Assessing the intrinsic resilience of a particularly fast-growing teleost prey species (red cod, Pseudophycis bachus)

2013 ◽  
Vol 64 (2) ◽  
pp. 130
Author(s):  
Jodie Kemp ◽  
Gregory P. Jenkins ◽  
Stephen E. Swearer
Keyword(s):  
Life History ◽  
Prey Species ◽  
First Year ◽  
Early Maturity ◽  
High Fecundity ◽  
Biomass Harvesting ◽  
Important Prey ◽  
Rapid Growth Rate ◽  
Poor Recruitment ◽  
Water Species

Understanding the life-history parameters that influence productivity is important in assessing the intrinsic resilience of a species to exploitation. The life-history characteristics of red cod, Pseudophycis bachus, were investigated to assess the intrinsic resilience of this important prey species to increased predation pressure by a range of high trophic-level predators. Red cod has a particularly short longevity; in Australian shelf waters it is uncommon to encounter individuals older than 2+ years. There are few shelf-water species that exhibit the rapid rate of growth that was observed where females and males attained ~300-mm total length in the first year. A particularly rapid growth rate, and a reproductive strategy characterised by early maturity and high fecundity, suggests that the species is relatively resilient. However, red cod is short lived, which exposes populations to large shifts in biomass. Harvesting of this species by predators, particularly during years of poor recruitment, may be significant in shaping the dynamics of red cod populations.

TOMATO MATURITY IN RELATION TO PRUNING AND CULTURE

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1119g-1119
Author(s):  
Clark W. Nicklow ◽  
Bruce Wenning
Keyword(s):  
First Year ◽  
Early Maturity ◽  
Cultural Methods ◽  
Black Plastic

Three different cultural methods were utilized in the evaluation of 150 indeterminate tomato hybrids. This study was conducted over a two year period. The hybrids were planted in the field through 1.52 m wide black plastic; (1) 30.5 cm apart in rows, trained upright end pruned to one growing point (1gp); (2) 91.4 cm apart in rows, trained upright end pruned to three growing points (3gp); and (3) 91.4 cm apart in rows end permitted to grow prostrate end unpruned (up). Accumulated total harvest patterns were different: August 5 (early yield) of the first year, the yield of all ripe or turning fruit was 2.43, 0.36 and 0.24 kg/m2 respectively; the yield resulting from pruning to 1gp was 6.75 X the yield of the plants with 3gp. Yields of plants with 1gp were 3.6 X and 2.6 X the yield of plants with 3gp, 20 and 40 days later respectively. The yield of the plants up were the lowest in early maturity but 40 days later surpassed the yield from plants with 1gp by 2.6 kg/m2.

Diet

2017 ◽  
Author(s):  
M.G.L. Mills ◽  
M.E.J. Mills
Keyword(s):  
Prey Species ◽  
Radio Tracking ◽  
Relative Occurrence ◽  
Important Prey ◽  
Individual Prey ◽  
Sibling Groups

Four methods were used to document the diet of cheetahs: incidental observations, radio tracking, tracking, spoor, and continuous follows. A combination of continuous follows and tracking spoor gave the best results. Steenbok were the most frequently killed species, but they did not dominate the diet in the same way as Thomson’s gazelle do in the Serengeti. Coalition males have a different diet profile from single males, single females, females with cubs, and sibling groups. For all but single males, the relative occurrence of prey species in the diet reflected its dietary importance in terms of kilograms of meat obtained. Gemsbok calves and adult ostrich were important prey for coalition males and springhares were important for single males. Three individual prey specializations for females were found; namely springbok specialists, steenbok/duiker specialists, and intermediates. Contrary to an earlier study, springbok were not found to be the most important prey species.

scholarly journals Transcriptomic analyses of the termite, Cryptotermes secundus, reveal a gene network underlying a long lifespan and high fecundity

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Silu Lin ◽  
Jana Werle ◽  
Judith Korb
Keyword(s):  
Life History ◽  
Social Insects ◽  
Social Communication ◽  
Gene Network ◽  
Social Insect ◽  
Nutrient Sensing ◽  
Model Organisms ◽  
Termite Species ◽  
High Fecundity ◽  
Trade Off

AbstractOrganisms are typically characterized by a trade-off between fecundity and longevity. Notable exceptions are social insects. In insect colonies, the reproducing caste (queens) outlive their non-reproducing nestmate workers by orders of magnitude and realize fecundities and lifespans unparalleled among insects. How this is achieved is not understood. Here, we identified a single module of co-expressed genes that characterized queens in the termite species Cryptotermes secundus. It encompassed genes from all essential pathways known to be involved in life-history regulation in solitary model organisms. By manipulating its endocrine component, we tested the recent hypothesis that re-wiring along the nutrient-sensing/endocrine/fecundity axis can account for the reversal of the fecundity/longevity trade-off in social insect queens. Our data from termites do not support this hypothesis. However, they revealed striking links to social communication that offer new avenues to understand the re-modelling of the fecundity/longevity trade-off in social insects.

