scholarly journals Small-scale variations in leaf shape under anthropogenic disturbance in dioecious forest forb mercurialis perennis: A geometric morphometric examination

2016 ◽  
Vol 68 (4) ◽  
pp. 705-713 ◽  
Author(s):  
Vukica Vujic ◽  
Luka Rubinjoni ◽  
Sara Selakovic ◽  
Dragana Cvetkovic
Keyword(s):  
Sexual Dimorphism ◽  
Leaf Shape ◽  
Size Variation ◽  
Leaf Size ◽  
Small Scale ◽  
Specific Response ◽  
Geometric Morphometric ◽  
Leaf Level ◽  
Leaf Size And Shape ◽  
Shape And Size

Plants are exposed to increasing levels of diverse human activities that have profound effects on their overall morphology and, specifically, on leaf morphology. Anthropogenic disturbances in urban and suburban forest recreational sites are attracting growing research interest. To explore the persisting recreational impact on leaf shape and size, we conducted a field study on the dioecious forb Mercurialis perennis L. (Euphorbiaceae), typical for undisturbed understory communities. We selected adjacent sites in a suburban forest, which experience contrasting regimes of disturbance by human trampling under otherwise concordant natural conditions. Patterns of leaf shape and size variation and putative sex-specific response to disturbance were analyzed using a geometric morphometric approach. In addition to leaf-level data, plant height, internode and leaf number were analyzed to explore the same response at the whole-plant level. The results show significant variations associated with disturbance at both levels: plants growing under a heavy disturbance regime had shorter stems with a greater number of wider and shorter leaves. Significant differences between sites were also found for leaf size, with larger leaves observed in an undisturbed site. The effects of sex and sex x site interaction on leaf size and shape were nonsignificant, pointing to the absence of sexual dimorphism and sex-specific response to disturbance. Contrary to leaf shape and size, all three analyzed shoot traits showed highly significant sexual dimorphism, with male plants being higher and having higher leaf and internode count.

The impact of leaf shape on the feeding preference of insect herbivores: experimental and field studies with Capsella and Phyllotreta

1996 ◽  
Vol 351 (1348) ◽  
pp. 1671-1677 ◽  
Keyword(s):  
Leaf Shape ◽  
Laboratory Data ◽  
Leaf Size ◽  
Field Studies ◽  
Feeding Preference ◽  
Insect Herbivores ◽  
Flea Beetles ◽  
Shape Effects ◽  
Leaf Size And Shape ◽  
The Impact

Leaves display an enormous array of sizes and shapes. Although these attributes appear to have evolved primarily in response to abiotic conditions in the plant’s habitat, the importance of insect herbivores as additional selective agents is still poorly understood. A necessary requirem ent for leaf size and shape to evolve in response to attack by insects is that insects must respond to and/or be affected by, leaf morphology. We tested leaf-shape preferences in adult flea beetles ( Phyllotreta spp.) feeding on the highly variable rosette leaves of Capsella bursa-pastoris . Contrary to theoretical expectation (Brown & Lawton 1991), leaves with deeply lobed margins were more intensely damaged, both in field-collected and experimental plants. In two ancillary experiments with Capsella , we found that Spodoptera caterpillars showed no preferences for leaf shape, but that adult vine weevils ( Otiorhynchus sulcatus ) did, preferring (as predicted), undivided over divided leaves. We conclude that Brown & Law ton’s (1991) hypothesis is at best weakly supported by laboratory data for vine weevils, refuted by laboratory data for Spodoptera , and consistently refuted by both laboratory and field data for flea beetles. Although the experiment tried to reduce confounding variables to a minimum, interpretation was complicated by correlations between leaf shape and other developmental parameters of the plants, and highlights the difficulty of disentangling leaf-shape effects from other confounding factors.

scholarly journals The significance of shared leaf shape in Alseuosmia pusilla and Pseudowintera colorata

