhibition of LeHB-1 mRNA accumulation in tomato fruit, using virus-induced gene silencing, greatly reduced LeACO1 mRNA levels, and inhibited ripening. Conversely, ectopic overexpression of LeHB-1 by viral delivery to developing flowers elsewhere on injected plants triggered altered floral organ morphology, including production of multiple flowers within one sepal whorl, fusion of sepals and petals, and conversion of sepals into carpel-like structures that grew into fruits and ripened. Our findings suggest that LeHB-1 is not only involved in the control of ripening but also plays a critical role in floral organogenesis.     

Pollinators exert selection on floral traits in a pollen-limited,narrowly endemic spring ephemeral

Premise

Floral traits are frequently under pollinator-mediated selection, especially in taxa subject to strong pollen-limitation, such as those reliant on pollinators. However, antagonists can be agents of selection on floral traits as well. The causes of selection acting on spring ephemerals are understudied though these species can experience particularly strong pollen-limitation. I examined pollinator- and antagonist-mediated selection in a narrowly endemic spring ephemeral, Trillium discolor.

Methods

I measured pollen limitation in T. discolor across two years and evaluated its breeding system. I compared selection on floral traits (display height, petal size, petal color, flowering time) between open-pollinated, and pollen-supplemented plants to measure the strength and mode of pollinator-mediated selection. I assessed whether natural levels of antagonism impacted selection on floral traits.

Results

Trillium discolor was self-incompatible and experienced pollen limitation in both years of the study. Pollinators exerted negative disruptive selection on display height and petals size. In one year, pollinator-mediated selection favored lighter petals but in the second year pollinators favored darker petals. Antagonist damage did not alter selection on floral traits.

Conclusions

Results demonstrate that pollinators mediate the strength and mode of selection on floral traits in T. discolor. Interannual variation in the strength, mode, and direction of pollinator-mediated selection on floral traits could be important for maintaining of floral diversity in this system. Observed levels of antagonism were weak agents of selection on floral traits.     

Pollen limitation, seed predation and scape length in Primula farinosa

Floral display and reward production may affect the attractiveness of a plant to a range of interacting animals including pollinators, herbivores, and vectors of pathogenic fungi. The optimal floral phenotype should therefore depend on the relative importance of selection exerted by both mutualistic and antagonistic animals. The perennial, rosette herb Primula farinosa is polymorphic for scape length. Natural populations may include both plants with flowers displayed well above the ground (the long-scaped morph) and those with flowers positioned very close to the ground (the short-scaped morph). In this study, we conducted a field experiment to examine how the relative fitness of the two scape morphs is affected by interactions with pollinators and fruit predators in two different microhabitats (high and low vegetation). As predicted based on the difference in floral display, supplemental hand-pollination showed that fruit initiation was more strongly pollen-limited in the short-scaped than in the long-scaped morph, and that this difference was significantly larger in high than in low vegetation. Moreover, plants with a short scape experienced lower levels of fruit predation than plants with a long scape. Among open-pollinated controls, there was no significant difference in seed output between the two scape morphs. However, among plants receiving supplemental hand-pollination, short-scaped plants produced significantly more seeds than long-scaped plants. The results suggest that the positive and negative effects of a prominent floral display (increased pollination and seed predation, respectively) balance in the study population, but also that the short-scaped morph would have an advantage at higher pollination intensities. Spatial and temporal variation in pollinator activity and seed predation should result in associated variation in the relative fecundity of the two scape morphs.