New book on urban wildlife – “Unseen City”

I came across this post while scrolling through my Facebook newsfeed today, and was pleasantly surprised to learn of a new book that was released just last month!

“Unseen City: The Majesty of Pigeons, the Discreet Charm of Snails & Other Wonders of the Urban Wilderness.” – the title says it all, doesn’t it? Urban synanthropes, urban adapters, they’re all here! Check out the trailer below!

This is definitely going into my to-read list! 🙂

All abuzz about bees

In yesterday’s lecture, we had the privilege of listening to Dr John Ascher share more about bees in the city. Of all the new information gleaned, perhaps the most relevant one – to daily life, that is – we learnt was how to differentiate between a wasp and a bee: bees are usually [1] hairy, with broad hind legs and a tongue for sipping nectar, all of which wasps lack. Because most people are unable to tell the difference, bees are often misrepresented as dangerous creatures when in fact, it is wasps that are much more aggressive and lethal [2] – as natural predators, their streamlined bodies allow them to attack at much greater speeds and sting their prey multiple times, whereas bees are much slower and die after stinging once.


This Greater Banded Hornet (a social wasp) is the deadly one! (Photographed by Eddie Tan, 2012 )

The giant honey bee, Apis dorsata, also has a deadly sting (if you’re allergic), but don’t worry, it lives in the treetops so you’re not likely to spot it! (Photographed by Zestin Soh, in (Soh & Ngiam, 2013))

The giant honey bee, Apis dorsata, also has a deadly sting (if you’re allergic), but don’t worry, it lives in the treetops so you’re not likely to spot it! (Photographed by Zestin Soh, in (Soh & Ngiam, 2013 [3])

Most bees we see in urban parks and gardens, unlike the giant honeybee (pictured above), are actually non-aggressive and also non-venomous [4]. Thus, there is actually no need to run away screaming whenever we see or hear that familiar buzzing sound – unless, of course, you think you’ve met a hornet, then by all means please do run! [5]

On a more serious note, we also learnt why cities are important habitats for bees – they serve as a refuge from agricultural pesticides, mammalian megafauna and droughts, especially in cities located in drier climates. In our own tropical garden city, bees are in fact more commonly found in rooftop gardens. This is because they are unable to thrive in heavily manicured ground-level vegetation, which often grow in compact soil that are not suitable nesting sites for ground-nesters. As early successional colonizers, bees prefer habitats that have weeds and shrubs, which provide good shelter and food resources.

Following Dr Ascher’s lecture, we had a hands-on activity whereby we were given datasets on Singapore bees, which were then mapped out using this really cool online mapping tool and analyzed. After playing around with the tabs and trying to figure out how things worked, I managed to map out the distribution of Hylaeus sp.

Hylaeus sp. (photographed by Zestin Soh, in (Soh & Ngiam, 2013))

Hylaeus sp. (photographed by Zestin Soh, in (Soh & Ngiam, 2013 [3])

Map of Singapore showing the distribution and density of Hylaeus sp. (Created using Cartodb)

Map of Singapore showing the distribution and density of Hylaeus sp. (Created using Cartodb)

At first glance, the distribution of Hylaeus sp is concentrated in the southern part of Singapore, though they are present in other parts of the city as well. Given that Hylaeus sp is found in a variety of green areas [6], they are likely to be urban adapters. This means that they are able to live opportunistically in close proximity to humans. Urban adapters are usually generalists – they aren’t picky about their meals, unlike specialists – and are able to live in altered habitats or patches. Thus, they are likely to be found in a range of urbanization gradients, which is what we see for Hylaeus sp.

However, upon closer look at the data, I realized that 1 sighting was recorded on 1876 while the rest were dated from 1972 to 1978. Hence, it is likely that the urban structure of Singapore has changed quite substantially since then (especially for the 19th century record) and the distribution seen on the map above may be misleading. To properly analyze the occurrence and habitat of Hylaeus sp, we would then need to refer to older maps of Singapore and match those with the data.

Still, based on the datasheet, we do know that Hylaeus sp is a native species and a cavity-nester. Thus, it is unsurprising that they are able to adapt well to urban environments, since man-made structures such as sidewalk or building cracks could very well serve as a home for these little creatures.

What do you guys think?


[1] Do note that there are always exceptions in nature!