Botany ◽  
2016 ◽  
Vol 94 (7) ◽  
pp. 555-564 ◽  
Author(s):  
Karl G. Yager ◽  
H. Martin Schaefer ◽  
Kevin S. Gould
Keyword(s):  
Spatial Variation ◽  
Plant Species ◽  
Altitudinal Gradient ◽  
Leaf Shape ◽  
Sympatric Species ◽  
Spatially Explicit ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Leaf Characteristics ◽  
Shape And Size

Leaf shape, size, and colour are used by herbivores to identify sources of palatable foliage for food. It is possible, therefore, that an undefended plant might gain protection from herbivores by matching leaf characteristics of a chemically defended species. We demonstrate the use of a geometric morphometric approach to quantify spatial variation in leaf shape and size across populations of Pseudowintera colorata (Raoul) Dandy, and a putative Batesian mimic, Alseuosmia pusilla (Colenso) A. Cunningham. These are unrelated, sympatric species that, to the human eye, bear strikingly similar foliage. Using the Cartesian coordinates of leaf margins as descriptors of leaf shape, we found that in the chemically defended P. colorata, leaves were morphologically distinct from all of the neighbouring species except for the undefended A. pusilla. Alseuosmia pusilla individuals were more similar to neighbouring than to distant P. colorata, and 90% of leaf shape variation in the two species varied similarly across an altitudinal gradient. The data are consistent with Batesian mimicry, wherein the conspicuous characteristic of a defended model is replicated by an undefended mimic across its entire growing range. Our study provides the first detailed and powerful quantitative leaf shape evidence of leaf shape being matched between an undefended plant species to a chemically defended unrelated species across a shared growing range, and highlights the importance of using a spatially explicit morphometric method when investigating leaf shape, especially in relation to plant mimicry.

No functional sexual dimorphism in Minorcan horse assessed by geometric morphometric methods

2015 ◽  
Vol 56 ◽  
pp. 91-95 ◽  
Author(s):  
Pere M. Parés-Casanova ◽  
C. Allés
Keyword(s):  
Sexual Dimorphism ◽  
Lateral View ◽  
Geometric Morphometric ◽  
Male And Female ◽  
Size And Shape ◽  
Morphometric Methods ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea ◽  
Age Range ◽  
Shape And Size

SummaryThe existence of sexual dimorphism in the Minorcan horse, an autochthonous breed from Minorca Island in the Balearic archipelago (NW Mediterranean Sea), is established in the official standard, with females being shorter and longer than males as well as having slenderer necks and a squarer croup. However, no study so far has explored the size and shape components of this dimorphism separately. The aim of this study was to analyse the morphology of this breed using geometric morphometric methods in order to find size and shape differences between sire lines. The analysis was based on landmarks digitized in lateral view from 38 registered adult Minorcan horses (20 males and 18 females) within an age range of 3–14 years (average 7 years) with different performance goals. The analyses did not reveal any significant differences between the “shape” and “size” of male and female animals, for the landmarks studied, so the sexes are functionally similar.

scholarly journals Sources of variation in leaf shape among two populations of Achillea lanulosa.

Genetics ◽  
1992 ◽  
Vol 130 (2) ◽  
pp. 385-394 ◽  
Author(s):  
J Gurevitch
Keyword(s):  
Leaf Shape ◽  
Bright Light ◽  
Leaf Size ◽  
Plastic Response ◽  
Lower Altitude ◽  
Growth Environment ◽  
Size And Shape ◽  
Shape Characters ◽  
Leaf Size And Shape ◽  
Response To Temperature

Abstract Achillea lanulosa has complex, highly dissected leaves that vary in shape and size along an altitudinal gradient. Plants from a high and an intermediate altitude population were clonally replicated and grown in a controlled environment at warm and cool conditions under bright light. There were genetic differences among populations and among individuals within populations in leaf size and shape. Heritabilities for leaf size and shape characters were moderate. Leaves of the lower altitude population were larger and differed from the higher altitude plants in both coarse and fine shape. Plastic response to temperature of the growth environment paralleled the genetic differentiation between low and high altitude populations. There was no apparent trade-off between genetic control over morphology and the capacity for directional plastic response to the environment. Differences in leaf dissection and size at contrasting altitudes in this species are the result of both genetic divergence among populations and of acclimative responses to local environments.

