Acoustic communication in anurans plays a critical role in species recognition, defending
territories and resources, and finding a mate. Anurans use a number of different call note types to
communicate, from which the most notable are advertisement- and aggression calls. Optimum
weather conditions are a precursor to the commencement of the breeding season for all frog
species and their calling behaviour is therefore readily influenced by atmospheric conditions.
Male frogs within a chorus also tend to call from territories within a specific range of distances
from one another. The objectives of this study were to 1) determine a possible context in which
call note types are produced, 2) to determine the effect of atmospheric conditions on calling
behaviour and 3) to determine the spacing distances between males and females in a chorus of
Queckett’s River Frog (Amietia quecketti). Pre-recorded note types were used in a playback
experiment to determine a context for elicited responses. A context was derived for six of the
responses. Advertisement (clicks and whines), aggression (creaks), encounter (tonal notes),
territorial (whine-tonal notes), and release calls (squeaks) were described. Calls and atmospheric
conditions were recorded and correlated for an entire breeding season. Water temperature, wind
speed, humidity and barometric pressure had a significant effect on calling intensity. As water
temperature decreased calling intensity increased, while increased wind temperature led to
increased calling intensity. Amietia quecketti calls from the water, explaining the effect while
increased wind speed decreases water temperature and can carry sound further. Both humidity
and barometric pressure showed increased calling intensity only at specific levels. Humidity and
barometric pressure have a direct effect on one another, which most likely causes the correlation
between calling intensity and both these variables. In this study A. quecketti was shown to have
breeding ponds for males and resting ponds and positions for non-gravid females. This prevents
unwanted or unnecessary amplexus. Males showed much smaller and less variable territory sizes
than females. This is most likely because males have a small range of optimal spacing distance
while females move towards and away from males. The presence of vegetation resulted in
smaller territories. This is possibly because smaller males act as satellite males and cannot be
seen by larger males in vegetation. The size of males did not affect territory size. Males have a
specific inter-male spacing distance regardless of size. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nwu/oai:dspace.nwu.ac.za:10394/14468 |
| Date | January 2015 |
| Creators | Brown, Lize |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0023 seconds