Predator/prey interactions

Emission of semiochemicals by insects is very closely associated with predator-prey interaction. Recent observations in connection with this topic will be discussed in the following paragraphs. 

Ants have developed various ways to overcome their prey. Examples of slave-making ants, thief ants and crypsis in ants are now well known. Ants invade termite nests, forage on them and return to their own colony without being molested. How can this occur  

Analysing the chemical stimuli involved in a predator-prey interaction, Longhurst et al observed that specialized ants preying on termites emit non-repellent aliphatic alcohols as major components of the secretion from their mandibular glands whereas nonspecialized ants release aldehydes and ketones 550). 

The mechanisms whereby parasitoids use kairomones to locate hosts are obviously of crucial importance in predator-prey interactions and may be divided in two categories depending on whether they are the result of long range or cole-range chemoreception. In some cases, olfaction can be influenced by the parasitoid s previous experience (551). A number of kairomones used by parasitoids as aids in host location have been identified. Hemolymph, cuticule, frass scale, mandibular gland and feces can be sources of such kairomones, and long-chain hydrocarbons are the main chemical stimuli responsible (150, 552-569). 

Like D. uelense ants, Solenopsis fugax ants and Nomada bees have developed a way of predation which permits them to invade and steal brood from their prey. The European thief ants S. fugax, steal brood from nearby nests of other ant colonies by building a system of subterranean tunnels which lead to the nest of their prey. Scout ants lay down trail pheromone from the Dufour s gland to attract nest mates 

Not surprisingly, much research in sharks, skates and rays has focused on the responses of sharks to human body odors. Human blood attracts sharks, while sweat does not, and urine was even slightly repellent (Tester, 1963). Practitioners use whale meat and mixtures of fish meal and fish oils as shark attrac-tants. In both carnivorous and herbivorous bony fish (Osteichthyes) smell deals with prey odors, social odors, and chemical stimuli in homing, and it is mediated by the first cranial nerve, the olfactory nerve. By contrast, taste serves in detection and selection of food and avoidance of toxic food, and it employs the facial, glossopharyngeal, vagal, and hypoglossal nerves. 

Numerous experiments with prey extracts have elucidated the stimuli that guide fish in their feeding behavior. These studies showed  

Smell receptors in the marine carnivorous Hawaiian goatfish, Parupeneus por-phyreus (Mullidae), located on the chin barbels, mediate both arousal and food searching in response to prey homogenate and rinse of intact live prey. The 

Prey fish may mask their own odors. Some marine fish avoid predation by covering their body odors. Some parrot fish (Scaridae) sleep in a mucus cocoon. It is believed that this covers up its scent and protects it from predation. Table 12.1 summarizes some chemical predator-prey relationships in marine fish. 

Cyprinuscarpio, are attracted to cysteine, asparagine, glutamic acid, threonine, and alanine. Extracts from Tubifexworms contain at least 17 amino acids. Of these, binary mixtures of one non-polar amino acid and one polar uncharged amino acid attracted carp most and led them to explore the area. Alanine, valine, and glycine proved to be the simplest combination to release significant attraction and exploration (Saglio etal, 1990). 

---

Internal regulatory processes (e.g. predator-prey interactions) Large habitat areas and spatial linkages between ecosystem Ecological gradients... 

Ham, L., R. Quinn, and D. Pascoe. 1995. Effects of cadmium on the predator-prey interaction between the turbellarian Dendrocoelum lacteum (Muller, 1974) and the isopod crustacean Asellus aquaticus (L.). Arch. Environ. Contam. Toxicol. 29 358-365. 

How is Le Chatelier s principle related to predator-prey interactions in ecosystems ... 

From a mathematical point of view, the onset of sustained oscillations generally corresponds to the passage through a Hopf bifurcation point [19] For a critical value of a control parameter, the steady state becomes unstable as a focus. Before the bifurcation point, the system displays damped oscillations and eventually reaches the steady state, which is a stable focus. Beyond the bifurcation point, a stable solution arises in the form of a small-amplitude limit cycle surrounding the unstable steady state [15, 17]. By reason of their stability or regularity, most biological rhythms correspond to oscillations of the limit cycle type rather than to Lotka-Volterra oscillations. Such is the case for the periodic phenomena in biochemical and cellular systems discussed in this chapter. The phase plane analysis of two-variable models indicates that the oscillatory dynamics of neurons also corresponds to the evolution toward a limit cycle [20]. A similar evolution is predicted [21] by models for predator-prey interactions in ecology. 

Dicke M, Vanbeek TA, Posthumus MA, Bendom N, Vanbokhoven H, Degroot AE (1990) Isolation and identification of volatile kairomone that affects acaiine predator-prey interactions -involvement of host plant in its production. J Chem Ecol 16 381-396... 

Acidification of acid-sensitive waters is accompanied by severe changes in biological communities. Effects range from reductions in diversity without changes in total biomass to elimination of all organisms. In many cases the immediate cause of the changes is unknown. Some effects are the result of H" toxicity itself or of the toxicity of metals mobilized from the watershed, others have more indirect causes such as changes in predator-prey interactions or in physical conditions of lakes (ex. transparency). [14]... 

Marchisin, A. (1980). Predator-prey interactions between snake-eating snakes and pit vipers. Ph.D. Thesis, Rutgers University, Newark, NJ, USA. 

Petranka, J. W., Kats, L. B., and Sih, A. (1987). Predator-prey interactions among fish and larval amphibians use of chemical cues to detect predatory fish. Animal Behaviour 35, 420-425. 

Dicke, M., Sabelis, M. W., Takabayashi, J., Bruin, J. and Posthumus, M. A. (1990a). Plant strategies of manipulating predator-prey interactions through allelochemicals prospects for application in pest-control. Journal of Chemical Ecology 16 3091-3118. 

Tsuchiya, H. M., Drake, J. F Jost, J. L. and Fredrickson, A. G. J. Bacteriol. 110 (1972) 1147. Predator-prey interactions of Dictyoselium discoidem and Eschericha coli in continuous culture. 

Multi-species tests (these should include many types of interactions, such as competition, symbiosis, parasitism, host-plant relationships, and predator-prey interactions. As with the population tests, the multi-species tests may have greater value as a research tool than as an across-the-board regulatory tool for herbicides in forestry). 

Both primary and secondary metabolites from marine organisms play an important role in mediating all phases of predator-prey interactions, from defending prey against detection and attack to helping predators locate prey from a distance and subdue it once it is captured. 

---