[2] That is, if you happen to have an allergic reaction to its sting

[3] Soh, Z. W. W., & Ngiam, R. W. J. (2013). Flower-visiting bees and wasps in Singapore Parks (Insecta: Hymenoptera). Nature in Singapore6, 153-172.

[4] some don’t even have stings!

[5] Perhaps this would be a good time to brush up your knowledge of the 3 hornets we have in Singapore.

[6] They seem to be able to survive in urban parks, forests, and mangroves

Book review: some thoughts on “Silent Spring”

I first came to know of this book in Year 1 while taking the module ENV1202 “Communications in Environment”, but never found the time/ motivation to read it. Hearing it being mentioned again during the introductory lecture of this module one month back, I thought it would be a good time to pick this book up. After all, now that I’m a Year 3 environmental studies student, I would probably be better able to appreciate her arguments and writing (as compared to when I was a blur freshie). In this post, I’ll share some personal reflections on Carson’s writing and highlight some points that tie in to what we’ve been learning in Urban Ecology.

In our first lecture, it was mentioned that Rachel Carson’s “Silent Spring” was monumental to the development of the environmental movement. Indeed, Carson’s book (first published in 1962) was arguably the catalyst that helped to put the environmental devastation wrought by man in the forefront of the public’s attention.

Silent Spring


There are 2 main reasons why I think her book was so successful in inspiring a change in public mindset:

Firstly, Carson’s background as a scientist and the fact that she was already a best-selling author [1] no doubt helped to establish credibility with her audience. The vocal criticisms by the pesticide industry probably also inadvertently increased publicity for her book and generated public sympathy, resulting in over 2 million copies sold.

Secondly, Carson’s lyrical and simple writing style and choice of examples allowed her engage her audience effectively. For instance, mitochondria are likened to ‘powerhouses’ of energy production (p. 107); acetylcholine is simply explained as a ‘chemical transmitter’ that ‘performs and essential function and then disappears’ (p. 24); highly emotive language such as ‘slaughter’ and ‘massacre’ (p. 52) are used to describe the extent of destruction wrought by overuse of pesticides. Moreover, many examples cited by Carson are not only backed up by statistics, but are also highly relatable to her target audience, showing the direct impact of indiscriminate spraying of insecticides on housewives (pets die), birdwatchers (birds die) and gardeners (plants die) alike.

Overall, I’m reminded of the importance of communicating science to the public in a way that is understandable to the layman, as has been repeatedly emphasized in ENV1202. After all, no matter how amazing or ground-breaking your research finding is, if no one except the scientific community understands its significance, it is unlikely to make any real-world impact.

In the recent lecture on urban vegetation, the Dutch elm disease (DED) was mentioned as an example of the intricate link between urban monocultures and disease prevalence. This example was also brought up in Carson’s book, which highlighted the failure of pesticides in solving the problem, instead compounding it through the bioaccumulation and biomagnification of DDT in the food chain, resulting in near-extermination of migratory robins. Carson thus advocates the use of mechanical (eg. removal of all diseased wood) and genetic controls (eg. producing hybrid elm resistant to DED) over chemical controls.

Beyond this example, Carson’s final chapter argues for the use of biological controls in tackling invasive species by sharing several successful case studies whereby newly introduced species were able to control pest population. However, she fails to mention that using nature to fight nature may backfire too. For instance, the introduction of the Cane toad in 1935 as a biological control against scarab beetles [2] inadvertently resulted in the poisoning of native animals. While we now have better understanding and better technology to mitigate such environmental problems, biological controls should not be seen as a silver bullet as ecosystems are usually more complex and multifaceted than what we imagine.

To conclude, although Silent Spring was published in 1962, it remains as relevant today, given the relentless pace of urbanization and its resultant impact on the environment. Although there has been greater awareness and legislative controls, chemical pollution resulting from pesticide use remains a major issue [3], especially when one considers the potential effects of mixing all these toxic chemicals in the ocean (a thought that frankly scares me).

So read this book, and hopefully when you finish, even though

“Most of us walk unseeing through the world, unaware alike of its beauties, its wonders, and the strange and sometimes terrible intensity of the lives that are being lived about us

you’ll be able to say “Nope, not me.”


[1] she had won the National Book Award for ‘The Sea Around Us

[2] These buggers were destroying Australia’s sugar cane crops

[3] See for instance, how the flower you give/ receive on Valentine’s day is not a very loving sentiment from the perspective of the environment