Not all weeds are created equal: A database approach uncovers differences in the sexual system of native and introduced weeds

Greek sport was in its earliest forms and predominantly thereafter a male activity. Greek masculine virtues were consistently reflected in texts discussing sport from Homer onward. The athletic and the martial spheres were often in tension regarding how greatly success in sport was valued as a measure of male excellence. The Greek gymnasium and athletic nudity were factors that fostered the Greek male sexual system of pederasty. Material culture in the form of sculpture, inscriptions, and vase paintings reflects the androcentrism of Greek sport. Female participation in Greek sport has a historical existence much less consistent and widespread than that of males, seen most prominently during the Roman empire.

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Karyotype description of three species of Loricariidae (Siluriformes) and occurrence of the ZZ/ZW sexual system in Hemiancistrus spilomma Cardoso & Lucinda, 2003

Neotropical Ichthyology ◽

10.1590/s1679-62252006000100010 ◽

2006 ◽

Vol 4 (1) ◽

pp. 93-97 ◽

Cited By ~ 22

Author(s):

Renildo Ribeiro de Oliveira ◽

Issakar Lima Souza ◽

Paulo Cesar Venere

Keyword(s):

Chromosome Pair ◽

Sex Chromosome ◽

Sexual System ◽

Freshwater Systems ◽

Phylogenetic Studies ◽

Cytogenetic Data ◽

Sex Chromosome System

The neotropical freshwater systems have a high number of catfish species (Siluriformes), and many of those are denominated "cascudos" in Brazil. Cytogenetic data about three "cascudos" species fished in the rio Araguaia are described in the present study. The Pterygoplichthys joselimaianus showed 2n=52, with 28 metacentrics (M) chromosomes, 16 submetacentrics (SM) and 8 subtelocentrics/acrocentrics (ST/A) in both sexes. Hemiancistrus spinosissimus showed 2n=52, with karyotype formulae 26M+22SM+4ST, in both sexes. Hemiancistrusspilomma also showed 2n=52, but in this species a ZZ/ZW sex chromosome system (25M+21SM+6ST in females and 24M+22SM+6ST in males) was observed. The cells from H. spinosissimus and P. joselimaianus showed one chromosome pair bearing Ag-NORs, while in the H. spilomma three chromosome pairs bearing Ag-NORs were detected. The data showed in this work reveal particular chromosomal characteristics, important for a good recognition of both Hemincistrus species, and also show the importance of the insertion of cytogenetic data on taxonomic phylogenetic studies.

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Dairy farm systems to aid persistence

NZGA: Research and Practice Series ◽

10.33584/rps.15.2011.3199 ◽

2011 ◽

Vol 15 ◽

pp. 199-209

Author(s):

K.A. Macdonald ◽

C. Matthew ◽

C.B. Glassey ◽

N. Mclean

Keyword(s):

Insect Pests ◽

Decision Rules ◽

Dairy Farm ◽

First Year ◽

Stocking Rate ◽

Pasture Management ◽

Nitrogen Fertiliser ◽

Feed Supplements ◽

First Year Of Life ◽

Introduced Weeds

This manuscript reviews fundamental pasture management principles relevant to pasture persistence. We first note some points of context, within which the debate on pasture persistence is occurring: the release of new pasture cultivars, the debate about climate change, and the effects of newly introduced weeds and pests. We then examine trends in farm practice. The critical management period (of most concern to farmers) has shifted from winter/autumn to summer. It is essential that farmers have and use sets of decision rules to govern when and how hard to graze, when to supplement and when to remove cows from pasture to allow pastures to be grazed appropriately to aid pasture persistence. Adaptations available to improve pasture persistence include: the use of nitrogen fertiliser to increase feed supply going into the summer, the use of crops or other feed supplements, stocking rate and on-off grazing to ensure the pastures are appropriately grazed in the summer. New pastures must be treated with care in their first year of life to ensure survival. The response of farmers to these variables to aid persistence of pastures is discussed. Keywords: climate, insect pests, pasture growth model, pasture renewal, weeds

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Molecular phylogenetics of Hydatellaceae (Nymphaeales): Sexual-system homoplasy and a new sectional classification

American Journal of Botany ◽

10.3732/ajb.1100524 ◽

2012 ◽

Vol 99 (4) ◽

pp. 663-676 ◽

Cited By ~ 20

Author(s):

William J. D. Iles ◽

Paula J. Rudall ◽

Dmitry D. Sokoloff ◽

Margarita V. Remizowa ◽

Terry D. Macfarlane ◽

...

