Competition for food

An inventory of known biomacromolecules is provided in Table 22.3. Many of these play essential metabolic roles in enabling growth and reproduction, such as the carbohydrates, lipids, proteins, and polynucleotides. Others are components of cell walls and exoskeletons. Some organisms, such as bacteria, plankton, plants, and lower invertebrates, synthesize biomolecules, called secondary metabolites, that are used to control ecological relationships, including predator/prey, host/symbiont, mating/spawning, and competition for food or space. 

Feeding Several feeding periods per day Competition for food Drinking by suction Ad libitum feeding Feeding barriers Drinking troughs... 

Feeding Omnivores Distinct forage seeking behaviour Competition for food Diverse diet Provision of roughages Separations at the trough... 

Competition for food between populations and between individual fish is an important part of feeding studies. The amount of foodstuff available in a body of water is not necessarily the most reliable indicator of food sufficiency for each consumer . It is helpful to know the actual numbers of consumers. Figure 13 shows the simple relationship between the richness of feeding and the fatness of the anchovy, but a better correlation is given in Figure 14, which takes into account the numbers of fish as well (Shulman, 1972a). 

Calculations show that total lipid production is 20-25% less in infested populations of anchovy and goby than in those clear of the parasites. What is more, infestation weakens fish, rendering them scarcely able to migrate, survive the winter or spawn. This thesis is not indisputable, however. Like predators, parasites regulate the numbers of their victims, rather than wiping them out, by withdrawing the most weakened or unviable hosts from the process of competition for food. 

F 2.3.4 (The Alice effect) For certain species of organisms, the effective growth rate n/n is highest at intermediate N. This is the called the Alice effect (Edel-stein-Keshet 1988). For example, imagine that it is too hard to find mates when N is very small, and there is too much competition for food and other resources when N is large. 

The competition for food is arguably the predominant cause of strife on this planet. Such a system mandates the production of psychic energy in the form of stress, pain, fear and aggression. If the physical body can only survive by eating physical food, the subtle bodies conceivably also require nourishment consisting of the same stuff they are made of, i.e., thoughts, emotions, drives, etc. This is presumably the "food" that we produce for the Archons. What may be a belief in the Christian Trinity or Islamic Jihad to humans, may be the equivalent of a T-bone steak to entities of the imaginal realm who depend upon that belief for their... 

In the Lotka-Volterra model (3.68)-(3.69), f(P) = P. Model (3.71)-(3.72) is by no means the only possibility. Another popular choice is to assume that the functional response / depends not only on the prey, but it is ratio-dependent, i.e. it depends on the a mount of prey per predator f = f(P/Z), modelling competition for food among predators, that is absent in the previous models. An example is ... 

Finally, there are the masses of saprophytic fungi in soil that are not classified as parasitic although they may through competition for food supplies, by antibiotic produc-... 

The overall conclusion from field studies, then, is that the periodicity of rainfall provides a situation in which prey are available to Plethodon cinereus at certain (wet) times and less available at other (dry) times. This periodicity in food availability causes bottleneck points when competition for food is intense, resulting in spacing among individuals and differential access to patches of prey. A similar situation occurs between species. 

Fraser (1976a, 1976b) examined two dissimilarly sized, sympatric species of salamanders in the mountains of Virginia Plethodon cinereus and jP. hoffmani. He found no evidence of direct competition for food, and as an alternative, he proposed that interspecific competition occurs for space. This was the first substantial indication that spacing behavior via territoriality might occur within or between species of salamanders. 

Suleman, M. (1982) The effects of intraspecific competition for food and space on the larval development of Culex quinquefaciatus. Mosq. News, 42, 347-56. 

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