Native Plant and Animal Relationships

Andrenids and Willow (Salix)

These small, often gold-colored bees, also known as miner bees, are oligolectic (species that only feed on a small number of related plants) and are highly sensitive to scents and signals released by willows as they begin to bud. Andrenids show a strong preference for male willow flowers, where they can not only collect nectar but pollen as well, which is essential for making bee bread! Many species of willow are in decline, and those native to the Northeast are getting hit harder than most. Ecologists consider willows to be a foundation species, providing large amounts of resources not just for bees but for a wide variety of other insects and animals.

Squirrels

Insects may have some of the longest relationships with plants, but they are not the only animals to rely on plants to survive. In spring, when resources are scarce, warm days and cold nights stimulate sap flow in maple trees, and red squirrels turn to these resources until other food sources are available. Next time you are in a maple grove, look for wet marks on the undersides or “armpits” of branches. Sap flow here is a great indicator of where these critters are feeding.

Blueberry Bee (Osmia atriventris) and Vaccinium

One of the showiest groups of bees in Maine is the nine native species of Osmia bees. Their small metallic blue or black bodies can often be seen ducking in and out of flowers in the Vaccinium genus, including one of Maine’s favorite crops, lowbush blueberries! One species, Osmia atriventris, can transport up to 13x as much pollen as a non-native honey bee pollinating the same blueberry plant (40-50 grains of pollen vs. 3-4 for a honey bee per trip)! Uniquely, these leafcutter bees carry pollen along the underside of their abdomen rather than on their legs!

Great Golden Digger Wasps and Swamp Milkweed

Large and charismatic Great Golden Digger Wasps (Sphex ichneumoneus) look scary but are incredibly docile. Sometimes you can spot them carrying a paralyzed cricket back to their burrows in sandy soil to be parasitized by their larvae. The young may be parasites, but the adults are vital pollinators to one of many gardeners’ favorite plants, swamp milkweed (Asclepias incarnata). Milkweeds aren’t just for monarchs! They provide floral resources to an incredible array of species. Their pollinarium (pollen packets) are too big and sticky for many other pollinators and require robust partners to transport, visit more plants, and transfer more pollen.

Flies and Skunk Cabbage

Early emergers in spring, these unique plants generate heat! The inside is kept around 50°F even when the outside temperature is below freezing. Warmth combined with a strong smell attracts our native scavenging flies as the primary pollinators of skunk cabbage. Many plants rely on flies to pollinate; they generally smell quite bad to humans, often have a mottled appearance with reds or purples, and some can produce heat to simulate a rotting carcass.

Ants and Lady’s Slippers

Some plant species depend on animals to transport their seeds, and squirrels and blue jays often take that role here in Maine. However, our native orchids, lady’s slippers (genus Cypripedium) take a different route. Tiny seeds nearly lacking in endosperm (the food source for a developing seedling) are picked up by ants, resulting in a short dispersal distance, contributing to the rarity of these delicate plants. Not only do lady’s slippers need ant partners, but they also require a specialized fungus to be present in the soil to supply the germinating plant with nutrients it otherwise lacks.

Aphids and Scales

Not all plant-animal relationships are mutually beneficial. Some insects, including aphids and scale insects, are parasites, meaning that although they feed on the plant, they rarely—if ever—directly kill the plant. Plants and their parasites are locked into a constant struggle as the plant evolves chemicals that discourage feeding by their toxicity or distastefulness, and the animals in turn evolve resistance to these chemicals. Because of this, many of the aphids and scales are highly adapted to feed on a single plant genus or sometimes even a single species.  

Herpetogramma and Ferns

Also known as fern leaf rollers, this group of brown and gray moths tie ferns into distinct balls or orbs with silk to create feeding and pupation shelters, emerging at night to feed and add to their constructions. Ferns that have been tied this way often last long after the moth itself has pupated and left, leaving a small hole. Other arthropods, especially spiders, will take over these shelters and use them to raise their own young later in the season.

Native plants and native animals have strong, mutually beneficial relationships. At the Gardens, we emphasize the importance of these relationships by using thoughtful horticulture practices that protect our native species. Watch these connections unfold in your backyard and throughout the Gardens!