the most parsimonious conclusion is only a bit simpler than the alternative
of multiple losses or gains of a character (Ryan 1996).
6.4. Historical Effects on Receiver Biases
6.4.1. Evolution of Communication from Prey Localization and
Predator Avoidance
Although we have concentrated on the receiver’s role in long-distance communication, hearing or, more generally, sensing ambient vibration patterns
plays a more general role in the behavior and ecology of many species.
Auditory receivers can partition their functions among different tasks.
As discussed above, for example, the frog-eating bat, Trachops cirrhosus,
exhibits a suite of neuroanatomical specializations that enhance hearing
of the relatively low-frequency calls of frogs while still maintaining their
ability to utilize ultrasonics for echolocation (Bruns et al. 1989). Alternatively, adaptations of a receiver for a noncommunication task might bias
the types of signals that can be used for communication. Two examples, one
involved in finding prey and the other in avoiding predators, illustrate this
point nicely.
Water mites do not “hear” in the sense that the vibrations they sense are
borne on the water’s surface rather than through the air. The vibratory patterns to which they are cued are produced by copepods, one of their main
prey items, and a number of species of water mites use this information for
prey localization. In one species, however, males mimic these vibrations and
use them to lure females. Females approach the source of this vibration and
then are courted by the male producing it (Proctor 1991). To show that the
female’s response appears to be incidental to courtship, Proctor (1991)
showed that females deprived of food were more likely to approach and
encounter courting males than were females who were satiated. The
courtship communication system seems to have evolved in an exploitative
process. Although many species of mites use copepod vibrations to hunt,
only one of those species is known to mimic food for sex (Proctor 1992).
Animals use their ability to sense ambient vibrations to avoid becoming
food as well as in finding food. In some moths, evolution of adaptations to
avoid bat predation seems to have dictated some aspects of the acoustic
courtship communication that has evolved.
Bats are major predators on moths, and many moths have responded to
this selection force by evolving the ability to detect ultrasonics, and a subset
of these moths also produce ultrasonics that seem to deter predation either
because they are aposematic signals (the moths are distasteful) or because
they interfere with the bats’ echolocation system (reviewed in Fullard
1998).
There are at least two groups of moths in which these predatoravoidance adaptations also serve the purpose of acoustic communication.
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of multiple losses or gains of a character (Ryan 1996).
6.4. Historical Effects on Receiver Biases
6.4.1. Evolution of Communication from Prey Localization and
Predator Avoidance
Although we have concentrated on the receiver’s role in long-distance communication, hearing or, more generally, sensing ambient vibration patterns
plays a more general role in the behavior and ecology of many species.
Auditory receivers can partition their functions among different tasks.
As discussed above, for example, the frog-eating bat, Trachops cirrhosus,
exhibits a suite of neuroanatomical specializations that enhance hearing
of the relatively low-frequency calls of frogs while still maintaining their
ability to utilize ultrasonics for echolocation (Bruns et al. 1989). Alternatively, adaptations of a receiver for a noncommunication task might bias
the types of signals that can be used for communication. Two examples, one
involved in finding prey and the other in avoiding predators, illustrate this
point nicely.
Water mites do not “hear” in the sense that the vibrations they sense are
borne on the water’s surface rather than through the air. The vibratory patterns to which they are cued are produced by copepods, one of their main
prey items, and a number of species of water mites use this information for
prey localization. In one species, however, males mimic these vibrations and
use them to lure females. Females approach the source of this vibration and
then are courted by the male producing it (Proctor 1991). To show that the
female’s response appears to be incidental to courtship, Proctor (1991)
showed that females deprived of food were more likely to approach and
encounter courting males than were females who were satiated. The
courtship communication system seems to have evolved in an exploitative
process. Although many species of mites use copepod vibrations to hunt,
only one of those species is known to mimic food for sex (Proctor 1992).
Animals use their ability to sense ambient vibrations to avoid becoming
food as well as in finding food. In some moths, evolution of adaptations to
avoid bat predation seems to have dictated some aspects of the acoustic
courtship communication that has evolved.
Bats are major predators on moths, and many moths have responded to
this selection force by evolving the ability to detect ultrasonics, and a subset
of these moths also produce ultrasonics that seem to deter predation either
because they are aposematic signals (the moths are distasteful) or because
they interfere with the bats’ echolocation system (reviewed in Fullard
1998).
There are at least two groups of moths in which these predatoravoidance adaptations also serve the purpose of acoustic communication.
262
M.J. Ryan and N.M. Kime