If there’s food on your table, you can thank a bee. Or a fly. Or even a moth.

They’re types of pollinators, and they help to produce about 75% of the world’s major food crops, according to Dr. Christina M. Grozinger, professor of entomology at Penn State University’s College of Agricultural Sciences.

Not only do they play a main role in agriculture, they are the building blocks of the Earth’s ecosystems and economies.

So if you’re celebrating Earth Day today, you can thank a pollinator.

Grozinger is director for Penn State’s Center for Pollinator Research, which notes that every plant that flowers requires pollination to reproduce. When pollen moves, seeds are created and new plants grow.

Some plants - like corn, oats and wheat - are pollinated by wind, Grozinger said. But others rely on insects that feed from flowers and move pollen on their bodies.

“Bees are the best pollinators because they actually collect the pollen to bring back to their nests to feed their babies, so they really move around a lot of pollen,” Grozinger explained.

Flies, or flower flies, are the second best, followed by butterflies, moths and beetles.

“Ninety percent of the flowering plants that we see use pollinators to move pollen around to effect seed and make fruit,” Grozinger said.

Three quarters of agricultural crops - things like apples, cherries and peaches - rely on pollinators. Different types of berries, along with tree nuts, pumpkins and squashes also do, too. Even the hay that livestock feed on is pollinated by insects.

In Pennsylvania, insect-pollinated agricultural products contribute millions of dollars to the state’s economy. Across the United States, those products amount to about $10 billion per year, according to the United States Department of Agriculture.

“And then on the ecological side, all the seeds from the fruits that the birds and the wildlife are eating are also coming from things that are pollinated,” Grozinger said.

The Center for Pollinator Research notes that approximately 80% of nonagricultural plants that benefit from pollination are the foundation of earth’s food chains.

“The leaves, fruit, and nuts that plants make are eaten by herbivores which in turn are hunted by predators. Furthermore, these plants provide shelter and nesting habitat for many different animal species,” it reports.

The USDA Forest Service adds that pollinators help with air quality since flowering plants produce oxygen. Plants also help to purify water and prevent soil erosion.

Grozinger noted that the world has 4,000 species of bees. Pennsylvania has 440 of them. Many look like the black and yellow honeybee, but they can come in showy metallic colors like blue or green.

“At this time of year, people will see really, really big bumblebees,” she explained of the yellow and black striped species. “Those are queen bumblebees and they are just starting to emerge from hibernation.”

Carpenter bees, which tunnel into wood, and mason bees, so named for their use of mud to line parts of their nests, are also making springtime rounds.

Grozinger said there are ways to support pollinators.

“The best thing you can do is to plant more flowering plants around your house or encourage your city or municipality to do so in parks and open spaces,” she said.

Trees shouldn’t be overlooked.

“I’ve really been pushing flowering trees, especially in the springtime when a lot of bees are getting a lot of their pollen,” Grozinger said. “Even from trees that are not flowering but produce a lot of pollen like oak and maple. They’re normally wind-pollinated but the bees can get a lot of pollen from them.”

Flowering bushes or shrubs are also a hit with pollinators. The best plants are typically those that are native to a region.

Grozinger recommended checking with local Penn State Extension offices, which offer suggestions on what to plant. Information on Pollinator Garden Certification is also available and can be found online through www.extension.psu.edu. The site recommends what to plant based on what an individual wants to attract.

For example, plants and trees for bees include service berry, eastern redbud, frost aster hoary verbena. To attract fly pollinators, choose black cherry, false aster and New Jersey tea.

“The other thing is to set aside habitat for pollinators,” Grozinger said. Since many bee species live underground, it’s good to have unplanted patches of earth for them to dig in, she said.

The extension also offers instructions on how to make homes for bees that build nests inside cavities or hollow tubes, such as the stems of plants.

The solitary bee “hotels” can be made in all sizes and shapes, and usually contain tubes between 6 and 8 inches. Grozinger said bee hotels can be purchased from stores, but they often contain tubes that aren’t long enough.

For more information, visit https://pollinators.psu.edu/.