Palatability to a generalist herbivore, defence and growth of invasive and native Senecio species: testing the evolution of increased competitive ability hypothesis

Oecologia ◽  
2008 ◽  
Vol 159 (1) ◽  
pp. 95-106 ◽  
Author(s):  
L. Caño ◽  
J. Escarré ◽  
K. Vrieling ◽  
F. X. Sans
Keyword(s):  
Competitive Ability ◽  
Generalist Herbivore ◽  
Herbivore Defence

scholarly journals Leaf trichomes and foliar chemistry mediate defence against glasshouse thrips; Heliothrips haemorrhoidalis (Bouché) in Rhododendron simsii

2016 ◽  
Vol 43 (12) ◽  
pp. 1170 ◽  
Author(s):  
Alison S. Scott-Brown ◽  
Tom Gregory ◽  
Iain W. Farrell ◽  
Philip C. Stevenson
Keyword(s):  
Leaf Tissue ◽  
Inverse Correlation ◽  
Feeding Damage ◽  
Specific Expression ◽  
Generalist Herbivore ◽  
Rhododendron Simsii ◽  
Plant Parts ◽  
Heliothrips Haemorrhoidalis ◽  
Herbivore Defence ◽  
Growth And Reproduction

Herbivore defence mechanisms are a costly diversion of resources away from growth and reproduction. Thus time-limited and tissue specific expression in critical plant parts is more efficient as defined by optimal defence theory. Surprisingly little is known about Rhododendron herbivore defence but it may be mediated by combined chemical and physical mechanisms. Rhododendron simsii Planch. survives cyclic infestations of a leaf-feeding thrips, Heliothrips haemorrhoidalis (Bouché), which severely damage mature leaves but avoid terminal young leaves suggesting specific, localised defence expression. We examined correlations between the distribution of thrips and feeding damage with density of trichomes and the concentration of the diterpenoid, grayanotoxin I, a compound implicated in but not previously reported to mediate invertebrate defence in Rhododendron. Our data show that as leaves matured the number of thrips and area of feeding damage increased as trichome density and grayanotoxin I concentration decreased, this inverse correlation suggesting trichomes and grayanotoxin I mediate defence in younger leaf tissue. Grayanotoxin I was tested against H. haemorrhoidalis and was toxic to immature life stages and repellent to the adult thrips, reducing numbers of first instars emerging on leaves when applied at ecologically relevant concentrations. This work demonstrates that the pattern of defensive traits in foliage of a species of Rhododendron is key to its ability to tolerate cyclic infestations of a generalist herbivore, effectively conserving vital tissues required for growth and reproduction.

Assessing the competitiveness of the resort area

2020 ◽  
Vol 18 (7) ◽  
pp. 1216-1231
Author(s):  
K.A. Nefedova ◽  
D.O. Maslakova
Keyword(s):  
Comparative Analysis ◽  
Competitive Ability ◽  
Effective Management ◽  
Development Indicators ◽  
Ski Resort ◽  
Ski Resorts ◽  
Ranking Score ◽  
Comprehensive Development ◽  
Differential Methods

Subject. This article discusses the issues of development of the Krasnaya Polyana resort area. Objectives. The article aims to assess the competitive ability and attractiveness of this resort area through developing indicators. Methods. For the study, we used a comparative analysis, and factor and ranking score techniques. Results. The article offers original methods to assess the competitiveness of the ski resort area and describes possible directions to increase and improve the competitiveness and attractiveness of ski resorts. Conclusions. Comprehensive development indicators help assess the competitive ability of the ski resort area. Modified expert, sociological, rating, and differential methods contribute to the effective management of the resort area's advantages.

A fungal endophyte of an annual weed reduces host competitive ability and confers associational protection to wheat

2021 ◽  
Vol 50 ◽  
pp. 16-24
Author(s):  
Pablo Adrián García-Parisi ◽  
Sebastián Aníbal Gavilán ◽  
Cecilia Casas ◽  
Pedro Emilio Gundel ◽  
Marina Omacini
Keyword(s):  
Competitive Ability ◽  
Fungal Endophyte

Leaf silicification provides herbivore defence regardless of the extensive impacts of water stress

2021 ◽  
Author(s):  
Rebecca K. Vandegeer ◽  
Ximena Cibils‐Stewart ◽  
Richard Wuhrer ◽  
Susan E. Hartley ◽  
David T. Tissue ◽  
...  
Keyword(s):  
Water Stress ◽  
Herbivore Defence

scholarly journals Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Edward Wright ◽  
Sven Grawunder ◽  
Eric Ndayishimiye ◽  
Jordi Galbany ◽  
Shannon C. McFarlin ◽  
...  
Keyword(s):  
Body Size ◽  
Competitive Ability ◽  
Dominance Rank ◽  
Male Body ◽  
Honest Signal ◽  
Sexual Competition ◽  
Mountain Gorillas ◽  
Temporal Characteristics ◽  
Gorilla Beringei Beringei ◽  
Vocal Signals

AbstractAcoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication.

scholarly journals Forage Potential of Cereal/Legume Intercrops: Agronomic Performances, Yield, Quality Forage and LER in Two Harvesting Times in a Mediterranean Environment

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 121
Author(s):  
Monica Bacchi ◽  
Michele Monti ◽  
Antonio Calvi ◽  
Emilio Lo Presti ◽  
Antonio Pellicanò ◽  
...  
Keyword(s):  
Crop Yield ◽  
Competitive Ability ◽  
Agronomic Traits ◽  
Italian Ryegrass ◽  
Forage Yield ◽  
Biological Efficiency ◽  
Common Vetch ◽  
Sole Crop ◽  
Cereal Grain ◽  
Green Fodder

The crop yield and quality of seven annual forages (four grasses and three legumes) in sole crop and in mixtures (ratio 50:50) for oat (Avena sativa L.), Italian ryegrass (Lolium multiflorum Lam.), triticale (x Triticosecale Wittmack), barley (Hordeum vulgare L.), pea (Pisum sativum L.), berseem (Trifolium alexandrinum L.) and common vetch (Vicia sativa L.) were evaluated in a two-year field experiment adopting two harvesting times, green fodder and silage. The main bio-agronomic traits, dry matter forage yield (DMY) and quantity of crude protein (CP) were determined in both sole crop and intercrop. The land equivalent ratio (LER) was used for evaluating biological efficiency and competitive ability of the intercrops. Our results showed that the total calculated LER for fodder and protein yields was always greater than one and corresponded to crop yield advantages of 16.0% and 11.5%, respectively. Our data also highlighted the low competitive ability of the ryegrass in intercrop, which achieved the lowest yield among all the mixtures. Conversely, the same grass showed the best green fodder quality, due to the high incidence of the legume, equal (on average) to 46%. Triticale and barley, harvested for silage (hard dough stage), provided the best quantitative and qualitative results both in sole crop and intercropped with common vetch and pea, determined mainly by the cereal grain.

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