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General observation -

If you live in the US and are reasonably in touch with nature, you may have noticed a decline in the number of butterflies you see each spring and summer.

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Supporting evidence -

Thanks to a comprehensive new study that combines data from various monitoring programs, we now have hard evidence to support that observation.

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Comprehensive study -

The study looked at years of butterfly data in the lower 48 states and found that, on average, numbers have been falling by 1.3% per year since 2000.

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The cumulative effect -

Although that may not sound like a huge decrease, in fact that cumulative effect is devastating. And there’s nothing to suggest this trend is going to let up.

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Cause -

In terms of what is causing America’s butterflies to disappear at such an alarming rate, experts believe there are several factors to consider.

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Combination of data -

The new study combined 76,957 surveys from 35 monitoring programs and ultimately counted 12.6 million butterflies over the decades.

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Very sparse species -

Of the 650 butterfly species known to inhabit the US, 96 species were so sparse that they did not even show up in the data.

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More sparse species -

A further 212 species were not found in sufficient number that the researchers could calculate trends.

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The species not included -

According to the experts, we should be most worried about the species that were not able to be included in the analyses.

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The St. Francis' satyr -

Once such species was the endangered St. Francis' satyr butterfly, which has been seen so rarely in recent years that it may be extinct.

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Already rare -

It is worth noting that the St. Francis' satyr was already a rare butterfly – it lived only on a bomb range at Fort Bragg in North Carolina.

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Drops in well-known species -

There were, however, some more common and well-known species that also experienced significant drops in numbers.

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The red admiral -

The red admiral–known for being so calm that it lands on people–was down by 44%.

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The American lady -

The American lady butterfly–recognizable by the two large eyespots on its back wings–decreased by 58%.

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The white cabbage -

Even the notoriously invasive white cabbage butterfly, which is known for being very resilient, fell by 50%.

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Combination of factors -

Experts believe that a harmful combination of climate change, habitat loss, and insecticides is working to weaken butterfly populations.

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The role of insecticides -

The research would suggest that of those three factors, the insecticides are causing the most damage.

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Changing use -

Indeed, the use of insecticides has changed dramatically since the turn of the century, and this may well be having a very negative impact on butterfly populations.

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The role of extreme weather -

It may also be the case that butterfly species are suffering at the hands of climate change-induced extreme weather.

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Geographical trends -

The data from the study showed that the biggest decrease in butterfly populations was in the Southwest, in Arizona, New Mexico, Texas, and Oklahoma.

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More than half -

In these states, the number of butterflies dropped by more than 50% in the 20-year period.

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Conclusions -

This prompted researchers to conclude that species in the driest and warmest areas of the country are faring particularly poorly.

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Direct comparisons -

Indeed, when they compared populations of species that live both in the North and in the South, those butterflies that lived in the cooler North seemed to be doing better.

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Why all this is worrying -

The decline in butterfly populations is worrying because these pretty winged creatures play an important role in pollination.

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Bad for pollination -

Although not as prolific as bees, butterflies are a major source of pollination of the Texas cotton crop, for example.

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Bad for mankind -

According to Cornell University butterfly expert Anurag Agrawal, the declining number of butterflies is also a bad thing from the human perspective.

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Important link with nature -

The beauty and fragility of butterflies makes them important for connecting people with nature.

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Getting back in touch -

In the digital age, it has never been more important to get back in touch with nature wherever possible. It makes us both healthier and happier individuals.

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General indication -

The decline in butterfly populations may be taken as a sign that, in general, the planet’s ecosystem is not doing so well.

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Implications for other species -

If butterflies are suffering so much, there are probably other, lesser studied species that are also going through the same challenges.

Sources: (CNN)

See also: How insects can boost your health

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