Biodiversity is the variety of animals, plants and fungi in an area. It is also the variety of genes within each species.
Many don’t know that Malaysia is country with mega biodiversity, which means that compared to the rest of the world we have many times more diversity. For example in Malaysia we have 6000 species of moths, 2000 species of bees, 8000 species of ants and 200 species of dung beetles.
Of course in cities there are far fewer species. The study of urban biodiversity is about what can survive in our cities and the unique new ecosystems that emerge in them.
An example of urban biodiversity is the patches of pavement plants that grow next to our pathways, or the banyans that take over buildings as soon as they are abandoned. These become the foundation for food chains that allow pollinators or fruit eating birds to live in our cities.
In terms of genetic variety, a good local example is the different breeds of banana that we enjoy. Malaysia has a wide variety of wild and domesticated banana species, and these allow us to have a wide selection of pisang goreng as well as the genetic diversity to breed more resilient crops in the future.
There are practices that we can do to make our cities more friendly to wildlife, this website is a repository of information on how we can create cities that can serve more than just humans.
This is a continuation of our series on pollinators. In this article I will cover flies, often overlooked pollinators of many plants.
As usual, keep in mind that a lot of the plant examples are not exclusively pollinated by a single pollinator. Often there can be several different pollinators visiting the same type of flower. For example anything that a fly can pollinate is usually also visited by bees.
I’m generalising larger flies into a single guild, and it is likely this group can be divided up into several sub-groups, but fly pollination is so poorly studied that we do not have a very broad picture of what flies are doing on flowers.
Flies usually feed on nectar when they land on flowers. Since they aren’t as fuzzy as bees, they don’t pick up as much pollen, but some are hairy enough to transfer pollen. Mango farmers take advantage of flies by putting prawn shells around their farms. This attracts carrion flies which then also pollinate the mango flowers.
Hoverflies are sometimes mistaken for bees. An easy way to tell hoverflies from bees is their flight pattern – they fly less frantically than a bee. They are not as fuzzy as bees and usually spend more time on flowers. They also tend to have shorter antenna compared to bees.
While pollinating they hunt for smaller insects and are good natural pest control.
Flower structure: Fly-pollinated flowers tend to be shallow and grow in clusters.
Plants that they pollinate: mangoes
Small flies and midges
Small flies are very important pollinators of important crops, without them we wouldn’t have cempedak, nangka or chocolate.
Some are very small and can hardly be seen while flying. These flies typically are attracted to downward facing flowers that are close to the ground. Some plants like Aristolochia have elaborate trap flowers that trap the flies for a while until they pick up enough pollen.
Examples: Small fruit flies (Drosophila spp.), Scuttleflies (Phoridae), Midges (Nematocera)
Flower structure: Usually not brightly-coloured, tube shaped flowers
Plants they pollinate: nangka, cempedak, cocoa, Aristolochia
This group of insects feed on carrion and other rotting material. Some plants take advantage of this by pretending to be rotting meat with foul-smelling and dark reddish or purple flowers.
While the confused insects, (usually carrion flies or carrion-feeding scarab beetles) crawl around the flower in search of food, sticky pollen gets all over them. When they give up and leave the flower, they bring the pollen to other flowers for pollination. Our famous Rafflesia flower uses this pollination system.
Often people ask me about how to make their gardens pollinator friendly. This is a tough question, because there are so many different types of pollinators. Guides usually don’t have all of them in one place.
Here, I’ll explain the categories of pollinators that visit plants, as well as the characteristics of the flowers that they pollinate. But be warned that a lot of the plant examples are not exclusively pollinated by a single pollinator. Often, there can be several different pollinators visiting the same type of flower.
To do this, I dug up a bunch of scientific papers and tried to summarise all of it in simple language here. Some of these categories correspond to categories used by scientists, while some have been simplified and combined for the general public.
Since there are so many pollinators I’ve split this up into a few different articles. This one will discuss bees and wasps.
Bees collect pollen on their hairy bodies and legs. There are 265 valid bee species in Malaysia. 62 species have been recorded in Kuala Lumpur alone (some of these may be undescribed). Bees can be divided into two guilds: large bees and small bees.
