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Synchronising catches, traps, nests and 2026 weather data…
EVOLUTION OF CATCHES
AND NESTS

Citizen catches, confirmed or neutralised nests, mean air temperature at 2 m above ground and biological reference points.

Dynamic monitoring 2026

Dynamic dashboard

Sources: Vespa Alert and weather API with Open-Meteo as fallback.

Important: the data are declarative. Catches and nests must not be added together: they describe two different types of information.
Cumulative catches
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Total reported by citizen traps.
Catches today
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According to today’s dated records.
Monitored nests
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Confirmed + neutralised.
Mean temperature today
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Mean daily air temperature at 2 m above ground, selected weather point.
Daily peak
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Maximum number of catches/day.
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1. Activity by week

Weekly catches, confirmed or neutralised nests, mean air temperature at 2 m above ground, aggregated by week, and indicative biological reference points.

Scroll horizontally to view the full chart

How to read the histogram?

By default, the graph is displayed by week. The yellow bars represent catches reported through citizen traps. The purple curve shows the moving average of catches: it smooths short-term fluctuations to make the overall trend easier to read. The black curve shows confirmed or neutralised nests. The orange curve represents the mean air temperature at 2 m above ground for the selected weather point. In weekly view, it is the average of the available daily mean temperatures for that week.

Moving average: in weekly mode, each point corresponds to the average catches for the last three available weeks. In daily mode, each point corresponds to the average for the last seven available days. This curve does not replace raw data: it helps distinguish a real biological trend from a short-term peak linked to weather, bait renewal, the number of active traps or delayed data entry.

  • The displayed temperature is not a maximum temperature, not a feels-like temperature and not a true spatial average across the whole region.
  • The horizontal temperature lines are indicative biological reference points: they help identify periods when foundresses and colonies may become more active.
  • An increase in catches may also reflect more active traps or more data entries, not only a real population increase.
  • Catches and nests must not be added together: they describe two different types of information.
Sources

Data sources and scientific sources

Data sources

  • Vespa Alert: declarative data from citizen traps and nest reports integrated into the platform.
  • Vespa Alert / IRM-KMI weather API: daily mean air temperatures at 2 m above ground for the selected weather point.
  • Open-Meteo: weather source used as fallback when IRM/KMI data are not available.
  • In weekly mode, the displayed temperature corresponds to the average of the available daily mean temperatures for the week.

Scientific sources used

  • Rome et al., work on embryonic, relocated and secondary nests of Vespa velutina.
  • Studies on seasonal activity and predation by Vespa velutina in relation to temperature.
  • Temperature reference points are indicative and are intended to make public interpretation easier.