PhD Defense Seminar cum Oral Examination
“Reproductive Ecology and Parental Care of a Southeast Asian Treefrog”
Dept. of Biological Sciences, NUS
Supervisor: Asst. Prof David Bickford
Fri 03 Oct 2014: 2.00pm
DBS Conference Room II (S1 Level 3, Mezzaine)
All are welcome
“Parental care is a reproductive strategy that increases fitness of parents by having more surviving offspring. The evolution of parental care is closely linked to sexual selection, mating systems, and other life-history characteristics of an organism. However, parental care can be overlooked or assumed in taxa that are underrepresented in the literature. Consequently, there is a gap between observations and analyses, which limits our understanding of general and taxa-specific trends associated with parental care.
I used in-situ observations and experiments to study the costs and benefits of parental behavior in a Southeast Asian treefrog, Chiromantis hansenae. Female frogs that attended egg clutches contributed to offspring survival primarily by preventing egg desiccation. Parental behavior was the main factor in determining offspring survival and was driven by harsh environmental conditions. Using a predatory katydid, I tested prediction of parental investment theories by observing anti-predator behavior of frogs. Defense against predators and ability to differentiate risk levels was sex-specific and only present in female frogs caring for their eggs. Maternal defense was positively correlated with predation risks and was not influenced by offspring age. These results are contrary to existing theory, which suggests investment ought to be negatively correlated with parental predation risks and affected by offspring age. Finally, I examined hatching plasticity of eggs. When exposed to predation cues, both young and old eggs shortened their embryonic period by hatching early. Hatching time was not correlated with duration of maternal egg attendance. Rather, embryonic response to cues depended on their developmental stage. Younger eggs, not yet capable of hatching, continued to develop after being exposed to predation cues, while older eggs hatched rapidly in response to predation of neighboring eggs.
This is the first empirical, experimentally-driven, parental care research on a Southeast Asian amphibian. Results demonstrate behavioral adaptations by parents and offspring to reduce egg stage mortality. It supports overarching theories of parental care evolution, but provides unexpected trends of parental investment in relation to certain life-history characteristic and environmental factors. This study highlights the importance of examining parental care in underrepresented taxa and geographical regions, and the potential of using C. hansenae as a study system. These findings form a basis for further research on reproductive strategy comparison and hatching plasticity that will lead to improved understandings of decisions involved in both adult and offspring behavior and the evolution of parental care.”
All are welcome”
Field assistant in mosquito vector and dengue research
Field sites in Singapore, mostly Geylang
Duties include: inspecting water bodies for mosquito larvae, assisting with laboratory experiments on adult mosquitoes
Duration: 16 hours per week, 4 months
Enquiries: A/P Theodore Evans, firstname.lastname@example.org
The Lee Kong Chian Natural History Museum (LKCNHM) of the National University of Singapore invites applications for a Museum Officer position.
For more information about the Museum Officer opening, visit the job opportunity page at News From Lee Kong Chian Natural History Museum. The closing date for applications is 10 October 2014.
We are playing catch-up on news about Seshadri, one of the PhD students in the Evolutionary Ecology and Conservation Lab who is back in Singapore after spending the summer in India doing field work.
Seshadri’s master’s research on the effects of selective logging on frogs in the Kalakad Mundanthurai Tiger Reserve was recently published in Biotropica and featured on the conservation website Mongabay.com. The reserve is part of the Western Ghats, which along with Sri Lanka is a biodiversity hotspot that is home to many threatened endemic amphibians. Seshadri found that negative impacts on densities and community composition of anurans persisted in logged forest even 40 years after moderate logging was ceased. The degradation from logging has led to the loss of ecological niches – particularly affecting stream- and litter-dwelling species. It appears that anuran assemblages in the region do not recover quickly from habitat degradation due to logging.
Seshadri will continue to work on threatened amphibians in the Western Ghats for his PhD dissertation, focusing on the ecology and behaviour of bamboo nesting frogs. His research will be supported by the Mohamed bin Zayed Species Conservation Fund and Chicago Zoological Fund, which are competitive grants awarded to conservation efforts to save species worldwide.
CITATION LINK: K.S. Seshadri (2014). Effects of Historical Selective Logging on Anuran Communities in a Wet Evergreen Forest, South India. Biotropica 46:615-623.
Department of Biological Sciences, NUS
” Modelling infectious disease emergence in the context of conservation, economics and development”
HOU Chia Yi
Dept. of Biological Sciences
National University of Singapore
Thu 18 Sep 2014: 2.00pm
DBS Conference Room 1 (S3 Level 5)
Supervisor: Asst Prof Roman Carrasco
Co-supervisor: John D. Mumford
All are welcome
Abstract: – Infectious diseases are emerging in real time, with the current epidemic of ebola in West Africa taking the headlines at more than 1,900 human deaths over the course of March to September 2014. Infectious disease emergence is a field that spans studies of wildlife, domestic animals, and humans, and is not only relevant in times like this, but also globally important in times of non-crisis. Overall, I will study the linkages between ecological and human systems to understand how these connections and interactions may affect risk of emergence, and ultimately how control and policy may fit in. Factors that are drivers of disease and dynamics may be affected by aspects and behaviors of both human populations and animal populations. The goal is to characterize and manage risk by examining connectedness, risk, and control allocations or actions that may be contributing to disease emergence. In order to capture how various factors may impact risk, this proposed PhD thesis approaches the modeling of the emergence of infectious diseases from multiple scales: global national, continental spatially explicit, regional, and landscape. In the first chapter, global official development assistance will be collated and compared with risk of emergence. The second chapter will look at Africa land use projections as a result of economic development and other ecological factors to understand how development activities may be managed to reduce future risk. The third chapter examines the trade connections in the Southeast Asian region, an area that may be considered a hotspot for biodiversity and development as well as disease emergence. In the last chapter, a case study in Thailand is proposed that follows human movement and connects it to mosquito sampling and clinical records of dengue and malaria in people.