Behavioral Interactions and Body Size Differences in Competition for Food among Juvenile Brown Bullhead (Ictalurus nebulosus)

1982 ◽  
Vol 39 (2) ◽  
pp. 316-320 ◽  
Author(s):  
W. Hubert Keen
Keyword(s):  
Body Size ◽  
Social Interactions ◽  
Growth Rates ◽  
Interference Competition ◽  
Size Difference ◽  
Food Level ◽  
Brown Bullhead ◽  
Exploitation Competition ◽  
Behavioral Interactions ◽  
Ictalurus Nebulosus

The effects of relative body size (larger or smaller fish), absolute body size differences, food level, and social interactions on the growth rates of juvenile brown bullhead (Ictalurus nebulosus) catfish were determined for pairs of fish. Overall growth rate of the larger fish was higher than for the smaller fish, although this difference did not depend on absolute body size difference within pairs. The reduced growth rates of both larger and smaller fish at limited food level was independent of both relative size difference and absolute body size difference within pairs. Both larger and smaller fish had highly variable growth rates. Size dominance and aggression were common within many pairs, yet this behavior was unrelated to food level and absolute body size difference. Aggression within pairs was not diminished by adding structural complexity to simple environments. It is suggested that the high variability in growth rates was due to differences in individuals within pairs with respect to the intensity of behavioral interactions. Social interactions within pairs offish were apparently unrelated to food level and were strong enough to mask both exploitative and interference mechanisms which may have been functional in competition for limited food.Key words: body size, dominance hierarchies, exploitation competition, food level, Ictalurus nebulosus, interference competition, behavioral interactions

scholarly journals Interference competition pressure predicts the number of avian predators that shifted their timing of activity

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180744 ◽  
Author(s):  
Yifan Pei ◽  
Mihai Valcu ◽  
Bart Kempenaers
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Interference Competition ◽  
Relative Importance ◽  
Exploitation Competition ◽  
Predator Species ◽  
Avian Predator ◽  
Avian Predators ◽  
Time Partitioning ◽  
Competition Pressure

Being active at different times facilitates the coexistence of functionally similar species. Hence, time partitioning might be induced by competition. However, the relative importance of direct interference and indirect exploitation competition on time partitioning remains unclear. The aim of this study was to investigate the relative importance of these two forms of competition on the occurrence of time-shifting among avian predator species. As a measure of interference competition pressure, we used the species richness of day-active avian predator species or of night-active avian predator species (i.e. species of Accipitriformes, Falconiformes and Strigiformes) in a particular geographical area (assemblage). As an estimate of exploitation competition pressure, we used the total species richness of avian predators in each assemblage. Estimates of the intensity of interference competition robustly predicted the number of Accipitriformes species that became crepuscular and the number of Strigiformes species that became day-active or strictly crepuscular. Interference competition pressure may depend on body size and on the total duration of the typical active period (day or night length). Our results support—to some extent—that smaller species are more likely to become time-shifters. Day length did not have an effect on the number of time-shifter species in the Accipitriformes. Among the large Strigiformes, more time-shifter species occur in areas where nights are shorter (i.e. where less of the typical time resource is available). However, in the small Strigiformes, we found the opposite, counterintuitive effect: more time-shifters where nights are longer. Exploitation competition may have had an additional positive effect on the number of time-shifters, but only in Accipitriformes, and the effect was not as robust. Our results thus support the interference competition hypothesis, suggesting that animals may have shifted their time of activity, despite phylogenetic constraints on the ability to do so, to reduce the costs of direct interactions. Our findings also highlight the influence of body size as a surrogate of competitive ability during encounters on time partitioning, at least among avian predators.

scholarly journals Cooperative growth regulation in coral-dwelling fishes

2006 ◽  
Vol 2 (3) ◽  
pp. 355-358 ◽  
Author(s):  
Philip L Munday ◽  
Adrian M Cardoni ◽  
Craig Syms
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Reproductive Success ◽  
Social Environment ◽  
Assortative Mating ◽  
Growth Rates ◽  
Growth Regulation ◽  
The Other ◽  
Size Difference ◽  
Matched Pairs

Dominant individuals often grow faster than subordinates because they gain a greater share of important resources. However, dominants should also strategically adjust their growth rates, relative to the size of subordinates, if this improves their reproductive success. Here, we show that individuals in breeding pairs of the coral-dwelling fish Gobiodon histrio regulate their growth to reduce the size difference between partners. In pairs where one individual was larger than the other, the smaller individual increased its growth rate and the larger individual decreased its growth rate, compared to individuals in size-matched pairs. The reproductive success of breeding pairs is limited by the size of the smallest individual in the pair. Therefore, it appears that the larger individual trades-off its own growth against that of the smaller individual, thereby improving the reproductive success of both individuals in the pair. This demonstrates a remarkable ability of individuals to strategically adjust their body size to suit the local social environment, and reveals a novel mechanism for size-assortative mating.

