The "deely bopper" isn't an antenna - it's part of the bug's feeding tools.
"I was so amazed that there are new species even in the Ateneo Campus in the middle of Manila," said Arielle Vidal, who at the time of find was enrolled in the department's life sciences program. "Then I was sure that I wanted to write my thesis on a taxonomic topic."
Kimberly Go, her thesis partner, added that they "pushed through and investigated a remote river catchment in Mindoro. We found several new species of the same genus there, too."
Hendrik Freitag, their thesis adviser and author of a recent ZooKeys paper on the bug, explained, "The long-palped water beetles (genus Hydraena) are in fact one of the most overlooked and diverse genera of aquatic beetles. Only 14 species of this genus - all endemic - are known from the country by now, but many more wait to be named and described.
"All of them display these extremely enlarged palps of the maxilla. These are real mouthpart appendages and not the antennae. Those species that were found in the Ateneo campus must have re-colonized the area after the tree cover has re-established in the last 50 years and the small creeks began to flow again."