These are your typical bees, locally called lebah or sometimes kumbang*. Only honey bees tend to sting, and only if aggressively disturbed.
They vary greatly in size, from 10mm to 40mm in length. Large bees tend to travel quite long distances in search of flowers, and due to this prefer flowers with more nectar.
Many of these bees are long tongued bees, they have long mouthparts that lets them suck up nectar that is deep in flowers. A subgroup of large bees are the very large carpenter bees, which tend to prefer larger flowers that can support their weight.
Flower structure: Usually these are not round and are somewhat tube shaped, often with a petal where the bee can land. However they also pollinate or steal pollen from round, shallow flowers by crawling around inside them.
Plants that they pollinate: tomatoes, eggplants, begonia, Senduduk, Coromandel, many wildflowers.
*In the Malay language, carpenter bees are kumbang kayu, although kumbang is also used for beetles.
This is a more diverse group of bees, but easily missed due to their small size (2-12mm). They include bees that live in colonies like stingless bees or solitary bees like sweat bees.
These bees are slower fliers with less range than larger bees. Some of these bees have shorter mouthparts and cannot harvest nectar from very deep flowers. They feed primarily on pollen, and therefore tend to prefer shallow round flowers that they can walk in and collect pollen.
Flower structure: Shallow round flowers which are not tube shaped.
Plants that they pollinate: Basil, lotus, water lily, Lantana, sunflowers, Beggarsticks,
Wasps are less furry and much thinner than bees. They can be identified by their thin “wasp waist”. While many are predatory, they sometimes pollinate flowers when they opportunistically feed on nectar or pollen. However they pollinate with less efficiency than bees because they lack the fuzz to trap pollen.
But there are flowers that are adapted to being exclusively pollinated by wasps, although a lot is still unknown about this type of interaction.
Examples: Hover wasps (Liostenogaster spp.), paper wasps (Ropalidia spp.)
Flower structure: Usually these flowers communicate with their pollinators by smell and taste of nectar (some of which cannot be detected by humans). Some orchids mimic wasps and transfer pollen as the wasp tries to mate the flower.
Plants they pollinate: Some species of Orchids such as Coelogyne sp., usually these have greenish-yellow colours. At the moment I can’t find any records of Malaysian plants being pollinated by non-fig wasps. (Any help on this would be appreciated)
Fig wasps are an example of a keystone species that nobody thinks about. Without fig wasps the fruiting events of figs which sustain most birds in urban settings would not be possible. The reason being that fig wasps are the exclusive pollinator of figs.
Fig flowers grow inwards, forming round structures called synconium. The synconium has a small hole in it that is just big enough for a fig wasp to enter. Female fig wasps lay eggs within fig flowers, while also pollinating the flower so it produces a fruit structure that the larva can feed on. The new females emerge, mate with wingless males, pick up pollen and escape the fig fruit to continue the cycle.
Examples: Fig wasp (Ceratosolen spp.)
Flower structure: Synconium. Flowers that grow inwards and look like round fruit.
Plants they pollinate: Figs
Cheng, J., Shi, J., Shangguan, F. Z., Dafni, A., Deng, Z. H., & Luo, Y. B. (2009). The pollination of a self-incompatible, food-mimic orchid, Coelogyne fimbriata (Orchidaceae), by female Vespula wasps. Annals of Botany, 104(3), 565-571.
Weiblen, G. D. (2002). How to be a fig wasp. Annual review of entomology, 47(1), 299-330.
A beginner’s butterfly garden uses host plants and flowering plants that grow wild. Shade is not an issue for many of these butterfly species here since they are adapted to living in hot open areas. Because this garden uses wild plants, it requires almost zero maintenance (except for occasional trimming).
For aesthetic value, you can hide the host plants behind or between ornamental plants, or use them as verges (edge or border plants).
Some of these butterfly species may already be present in your gardens. But enriching your garden for butterflies can bring them closer for you to view.
These are recent introductions to Malaysia; they can use passionflower vines as a food source for their caterpillars
Coromandel and Cleome butterflies
These butterflies have a variety of host plants but they can use coromandel and cleome as host plants.
These butterflies lay their eggs in lawns on low growing plants that can withstand being mowed.
