The behaviour of an omnivorous protozoan affects the extent of induced morphological defence in a protozoan prey

2004 ◽  
Vol 49 (6) ◽  
pp. 801-809 ◽  
Author(s):  
Krzysztof Wiackowski ◽  
Janusz Fyda ◽  
Aneta Ciecko
Keyword(s):  
Morphological Defence

scholarly journals Which Seed Properties Determine the Preferences of Carabid Beetle Seed Predators?

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 757
Author(s):  
Foffová Hana ◽  
Ćavar Zeljković Sanja ◽  
Honěk Alois ◽  
Martinková Zdenka ◽  
Tarkowski Petr ◽  
...  
Keyword(s):  
Seed Coat ◽  
Explanatory Power ◽  
Seed Mass ◽  
Carabid Beetles ◽  
Plant Strategy ◽  
Seed Predators ◽  
Lack Of Information ◽  
Complete Set ◽  
Morphological Defence ◽  
Explained Variance

Ground beetles are important invertebrate seed predators in temperate agro-ecosystems. However, there is a lack of information regarding which seed properties are important to carabids when they select seeds for consumption. Therefore, seed properties, such as size, shape, morphological defence, and chemical composition, were measured, and in addition to seed taxonomy and ecology, these data were used to explain carabid preferences. Carabid preferences were assessed using a multi-choice experiment with 28 species of weed seeds presented to 37 species of Carabidae. Multiple regression on distance matrices (MRM) was used to determine the importance of particular sets of seed properties for carabids. The analysis was conducted for the full set of carabids (37 species) as well as for subsets of species belonging to the tribes of Harpalini or Zabrini. For the complete set of species, seed dimensions, seed mass, taxonomy, plant strategy, and seed coat properties significantly explained carabid preferences (proportion of explained variance, R2 = 0.465). The model for Harpalini fit the data comparably well (R2 = 0.477), and seed dimensions, seed mass and seed coat properties were significant. In comparison to that for Harpalini, the model for Zabrini had much lower explanatory power (R2 = 0.248), and the properties that significantly affected the preferences were seed dimensions, seed mass, taxonomy, plant strategy, and seed coat properties. This result suggests that the seed traits that carabids respond to may be specific to taxonomic and likely relate to the degree of specialisation for seeds. This study contributes to understanding the mechanisms that determine the preferences of carabid beetles for seeds.

Does living in streams with fish involve a cost of induced morphological defences?

2003 ◽  
Vol 81 (11) ◽  
pp. 1825-1828 ◽  
Author(s):  
Jonas Dahl ◽  
Barbara L Peckarsky
Keyword(s):  
Brook Trout ◽  
Chemical Cues ◽  
Additional Data ◽  
Field Survey ◽  
Larval Mortality ◽  
Negative Relationship ◽  
Relative Length ◽  
Inducible Defences ◽  
Morphological Defences ◽  
Morphological Defence

Previous studies have shown that chemical cues from brook trout (Salvelinus fontinalis) induce relatively longer caudal filaments and heavier exoskeletons in the mayfly Drunella coloradensis. These characters constitute morphological defences that reduce larval mortality from brook trout predation. There is also a potential fitness cost of living in streams with trout, as D. coloradensis females emerge at smaller sizes from streams with fish compared with females in streams without fish. In this study, we obtained additional data to evaluate the hypothesis that these costs of living in streams with fish could be attributed to inducible defences. A field survey of seven different streams showed that mature (black wing pad) female larvae from streams with fish invested a smaller proportion of their body mass in eggs than females maturing in streams without fish. Furthermore, a negative relationship between female allocation to eggs and to morphological defence characters (relative length of the caudal filament) provides evidence of a cost of inducible defences in this species.

scholarly journals Ocean acidification disrupts induced defences in the intertidal gastropod Littorina littorea

2007 ◽  
Vol 3 (6) ◽  
pp. 699-701 ◽  
Author(s):  
Ruth Bibby ◽  
Polly Cleall-Harding ◽  
Simon Rundle ◽  
Steve Widdicombe ◽  
John Spicer
Keyword(s):  
Ocean Acidification ◽  
Biological Effects ◽  
Littorina Littorea ◽  
Direct Effects ◽  
Joint Stress ◽  
Seawater Ph ◽  
Induced Defences ◽  
Intertidal Gastropod ◽  
High Predation ◽  
Morphological Defence

