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British moths declining but aphid numbers stable - Rothamsted Research

Analysis of 24 million individual insects paints a complicated picture of changing population dynamics

Suggestions of an imminent ‘insectageddon’ have received a great deal of attention recently, but many scientists have questioned the accuracy of such predictions.

Now a study of more than 24 million individual insects caught over a period of almost half a century has revealed a greater understanding of their populations - and whether they really are being driven to an impending extinction.

In this new report, data collected by the Rothamsted Insect Survey from 137 insect traps sited across Great Britain between 1969 and 2016 provides very different narratives for the two insects groups under investigation.

Comparing 47 years’ worth of data collected from 1969 onwards, moth numbers have declined by 31% - however, this long-term downward trend was punctuated by several shorter periods of partial recovery, painting a complicated picture of moth population dynamics.

For aphids, the story is very different, and despite their totals fluctuating wildly from one year to the next, their overall number has remained pretty much constant across the decades.

Published in a special issue of the journal Insect Conservation and Diversity which focuses solely on the purported ‘insectageddon’, the study perfectly illustrates the dangers of comparing data from just a handful of years.

Read the paper: Bell, J.R., Blumgart, D. and Shortall, C.R. (2020), Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain. Insect Conserv Divers, 13: 115-126. doi:10.1111/icad.12412

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