Roadside tree butterflies
These butterflies can use common roadside trees as a host. This means that you don’t have to plant their host plants but they will still be attracted to your garden.
This is the list of host plants that can be planted in a beginner butterfly garden. You can choose to plant all or just some of them. A few of these are common urban wildflowers.
Passionflowers are creeping vines that can be grown on fences. Sometimes they can be found growing on the borders of drains or other plants.
Coromandel and Cleome are two easily grown wildflowers that are almost everywhere and require almost no maintenance. They grow low and won’t take over your garden, so a small patch or planting them between pots is possible. Both these plants produce seed pods that can be easily harvested from patches of wildflowers.
Lawn plants like grasses and some plants that grow together with grasses, such as Semalu and Desmodium, are also used by lawn butterflies.
As with wildflower patches, allowing other plants to grow in between the host plants helps to fertilise the soil and lower the need for maintenance. Let it grow wild without pesticides and you might get additional biodiversity such as stingless bees and ladybugs.
Coromandel flowers can double as a nectar source for adult butterflies. Easily grown wildflowers such as Goat weed, Cupid’s shaving brush, Tridax daisy and Beggarticks are suitable sources of nectar since they are almost always flowering. Since all of these are from the sunflower family, they produce dandelion like seeds that reseed the plot after the wilt.
The seeds can be harvested from wild patches and placed in a plot.
Butterflies are nice to have in a garden, they help to make it feel alive with colour and movement. They also become food for birds and carry out important pollination of plants.
To have butterflies in a garden, you have to meet the requirements of butterflies. In no particular order, the requirements are: host plants (for caterpillars), flowering plants (for adults) and suitable amounts of shade.
These are plants that caterpillars feed on before they become butterflies. Many butterflies have specific host plants, while some common species have a variety of plants that they can feed on. Sometimes the host plants of butterflies are plants that we eat or use for decoration.
If you are preparing a butterfly garden, please tolerate a few chewed up leaves. Natural predators like wasps and birds can help to keep caterpillar numbers manageable, so preparing habitat for them too can help to bring a balance to your garden.
Plants which regularly flower are very attractive to butterflies. These flowers are not necessarily big, but they usually occur in clusters that the butterflies can walk across.
Wildflower patches are a simple way to make habitat for adult butterflies to feed, although edible plants such as Ulam raja and some ornamental flowers such as Lantana, Ixora and Saraca are attractive to butterflies as well.
Butterflies are cold blooded creatures, so they control their body temperature by exposing themselves to sunlight. However, too much sunlight can be harmful to them. Many species of butterflies prefer shadier conditions where they can rest and cool off. Some forest butterflies never leave the shade of the forest, while open area butterflies can tolerate intense heat from the sun.
Keeping these three things in mind will help make your garden a suitable habitat for butterflies. However, you can meet the requirements of some species of butterflies and still not get a desired species. This is because butterflies have to get to your garden, and usually, species that are more sensitive to urban environments may need pathways from forest patches that they can safely migrate through. So it is good to keep in mind that connectivity to forest patches is a good way to ensure that butterflies can establish themselves in home gardens.
If you want to experiment with these concepts, you can try planting a beginner butterfly garden that attracts very hardy urban butterflies.
We might not all recognize them, and we might not recognize all of them but fig trees are among the native flora that have come to settle in cities with us.
Some are intentionally planted in urban areas, while others continue to appear spontaneously, self-sowing, even in the less than ideal habitat that is the city landscape.
Fig plants belong to the genus Ficus and there are over 700 species of fig species spread throughout the tropical and subtropical regions of the world. Throughout Peninsular Malaysia alone, there are around a hundred Ficus species native to the peninsula.
This large group of flowering plants has a diverse growth pattern and, depending on species, can be
epiphytes (plants which live on the surface of other plants for support)
In the wild, these plants are important sources of food and shelter for wildlife. In some natural ecosystems, they are so important that they are described as keystone species.
Keystone species are organisms in a community that have a great influence on other members, regardless of their actual size or number. Although all organisms will have a role to play in a given habitat, the presence of keystone species can be critical to the welfare of the other organisms.
But what role can these plants play in cities?
