RESEARCH
Neurophysiological techniques provide a window into the sensory experiences of animals, and data collected with these methods can be used to test many basic hypotheses concerning the evolution of sensory systems and their relationship to animal behavior and ecology. I use an interdisciplinary approach to investigate questions in sensory ecology at three levels:
- the physiology of the sensory cells that capture the information from the environment
- the behavior of the individual that is elicited by this information
- the impact of this individual's behavior on other individuals in the community, such as predators, prey, mates, and competitors
In addition, by combining lab and field experiments, a high degree of both control and biological relevance can be achieved.
My main study system has been bats and their insect prey. Insectivorous bats find their prey using echolocation or by listening to prey sounds, and many insects have ears that are sensitive to the ultrasonic calls of bats, a testament to the pressure exerted on nocturnal insects by these predators. Thus, in this system, both predators and prey use the single modality of hearing to detect each other. Two of the most intensely studied insect orders with respect to auditory physiology are the Lepidoptera (moths) and Orthoptera (crickets and katydids). When moths hear the echolocation calls of bats, they perform flight maneuvers that reduce their chances of being captured. Orthopterans present a more complicated example in which hearing is used for both predator detection and social communication.
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Anti-predator defenses: Although strong relationships between morphology and behavior are known, fewer studies have considered the relationship between sensory capabilities and behavioral and evolutionary ecology. The simple ears of moths, with only 1-4 receptor cells per ear, allow us to quantify the total neural input to the auditory pathway and assess how such a small amount of information can be used to trigger appropriate reactions to predatory bats in different situations.
| ter Hofstede HM*, Goerlitz HR*, Ratcliffe JM, Holderied MW, Surlykke A (2013) The simple ears of moths are tuned to the calls of their sympatric bat community. J Exp Biol 216: 3954-3962. |
| ter Hofstede HM*, Goerlitz HR*, Montealegre-Z F, Robert D, Holderied MW (2011) Tympanal mechanics and neural responses in the ears of a noctuid moth. Naturwissenschaften 98:1057-1061. |
| ter Hofstede HM, Ratcliffe JM, Fullard JH (2008) Nocturnal activity positively correlated with auditory sensitivity in noctuoid moths. Biol Lett 4:262-265 |
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Predation strategies: I am interested in learning if and how predators have adapted to the defenses of their prey. Bats provide an enormous amount of information to their prey due to their reliance on echolocation, but some bat species might adapt their echolocation behavior to make themselves less conspicuous to their prey. This provides an interesting opportunity to investigate sensory-based predator-prey coevolution.
| Goerlitz HR*, ter Hofstede HM*, Zeale MRK*, Jones G, Holderied MW (2010) An aerial-hawking bat uses stealth echolocation to counter moth hearing. Current Biology 20:1568-1572 |
| ter Hofstede HM, Ratcliffe JM, Fullard JH (2008) The effectiveness of katydid (Neoconocephalus ensiger) song cessation as antipredator defence against the gleaning bat Myotis septentrionalis. Behav Ecol Sociobiol 63:217-226 |
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Interactions between natural and sexual selection: Predators that eavesdrop on mating signals select for less conspicuous signals, whereas mates select for more conspicuous signals, and these conflicting selection pressures can have complex evolutionary consequences. Orthopteran insects such as crickets and katydids are known for producing loud calling songs, and they use hearing for detecting predators, mates, and rivals. Some species of gleaning bats (those that capture prey off surfaces) use the calling songs of orthopterans to locate them as prey. I am interested in how the conflict between attracting mates and avoiding predation has shaped both the sensory systems and behavioral ecology of these insects.
| ter Hofstede HM, Kalko EKV, Fullard JH (2010) Auditory-based defence against gleaning bats in Neotropical katydids (Orthoptera: Tettigoniidae). J Comp Physiol A 196:349-358 |
| ter Hofstede HM, Killow J, Fullard JH (2009) Gleaning bat echolocation calls do not elicit antipredator behaviour in the Pacific field cricket, Teleogryllus oceanicus (Orthoptera: Gryllidae). J Comp Physiol A 195:769-776 |
| ter Hofstede HM, Fullard JH (2008) The neuroethology of song cessation in response to gleaning bat calls in two species of katydids, Neoconocephalus ensiger and Amblycorypha oblongifolia. J Exp Biol 211:2431-2441 |
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* indicates equal contribution of authors
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