Competition between recolonizing wolves and resident lynx in Sweden

2010 ◽  
Vol 88 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Camilla Wikenros ◽  
Olof Liberg ◽  
Håkan Sand ◽  
Henrik Andrén
Keyword(s):  
Roe Deer ◽  
Interference Competition ◽  
Capreolus Capreolus ◽  
Local Area ◽  
Home Range Size ◽  
Size Difference ◽  
Lynx Lynx ◽  
Exploitation Competition ◽  
South Central ◽  
Before And After

We studied the effect of a recolonizing wolf ( Canis lupus L., 1758) population on a resident lynx ( Lynx lynx (L., 1758)) population in south-central Sweden. Wolf and lynx share the same prey species, western roe deer ( Capreolus capreolus (L., 1758)), and the size difference between the two species suggests a strong potential for interference competition. The spatial distributions of lynx family groups (n = 378) over four winters were not significantly affected by the increase in size and range of the wolf population. Survival of lynx kittens until 9 months of age did not differ significantly inside (54%; n = 37) and outside (62%; n = 42) wolf territories, and female lynx (n = 3) selected natal den sites (n = 19) in the same local area before and after wolf establishment. Furthermore, lynx home-range size (n = 42) did not increase as a result of presence of wolves and space use by female lynx (n = 3) was not affected by wolf establishment. We found no evidence of cleptoparasitism by wolves on roe deer killed by lynx. We conclude that the intensity of interference and exploitation competition between wolves and lynx was low.

Maternal body size and condition determine calf growth rates in southern right whales

2018 ◽  
Vol 592 ◽  
pp. 267-281 ◽  
Author(s):  
F Christiansen ◽  
F Vivier ◽  
C Charlton ◽  
R Ward ◽  
A Amerson ◽  
...  
Keyword(s):  
Body Size ◽  
Growth Rates ◽  
Maternal Body ◽  
Calf Growth ◽  
Right Whales ◽  
Southern Right Whales

scholarly journals Mechanisms Involved in Interspecific Communication between Wine Yeasts

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1734
Author(s):  
Ana Mencher ◽  
Pilar Morales ◽  
Jordi Tronchoni ◽  
Ramon Gonzalez
Keyword(s):  
Alcoholic Fermentation ◽  
Yeast Species ◽  
Interspecific Interactions ◽  
Interference Competition ◽  
Weighted Average ◽  
Starter Cultures ◽  
Simple Consequence ◽  
Wine Yeasts ◽  
Exploitation Competition ◽  
Metabolic Intermediates

In parallel with the development of non-Saccharomyces starter cultures in oenology, a growing interest has developed around the interactions between the microorganisms involved in the transformation of grape must into wine. Nowadays, it is widely accepted that the outcome of a fermentation process involving two or more inoculated yeast species will be different from the weighted average of the corresponding individual cultures. Interspecific interactions between wine yeasts take place on several levels, including interference competition, exploitation competition, exchange of metabolic intermediates, and others. Some interactions could be a simple consequence of each yeast running its own metabolic programme in a context where metabolic intermediates and end products from other yeasts are present. However, there are clear indications, in some cases, of specific recognition between interacting yeasts. In this article we discuss the mechanisms that may be involved in the communication between wine yeasts during alcoholic fermentation.

Changes in the blood of the brown bullhead (Ictalurus nebulosus (Lesueur)) following short and long term exposure to copper(II)

1972 ◽  
Vol 23 (3) ◽  
pp. 417-427 ◽  
Author(s):  
G.M. Christensen ◽  
J.M. McKim ◽  
W.A. Brungs ◽  
E.P. Hunt
Keyword(s):  
Brown Bullhead ◽  
Ictalurus Nebulosus ◽  
Short And Long Term

Maximum growth rates of aquatic ciliated protozoa: the dependence on body size and temperature reconsidered

1993 ◽  
Vol 126 (3) ◽  
pp. 315-327
Author(s):  
Helga Müller ◽  
Walter Geller
Keyword(s):  
Body Size ◽  
Growth Rates ◽  
Maximum Growth ◽  
Ciliated Protozoa

scholarly journals Competition among Nasal Bacteria Suggests a Role for Siderophore-Mediated Interactions in Shaping the Human Nasal Microbiota

2018 ◽  
Vol 85 (10) ◽  
Author(s):  
Reed M. Stubbendieck ◽  
Daniel S. May ◽  
Marc G. Chevrette ◽  
Mia I. Temkin ◽  
Evelyn Wendt-Pienkowski ◽  
...  
Keyword(s):  
Nasal Cavity ◽  
Iron Acquisition ◽  
Interference Competition ◽  
Human Microbiome ◽  
Human Microbiome Project ◽  
Siderophore Production ◽  
Coagulase Negative Staphylococci ◽  
Exploitation Competition ◽  
Content Type