The Ficus species that survive in cities tend to be those that come from relatively dry and exposed natural habitats like the edges of forests. Or they are the kinds that are capable of sprouting (from seeds dropped by animals) from crevices, to cling to and grow on vertical surfaces like stone walls.
While not all species of native figs can tolerate city conditions, those that do, share the features that make these groups of plants valuable in the wild. They produce fruits that a large variety of urban wildlife, including squirrels, shrews, primates, bats, and fruit-eating birds, find palatable.
The dense crowns and surface roots of fig trees on the other hand, are of value to urban residents where they can offer shade and stabilize and enrich soil cover. Fallen leaf litter decompose and return nutrients to soil and the spreading, surface roots of the trees help prevent soil erosion by improving the soil structure.
Fig trees will also do what trees do so well—provide spaces (holes, branches) for animals to build shelter and nests. In return, animals spread the seeds from fig fruits far and wide.
But there is one animal, an insect, with which figs have a somewhat unique relationship. One which determines how it flowers and fruits, thereby helping make it the important food source that it is.
The very old tale of the fig and the wasp
For each fig species, there is a single wasp species capable of transferring the flowers’ pollen to allow the plant to reproduce. The wasp species in turn relies solely on that fig flower to complete its life cycle (to live in and lay its eggs). One would not survive without the other.
As important as these two groups of plants and insects are to each other, their interdependent relationship affects other life forms as well.
The reason that fig plants are considered keystone species is tied to this relationship with wasps. In order for there to be enough chances for the short-lived wasps to find flowers or fruits to live in, individual plants produce flowers and fruits at different times throughout a year.
This means that there is almost always a fruiting fig tree. Even when other plants in some forest communities fail to produce fruit or are not in season, fruit eating mammals and birds would be able to find a supply of food at a fig plant.
Nature in cities
The fig tree is a good example of a tree that is traditionally popular, capable of withstanding urban conditions and has ecological significance (for both humans and wildlife).
Lok, A. F. S. L., W.F. Ang, B.Y.Q. Ng, T.M. Leong, C.K. Yeo & H.T.W. Tan (2013). Native fig species as a keystone resource for the Singapore urban environment. Singapore: Raffles Museum of Biodiversity Research.
Shanahan, M., So, S., Compton, S. G., & Corlett, R. (2001). Fig-eating by vertebrate frugivores: a global review. Biological Reviews, 76(4), 529-572.
Most days, a city tree is just a tree. It stands there, out of the way, but close enough if you need a shaded parking or walk. Other days, a tree will make one pause and wonder.
Cities all over the world remember to add trees to their streets and build parks from scratch to bring some nature closer to citizens. Parks and city gardens will have collections of beautiful trees which, much like a city’s inhabitants, are brought together from near and far.
Tall, elegant palm trees along the side of roads, or trees with spreading crowns so people can walk beneath; flowering trees that add hints of color, and trees with round crowns to soften the city landscape.
How do we choose which trees move to the city with us?
Tree choices can tell us something of the history and importance of a place, and the nature of the tree.
Cities built in the colonial era have plenty of introduced trees, sometimes because more was known about them than native trees. Newer parts of an urban area might have trees that mature fasterso they are ready to adorn the city.
Trees that make it to the city are usually tougher, so to speak, chosen for their ability to withstand disturbances like road vibrations and strong winds, and their tolerance for fumes. There are also practical considerations. Trees that bear heavy, falling fruits or have large roots near the ground surface are not good choices where they pose hazards to people, property or infrastructure.
Urban trees are also chosen for their aesthetic or distinguishing qualities, especially those we find in public parks, open spaces or around prestigious public buildings. They are chosen depending on the context to produce a certain effect: comfort, grandeur, delight.
How trees benefit cities
Just like in their natural habitats, the roles that trees play in urban ecosystems are much more than meets the eye. Like all plants, they help keep excess carbon out of the air within their trunks and roots; their leaves and textured wood filter particulate matter and gases that are released by engines.
Our building materials and activities in cities make urban temperatures higher than they would be otherwise. Trees can cool cities as they release water vapor through their leaves and also by creating shade cover. The right tree selection and arrangement can also help block some of the noisewe create as we travel, build and work in cities.