A morphometric and taxonomic reevaluation of Haenianthus (Oleaceae)

1991 ◽  
Vol 69 (3) ◽  
pp. 489-493
Author(s):  
Scott Zona
Keyword(s):  
Puerto Rico ◽  
Key Words ◽  
Morphometric Analysis ◽  
Leaf Shape ◽  
Leaf Size ◽  
Cloud Forests ◽  
Size And Shape ◽  
Leaf Size And Shape ◽  
Key Words Caribbean

Leaf size and shape, long used to differentiate taxa in Haenianthus, were found to be less useful than previously believed. Nevertheless, two species can be recognized on the basis of leaf shape, H. incrassatus and H. salicifolius. The former species has long petioles, attenuate leaf bases, and thin laminas and is endemic to cloud forests of Jamaica. The latter species, with short petioles, acute to acuminate leaf bases, and thick laminas, has two varieties, H. salicifolius var. salicifolius of Cuba and Haiti, and H. salicifolius var. obovatus of Cuba, Hispaniola, and Puerto Rico. Key words: Caribbean, Haenianthus, morphometric analysis, Oleaceae.

scholarly journals Geometric morphometrics for the study of hemicoxae sexual dimorphism in a local domestic equine breed

2014 ◽  
Vol 31 (04) ◽  
pp. 214-218 ◽  
Author(s):  
P. Parés-Casanova
Keyword(s):  
Sexual Dimorphism ◽  
Morphometric Analysis ◽  
Reliable Method ◽  
Sex Differentiation ◽  
Horse Breed ◽  
Geometric Morphometric ◽  
Photographic Images ◽  
Average Accuracy ◽  
Pelvic Shape ◽  
Shape And Size

Abstract Introduction and material and methods. Twenty-height skeletonised hemicoxae from young animals (yearlings, 13 males and 15 females) belonging to the “CavallPirinencCatalà” horse (Catalan Pyrenean Horse) breed were studied by means of geometric morphometric (GM) methods. Morphometric analysis was based on coordinates of 16 landmarks of the ilium and ischiopubic regions that were digitised on 2D photographic images. Sexes did not appear separated either by size or shape, the latter being independent of the former.K-means clustering of shape variables were used in order to classify individuals by sex and an average accuracy of 57.1% was achieved. Results. Males were misclassified more frequently than females. For the iliac landmarks, which contributed to the total variance of shape with the higher degree, the value obtained increased to 60.7% for k-means. The ischiopubic complex contributed less to sex differentiation according to shape. Conclusion. It is concluded that the use of GM and multivariate statistics is not a reliable method to quantify pelvic shape and size differences between the sexes for equine yearlings. This is the irst known study to apply GM to the hip of an equine breed.

scholarly journals Shape and size variations of Aegla uruguayana (Anomura, Aeglidae) under laboratory conditions: A geometric morphometric approach to the growth

2015 ◽  
Vol 105 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Valeria P. Diawol ◽  
Federico Giri ◽  
Pablo A. Collins
Keyword(s):  
Life Cycle ◽  
Sexual Dimorphism ◽  
Geometric Morphometrics ◽  
Individual Growth ◽  
Freshwater Crab ◽  
Dorsal Region ◽  
Geometric Morphometric ◽  
Life Cycle Stages ◽  
Morphometric Methods ◽  
Shape And Size

