Pollinators

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Monarch nectaring on New England Aster during migration in Southeast Iowa
What’s a Pollinator?

A pollinator is any organism that helps with the cross-pollination of plants. They are vital to the survival of most of the world’s ecosystems, with an estimated 70-87% of flowering plants relying on pollinators! Many of these plants are food crops that humans rely upon and most of the others are key members of all our natural ecosystems. Bottomline: Pollinators are extremely important!

In Iowa, pollinators include numerous insects and perhaps the Ruby-throated Hummingbird. In other parts of the world, bats can also play a role in pollination. However, in Iowa, pollination is overwhelmingly helped along by insects, most notably bees but also butterflies, moths, and even flies and beetles. The most important pollinators are bees and wasps, butterflies and moths.


The Monarch Butterfly

One of the most famous pollinators, which has been in the news a lot lately, is the Monarch butterfly. Probably no other insect species is as well known and evokes the amount of love as this species. Most children, at least in Midwestern states like Iowa, are introduced to the process of monarch metamorphosis at least once in their elementary school when a yellow, black and white monarch caterpillar is brought into their classroom. 

monarch butterfly caterpillar feasting on butterfly milkweed.

The eastern Monarch butterfly population, of which Iowa’s Monarchs are a part, is famous for its annual southward fall migration from the United States and Canada to central Mexico, flying a distance of roughly 3,000 miles (4,800 km). For comparison, Iowa at its widest point from the Mississippi to the Missouri is just a smidge over 300 miles, 1/10 of the distance most migratory Monarchs fly. Pretty astounding for such a small critter!

In recent years there has been increasing concern about the health of the population and migration of Monarch Butterflies. Their numbers have dropped significantly in the last 10-15 years. For more information on what’s happening nationally visit the U.S. Fish and Wildlife Service’s Save the Monarch page. Iowa is a very important state for this species and the Iowa DNR along with numerous partners AND many citizens have been working hard to make sure the Monarch Butterfly is here to delight us for many years to come. Read below for more information about the Monarch Butterfly in Iowa!

Learn more about the monarch:

First instar monarch larvae feeding on common milkweed, May 2017 in Fremont County, Iowa

The most important thing to know about the Monarch butterfly is that it needs Milkweed. Any plant in the genus Asclepias will do; Common Milkweed, Swamp Milkweed, Whorled Milkweed, Butterfly Weed to name a few; but the Monarch must have some milkweed to eat as a caterpillar in order to complete its life cycle which it will go through several times in a year’s span. In the middle of all of this, Monarchs throw in that truly astounding migration to Mexico and back.

Monarchs usually show up in Iowa late in the month of May and in force in June. These individuals are “2nd generation” meaning that they are the offspring of butterflies that left Mexico in March and stopped over in the Southern U.S. (primarily Oklahoma and Texas) to reproduce. These first Monarchs to arrive in Iowa start nectaring and laying eggs on milkweeds which then develop through 5 stages or instars of caterpillar before forming a chrysalis and emerging as an adult butterfly. This entire cycle from egg to adult monarch takes roughly 20 - 30 days (the length of time is somewhat temperature dependent) and then the adults live for about 2-6 weeks.

This cycle repeats itself at least twice more in Iowa before the notable and special migratory generation is produced (usually the 4th generation of individuals produced in the U.S.), let’s call it the Super Generation. This Super Generation is produced in late August and early September in Iowa and they start their much longer life span (6-7 months) by beginning the journey south to Mexico, nectaring along the way. A few may stop to breed again further south but most keep flying until they reach Mexico, stopping only to gather energy from nectar producing plants and often gathering in large roosts in trees along the way.

Timeline:

  • Arrive in Iowa: Late May/Early June
  • First Iowa Generation: June-July
  • Second Iowa Generation: July to August
  • Third Iowa Generation “The Super Generation”: August to Early September
  • Migration to Mexico!: Late August through September
  • In Mexico for the Winter: October-March

 

So where can you find Monarchs while they are in Iowa? Almost anywhere! Monarchs are strong flyers and they will use that ability to seek out milkweed and flowers to nectar on wherever they can find it. Usually, because these types of plants need sunlight, monarchs are found in open areas dominated by grass and flowering plants. This could be your yard, a “weedy” roadside, a native prairie, an old field, that odd ½ acre not planted to crops...you name it! If it has milkweed, or some tasty flowers, a Monarch can find it.