Trees and urban biodiversity
Urban trees also cater to the city wildlife. Tree flowers offer nectar to many kinds of bees, butterflies and moths, and fruits and seeds feed birds, squirrels and shrews. Tree branches and canopies provide spaces for nests and shelters and oftentimes, convenient transit throughout the city.
Trees also make it possible for more plants to flourish in cities as they offer shade for young shoots growing beneath their canopies and support for ferns and climbing plants.
Perhaps cities can offer trees something in return too.
City residents can experience and appreciate trees in a slightly different way than they would in the wild.
A bird’s-eye view of massive trees from atop the LRT, or high rise windows that offer a view of tree tops laden with tiny flowers and hidden nests.
And the luxury of time to watch and follow a sapling’s growth into a grand tree that flowers and fruits, nurtures and shelters, in a suburban backyard.
In recent years, ecologists have begun to take a second look at plants and animals appearing in cities. There seems to be more ‘nature’ in urban areas than one would expect. Cities are supposed to be human territories—steel, brick and concrete—not exactly welcoming to wildlife. But urban places display a variety of species and habitats – biodiversity—in places we did not plan for them.
This makes us ask some questions:
Why are these plants and animals surviving in human settlements while others disappear? How and when did they move in? How many of them can survive in our cities?
Urbanized areas often share characteristics like:
hard surfaces (roads, pavement)
roads and buildings that break up natural, vegetated spaces
bright light at night, loud sounds, water and soil pollution
All of these are known to make it difficult for ‘natural’ habitats to survive near cities.
But there are also ‘built’ green spaces like public parks and private gardens that cultivate a wide range of native and exotic plants. These can form the bases of food chains that attract consumers (like ants, grasshoppers, bees, beetle, squirrels) and their predators (lizards, birds, and monkeys), without our approval. If left uninterrupted, patches of wild ecosystems can be established within these built spaces.
But exactly which species of birds, bees and trees settle in cities? Where in a city are you more likely to come across wildlife? And, how come I can see kingfishers in one district but not another?
Another attribute of cities is the diversity of the habitats (or shelters) they can, unintentionally, form. Within one city, you can find
old buildings that create dark and cool shelters
long stretches of roadside vegetation
Each of these will have unique structural features, creating different kinds of habitats.
For instance, reptiles that inhabit open spaces within their original forest habitats will probably adapt well to places in cities that have widely spaced trees and vegetation.
Wildflowers too benefit from the abundant sunlight and absence of competition (bigger plants) in urban patches. These are conditions not found beneath dense, natural forest canopies.
A more familiar example is the ubiquitous city pigeon. Have you ever wondered why this bird in particular flocks in cities worldwide? One reason might be the similarity between its original habitat – rocky cliffs – and the hard, ledged surfaces of city buildings that offer it space for nesting.
There is also another feature of cities that might be important for supporting biodiversity – the greater amount of food available. For species that are not very particular about their diet, gardens, cafeterias, litter, bird feeders, ornamental trees and nutrient-rich waterways offer abundant food resources.
So what does this mean for us?
One reason that ecologists are interested in urban wildlife is the benefits associated with biodiversity.
In natural ecosystems, there is abundant tree and vegetation cover, and processes like pollination, seed dispersal and decomposition that are carried out by large and small animals. All of these contribute services like food production, climate and water supply regulation.
These benefits (also known as ecosystem services) are important for us. If cities can support biodiversity, then they can help in species conservation and contribute these services that keep our environment healthy.
Urban biodiversity still poses many questions for ecologists to explore.
How much green space is enough for biodiversity conservation?
What ecosystem services can we expect from urban biodiversity?
How are urban plants and animals different from those in natural habitats?
How and why do biodiversity patterns vary among cities and geographical regions?
Answering these questions will take time and require that we pay closer attention to the other lives unfolding parallel to ours.
Resources for further reading:
Müller, N., Ignatieva, M., Nilon, C. H., Werner, P., & Zipperer, W. C. (2013). Patterns and trends in urban biodiversity and landscape design. In Urbanization, biodiversity and ecosystem services: Challenges and opportunities (pp. 123-174). Springer, Dordrecht.
Schilthuizen, M. (2019). Darwin comes to town: How the urban jungle drives evolution. Picador.
