scholarly journals Changes in predator exposure, but not in diet, induce phenotypic plasticity in scorpion venom

2017 ◽  
Vol 284 (1863) ◽  
pp. 20171364 ◽  
Author(s):  
Alex N. Gangur ◽  
Michael Smout ◽  
Michael J. Liddell ◽  
Jamie E. Seymour ◽  
David Wilson ◽  
...  
Keyword(s):  
Scorpion Venom ◽  
Relative Increase ◽  
Trophic Levels ◽  
Adaptive Plasticity ◽  
Arms Races ◽  
Invertebrate Prey ◽  
Venomous Animals ◽  
Venom Composition ◽  
The Stability ◽  
Dead Prey

Animals embedded between trophic levels must simultaneously balance pressures to deter predators and acquire resources. Venomous animals may use venom toxins to mediate both pressures, and thus changes in this balance may alter the composition of venoms. Basic theory suggests that greater exposure to a predator should induce a larger proportion of defensive venom components relative to offensive venom components, while increases in arms races with prey will elicit the reverse. Alternatively, reducing the need for venom expenditure for food acquisition, for example because of an increase in scavenging, may reduce the production of offensive venom components. Here, we investigated changes in scorpion venom composition using a mesocosm experiment where we manipulated scorpions' exposure to a surrogate vertebrate predator and live and dead prey. After six weeks, scorpions exposed to surrogate predators exhibited significantly different venom chemistry compared with naive scorpions. This change included a relative increase in some compounds toxic to vertebrate cells and a relative decrease in some compounds effective against their invertebrate prey. Our findings provide, to our knowledge, the first evidence for adaptive plasticity in venom composition. These changes in venom composition may increase the stability of food webs involving venomous animals.

Switching effect on the stability of the prey-predator system with three trophic levels

1986 ◽  
Vol 122 (3) ◽  
pp. 251-262 ◽  
Author(s):  
Hiroyuki Matsuda ◽  
Kohkichi Kawasaki ◽  
Nanako Shigesada ◽  
Ei Teramoto ◽  
Luigi M. Ricciardi
Keyword(s):  
Trophic Levels ◽  
Switching Effect ◽  
The Stability ◽  
Predator System

The arms trade and the stability of regional arms races

1997 ◽  
Vol 21 (2-3) ◽  
pp. 631-654 ◽  
Author(s):  
Paul Levine ◽  
Ron Smith
Keyword(s):  
Arms Races ◽  
Arms Trade ◽  
The Stability

scholarly journals Fishing effects on elasmobranchs from the Pacific Coast of Colombia

2016 ◽  
Vol 21 (1) ◽  
pp. 9 ◽  
Author(s):  
Andrés Felipe Navia ◽  
Paola Andrea Mejía-Falla
Keyword(s):  
Species Composition ◽  
Pacific Coast ◽  
Trophic Levels ◽  
Functional Level ◽  
The Pacific ◽  
The Mean ◽  
The Stability ◽  
Large Predators ◽  
Average Catch ◽  
Index Of Diversity

<p>During 1995, 2001, 2003, 2004 and 2007; we studied the temporal variation in the structure of the elasmobranch assemblage along the Colombian Pacific coast using: the community index of diversity, heterogeneity, equitability, species composition, average catch sizes, and mean trophic levels. A total of 1 711 specimens from 19 species<br />(7 sharks and 12 rays) were collected during the 90 trawling operations. The number of species captured varied between 7 (1995) and 12 (2007) demonstrating a trend towards an imbalance in the assemblage attributes. In 1995, the mean trophic level (TLm) of the assemblage was 3.60, but in 2007 it decreased to 3.55 when the functional level of large predators was absent (TL ≥ 4). These results suggest changes in species composition, structural attributes, and a reduction of the highest functional level. Alterations to the catch proportions were also found: i.e. a greater abundance of rays of lower trophic levels. This study suggests an effect of trawling on the stability of this tropical coastal ecosystem.</p>

scholarly journals Loss of top-down biotic interactions changes the relative benefits for obligate mutualists

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182501 ◽  
Author(s):  
Rong Wang ◽  
Xiao-Yong Chen ◽  
Yan Chen ◽  
Gang Wang ◽  
Derek W. Dunn ◽  
...  
Keyword(s):  
Biotic Interactions ◽  
Trophic Levels ◽  
Fig Wasp ◽  
Negative Effects ◽  
Top Down ◽  
Top Predators ◽  
Natural Range ◽  
Obligate Mutualism ◽  
The Stability ◽  
Food Web Complexity