ABSTRACTResources available in the human nasal cavity are limited. Therefore, to successfully colonize the nasal cavity, bacteria must compete for scarce nutrients. Competition may occur directly through interference (e.g., antibiotics) or indirectly by nutrient sequestration. To investigate the nature of nasal bacterial competition, we performed coculture inhibition assays between nasalActinobacteriaandStaphylococcusspp. We found that isolates of coagulase-negative staphylococci (CoNS) were sensitive to growth inhibition byActinobacteriabut thatStaphylococcus aureusisolates were resistant to inhibition. AmongActinobacteria, we observed thatCorynebacteriumspp. were variable in their ability to inhibit CoNS. We sequenced the genomes of 10Corynebacteriumspecies isolates, including 3Corynebacterium propinquumisolates that strongly inhibited CoNS and 7 otherCorynebacteriumspecies isolates that only weakly inhibited CoNS. Using a comparative genomics approach, we found that theC. propinquumgenomes were enriched in genes for iron acquisition and harbored a biosynthetic gene cluster (BGC) for siderophore production, absent in the noninhibitoryCorynebacteriumspecies genomes. Using a chrome azurol S assay, we confirmed thatC. propinquumproduced siderophores. We demonstrated that iron supplementation rescued CoNS from inhibition byC. propinquum, suggesting that inhibition was due to iron restriction through siderophore production. Through comparative metabolomics and molecular networking, we identified the siderophore produced byC. propinquumas dehydroxynocardamine. Finally, we confirmed that the dehydroxynocardamine BGC is expressedin vivoby analyzing human nasal metatranscriptomes from the NIH Human Microbiome Project. Together, our results suggest that bacteria produce siderophores to compete for limited available iron in the nasal cavity and improve their fitness.IMPORTANCEWithin the nasal cavity, interference competition through antimicrobial production is prevalent. For instance, nasalStaphylococcusspecies strains can inhibit the growth of other bacteria through the production of nonribosomal peptides and ribosomally synthesized and posttranslationally modified peptides. In contrast, bacteria engaging in exploitation competition modify the external environment to prevent competitors from growing, usually by hindering access to or depleting essential nutrients. As the nasal cavity is a nutrient-limited environment, we hypothesized that exploitation competition occurs in this system. We determined thatCorynebacterium propinquumproduces an iron-chelating siderophore, and this iron-sequestering molecule correlates with the ability to inhibit the growth of coagulase-negative staphylococci. Furthermore, we found that the genes required for siderophore production are expressedin vivo. Thus, although siderophore production by bacteria is often considered a virulence trait, our work indicates that bacteria may produce siderophores to compete for limited iron in the human nasal cavity.

Effect of two microalgae concentrations on body size and egg size of the rotifer Brachionus calyciflorus

Biologia ◽  
2008 ◽  
Vol 63 (3) ◽  
Author(s):  
Abdolmohammad Kennari ◽  
Nasrollah Ahmadifard ◽  
Maryam Kapourchali ◽  
Jafar Seyfabadi
Keyword(s):  
Body Size ◽  
Population Growth ◽  
Egg Size ◽  
Scenedesmus Obliquus ◽  
Exponential Phase ◽  
The Body ◽  
Brachionus Calyciflorus ◽  
Food Level ◽  
Chlorella Sp ◽  
Rotifer Brachionus Calyciflorus

AbstractThe rotifer, Brachionus calyciflorus, was grown with two algae species (Chlorella sp. and Scenedesmus obliquus) at different concentrations (0.1, 1 and 10 × 106 cells ml−1). The body size (lorica biovolume) of individual rotifer and their egg size were measured when the populations were roughly in the exponential phase of population growth. The body size of the rotifers differed significantly (P < 0.05) among the two algae species used, however this effect was not observed for egg size. The body size of rotifers fed on higher densities of Chlorella sp. (10 × 106 cells ml−1) was significantly larger than for those fed on lower and medium densities (0.1 and 1 × 106 cells ml−1). Body size and egg size of rotifers fed with different amounts of Scenedesmus did not differ significantly. The egg size was significantly larger at higher food level of Chlorella. A significantly positive correlation was observed between the adult rotifer body size and their egg size.

scholarly journals Variation in growth and instar number in field and laboratory Manduca sexta

2007 ◽  
Vol 274 (1612) ◽  
pp. 977-981 ◽  
Author(s):  
Joel G Kingsolver
Keyword(s):  
North Carolina ◽  
Body Size ◽  
Manduca Sexta ◽  
Growth Rates ◽  
Developmental Plasticity ◽  
Larval Growth ◽  
Physiological Control ◽  
Larval Instars ◽  
Laboratory Colony ◽  
Early Larval Development

The tobacco hornworm Manduca sexta has been an important model system for understanding physiological control of growth, development and metamorphosis of insects for more than half a century. Like all Manduca , M. sexta typically has five larval instars, with developmental commitment to metamorphosis occurring early in the 5th (final) instar. Here we show that M. sexta from a field population in North Carolina (USA) shows substantial intraspecific variation in the number of larval instars when feeding on a modified artificial diet. Individuals with six instars consistently exhibited slower growth rates during early larval development than individuals with five instars. The frequency of individuals with six instars decreased with increased rearing temperature. In contrast, M. sexta from a laboratory colony consistently had five instars, and had more rapid larval growth rates than M. sexta from the field. We identify a threshold body size at the start of the 5th instar that predicts whether an individual will have five (greater than 600 mg) or six instars (less than 600 mg). Variation in field populations in Manduca provides an important resource for understanding physiological control, developmental plasticity and evolution of growth rate, body size and instar number.

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