You want them dead, but roaches, spiders on PH ‘must-save’ list

MANILA, Philippines – While the sight of cockroaches and spiders can leave some fleeing in fear, there is a new reason to rally behind insects and spiders that are not so loved by many.

For the first time, invertebrates, including insects, arachnids and land snails, have been included on the country’s updated “Red List,” or the National List of Threatened Terrestrial Fauna of the Philippines, expanding the knowledge on critical and vulnerable species in our biodiversity-rich country.

Scientists and conservationists assessed a total of 784 species of cockroaches, beetles, true bugs, wasps, butterflies, moths, dragonflies, damselflies, leaf insects, stick insects, spiders and land snails, accounting for nearly 70 percent of all the species listed.

Led by the Philippine Red List Committee (PRLC), the review is a long-awaited update of the Red List for terrestrial animals, the first of which was published in 2004.

The new list, presented at the 28th Philippine Biodiversity Symposium in Baybay, Leyte province, last week, assessed nearly 2,000 species of mammals, birds, reptiles, amphibians and invertebrates. It now awaits publication by the Department of Environment and Natural Resources.

1,105 species threatened

From the assessed species, 1,105 or 55 percent were placed under four threatened categories—critically endangered, endangered, vulnerable and other threatened species.

PRLC chair Juan Carlos Gonzalez, a professor at the University of the Philippines Los Baños, said the first-time inclusion of invertebrates was made possible by the strong collaboration between scientists and institutions, allowing more knowledge sharing and research about species otherwise ignored.

Of the 784 invertebrates, 13 were considered critically endangered, while six were listed as endangered. A total of 321 species were placed under vulnerable status.

Among the critically endangered insects were the Marinduque swallowtail (Menelaides luzviae) and the Leyte swallowtail (Chilasa osmana), both butterflies heavily collected for international trade.

Both are endemic species known from extreme limited range and habitat, with unstable populations and are prone to poaching and illegal trade.

Cave-dwelling roaches

Two cockroaches, the Antipolo blind cave cockroach (Nocticola caeca) and Simon’s cave cockroach (Nocticola simoni) were considered endangered.

Both are strictly cave-dwelling roaches and are only known from their original collection from caves in Antipolo and San Mateo in Rizal province, way back in the 1890s.

Five other cockroach species were listed as vulnerable, as similar-looking species are either sold off as pets or used in Chinese medicine.

According to a PRLC article in the Sylvatrop journal, overharvesting is the most commonly cited threat to invertebrate species.

Spider wrestling

Stick insects, beetles and wasps are often poached and illegally traded for personal collections. Spider populations are threatened by poaching for pet trade and spider wrestling.

Butterflies, meanwhile, appear heavily in international markets.

Several endemic species also have unstable populations and their habitats are often degraded and heavily polluted, leading to decline in numbers.

“You remove one member of the food chain, that affects another,” Gonzalez said. “That may be just a moth or a caterpillar, but they are food for certain birds. The birds’ survival may change by just removing them [from the chain].”

Habitat, land conversion

Beyond invertebrates, the threats for many terrestrial animals remain, which are mostly due to human activity.

Habitat destruction, hunting and rampant land conversion are just some of the key challenges that policymakers and other stakeholders need to focus on, said Cynthia Layusa, vice president of the Biodiversity Conservation Society of the Philippines and one of the main authors of the journal article.

At least six species have been uplisted in their threatened status, including the Palawan pangolin (Manis culionensis) and the Palawan flying fox (Acerodon leucotis), which were moved from vulnerable to endangered status.

The golden-crowned fruit bat (Acerodon jubatus), meanwhile, was elevated from endangered to critically endangered, after recent observations showed declining population due to heavy hunting, continuous roost disturbance and reduction of lowland forests on which it depends for food and shelter.

But there is a ray of hope. Gonzalez said that despite having several threatened species, the continuous survival of many critically endangered animals also showcase the resilience of many species.

“I think we are doing something right collectively,” he said. “But there should be more awareness programs. And efforts must focus not only on the species but also on people—improving their livelihood and helping them understand the animals.”