Blue Dasher

Pachydiplax longipennis

The blue dasher is an insect of the skimmer family. It is the only species in the genus Pachydiplax. It is widely distributed throughout North America and into the Bahamas. Source

Where it is now

In the last 8 weeks this insect was recorded 102 times across 11 areas (each area is a 5 degree square).

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Movement and weather

Each season it is first heard regularly where daytime highs are around 26°C (typically 23 to 28°C, from 7 areas). That holds across 20° of latitude, which suggests its timing follows temperature more than the calendar.

Over the weeks it was present in the past year, its centre in North America ranged from 29°N in March to 41°N in July, about 1,300 km apart.

Arrival dates

The week it was first heard regularly in each region, after at least six weeks away. Dates differ from south to north, so a region has a range.

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Figures are effort corrected and come from automatic sound identification, which makes mistakes. How this is measured and how it compares with human observers.