The collapse of mutualisms owing to anthropogenic changes is contributing to losses of biodiversity. Top predators can regulate biotic interactions between species at lower trophic levels and may contribute to the stability of such mutualisms, but they are particularly likely to be lost after disturbance of communities. We focused on the mutualism between the fig tree Ficus microcarpa and its host-specific pollinator fig wasp and compared the benefits accrued by the mutualists in natural and translocated areas of distribution. Parasitoids of the pollinator were rare or absent outside the natural range of the mutualists, where the relative benefits the mutualists gained from their interaction were changed significantly away from the plant's natural range owing to reduced seed production rather than increased numbers of pollinator offspring. Furthermore, in the absence of the negative effects of its parasitoids, we detected an oviposition range expansion by the pollinator, with the use of a wider range of ovules that could otherwise have generated seeds. Loss of top-down control has therefore resulted in a change in the balance of reciprocal benefits that underpins this obligate mutualism, emphasizing the value of maintaining food web complexity in the Anthropocene.

Influence of post-starvation extraction time and prey-specific diet in Tityus serrulatus scorpion venom composition and hyaluronidase activity

Toxicon ◽  
2014 ◽  
Vol 90 ◽  
pp. 326-336 ◽  
Author(s):  
Manuela Berto Pucca ◽  
Fernanda Gobbi Amorim ◽  
Felipe Augusto Cerni ◽  
Karla de Castro Figueiredo Bordon ◽  
Iara Aimê Cardoso ◽  
...  
Keyword(s):  
Scorpion Venom ◽  
Extraction Time ◽  
Hyaluronidase Activity ◽  
Venom Composition ◽  
Tityus Serrulatus ◽  
Specific Diet

scholarly journals Effect of time delay on a detritus-based ecosystem

2006 ◽  
Vol 2006 ◽  
pp. 1-28 ◽  
Author(s):  
Nurul Huda Gazi ◽  
Malay Bandyopadhyay
Keyword(s):  
Time Delay ◽  
Equilibrium Points ◽  
Equation Model ◽  
Model System ◽  
Trophic Levels ◽  
Dynamical Analysis ◽  
Discrete Time Delay ◽  
Growth Equations ◽  
The Stability ◽  
Delay Differential

Models of detritus-based ecosystems with delay have received a great deal of attention for the last few decades. This paper deals with the dynamical analysis of a nonlinear model of a detritus-based ecosystem involving detritivores and predator of detritivores. We have obtained the criteria for local stability of various equilibrium points and persistence of the model system. Next, we have introduced discrete time delay due to recycling of dead organic matters and gestation of nutrients to the growth equations of various trophic levels. With delay differential equation model system we have studied the effect of time delay on the stability behaviour. Next, we have obtained an estimate for the length of time delay to preserve the stability of the model system. Finally, the existence of Hopf-bifurcating small amplitude periodic solutions is derived by considering time delay as a bifurcation parameter.

scholarly journals “Beyond Primary Sequence”—Proteomic Data Reveal Complex Toxins in Cnidarian Venoms

2019 ◽  
Vol 59 (4) ◽  
pp. 777-785 ◽  
Author(s):  
Adrian Jaimes-Becerra ◽  
Ranko Gacesa ◽  
Liam B Doonan ◽  
Ashlie Hartigan ◽  
Antonio C Marques ◽  
...  
Keyword(s):  
Adaptive Significance ◽  
Proteomic Data ◽  
Body Regions ◽  
Venomous Animals ◽  
Venom Composition ◽  
Toxin Protein ◽  
Clustering Approach ◽  
Venom Evolution ◽  
Present Understanding ◽  
Dual Functions

Abstract Venomous animals can deploy toxins for both predation and defense. These dual functions of toxins might be expected to promote the evolution of new venoms and alteration of their composition. Cnidarians are the most ancient venomous animals but our present understanding of their venom diversity is compromised by poor taxon sampling. New proteomic data were therefore generated to characterize toxins in venoms of a staurozoan, a hydrozoan, and an anthozoan. We then used a novel clustering approach to compare venom diversity in cnidarians to other venomous animals. Comparison of the presence or absence of 32 toxin protein families indicated venom composition did not vary widely among the 11 cnidarian species studied. Unsupervised clustering of toxin peptide sequences suggested that toxin composition of cnidarian venoms is just as complex as that in many venomous bilaterians, including marine snakes. The adaptive significance of maintaining a complex and relatively invariant venom remains unclear. Future study of cnidarian venom diversity, venom variation with nematocyst types and in different body regions are required to better understand venom evolution.

