Chemical arms race between predator and prey: a test of predator digestive countermeasures against chemical labeling by dietary cues of prey

Abstract

Prey fishes use chemical cues in their predator's diet to cue the context and timing of antipredator behaviors that reduce the risk of predation. They also use dietary cues to learn to recognize and later detect the presence of a predator. Because dietary chemical information decreases hunting success of predators there should be selection on predators to mask or obliterate these cues through biochemical processes in their digestive tract. In this study, we compared response intensity of predator-na€ ıve fathead minnows to the signature odors of two novel predators that had been fed either a minnow diet or a non-minnow diet. Unprocessed minnow mash and dechlorinated blank water were used as positive and negative controls, respectively. One predator was from a relatively ancestral fish group, the order esociformes, while the other predator was from a relatively derived group, the order perciformes. Na€ ıve minnows were able to detect the presence of minnows in the diet of the ancestral and derived predators with equal efficiency and behavioral responses to minnow dietary cues were significantly different from non-minnow dietary treatments. We found no evidence that fish of relatively derived phylogeny have evolved counter-labeling strategies through enhanced biochemical processes during digestion.

The alarm cue obstruction hypothesis: isopods respond to alarm cues, but do not respond to dietary chemical cues from predatory bluegill

“…Subsequent authors proposed that these sculpin evolved the ability to mask or break down the alarm cues released from the tadpoles (Chivers & Smith, 1998;Ferrari et al, 2008;Wisenden et al, 2009). In contrast, a recent study by Sutrisno et al (2014) did not find support for the alarm cue obstruction hypothesis, specifically in bluegill. In this study, fathead minnows (Pimephales promelas) responded to dietary alarm cues from bluegill with the same intensity as they did to dietary alarm cues processed by a distantly related fish, indicating that the more phylogenetically derived bluegill do not chemically alter the alarm cue from fathead minnows.…”

“…In this study, fathead minnows (Pimephales promelas) responded to dietary alarm cues from bluegill with the same intensity as they did to dietary alarm cues processed by a distantly related fish, indicating that the more phylogenetically derived bluegill do not chemically alter the alarm cue from fathead minnows. Different prey species (vertebrate vs. invertebrate) were used in our study and that by Sutrisno et al (2014), which may account for the differing results. Nevertheless, additional research, especially related to the chemical composition of alarm cues in different taxa, is necessary to determine whether bluegill have the capacity to modify the alarm cue from at least some prey to facilitate prey capture.…”

Numerous Paradoxes Explained by Bandwagoning

“…When organisms increase their exposure, and susceptibility, to predators, this accelerates the evolution of the adaptations used to evade predators, while simultaneously slowing the evolution in the predator populations of adaptations used to pursue prey (the prey being the focus population). This may help explain cases in which a focus population "stays ahead" of its predators (e.g., Sutrisno et al, 2014), as the predators stay ahead of their own predators.…”

Predators marked with chemical cues from one prey have increased attack success on another prey species

“…If cues associated with the diet of predators induce efficient anti‐predator behaviour in prey, there is likely to be selection for predators that do not release such cues (Sutrisno et al ., ). So far, three papers independently proposed the idea that if diet‐related chemical cues enable prey to discriminate between harmless and dangerous predators, predators may ‘chemically disguise’ themselves by eating other prey species (Venzon et al ., ; Lima et al ., ; Stabell et al ., ).…”