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More than Monarchs: North American Bats

Oct 18, 2021


  • More than Monarchs

Why Monarchs? While monarchs are intrinsically important, conserving monarchs matters for more than just their own protection. We’re exploring the ways that monarch habitat and conservation helps people, other wildlife and the environment in this ‘More than Monarchs?’ series! Join us to learn more.

Beyond the fact that bats and monarchs both fly, at first glance they don’t seem to have much in common.  Differences are pretty obvious – bats are night-flying mammals and monarchs are day-flying insects.  Speaking of insects, that’s what most of our North American bats eat (but not monarchs).  By contrast, adult monarchs feed on nectar from flowers while the larvae eat milkweed.  But if we take a step beyond these obvious differences, we’ll find that bats and monarchs share more than just wings. For instance, both are crucial to food production.  Unfortunately, another feature that many species of bats have in common with monarchs is that their populations are declining.  Fortunately, efforts to conserve monarch butterflies can also benefit bat populations. 

Of the 47 species of bats that spend at least part of the year in North America, four are classified as nectarivores, including the Mexican long-nosed bat, which is federally endangered under the Endangered Species Act.  This is one of three North American species that feed exclusively on the fruit and nectar of night-blooming cacti including saguaro and organ pipe, as well as many species of agave.  Mexican long-nosed bats synchronize their arrival in Texas with the summer blooming cycle of agave plants on which they rely for pollen and nectar. Other nectar-feeding bats that occur in the Southwest include the Mexican long-tongued bat and the lesser long-nosed bat. Like adult monarch butterflies, the diet of these bats consists primarily of nectar and they migrate to the U.S. to take advantage of nectar resources in the summer.  

Most bats don’t share these habits with monarchs -- the vast majority of bats in North America are insectivores.  But just because these bats don’t share the diet of monarchs doesn’t mean they don’t benefit from efforts to conserve monarchs and other pollinators.  Habitat loss and degradation as well as exposure to pesticides are threats shared by insect-eating bats and monarchs.  As we work to manage those threats, we benefit both bats and butterflies.  

As native prairies and grasslands are turned into city blocks and croplands, the abundance and diversity of insects and nectar sources drop, posing a threat to monarchs and other pollinators.  One important way to counter this threat is to create pollinator-friendly plantings next to roadways, within rights of way, along edges of agricultural fields and in our backyards.  Key insect groups like moths, beetles and flies, the primary food for many insectivorous bats, benefit from these management efforts.  So, when we help pollinators, we are increasing the prey base for bats at the same time.  

Pesticides are also a primary threat to monarchs.  To help them, efforts are underway to reduce pesticide use, or to find the least toxic alternatives.  Bats roosting near sites where pesticides are used can suffer reduced fitness, even death, from consuming insects that have been exposed to pesticides.  While reducing the pesticide threat to monarchs, we are reducing contamination of the bat food supply.

The candidate conservation agreement for monarchs, launched in 2020, is a good example of a program benefiting monarchs as well as insectivorous bats.  Under the Monarch Butterfly Candidate Conservation Agreement, energy and transmission companies and state departments of transportation across the country voluntarily manage millions of acres to benefit monarchs in rights of way along transmission lines and roadways.  At the same time, these acres produce food for bats and create excellent travel corridors for bats, many of which are known to use rights of way or other edge habitats to forage and travel between forested patches.  

These are just a few examples of the work we are doing to protect both butterflies and bats, but we should take a moment to talk about what they do to protect us … and our food supply.  While we sleep, bats are patrolling the night skies and eating vast quantities of insects – including many agricultural pests.  A paper published in Science estimates that bats typically save farmers $74 per acre, and that the value of bats to agriculture in the continental United States is roughly $22.9 billion annually.  During the day, pollinators – including bees and butterflies – also provide billions of dollars in ecosystem services for those same crops by performing the critical job of pollination  

The next time you are treated to the silhouette of a bat flying against the night sky, you can ponder what tasty bug snack it just enjoyed … maybe it was a moth that was sustained by your backyard pollinator planting!     

How bats benefit is just one example of how the work we do for monarchs can make a difference in many ways. What are the co-benefits of monarch conservation that matter most to you? Keep following our “More than Monarchs?” series to hear more stories of what monarchs can do for us, our communities and our world.

Article contributed by Lori Pruitt, USFWS, for the Monarch Joint Venture Communications Working Group and NAPPC Pollinator Communications Taskforce's More than Monarchs Series.  Photos: Indiana bat. Photo by Ann Froschauer/USFWS. Monarchs and other insects on purple coneflower. Photo by Jim Hudgins/USFWS. 

The Monarch Joint Venture is a national partnership of federal and state agencies, non-governmental organizations, businesses and academic programs working together to conserve the monarch butterfly migration. The content in this article does not necessarily reflect the positions of all Monarch Joint Venture partners.