Good vibrations: Assessing the stability of snake venom composition after researcher-induced disturbance in the laboratory

Toxicon ◽  
2017 ◽  
Vol 133 ◽  
pp. 127-135 ◽  
Author(s):  
Natalie M. Claunch ◽  
Matthew L. Holding ◽  
Camilo Escallón ◽  
Ben Vernasco ◽  
Ignacio T. Moore ◽  
...  
Keyword(s):  
Snake Venom ◽  
Venom Composition ◽  
The Stability

scholarly journals Trophodynamics and stability of regional scale ecosystems in the Northeast Atlantic

2012 ◽  
Vol 69 (5) ◽  
pp. 764-775 ◽  
Author(s):  
Niall McGinty ◽  
Anne Marie Power ◽  
Mark P. Johnson
Keyword(s):  
Control Charts ◽  
Marine Ecosystem ◽  
Regional Scale ◽  
Trophic Levels ◽  
Northeast Atlantic ◽  
Long Term Stability ◽  
Large Marine Ecosystem ◽  
Trends Over Time ◽  
The Stability ◽  
Multivariate Control

Abstract McGinty, N., Power, A. M., and Johnson, M. P. 2012. Trophodynamics and stability of regional scale ecosystems in the Northeast Atlantic. – ICES Journal of Marine Science, 69: 764–775. This study addresses the long-term stability of three trophic groupings in the Northeast Atlantic at regional scales. The most abundant taxa representing phytoplankton, herbivorous copepods, and carnivorous zooplankton were examined from the Continuous Plankton Recorder database. Multivariate control charts using a Bray–Curtis similarity metric were used to assess whether fluctuations within trophic groupings were within or beyond the expected variability. Two evaluation periods were examined: annual changes between 1960 and 1999 (2000–2009 baseline) and recent changes between 2000 and 2009 (1960–1999 baseline). The trends over time in abundance/biomass of trophic levels were region-specific, especially in carnivorous copepods, where abundance did not mirror trends in the overall study area. The stability of phytoplankton was within the expected limits, although not in 2008 and 2009. Higher trophic levels were less stable, perhaps reflecting the added complexity of interactions governing their abundance. In addition, some regions were consistently less stable than others. Correlations in stability between adjacent trophic levels were positive at large marine ecosystem scale but generally non-significant at regional scales. The study suggests that certain regions may be particularly vulnerable to periods of instability in community structure. The benefits of using the control chart method rather than other multivariate measures of plankton dynamics are discussed.

scholarly journals Body size dependent dispersal influences stability in heterogeneous metacommunities

2021 ◽  
Author(s):  
Kurt E. Anderson ◽  
Ashkaan K. Fahimipour
Keyword(s):  
Body Size ◽  
Food Web ◽  
Trophic Levels ◽  
Dispersal Rate ◽  
Ecological Stability ◽  
Size Dependent ◽  
Heterogeneous Habitat ◽  
Body Sizes ◽  
Demographic Processes ◽  
The Stability

AbstractBody size affects key biological processes across the tree of life, with particular importance for food web dynamics and stability. Traits influencing movement capabilities depend strongly on body size, yet the effects of allometrically-structured dispersal on food web stability are less well understood than other demographic processes. Here we study the stability properties of spatially-arranged model food webs in which larger bodied species occupy higher trophic positions, while species’ body sizes also determine the rates at which they traverse spatial networks of heterogeneous habitat patches. Our analysis shows an apparent stabilizing effect of positive dispersal rate scaling with body size compared to negative scaling relationships or uniform dispersal. However, as the global coupling strength among patches increases, the benefits of positive body size-dispersal scaling disappear. A permutational analysis shows that breaking allometric dispersal hierarchies while preserving dispersal rate distributions rarely alters qualitative aspects of metacommunity stability. Taken together, these results suggest that the oft-predicted stabilizing effects of large mobile predators may, for some dimensions of ecological stability, be attributed to increased patch coupling per se, and not necessarily coupling by top trophic levels in particular.

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