scholarly journals Prey consumed by Guiana dolphin Sotalia guianensis (Cetacea, Delphinidae) and franciscana dolphin Pontoporia blainvillei (Cetacea, Pontoporiidae) in an estuarine environment in southern Brazil

2012 ◽  
Vol 102 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Marta J. Cremer ◽  
Pedro C. Pinheiro ◽  
Paulo C. Simões-Lopes
Keyword(s):  
Prey Species ◽  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Teleost Fishes ◽  
Southern Brazil ◽  
Sympatric Populations ◽  
Sotalia Guianensis ◽  
Important Prey ◽  
Pontoporia Blainvillei ◽  
Lolliguncula Brevis

The present study provides information about the diet of sympatric populations of small cetaceans in the Babitonga Bay estuary. This is the first study on the diet of these species in direct sympatry. The stomach contents of seven Guiana dolphins Sotalia guianensis and eight franciscanas Pontoporia blainvillei were analyzed. The prey of both cetaceans was mostly teleost fishes, followed by cephalopods. We identified 13 teleost fishes as part of the diet of the franciscanas, and 20 as part of the diet of Guiana dolphins. Lolliguncula brevis was the only cephalopod recorded, and was the most important prey for both cetaceans. Stellifer rastrifer and Gobionellus oceanicus were also important for franciscana, so as Mugil curema and Micropogonias furnieri were important for Guiana dolphins. Stellifer rastrifer and Cetengraulis edentulus were the fishes with the highest frequency of occurrence for franciscana (50%), while Achirus lineatus, C. edentulus, S. brasiliensis, Cynoscion leiarchus, M. furnieri, M. curema, Diapterus rhombeus, Eugerres brasilianus and G. oceanicus showed 28.6% of frequency of occurrence for Guiana dolphins. Franciscanas captured greater cephalopods than the Guiana dolphins in both total length (z= -3.38; n= 40; p< 0.05) and biomass (z = -2.46; n = 40; p<0.05). All of the prey species identified occur inside the estuary, which represents a safe habitat against predators and food availability, reinforcing the importance of the Babitonga Bay for these cetacean populations.

scholarly journals Creation of a new breeding material for creeping clover (Trifolium repens L.) hay-pasture type using the hybridization method

2021 ◽  
Vol 901 (1) ◽  
pp. 012046
Author(s):  
A A Ivanova
Keyword(s):  
Trifolium Repens ◽  
Hydrocyanic Acid ◽  
First Year ◽  
Hybridization Method ◽  
Seed Productivity ◽  
Early Maturity ◽  
Breeding Material ◽  
Reciprocal Crossing ◽  
Trifolium Repens L ◽  
First Year Of Life

Abstract The studies were carried out in the Moscow region in 2019-2021. In order to create a new breeding material for creeping hay-pasture clover, samples of the Lodian type (giganteum variety), characterized by high peduncles and longer leaf petioles, and a low content of hydrocyanic acid (0.3 mg%), were selected as parental forms. Reciprocal crossing was carried out. Hybrids F1 and F2 in the first year of life were assessed by the main economic and biological characteristics: the length of the peduncles, the number of inflorescences on the plant, fodder and seed productivity, early maturity, winter hardiness and other indicators. Based on the assessment results, the best hybrids and individual biotypes were identified.

scholarly journals Feeding Ecology of Short-Toed Snake-Eagle (Circaetus gallicus [Gmelin, 1788]) in the Montados of Iberian Peninsula

2020 ◽  
Vol 28 (2) ◽  
pp. 155-179
Author(s):  
Nuno Onofre ◽  
Luís Sampaio
Keyword(s):  
Relative Abundance ◽  
Diet Composition ◽  
Prey Species ◽  
Prey Selection ◽  
Prey Type ◽  
Generalist Predator ◽  
Important Prey ◽  
Psammodromus Algirus ◽  
Circaetus Gallicus ◽  
Water Snakes

The diet of Short-toed Snake-eagle (Circaetus gallicus) during the breeding season in an area dominated by cork and holm oak parkland forests (Montados) was analyzed in this study. As expected, results showed that snakes are the dominant prey in the diet of this eagle, comprising up to 92.5% of the identified items, if potential secondary prey species were excluded. The Montpellier Snake (Malpolon monspessulanus) was the most consumed one (42.2%), followed by the Ladder Snake (Zamenis scalaris) (28.0%), and the water snakes (Natrix spp.) (14.2%). According to the same criteria, lizards (mainly Psammodromus algirus) and mammals represent between 4.8 and 2.2%, respectively. Other animals such as pond turtle and amphibians are irregular prey (<1%), and no bird remains were found at all. Short-toed Snake-eagle is usually referred as a stenophagic predator where snakes are by far its most important prey type, and where within this taxonomic group it behaves as a generalist predator. In this study this premise was then tested comparing the relative abundance of the snake species with their proportion in the diet composition of the eagle in order to know whether or not prey selection exists with regard to the species of snakes in this region. Results point to a quite plausible "preference" for the Ladder Snake and an "avoidance" for the smooth snakes group (Macroprotodon brevis/Coronella girondica), and possibly for the Horseshoe Whip (Hemorrhois hippocrepis). The avoidance to the Horseshoe Whip must be indirect and habitat related, while in relation to the two smooth snakes it may be due in large extend to its small size, in particular.

