Predator attraction

Takabayashi J, Dicke M, Posthumus MA. Variation in composition of predator-attracting allelochemicals emitted by herbivore-infested plants relative influence of plant and herbivore. Chemoecol-ogy 1991 2 1-6. 

Good predator attraction. Researchers in the Netherlands were studying the mustard plant, AraMdopsis thaliana, which is very susceptible to attack by herbivorous spider mite predators. They introduced a strawberry gene into the mustard plants that produces a chemical attractant for predatory mites that eat the herbivorous spider mites. 

ERBILGIN, N., RAFFA, K.F., Modulation of predator attraction to pheromones of two prey species by stereochemistry of plant volatiles., Oecologia, 2001, 127, 444-453. 

The variety of functional niches occupied by these injury-released compounds suggests conflicts between the requirements of various functions . Selection on senders and receivers may each exert pressure on the system. For example, predator attraction as a defense mechanism may conflict with abrasive spawning behavior and resistance to digestive processes may conflict with optimal breakdown rates for alarm signaling. 

Predator attraction as a strategy favoring senders would favor chemical secretions that were easily detected by predators. Both alarm signaling and predator attraction should favor easy detection. However, there could be conflict between attracting predators and repelling conspecifics, so a compound or mix of compounds that was a general attractant or repellant would favor one function over the other. If that is so, predator attraction seems to have won out in fathead minnows. However, compounds that attract predators are best avoided by prey, increasing selection on prey for defensive responses to the cue. 

It seems logical that some alarm pheromones might evolve from repellant compounds but these seem poor candidates for the predator attraction mechanism if the compound is inherently offensive. We should look for at least two categories of alarm pheromones, probably in different species, one evolved from predator repellants and the other from non-repellant or attractive compounds both types of compounds could act as alarm pheromones for the sender s conspecifics but one would deter predators and the other would attract predators. Presumably some evolutionary pathways would be more likely than others, e.g., an initially repellant compound might rarely or never come to act as a predator attractant. 

Taxonomic Comparisons. Obviously there are many variations on the basic injury released alarm pheromone theme in fishes and other organisms. A more comprehensive examination of the distribution and variations of this phenomenon might reveal patterns. For example, are there alarm substances that are predator attractants and others that are predator repellants Are some ecological niches more amenable to chemical alarm signaling than others Electrical ostariophysans, for example, seem to lack the alarm pheromone system (Pfeiffer 1977) but may use their electrical signals in some comparable manner. 

Mathis, A., Chivers, D.P. R.J.F Smith. 1995. Chemical alarm signals predator-deterrents or predator attractants Am. Nat., 145, 994-1005. 

The accumulation of secondary products is in most plants and microorganisms an important means for survival, which in several respect is equivalent to the mobility of most animals it deters potential predators, attracts pollinators (corresponding to sexual mates), discourages competing species etc. (E 5). 

Induction of Direct and Indirect Defence (Parasitoid or Predator Attraction) by External Signals, Both Aerially and Through the Rhizosphere... 

Linalool Insect repellent, predator attractant, pathogen resistance... 

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