Neostylopyga rhombifolia
In 3 days ~20% in a week ~30%
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 New Delhi on a given day, based on 12 verified sightings from GBIF citizen-science data. It is the 106th most-seen of the 174 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
April
In that month about 20% of wildlife watchers report a Harlequin Cockroach in New Delhi on a given day, against under 5% in May and July–March, the lowest months. That is one of New Delhi's driest months, with about 15 mm of rain against 220 mm in July.
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.
6th of 9
Of the 9 cities where we can rate Harlequin Cockroach sightings, New Delhi ranks 6th at about 10%. The best odds are in Davao City (Philippines, about 30%), Yogyakarta (Indonesia, about 10%) and Manila (Philippines, about 10%).
GBIF citizen-science records
It is estimated from how often the Harlequin Cockroach is recorded against all the insects logged in New Delhi (12 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.