Draco gliding lizards are interesting tropical animals. They have ‘wings’ that fold out from their ribs and allow them to glide from tree to tree. They also have a small flap under their chins that acts as both a flag to communicate and like the tail of a plane to stabilise their flight. When I read about them as a kid, they always struck me as incredibly exotic animals that would be really hard to find. It turns out that they are quite well adapted to living in our cities.
There are 11 species of Draco in Peninsular Malaysia. In the natural world, they tend to be found in forest clearings where there is space between trees and not too much dense vegetation. These gaps between trees are usually created by tree fall events. In a mature rainforest, trees fall very often, either due to old age, disease, or unstable soil. Rainforest trees are often connected to other trees by vines or lianas, so when one tree goes down, it can pull down others and crush anything smaller in its path. This is a natural disturbance that creates gaps in the otherwise dense canopies of the rainforest. Young trees and saplings use this opportunity to fill the gap and start the cycle over again.
Many species are known to take advantage of these forest gaps, including gliding lizards. The constant disturbance of tree falls creates more diverse patches of forest, where trees of different species and ages are always going through tree falls and regrowth, nothing staying permanent. This, in turn, creates space for all sorts of gap species that are adapted to these environments. The layperson may view change and disturbance as something undesirable or negative, but these are necessary processes to keep the ecosystem in balance.
In cities, humans are the main force of disturbance. We cut weeds and shrubs and maintain clear gaps between trees. While this may not be good for animals that prefer some shelter, the lack of dense vegetation seems to be a boon for gliding lizards. They can bask in the sunlight created by our sparsely planted trees and glide in between them with ease. Scientists call this pre-adaptation – an organism is predisposed to survive in certain habitat structures, allowing it to take advantage of new habitats with similar features.
A lot of our urban species have, by luck of the draw, found a place for themselves in our urban spaces. So perhaps we should ask the question of how we should use disturbance as a tool for biodiversity and healthier ecosystems, instead of maintaining landscapes just for the sake of maintaining aesthetic practices.
Whitmore, T. C. (1984). Tropical rain forests of the Far East. Oxford University Press, Oxford.
Grismer, L. L. (2008). A revised and updated checklist of the lizards of Peninsular Malaysia. Zootaxa, 1860(1), 28-34.
Naturally occurring wildflower patches are the first step in succession. These small sun loving plants are usually the first to colonise bare land. They then help to regenerate the soil and make it suitable for secondary vegetation like shrubs and small trees to grow.
It should be stated that modern wildflower meadows are not native ecosystems. Many wildflowers found along our roads and in our fields are not native to Malaysia. Some are escaped ornamental plants that have gone wild, others have been brought accidentally by trade and a few have been introduced because of their usefulness to humans.
However, a patch of many small flowers and shrubs are more beneficial to pollinators and wildlife than just a lawn of grass. Stingless bee farms often encourage the growth of wildflowers such as Beggarsticks (Bidens alba, Biden pilosa), Coralvines (Antigonon leptopus), Goat weed (Ageratum conyzoides) and Cupids shaving brushes (Emilia sonchifolia) due to the nectar and pollen that they produce.
Some wildflowers are also food plants adult butterflies and host plants for caterpillars. Passion flowers (Passiflora spp.) are the host plants for the Tawny Coster (Acraea terpescore) and Julia Heliconian (Dryas iulia), while the Touch-me-not plant (Mimosa pudica) is the host for Lesser Grass Blues (Zizina otis lampa) and the Peacock Pansy (Junonia almana).
Some wildflower patches produce fruit and seeds which are eaten by birds. The small sour fruit of the Lavender Sorrel (Oxalis barrelieri) are eaten by Zebra Doves (Geopelia striata) and other small birds. Insects such as grasshoppers, true bugs, crickets, ants and moths that hide in the wildflowers are also the food of insect eating birds. Occasionally smaller water birds will also forage these sites for insects too. Be careful if you intend to use any wildflowers, not all plants are safe to consume or use as medicines. Some wildflowers are harmful to humans and vertebrates, as they can contain poisons that can harm your liver or cause blindness. Be sure to ask an expert before you decide to use any part of a wildflower.