If you’re moving pollen from one plant to another, you could be a pollinator. Fuzzy, pollen-laden bumblebees don’t have a monopoly on ensuring flowers bloom again and blossoms turn into fruit — these amazing animals come in all shapes and sizes.
Pollinators can be butterflies, beetles, birds, bats or even humans — the only job requirement is that they transfer pollen from stamen to pistil (flowering plant male and female organs). As pollinators visit flowers to drink nectar or feed on pollen, they move pollen from flower to flower and help plants reproduce. Pollination is an ecological service — a role an organism plays in its ecosystem that is also essential to human life — that we benefit from every day.
Bees are some of the most important crop pollinators, which are needed to increase production of about 75% of our crop species. When we think of bees, we tend to think of fat, fuzzy, black and yellow insects bumbling around the flowers in our garden. But across North America alone, there are more than 4,000 wild bee species of all shapes and sizes, from the fluffy bronze Tetralonielladavidsoni to the iridescent emerald Agapostemon texanus. Researchers have been finding that this staggering biodiversity — besides making our gardens and countryside beautiful — is critical for many types of ecological services, including pollination.
NSF-funded researcher Rachael Winfree and her team at Rutgers University revealed just how important pollinator biodiversity is for crops in a recent study conducted across dozens of watermelon, cranberry and blueberry farms in the mid-Atlantic United States. Though many farmers use domesticated, non-native honey bee colonies to help with crop pollination, researchers estimate that wild pollinators provide half of the crop-pollination services worldwide.
Winfree’s team found that while five or six wild bee species could provide half of the pollination on any one farm, most of the 100 bee species observed in the study were needed to meet that same threshold across the nearly 50 farms across the region. This means that although a few dominant species are critical at smaller scales, when an entire region is considered, a high level of biodiversity is needed to ensure that farmers’ crops receive adequate pollination services.
But biodiversity isn’t just for “country” bees on farms. A former NSF PhD student in David Holway’s lab at the University of California San Diego, James Hung investigated the effects of urbanization on changes in wild bee diversity over time. Man-made disturbances to habitats is creating big problems for pollinator communities, including significant biodiversity loss.
Hung’s research revealed that habitat fragmentation due to human activity not only reduces bee diversity, it also creates a shift in the timing of natural seasonal changes in the kind and number of bees present. Though the total number of bees was similar, that number peaked later in the year in fragmented habitats compared to undisturbed ones. On top of that, Hung found that bees living in urban scrub fragments possess relatively less variation in behaviors and physical characteristics (for example, food preferences), meaning that they might not be able to render the range and quality of pollination services that bee communities in undisturbed habitats can provide. This diversity loss and changes to seasonal turnover of bee species may threaten plant pollination in the community — potentially even crops that rely on wild bee species for pollination.
So what can we do to protect biodiversity and help both our pollinator friends and ourselves at the same time? Farmers can also help by planting fallow fields and road edges with flowering plants to support wild pollinators throughout the growing season, and by reducing pesticide use, especially during crop bloom when more bees are in their fields. But the average person can help, too — by filling their garden with diverse, native plant species and limiting pesticides, anyone can create more pollinator-friendly spaces within disrupted environments and help keep their local pollinator community diverse, healthy and beautiful.