Butterflies in a filthy city

Font Size

By Michelle Anne P. Soliman, Reporter

Air pollution is a health risk, and, naturally, urban areas are more exposed to air pollution and its attendant risks than rural areas. Air pollution does not only affect the human population, but also the quantity and quality of urban biodiversity. And this includes one of the smallest of creatures — the butterfly.

As a first step in preserving the urban ecosystem, a team of professors from universities within Manila has collaborated to provide a baseline study on the effects of air pollution on the preservation of butterfly diversity.

And Manila is a good place to start — after all, there is no doubt that the city’s air quality is terrible. After all, while the World Health Organization considers the safe level for 2.5 micrometer-sized particular matter in the air is “10 micrograms per cubic meter (μg/m3) of air in a year,” Manila’s “annual average of these pollutants is at 17 μg/m3, 70% more than the recommended safe level” according to an article published by the Department of Environment and Natural Resources (DENR) in 2017.

In the middle of 2017, the Commission on Higher Education (CHED) made a call for research studies for the Discovery-Applied Research and Extension for Trans/Inter-disciplinary Opportunities (DARE TO) research grant which amounts to P15 million for a two-year project. The grant is aimed at enabling collaborative research among faculty and staff members of educational institutions during the K to 12 transition. The disciplines of the research proposals may range from food safety, environment, biodiversity, and health systems, to education for science, technology, engineering, arts and music (STEAM).


According to CHED Research Management Division Chief Custer C. Deocaris, PhD, around 400 proposals were accepted this year, and the study on pollution and its effect on butterfly diversity was one of the shortlisted proposals from Luzon.

“Complex problems require multi-disciplinary thinking. The 21st century is a very complicated world… The direction of CHED is for people to be able to work across disciplines,” Dr. Deocaris said of the interdisciplinary nature of the research study.

The study, titled “Using Wireless Monitoring Environmental Sensors in Assessing the Impact of Megacity Environmental Pollutions and Local Climate on Butterfly Diversity in Manila City,” is a project by seven university professors from Mapua University, De La Salle University, the University of Santo Tomas, and Universidad de Manila. The team has been gathering data since January this year.

Despite the fact that 90% of butterflies are found in tropical regions, there is little information known about behavior and diversity of butterflies in the Philippines. The study aims to understand the effects of environmental pollution on the butterflies’ behavioral patterns.

Butterfly expert Alma E. Nacua, PhD, a butterfly expert, university professor at the Universidad de Manila, and project leader, said that the team chose butterflies as the main specie of their study simply because they find the flying insect “fascinating.”

Talking at a media briefing on June 23 at the Bayleaf Hotel in Intramuros, she pointed out that small butterflies live for just three to five days — bigger ones may live for two to three weeks, depending on species and family they belong to. Butterflies can lay over 400 to 600 eggs, but only 2% of these survive. She added that butterflies are also host plant-specific (plants whose pollinators are butterflies) and that they make good indicators for environmental changes based on weather changes.

Their study aims to identify butterfly species and their diversity in Manila, evaluate the effects of city pollution to the species, correlate the degree of pollution to its diversity, and determine how the structure of urban butterfly diversity is affected by larval host plants, nectarine food plants, and natural enemies and diseases.

Data is gathered monthly at the chosen sampling sites: Arroceros Park, Mehan Garden, Manila Zoological and Botanical Garden, and Rizal Park, all in Manila. A wireless monitoring device determines air quality parameters such as particulate matter, carbon dioxide, and sulfur dioxide in the locations.

To date the team has identified 30 butterfly species in Manila, three of which are endemic to the Philippines including the Golden Birdwing (scientific name: Troides rhadamantus), a specie regulated under Appendix II of CITES as “threatened with extinction if population is not controlled.” It was found in Arroceros Park.

Some species were collected for the study at the Urban Biodiversity Laboratory of the Universidad de Manila.

“We really need to educate people [in Manila] since these (butterflies and host plants) are still available in Manila. They are not aware of what the host plants are. Those are where the butterflies eat from. When it disappears, there will be no source of food for the butterflies,” Dr. Nacua said. “The [host] plant is sensitive to pollution — if the plant goes extinct, the butterflies will not thrive,” she noted, citing aristolochia tagala (locally known as timbangan) as one of the host plants found in the gardens of Manila.

The team aims to discover more species and identify if they are at a threatened or endemic specie, how are they affected by pollution (water, air, soil), prove that they are decreasing, and promote their conservation.

“The loss of population in the ecosystem is actually a domino effect not just on the butterfly population but other species as well,” said Ken Joseph E. Clemente, MSc, an ecologist at UST.

“We know that butterflies are effective pollinators, meaning they drive the reproduction of other species, particularly plants. If they decrease, a certain population of plants are affected whose pollinators are not bees,” he said. “If a specific plant’s pollinator is a butterfly, but butterflies decrease, the plant is affected.”

He made another observation: “Butterflies are competitors of wasps. If one specie is lost, the other population of insects will increase. It will result to an imbalance in the ecosystem.”

The team hopes that their research would be a baseline study for future studies. Mr. Clemente said that there is “zero literatures about urban biodiversity,” and there is a lack of knowledge on species present and their quantity. “We want our work to serve as an inspiration to the academe,” he said.

The team plans to publish their research in a scientific journal upon accomplishment in April 2019.