30 May 2020

The COVID-19 Effect

The COVID-19 Effect
A National Lockdown, Wildflowers and Butterflies

It is hard to read any news portal or watch a TV broadcast today and avoid the dreaded C-word. The pandemic is a global phenomenon, and I cannot imagine that anyone in the world has not heard of COVID-19/Coronavirus, unless he or she has been hiding in some cave for the past 6 months. This is an unprecedented moment in history where the entire world is facing the same 'storm' that has affected lives and livelihoods.

A Peacock Pansy feeding on the flowers of the Common Vernonia (Cyanthillium cinereum) an urban weed

Over here in Singapore, we are at the tail end of our "circuit breaker" or our version of a modified national lock-down that started nearly 2 months ago. As the residents look forward to a more normal life, the authorities have announced that any changes will not be abrupt and things will have to take a cautious stepped approach as the economy is resuscitated.

An open grass field covered with Coat Button flowers, fronting a HDB residential apartment in the background.  Due to the lockdown, grass cutters have left many such grassy areas without any maintenance or grass cutting, allowing these "weeds" to grow wild.

So, what has the COVID-19, a circuit-breaker, wildflowers and butterflies have in common? Observant residents have noticed that Singapore's manicured roadside verges and grassy patches are overgrown with "weeds" and pretty wildflowers. This is a result of the lockdown and reduction of non-essential activities like cutting grass, plus the reduction of the availability of the migrant worker population due to a sudden rise in COVID-19 infections amongst these workers who live in their assigned dormitories all around the island.

Another pretty weed that has grown wild is the Touch-Me-Not plant (Mimosa pudica).  Whilst its flowers do not usually attract butterflies, their leaves are the host plant for the caterpillars of the Lesser Grass Blue. However, this thorny low-growing weed is unwelcome in our managed and manicured greenscapes in the city.

The appearance of wildflowers has attracted our urban insects like bees and butterflies to feed on them. In recent weeks, there was an increase in sightings of urban species of butterflies amongst these temporarily unkempt greenery. Taking a quick look around my housing estate where I have my daily exercise routine, it was indeed the case, as the nectar-laden wildflowers offered a delectable buffet to our winged friends.

The Striped Albatross (top : female, bottom : male) was also observed in numbers over the past two months, usually feeding on the flowers of the Coat Button.  Their host plant, Purple Cleome (Cleome rutidosperma) also grows wild along roadside grass verges and open fields during the "circuit breaker" period.

But what are these wildflowers and what butterfly species have been spotted across many urban areas across the island? Taking a walk around my residential area and checking on social media and the snippets of commentaries from nature lovers and enthusiasts, the urbanscape's wildflowers are pretty limited to a handful of species. Of these, the top few are :

Coat Buttons (Tridax procumbens)
Touch-Me-Not plant (Mimosa pudica)
White Weed (Ageratum conyzoides)
Common Vernonia (Cyanthillium cinereum)
Cupid's Shaving Brush (Emilia sonchifolia)
Purple Cleome (Cleome rutidosperma)

A solitary Tawny Coster enjoys a buffet of nectar from the abundant Coat Button flowers at a residential area

The explosion of these flowering weeds and nectaring sources has a trickle-down effect on butterflies, especially the urban species like :

Striped Albatross (Appias olferna olferna)
Lesser Grass Blue (Zizina otis lampa)
Pygmy Grass Blue (Zizula hylax pygmea)
Blue Pansy (Junonia orithya wallacei)
Chocolate Pansy (Junonia hedonia ida)
Tawny Coster (Acraea terpsicore)
Common Grass Yellow (Eurema hecabe contubernalis)

A Lesser Grass Blue feeding on the flower of the Coat Buttons

A Pygmy Grass Blue feeding on the flower of the Common Vernonia

These butterflies are sighted more frequently over the past 2 months, feeding at the wildflowers in our urban residential estates. The diminutive Lesser Grass Blue and its related Pygmy Grass Blue (Zizula hylax pygmea) can sometimes even be abundant, with 20 or more individuals fluttering amongst the wildflowers. The same can be said of the Striped Albatross (Appias olferna olferna) which is more regularly seen in numbers over the past few weeks.

A Common Grass Yellow feeding on the flower of the Coat Buttons

The blooming of these wildflowers and areas which were left unmaintained by landscaping contractors and the town councils sparked off some debates as to whether there should be areas which could be left "wild" for the biodiversity to thrive. Comments that there is "beauty" in these wildflower meadows that add a different perspective to our urban greenery, are counterbalanced with opposing views that these unkempt areas may attract snakes, mosquitoes and other undesirable vermin.

A field of wild-growing Coat Buttons with residential apartments in the background

However, government agencies in charge of the maintenance of our landscaped greenery across the island have indicated that "operations include preventive tree pruning and landscape works such as grass cutting for vector control, and the prevention of vegetation fires in parks and gardens. Grass cutting is also carried out on road verges." It would logically be assumed that any grass cutting would obviously take out these wildflower "weeds" as well.

An open field of White Weed (Ageratum conyzoides) growing in abundance with no grass cutters in sight over the past two months

A Lesser Grass Blue feeding on the flower of the Common Vernonia

To further quote the article, "Assistant Professor John Ascher from the National University of Singapore's biological sciences department is among those in favour of the island's new rustic look, saying that "overzealous" removal of weeds may have led to low bee numbers at many managed sites in Singapore, including nature parks. Weeds are a food resource for bees, he said. "I suppose I am in the minority to be happy if more weeds lead to more 'bugs', at least with respect to wild bees, butterflies, flower flies and other attractive or beneficial species," added Prof Ascher."

Blue Pansy feeding on the flower of the Coat Buttons

Butterfly conservationists will know that even if there are a lot of wildflowers, the ecosystem also needs to support adequate caterpillar host plants of these species. Otherwise the number of butterflies will be limited by the availability of their host plants. Hence other "weeds" like Chinese Violet (for the Blue Pansy), Purple Cleome (for the Striped Albatross), Mimosa (for the Grass Blues), Stinking Passionflower (for the Tawny Coster) and so on, must be allowed to grow, to complement the wildflower nectaring sources.

A Tawny Coster feeding on the flower of a Coat Buttons in an urban residential estate

It is encouraging that we see so many butterflies out and about when these wildflowers provide nectar for them. Other urban resident insects like bees, flies and others will also benefit. Perhaps, in the management of our urban spaces, NParks could create "wild miles" or "wild squares" that are left to grow naturally with minimal grass-cutting and pruning? These can complement the pristine and manicured areas so that there is a balance between biodiversity conservation and aesthetics/safety for human parks users.

Text by Khew SK : Photos by Khew SK, Michael Khor, Jonathan Soong, Horace Tan, Jacob Tan and Pauline Tan

Further Reading / Reference Articles :