Carbon dioxide-induced ocean acidification is predicted to have major implications for marine life, but the research focus to date has been on direct effects. We demonstrate that acidified seawater can have indirect biological effects by disrupting the capability of organisms to express induced defences, hence, increasing their vulnerability to predation. The intertidal gastropod Littorina littorea produced thicker shells in the presence of predation (crab) cues but this response was disrupted at low seawater pH. This response was accompanied by a marked depression in metabolic rate (hypometabolism) under the joint stress of high predation risk and reduced pH. However, snails in this treatment apparently compensated for a lack of morphological defence, by increasing their avoidance behaviour, which, in turn, could affect their interactions with other organisms. Together, these findings suggest that biological effects from ocean acidification may be complex and extend beyond simple direct effects.

scholarly journals The correlated evolution of antipredator defences and brain size in mammals

2017 ◽  
Vol 284 (1846) ◽  
pp. 20161857 ◽  
Author(s):  
Theodore Stankowich ◽  
Ashly N. Romero
Keyword(s):  
Cognitive Abilities ◽  
Brain Size ◽  
Three Dimensional ◽  
Mammal Species ◽  
Body Armour ◽  
Encephalization Quotient ◽  
Open Environments ◽  
Morphological Defence ◽  
Antipredator Defences ◽  
Comparative Phylogenetic Analysis

Mammals that possess elaborate antipredator defences such as body armour, spines and quills are usually well protected, intermediate in size, primarily insectivorous and live in simple open environments. The benefits of such defences seem clear and may relax selection on maintaining cognitive abilities that aid in vigilance and predator recognition, and their bearers may accrue extensive production and maintenance costs. Here, in this comparative phylogenetic analysis of measurements of encephalization quotient and morphological defence scores of 647 mammal species representing nearly every order, we found that as lineages evolve stronger defences, they suffer a correlated reduction in encephalization. The only exceptions were those that live in trees—a complex three-dimensional world probably requiring greater cognitive abilities. At the proximate level, because brain tissue is extremely energetically expensive to build, mammals may be trading off spending more on elaborate defences and saving by building less powerful brains. At the ultimate level, having greater defences may also reduce the need for advanced cognitive abilities for constant assessment of environmental predation risk, especially in simple open environments.

scholarly journals Aggregates of the acritarch <i>Dilatisphaera laevigata</i>: faecal pelletization, phytoplankton bloom or defence against phagotrophy?

2003 ◽  
Vol 22 (2) ◽  
pp. 163-167 ◽  
Author(s):  
Gary L. Mullins
Keyword(s):  
Surface Waters ◽  
Phytoplankton Bloom ◽  
Parasitic Infection ◽  
Phytoplankton Blooms ◽  
Sample Processing ◽  
Morphological Defence

Abstract. Monospecific aggregates of 2–7 individuals of the Silurian acritarch Dilatisphaera laevigata Lister are described. Each generally consists of a central collection of vesicles surrounded by elongate, radiating processes. Acritarchs could aggregate by chance during sample processing, or they may have formed within a sporangia-like structure, although such structures are considered unlikely for D. laevigata. Analogies with modern algae suggest that the aggregates of D. laevigata could have formed by faecal pelletization in the surface waters, or by coagulation of individuals during phytoplankton blooms. In this latter instance the baculate/spinose vesicle ornament and digitate-like branching of the processes may have increased the chances of adhesion. It is also plausible that the aggregates may represent a morphological defence against predation or parasitic infection.

scholarly journals Express yourself: bold individuals induce enhanced morphological defences

2014 ◽  
Vol 281 (1776) ◽  
pp. 20132703 ◽  
Author(s):  
Kaj Hulthén ◽  
Ben B. Chapman ◽  
P. Anders Nilsson ◽  
Johan Hollander ◽  
Christer Brönmark
Keyword(s):  
Crucian Carp ◽  
Personality Types ◽  
Interindividual Variation ◽  
Behavioural Plasticity ◽  
Inducible Defences ◽  
Morphological Defences ◽  
Risky Behaviours ◽  
Morphological Defence ◽  
Considerable Interindividual Variation ◽  
Defence Strategies

Organisms display an impressive array of defence strategies in nature. Inducible defences (changes in morphology and/or behaviour within a prey's lifetime) allow prey to decrease vulnerability to predators and avoid unnecessary costs of expression. Many studies report considerable interindividual variation in the degree to which inducible defences are expressed, yet what underlies this variation is poorly understood. Here, we show that individuals differing in a key personality trait also differ in the magnitude of morphological defence expression. Crucian carp showing risky behaviours (bold individuals) expressed a significantly greater morphological defence response when exposed to a natural enemy when compared with shy individuals. Furthermore, we show that fish of different personality types differ in their behavioural plasticity, with shy fish exhibiting greater absolute plasticity than bold fish. Our data suggest that individuals with bold personalities may be able to compensate for their risk-prone behavioural type by expressing enhanced morphological defences.

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