Emergent Facilitation among Predators on Size-Structured Prey

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Life History ◽  
Prey Species ◽  
The Other ◽  
Positive Interactions ◽  
Predator Species ◽  
Life History Stages ◽  
Specific Predator ◽  
Specialist Predators

This chapter discusses a variety of positive interactions between predators foraging on different stages of the same prey species, which all emerge owing to the biomass overcompensation that may occur in prey life history stages in response to increased mortality. These interactions include emergent facilitation of specialist predators by generalists that forage on the same prey individuals as the specialists, but in addition forage on smaller or larger prey individuals as well. Furthermore, the chapter shows that two predators that specialize on different life-history stages of prey can facilitate each other to the extent that one predator relies on the presence of the other for its persistence. A stage-specific predator may act as a catalyst species, which promotes and in fact is necessary for the invasion of another predator species, but is subsequently outcompeted by the latter.

scholarly journals Evolution in interacting species alters predator life-history traits, behaviour and morphology in experimental microbial communities

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200652
Author(s):  
Johannes Cairns ◽  
Felix Moerman ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt ◽  
Teppo Hiltunen
Keyword(s):  
Life History ◽  
Prey Species ◽  
Rapid Evolution ◽  
Prey Type ◽  
Automated Image Analysis ◽  
Foraging Efficiency ◽  
Predator Prey ◽  
Evolving Systems ◽  
Interacting Species ◽  
Evolutionary Response

Predator–prey interactions heavily influence the dynamics of many ecosystems. An increasing body of evidence suggests that rapid evolution and coevolution can alter these interactions, with important ecological implications, by acting on traits determining fitness, including reproduction, anti-predatory defence and foraging efficiency. However, most studies to date have focused only on evolution in the prey species, and the predator traits in (co)evolving systems remain poorly understood. Here, we investigated changes in predator traits after approximately 600 generations in a predator–prey (ciliate–bacteria) evolutionary experiment. Predators independently evolved on seven different prey species, allowing generalization of the predator's evolutionary response. We used highly resolved automated image analysis to quantify changes in predator life history, morphology and behaviour. Consistent with previous studies, we found that prey evolution impaired growth of the predator, although the effect depended on the prey species. By contrast, predator evolution did not cause a clear increase in predator growth when feeding on ancestral prey. However, predator evolution affected morphology and behaviour, increasing size, speed and directionality of movement, which have all been linked to higher prey search efficiency. These results show that in (co)evolving systems, predator adaptation can occur in traits relevant to foraging efficiency without translating into an increased ability of the predator to grow on the ancestral prey type.

scholarly journals Knowing the Enemy: Inducible Defences in Freshwater Zooplankton

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 147 ◽  
Author(s):  
Patricia Diel ◽  
Marvin Kiene ◽  
Dominik Martin-Creuzburg ◽  
Christian Laforsch
Keyword(s):  
Life History ◽  
Chemical Cues ◽  
Prey Species ◽  
Inducible Defences ◽  
Animal Kingdom ◽  
Predator Species ◽  
Freshwater Zooplankton ◽  
Taxonomic Range ◽  
Set Up ◽  
Made In

Phenotypic plasticity in defensive traits is an appropriate mechanism to cope with the variable hazard of a frequently changing predator spectrum. In the animal kingdom these so-called inducible defences cover the entire taxonomic range from protozoans to vertebrates. The inducible defensive traits range from behaviour, morphology, and life-history adaptations to the activation of specific immune systems in vertebrates. Inducible defences in prey species play important roles in the dynamics and functioning of food webs. Freshwater zooplankton show the most prominent examples of inducible defences triggered by chemical cues, so-called kairomones, released by predatory invertebrates and fish. The objective of this review is to highlight recent progress in research on inducible defences in freshwater zooplankton concerning behaviour, morphology, and life-history, as well as difficulties of studies conducted in a multipredator set up. Furthermore, we outline costs associated with the defences and discuss difficulties as well as the progress made in characterizing defence-inducing cues. Finally, we aim to indicate further possible routes in this field of research and provide a comprehensive table of inducible defences with respect to both prey and predator species.

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