This is one thing Monarchs have in their favor and the best thing all of us can do to help save the monarch is put habitat, containing milkweeds and nectar plants, on the ground. See the “Creating Habitat for all Pollinators” section for tips on how to do this.

 

Iowa is a very important state for the conservation of Monarch butterflies. An estimated 38% of Monarchs (Summary of Study on Monarch Joint Venture website) that end up in Mexico for the winter come from the Upper Midwest with Iowa right at its heart.

No comprehensive population estimate of Monarchs exist for Iowa but we have been recording them as part of wider butterfly surveys across the state, mostly on public land. The Monarch is still one of the most abundant butterflies that are recorded on these surveys but the trend over the last ten years has mirrored the downward trend that has been documented in the wintering population in Mexico.

Their migratory lifestyle, puts monarchs at risk and requires them to have especially large populations to be able to sustain a healthy existence as a species. This means, unlike other imperiled species which are difficult to find, just because the Monarch may still be seen regularly does not mean it isn’t in trouble. Wider continuous monitoring of the Iowa population will be necessary moving forward!

 

Creating Habitat for all Pollinators

One thing pollinators have going for them is that most species can take advantage of habitat almost anywhere it is provided. This means that any landowner, whether they own a lot that can be measured in square feet or one that is many acres, can create habitat for pollinators.

The main characteristics a good pollinator garden needs to have are: 1) flowering plants in a 2) sunny spot that 3) bloom from Spring through Fall. We would also recommend, if possible, to consider using predominantly plant species that are native to Iowa. There are many species to choose from and they are adapted to Iowa’s environment.  Most are perennials or good self-seeders (less maintenance!) and our native pollinators love them.

Golden Alexander, a native prairie plant

A pollinator garden can be as formal or as “wild” as you would like. If planting a smaller area that you want to look more formal, it is likely best to plant plugs of prairie species rather than trying to spread seed. If planting a larger area and a more natural look is okay, a mix diverse in flowering prairie species will be more economical, though it will take a bit longer (2-3 years) and a little more maintenance (mowing) before it starts looking its best.

The following pdf includes a more detailed description of how to create monarch and pollinator habitat, both large and small, and includes a species list and links to more resources.

Creating Habitat for Monarchs and Other Pollinators

For larger areas, if you'd like some assistance, landowners can contact the DNR Wildlife Bureau’s Private Lands biologists for advice and assistance. The DNR also has staff that can work with private landowners and you will find a great guide to shrubs and trees that are good for pollinators on their webpage.


What you can do to help!

Prominent Pollinators

BEES and WASPS:
There are 4000 species of bees in North America. The exact number of species in Iowa is unknown but there are likely between 300-400 native species. The species people are most familiar with, the Honey bee, is not a native species but was introduced to the United States for its ability to produce honey. There are many more species of native bees, like bumble and mason bees, which also play an important role in pollination. 

The Rusty Patched Bumble Bee (Bombus affinis) which has a few occurrences in Iowa, recently became the first bumblebee to be listed as endangered under the federal Endangered Species Act.


MOTHS:
More than 2000 species of moths have been recorded in the state of Iowa! There are day-flying and night-flying moths, micromoths with a wingspan of 3 mm and giants like the Luna moth which can measure up to 114 mm from wingtip to wingtip. Little is known about the status of any of the moth species in the state.


BUTTERFLIES:
There are about 110 species of butterfly that reproduce in Iowa. 51 are designated Species of Greatest Conservation Need in Iowa’s Wildlife Action Plan or 46% of the total species in the state. Two species are federally listed under the Endangered Species Act; the Poweshiek Skipperling (Oarisma poweshiek) and Dakota skipper (Hesperia dacotae).