Crustacean growth studies typically use modal analysis rather than focusing on the growth of individuals. In the present work, we use geometric morphometrics to determine how organism shape and size varies during the life of the freshwater crab, Aegla uruguayana Schmitt, 1942. A total of 66 individuals from diverse life cycle stages were examined daily and each exuvia was recorded. Digital images of the dorsal region of the cephalothorax were obtained for each exuvia and were subsequently used to record landmark configurations. Moult increment and intermoult period were estimated for each crab. Differences in shape between crabs of different sizes (allometry) and sexes (sexual dimorphism; SD) were observed. Allometry was registered among specimens; however, SD was not statistically significant between crabs of a given size. The intermoult period increased as size increased, but the moult frequency was similar between the sexes. Regarding ontogeny, juveniles had short and blunt rostrum, robust forehead region, and narrow cephalothorax. Unlike juveniles crabs, adults presented a well-defined anterior and posterior cephalothorax region. The rostrum was long and stylised and the forehead narrow. Geometric morphometric methods were highly effective for the analysis of aeglid-individual- growth and avoided excessive handling of individuals through exuvia analysis.

scholarly journals Spatiotemporal variation in leaf size and shape in response to climate

2019 ◽  
Vol 13 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Yaoqi Li ◽  
Dongting Zou ◽  
Nawal Shrestha ◽  
Xiaoting Xu ◽  
Qinggang Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Intraspecific Variation ◽  
Leaf Shape ◽  
Leaf Size ◽  
Leaf Length ◽  
Herbarium Specimens ◽  
Size And Shape ◽  
Length Width ◽  
Leaf Size And Shape ◽  
Over Time

Abstract Aims Morphological variation of leaves is a key indicator of plant response to climatic change. Leaf size and shape are associated with carbon, water and energy exchange of plants with their environment. However, whether and how leaf size and shape responded to climate change over the past decades remains poorly studied. Moreover, many studies have only explored inter- but not intraspecific variation in leaf size and shape across space and time. Methods We collected >6000 herbarium specimens spanning 98 years (1910–2008) in China for seven representative dicot species and measured their leaf length and width. We explored geographical patterns and temporal trends in leaf size (i.e. leaf length, leaf width and length × width product) and shape (i.e. length/width ratio), and investigated the effects of changes in precipitation and temperature over time and space on the variation in leaf size and shape. Important Findings After accounting for the effects of sampling time, leaf size decreased with latitude for all species combined, but the relationship varied among species. Leaf size and shape were positively correlated with temperature and precipitation across space. After accounting for the effects of sampling locations, leaf size of all species combined increased with time. Leaf size changes over time were mostly positively correlated with precipitation, whereas leaf shape changes were mostly correlated with temperature. Overall, our results indicate significant spatial and temporal intraspecific variation in leaf size and shape in response to climate. Our study also demonstrates that herbarium specimens collected over a considerable period of time provide a good resource to study the impacts of climate change on plant morphological traits.

The Use of Geometric Morphometric Techniques to Identify Sexual Dimorphism in Gait

2016 ◽  
Vol 32 (5) ◽  
pp. 441-448 ◽  
Author(s):  
Claire Waldock ◽  
Nick Milne ◽  
Jonas Rubenson ◽  
Cyril Jon Donnelly
Keyword(s):  
Sexual Dimorphism ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Body Shape ◽  
Stance Phase ◽  
Gait Cycle ◽  
Geometric Morphometric ◽  
Males And Females ◽  
Components Analysis ◽  
Shape And Size

This study attempts to apply geometric morphometric techniques for the analysis of 3D kinematic marker-based gait data. As a test, we attempted to identify sexual dimorphism during the stance phase of the gait cycle. Two techniques were used to try to identify differences in the way males and females walk without the results being affected by individual differences in body shape and size. Twenty-eight kinematic markers were placed on the torso and legs of 6 male and 8 female subjects, and the 3D time varying coordinates of the kinematic markers were recorded. The gait cycle trials were time-normalized to 61 frames representing the stance phase of gait, and the change in the shape of the configuration of kinematic markers was analyzed using principal components analysis to produce ‘gait signatures’ that characterize the kinematics of each individual. The variation in the gait signatures was analyzed with a further principal components analysis. These methods were able to detect significant sexual dimorphism even after the effects of sexual body shape and size differences were factored out. We discuss insights gained from performing this study which may be of value to others attempting to apply geometric morphometric methods to motion analysis.

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