To learn the secrets of bees, count them one by one

Throughout late summer and early fall, Max McCarthy, a Rutgers University graduate student, roamed the wetlands of northern New Jersey with a mesh net catching bees, qu ‘he marked with tiny colored pens. Three dots, each a different color, on the tiny thorax of the bees before releasing them again. He wrote this information down in his notebooks, counting the insects one by one.

These are not just any bees. Mr. McCarthy hunts a rare bee called Andrena parnassiae. The species is only found near a flowering plant called Parnassus grass, which in the northeastern United States only grows in alkaline wetlands, or fens.

In tagging bees, Mr McCarthy, along with his advisor Rachael Winfree, an ecologist at Rutgers, is trying to see how easily these insects can move between habitat patches and how far. As their ecosystem is disrupted by climate change, development and invasive species, how well will insects adapt?

The researchers hope that their data on this little-known species will shed light on an urgent and complex problem: the decline of pollinators.

Pollinators, including bees, play a vital role in natural ecosystems. Almost 90 percent of flowering plants depend on animal pollinators for reproduction, and about 35 percent of the world’s crops also depend on pollinators. The economic value of bees is estimated at tens, if not hundreds of billions of dollars. Although domesticated pollinators like bees can be used as agricultural substitutes, they cannot fully fulfill the role of wild pollinators.

Despite this severity, the extent of the decline in pollinators is not well understood. What the scientific community knows comes from a small selection of local studies and anecdotal evidence from older naturalists.

“There are strong indications that pollinator populations have declined dramatically, but we are only just beginning to understand how deep and widespread the problem is,” said David Wilcove, professor of conservation biology and public policy at Princeton University which is not involved. in the research of Mr. McCarthy and Dr. Winfree.

Understanding which species are in decline, why and how they respond to changing habitats could help scientists anticipate these types of environmental changes. “People don’t like to count bugs, but those who count them can tell us things that no one else can,” added Dr. Wilcove.

Bees are the hardiest pollinators in North America. But in the United States, the most extensive and oldest bee research has focused on the genus Bombus, the bumblebee, and it is unclear whether this data is relevant to the hundreds of other bee groups in the world. country. While scientists have plans underway to list bee species native to states like Pennsylvania and New York, there is little data for the vast majority of states.

There are technical reasons for this scarcity of data on bee populations. Bees are small, “and identification is just plain difficult,” said Dr. Winfree. In order to track their movements and count the size of their population, she explained, bees must be monitored individually.

What can help researchers is to narrow down where the bees might be. But bees that only pollinate specific plants, like blueberries, are also difficult to track because the plants are usually too widespread.

Mr. McCarthy, however, is able to know the location of each A. parnassiae population of the north of Jersey because they will always be found around the grass of Parnassus, which only grows in fens. “There are a lot of bees that are specialized, but fewer that are specialized on plants that are also specialized,” he said.

Although Mr. McCarthy is only in his second year of research, he probably knows more about A.’s behavior. parnassiae. than any other living scientist – partly because the species is rare (it has only been documented in a few states), and partly because it pollinates in swamps, which have little agricultural value. Dr Winfree even pointed out, as he stood next to a flowering Parnassus, that Mr McCarthy was the first to spot the bee in the area. He had not been seen in New Jersey until last year.

The pair had driven to a small swamp in late summer on the shore of White Lake in Hardwick Township. Mr. McCarthy had roamed the area for 30 minutes, catching 10 bees with practiced shots of his net. Sitting under a tree with one of the insects in his hand, he peered through his glasses at his back, which was covered in pollen. Pulling a thorn from a nearby Japanese barberry bush, he scraped off the yellow dust, revealing three painted dots below. Blue, yellow and white. He had already marked this one. He wrote “BYW” in his notebook and released the bee.

It’s tedious work, but Mr McCarthy and Dr Winfree hope their findings – about the size of the local population and whether insects move between swamps – can serve as a data point in the global problem of declining landfills. pollinators. How resilient will animals be to habitat destruction? How fast are they dying? To answer these questions, start with a single bee.

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