BIOL 3300 Vertebrate Zoology:
Ectotherms - Herpetology
http://www.amphibian.com.au/
How do “herps” communicate?
• Play clip of H. Microcephala
(http://www.fonozoo.com/eng/versonidoAmphibia.php?id=68442&registro=po)
• Play clip of L. Catesbeianus
(http://www.californiaherps.com/frogs/pages/r.catesbeiana.sounds.html)
What to do when there is more than “you”?
What about multiple species choruses?
What about multiple species choruses?
When sounds collide: the effect of anthropogenic noise on a
breeding assemblage of frogs in Belize, Central America
Authors: Kaiser et al.
Abstract:
Many organisms depend on acoustic communication for myriad functions, and have
evolved behaviours to minimize effects of naturally occurring acoustic interference.
However, as habitats are subject to increased alteration, anthropogenic noise becomes
unavoidable, and how animals overcome such interference is not well understood. In
most ecosystems, only a subset of frog species is associated with disturbed habitats; the
ability of these species to overcome exogenous noise suggests that habitat associations
may be related to species' response to noise. We tested the hypothesis that frogs
associated with largely undisturbed forest habitat would be less likely to increase call
output in response to exogenous noise than would those associated with disturbed or
open habitat. While this relationship was not significant, we found a slight trend
supporting the hypothesis. We then asked whether anthropogenic noise affects chorus
tenure at individual- or at chorus-levels. Male frogs exposed to anthropogenic noise
decreased both the number of days present at the chorus and the nightly chorus
duration relative to controls. Because females generally join choruses late at night to
breed, the effects of noise shown here are likely to substantially decrease frog
reproductive success; thus, the acoustic environment may play an important role in
shaping population dynamics and in amphibian declines.
What are the constraints on communicating?
• Physical & Biological limitations
• Small sizes = shorter distances
• Distance is proportional to size of signaler
AND amplitude of display
• Small animals =
high frequency sounds
• Temperature
influences frequency
• Energetic costs a/the
major constraint
What are the costs of communicating?
http://www.youtube.com/watch?v=nSuTbkftrXQ&NR=1
Sonograms (top) and oscillograms (bottom) of a whine-plus-chuck call of a túngara frog
(Physalaemus pustulosus; left) and a call group of a cricket frog (Acris crepitans; right).
Sun L et al. Behavioral Ecology 2000;11:102-109
International Society for Behavioral Ecology
What are the costs of communicating?
What are the constraints on communicating?
• Noise
• Auditory noise from environment…
Wind
Rain
Flowing water
Approaches to overcome include…
Stereotyped call
Adjusted timing
Alternate channels
What are the constraints on communicating?
• Maximizing Signal to Noise Ratio
Alternate channels
Ex. seismic communication
Puerto Rican white-lipped frog (Leptodactylus albilabris)
http://learning.richmond.edu/Leptodactylus/calls.cfm
What are the constraints on communicating?
• Maximizing Signal to Noise Ratio
Alternate channels
Ex. Seismic communication
Red-eyed treefrog (Agalychnis callidryas)
http://www.youtube.com/watch?v=4PXN6ovRFLM
What are the major modes of communicating
for Urodelans?
• Unable to transmit signal…
• Plethodontid salamanders are
actively mainly at night… visual
signals have limited usefulness.
•Rely on chemical
communication!
Airborne volatile compounds
detected with
olfactory epithelium
Non-volatile compounds
detected with
vomeronasal organ.
What are the major modes of communicating
for Urodelans?
• What are they smelling for?
Pheromones
Fecal pellets
Species
Gender
Food
Plethodon kentucki
Plethodon tayahalee
Plethodon glutinosus
Plethodon aureolus
What are the major modes of communicating
for Urodelans?
• Tail-fanning an adaptation for aquatic
communicating in newts
Why the elaborate efforts in
communicating in Urodelans?
What are the major modes of communicating
for Anurans?
• Chemical
• Fecal pellet information in Leipelma hamiltoni
• ? Ascaphus montanus?
•Visual
• Foot-flagging
• Hand waving
(semaphoring)
• Acoustic
What are the major modes of communicating
for Anurans?
• Acoustic
What are the major modes of communicating
for Anurans?
• Acoustic
Hyla chrysoscleis
Hyla versicolor
What are the major modes of communicating
for Anurans?
• Acoustic
• Other types of calls?
• Advertisement
• Courtship
• Aggressive/Defensive
• Reciprocal
• Release