biol 3300 vertebrate zoology: ectotherms - herpetology

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?

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.

When sounds collide: the effect of anthropogenic noise on a breeding assemblage of frogs in Belize, Central America

Authors: Kaiser et al.

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…

WindRainFlowing water

Approaches to overcome include… Stereotyped callAdjusted timingAlternate channels

What are the constraints on communicating?

• Maximizing Signal to Noise RatioAlternate 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 RatioAlternate channels Ex. Seismic communication Red-eyed treefrog (Agalychnis callidryas)

http://www.youtube.com/watch?v=4PXN6ovRFLM

• 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?

PheromonesFecal pellets Species Gender Food

Plethodon glutinosus

Plethodon aureolus

Plethodon kentucki

Plethodon tayahalee

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 Urodelans?

• Chemical• Fecal pellant 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

What are the major modes of communicating for Anurans?

Hyla versicolorHyla chrysoscleis

• Acoustic• Other types of calls?

• Advertisement• Courtship• Aggressive/Defensive• Reciprocal• Release

What are the major modes of communicating for Anurans?