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Net Results

A memorable Memorial Day Weekend began at Pella’s Big Rock Park with Dr. Paulina

Mena orchestrating a nature foray for an enthusiastic and multigenerational crowd on

Saturday, May 25, 2024.   Dr. Mena provided context and displayed some of her

collection of bees and bee mimics so that we could see the difference in sizes and the

characteristics that distinguished the impersonators such as flies. When asked about the

honeybee, Dr. Mena noted that it was an invasive species and domesticated for

agriculture. She described it as more akin to a chicken than a cardinal. She answered

other questions, taught us how to net, and showed us the “net results” of bees,

dragonflies, beetles, flies, a crab spider, and other natural treasures.  Dr. Mena’s

daughter and other children brought out a sense of wonder and delight as they shouted

out the name of each discovery. The mother of one of the children was asked if her

daughter always liked bees and bugs; the mother replied, "She does today!” We all

seemed captured by the excitement and celebration of invertebrates.

Attendees played with bee netting techniques , too.

As we noted in last year’s blog from April 25, 2023 about the “The Magnificent Splendor

of Native Bees,” Iowa has over 400 species of native bees, all better pollinators and

more well-adapted to our climate than the well-known but non-native honeybee. Iowa

bees have co-evolved with native Iowa plants. They are important to our Big Rock old

growth savannah ecosystem.

Even better, our native bees are mild mannered, having no hives to protect. Unlike

honeybees, they can sting many times but without venom, making the stings less

painful. Aggressive honeybees and wasps will tag intruders with pheromones and the

hive will follow them in attack mode. You’ll get none of this aggression with native bees.

Many native bees are specialized pollinators, fitting in well to their plant niches. Squash

bees for example are early risers, pollinating the morning blooming squash blossoms

and napping in the withered blossoms. Most native Iowa bees are buzz pollinators.

Buzz pollinators such as bumble bees and mason bees are essential for the pollination

of plants with deeply held pollen. Food crops such as eggplant, tomatoes, and

blueberries rely on these bees to produce fruit. These calm bees are not likely to sting.

Bumble bees nest in the ground and each magnificent queen can chose the sex of each

egg as she lays it. The queen will make a honey pot filled with nectar as a food storage

for herself as she incubates her eggs and for the emerging young.

It’s incredibly difficult to identify most native bees by sight. People who can do this,

taxonomists, are older and retiring. Modern bee enthusiasts use DNA testing to help

identify bees.

Over thirty unique species of bees who call Big Rock Park home have been identified by

Dr. Mena and her students. The most prevalent bees catalogued have been Augochlora

pura, a common bee that nests in rotting wood and is a walnut pollinator, Calliopsis

adreneformis, a ground nesting bee and important pollinator of many flowers, including

phlox, and Coelioxys modesta, a parasitic species and pollinator which nests in the soft

soil in the park. Another common bee is Megachile companulae, also known as the

Bellweather resin bee is a special pollinator of tall American Bellflower.

One of Dr. Mena’s exciting findings is that Big Rock Park may be the home of a formerly

undiscovered species of bees! This species would be in the genus Andrena and was

first found by Dr. Steve Johnson. This type of bee is an important native pollinator,

especially for apples and blueberries. Today we caught another bee in the Andrena

family and we will be eager to hear the “net results.”

Honeybees may be well-known but our native bees are hard working pollinators and we

need them. Ways to help them in your yard are to refrain from planting pesticide treated

seeds and to not burn downed wood in the early spring when the young Augochlora

bees are emerging. Our park is the perfect home for them. Let’s keep it that way!

For anyone looking for a good school lesson for and video about the magnificent bees

and related careers, click here.

Dr. Mena enjoyed this year’s foray too. When the directors of Friends of Big Rock Park

emailed her a thank you, she responded immediately; “Thank you so much for the

opportunity to do this. It’s so much fun to interact with people that want to learn about

nature. So many good questions!” 

Thank you to Marion County Community Foundation and Pella Community Foundation

for sponsoring our scientists and events.


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