Keyword(s):

Molecular Phylogenetics ◽

Sexual System ◽

Sectional Classification

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Cryptic dioecy in Actinidia polygama: a test of the pollinator attraction hypothesis

Canadian Journal of Botany ◽

10.1139/b03-150 ◽

2004 ◽

Vol 82 (2) ◽

pp. 214-218 ◽

Cited By ~ 25

Author(s):

Tetsuhiro Kawagoe ◽

Nobuhiko Suzuki

Keyword(s):

Fruit Production ◽

Sexual System ◽

Dioecious Species ◽

Pollinator Attraction ◽

Cryptic Dioecy ◽

Actinidia Polygama ◽

Unisexual Flowers ◽

Sterile Pollen ◽

Female Flowers

Female flowers of some dioecious species are known to develop stamens with sterile pollen, a sexual system known as cryptic dioecy. A convincing hypothesis explaining this phenomenon is that stamens in female flowers attract pollinators and so ensure seed production. However, because this hypothesis has rarely been tested experimentally, we tested it in a cryptically dioecious species, Actinidia polygama (Sieb. et Zucc.) Planch. ex Maxim. Our findings show that pollinators do not show a consistent preference based on the sex of the flowers, and that the removal of stamens from female flowers results in a significant reduction in the frequency of insect visits and fruit production. These results strongly support the pollinator attraction hypothesis in A. polygama. Given the evident role of stamens in female flowers in A. polygama reproduction, we discuss why cryptic dioecy is a rare phenomenon.Key words: Actinidia polygama, cryptic dioecy, pseudopollen, pollinator attraction, unisexual flowers.

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Outbreeding and inbreeding strategies in herbaceous-shrubby communities in the Venezuelan Gran Sabana Plateau

AoB Plants ◽

10.1093/aobpla/plz032 ◽

2019 ◽

Vol 11 (4) ◽

Author(s):

Nelson Ramírez ◽

Omaira Hokche

Keyword(s):

Plant Species ◽

Carbon Metabolism ◽

Life Form ◽

Sex Expression ◽

Perennial Herb ◽

Sexual System ◽

Dioecious Species ◽

Successional Stage ◽

Sexual Systems ◽

Perennial Herbs

Abstract Breeding system, sexual system, temporal variation in sex expression and herkogamy were evaluated in seven herbaceous-shrubby communities from the Gran Sabana Plateau, Venezuela. This analysis was conducted considering the life form, substrate type, succulence, carbon metabolism, nutritional relation, successional stage, pollination system specificity and endemism of plant species. Of the 348 plant species studied, 73.8 % were hermaphrodite, 16.9 % were monoecious and 9.2 % were dioecious. Plant sexual systems such as dichogamy and herkogamy were associated with life form, nutritional relations, carbon metabolism and pollination systems. Most species were adichogamous, followed by protandrous and protogynous. Protandry was high for perennial herbs, annual herbs and trees, and protogyny was most frequent in perennial herbs. Protandrous and protogynous species were frequently anemophilous. Herkogamy was higher than non-herkogamy. Herkogamy was higher for trees, shrubs and liana; higher in monophilous and lower in anemophilous species. Most of the hermaphrodites were herkogamous and adichogamous species. In contrast, monoecy were commonly perennial herb and dichogamous species and frequently associated with anemophily. Dioecious species were trees and shrubs and with polyphilous pollination. Dioecy was the most frequent sexual system for endemic species. Hermaphrodite species were similarly distributed across plant communities. Monoecy was slightly higher for savanna and fallow than the other communities, and dioecy was higher for shrublands and secondary bushland. Most plant species were non-agamospermous, non-spontaneous self-pollinated and xenogamous. Partially self-incompatible dominated, followed by self-incompatible, partially cross-incompatible and the lowest frequency corresponded to cross-incompatible species. All these results are discussed in the context of evolutionary and ecological trends.

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