Neostylopyga rhombifolia
In 3 days ~20% in a week ~50%
Neostylopyga rhombifolia, the harlequin roach, is a species of flightless cockroach in the family Blattidae. It is a synanthropic species, often found in houses, and it is usually considered a pest. It has been introduced globally to tropical and subtropical regions as a result of trade. Its original native range is unknown, but is believed to be somewhere in tropical Asia.
Harlequin roach adults are around 20 to 27 mm (0.79 to 1.06 in) long. Both males and females are flightless. They lack hindwings, and the forewings (tegminia) are reduced to two small lobes. Both also have distinctive black and yellow patterns. Females are typically larger and stouter than males. Harlequin roaches are popular as pets due to their striking coloration.
Harlequin roaches produce a strong-smelling chemical defense, amyl acetate, that has been compared to almond, cherry, pear, or banana extracts. The mitochondrial genome of the harlequin roach was sequenced in 2016. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Ankarafantsika National Park | 🇲🇬 Madagascar | |
| 2 | Cabo Pulmo National Park | 🇲🇽 Mexico |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Davao City | 🇵🇭 Philippines | |
| 2 | Yogyakarta | 🇮🇩 Indonesia | |
| 3 | Manila | 🇵🇭 Philippines | |
| 4 | Colombo [Sri Jayawardenepura Kotte] | 🇱🇰 Sri Lanka | |
| 5 | Jakarta | 🇮🇩 Indonesia | |
| 6 | New Delhi | 🇮🇳 India | |
| 7 | Kaohsiung | 🇹🇼 Taiwan | |
| 8 | Monterrey | 🇲🇽 México | |
| 9 | Guadalajara | 🇲🇽 México |
With luck
About 10% of wildlife watchers report a Harlequin Cockroach sighting in Manila on a given day, based on 9 verified sightings from GBIF citizen-science data. It is the 75th most-seen of the 122 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 50%, if each day is a fresh chance.
April–June, August and October–January
In those months about 10% of wildlife watchers report a Harlequin Cockroach in Manila on a given day, against under 5% in February–March, July and September, the lowest months.
Between 8 and 11 pm
Across all the parks we cover, that three-hour window holds the most Harlequin Cockroach sightings with a recorded time, and about 7 in 10 of them come between 6 pm and 6 am: it is mostly seen at night.
3rd of 9
Of the 9 cities where we can rate Harlequin Cockroach sightings, Manila ranks 3rd at about 10%. The best odds are in Davao City (Philippines, about 30%) and Yogyakarta (Indonesia, about 10%).
GBIF citizen-science records
It is estimated from how often the Harlequin Cockroach is recorded against all the insects logged in Manila (9 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
