Hello everyone! I’m Yong Xu, a Year 3 student from the Asian School of Environment specialising in Ecology. During my last summer break, I was searching for an opportunity to get hands-on experience in research under the module Environmental Earth Systems Science Research (ES3008). That was when I chanced upon Prof Eleanor’s work on dung beetles, and my journey began!
My project was to determine if there are changes in dung beetle diversity and community composition among trap types and across a habitat type gradient in Singapore. Given that so little work is done on collating the dung beetle species in urban and even the forested parks in Singapore, we were interested to find out if dung beetle abundance, species richness, diversity and community composition would differ across a Habitat Type Gradient from Forests, Forested Parks to Urban Parks. This project was conducted in 12 different sites including places such as Pulau Ubin, Bukit Batok Nature Park and Bishan-Ang Mo Kio Park. Moreover, there has been little variation in trap types used to capture dung beetles in Singapore. Besides the usage of dung-baited pitfall traps, there has not been instances where differently-baited pitfall traps were tried in Singapore to attract dung beetle specialists that are not attracted to dung. Thus, Flight-Interception Traps, as well as pitfall traps baited with human dung, rotting chicken and rotting fruit were laid to determine diversity and community differences among trap types. This also allows us to comprehensively survey dung beetles in Singapore! One semester seemed all too short for all of this, but we made good use of our time. My research buddy, Zann, was of immense help, being my partner-in-crime from supplies runs to mounting all the dung beetles we collected. My supervisor Prof Eleanor, PhD student Xin Rui, and of course, our lab manager Marx, never failed to lend a helping hand and guide me throughout this project.
Some of the more memorable moments we had include the first time we had to handle rotting chicken and human dung. The smell was terrible but grew bearable over time, until it has become almost second nature to me and Zann! Here is a picture of Zann preparing the baits:
Setting up the traps and collecting them was a different challenge as well! Big thanks to everyone from TEE Lab including Breanna and Xuan for coming down to help us, we couldn’t have done all this without everyone’s help.
After collection, we had lab work awaiting us. Sorting the dung beetles out of the samples was always exciting, because some look so different from the others and it’s always a surprise! Afterwards, Zann had to pluck a leg out for her project, while we pinned the beetles up and popped them into the oven. A few hours later, we mounted and sorted them into morphospecies. This was tedious work but very rewarding because we get to see cute dung beetles up close.
After analysis using R software, there were some surprising results. There was a significant effect of Trap Type on dung beetle diversity metrics and community composition, but no significant effect of Habitat Type on both. There was no significant interaction between Habitat Type and Trap Type as well. This absence of interaction could be due to the fact that forest types in Singapore are quite homogenous. In fact, the lack of significant effect of Habitat Type on diversity metrics and community composition could indicate homogeneity and overall high disturbance of vegetation in Singapore.
There is, however, greater similarity in community composition between Forested Park sites and Urban Park sites, which support our understanding that dung beetles are affected by the size and isolation of forest fragments, given that Forested and Urban Parks are more similar by being more well-managed. There is also an overwhelmingly large number of dung beetles caught in the Forest sites, mainly from Pulau Ubin, and suggests the difference between a Forest site with long-established populations of larger mammals (wild boar and long-tailed macaque) and other sites that lack such established medium to large-sized mammalian populations.
There was also an interestingly large number and diversity of dung beetles in the Urban Park Bishan-Ang Mo Kio Park, which could be due to the presence of the dog run and naturalisation of the canal that introduced a lot of other wildlife. Another interesting thing we observed was the disparately large number of Onthophagus semifex in Kent Ridge Park, a known carrion specialist and generalist dung feeder of reptilian dung in Singapore. In fact, dung beetles are known to turn to necrophagy as a replacement of dung in the reduction of large mammals. This could mean that the reduction in large mammals in mainland Singapore led to the diversification in food sources of dung beetles and increased number of species that are necrophagic.
Within such a short period of time, I learnt so much about the dung beetles of Singapore! It has been an incredible semester largely due to this project and I am so thankful for the experience I had. If I could turn back time, I would still choose to join TEE Lab and embark on this amazing journey. Thank you everyone from TEE Lab for guiding me and giving me the space to learn what it’s like having my own research project! Excited to see what TEE Lab has more to come!
Written by: Leong Yong Xu