Iowa Fireflies and The Firefly Atlas

What’s more evocative of a beautiful summer’s night outside, then the twinkle and flash of fireflies? Most of us have seen them, marveled at them, enjoyed them and maybe even caught them and admired them in a jar.

“For many people, fireflies keep special memories alive, strengthening our ties to the people and places we love. As if that weren’t enough, they also play important ecological roles in grasslands, wetlands, forests and gardens, and can be indicators of healthy soil,” said Xerces Society firefly conservation biologist Richard Joyce.

But most of us also know very little about these “lightning bugs” that make our summer evenings magical and cozy. For example, you may be familiar with the adult form of the firefly, which lights up our backyard but did you know that some fireflies don’t light up? Or that they can spend 1-2 YEARS in the larval life stage, way longer than the few weeks they spend as adults? That females often signal from the ground and in some species cannot even fly?

If you did know these things, that’s wonderful! For the rest of us here is a crash course in fireflies:

Firefly Facts

• Fireflies are beetles and have a “complete” life cycle with 4 life stages going from egg, to larva, to pupa, and finally adult.
• The longest life stage is as a larva which are often referred to as glow worms and yes, most do light up as larvae.
• Most larvae live in the leaf litter or soil and are predators, consuming slugs, snails, other insects or earthworms. They are segmented and have an armored appearance, sort of like the insect version of an armadillo!
• • The light displays in the air are mostly put on by males and are used to signal to any females in the area. The females will usually reply from a stationary position, often from the ground or the vegetation. This is why some females are flightless.
  • There are some day-flying fireflies that do not light up but instead use pheromones to find a mate.
  • Most fireflies seem to like moisture with several species occurring in wetland habitats. Early, wet springs after a mild winter can lead to a good mating season in the summer.
  • There are roughly 178 known species of firefly in the United States and Iowa has 17 known species, most from historic records, and this is likely not a complete list!
  • Fireflies are facing a lot of threats currently including artificial light at night, pesticides, habitat loss and a changing environment.

  Paying attention to these small, flashing insects has many rewards.

  “When you pay closer attention to fireflies, one of the rewards is an appreciation for their diversity. A healthy habitat in Iowa might have half a dozen species, each blinking a luminous love song like different instruments in a band. Community scientists have a vital role to play in understanding firefly species and how to best conserve their populations,” Joyce said.

  There is so much more to learn about fireflies and community scientists can help increase our knowledge. The Xerces Society coordinates a project that teaches about fireflies and enables Iowans to get involved in their conservation by filling in knowledge gaps for national and state scientists. This project is called the Firefly Atlas.
  The Xerces Society is a non-profit organization with a mission to conserve insects. The nationwide Bumble Bee Atlas was launched here in Iowa two years ago, thanks to the Xerces Society’s efforts. Xerces also coordinates a national Firefly Atlas and anyone that is interested can get involved. The Iowa DNR would love to learn more about the state’s fireflies, so we are encouraging interested Iowans to get involved.

  The first step is to visit the Firefly Atlas website to learn more about it. It is a survey that will require practice and persistence and is for people who enjoy a challenge and want to contribution to our knowledge.  If it sounds like something you’d like to try, you can sign up for the Firefly Atlas newsletter and create an account.

  Surveys are best done by a pair or more of adventurous people because you’ll be collecting data at night in a natural area. To conduct a survey, participants record the flash pattern of an individual firefly then try to catch that individual to get photos.

  To simplify and focus Iowa efforts, we are encouraging firefly fanatics to particularly collect data on three species of firefly.

  1. Pyractomena borealis also known as the Spring Treetop Flasher
  • WHY: Sparse records in Iowa and an early flying species.
  • WHERE: Field edges along deciduous or mixed woodland. Likely statewide.
  • WHEN: April-May

         2. Pyractomena angulata also known as the Candle Firefly

  • WHY: Only a few records in Iowa and when found it is usually in small numbers. Relatively “easy” flash pattern to identify.
  • WHERE: Forests, usually in proximity to creeks or marshes. Likely statewide.
  • WHEN: June-July

         3. Photinus punctulatus also known as the Punctate Firefly

  • WHY? This species has a distribution range limited to central part of the country from Iowa to Texas. Iowa is the northernmost state and it is the only known species in the state to have a flightless female.
  • WHERE? Meadows and grassy areas, even lawns. They may be more abundant in the southern half of the state but have been found as far north as Cedar Rapids and could be statewide.
  • WHEN: This species’ flight peaks in June but is also active in May. They begin displaying 30 minutes post sunset.

  • Even incidental sightings and photos of these species would be helpful and those can be reported through iNaturalist.

    Richard encourages conducting surveys in a variety of habitats to document rarer species.

    “While some firefly species in Iowa are common and widespread, others have only been documented a handful of times in the state, and may depend on particular habitat types, like wetlands or forests,” he said.

    To Recap…

    Aspiring Firefly Atlas participants have several ways they can approach the survey; 1) learning how to find and survey any and all the species in the state, 2) start by focusing on the three species mentioned above or 3) keeping an eye out during your regular activities, documenting and reporting any fireflies you see on iNaturalist. All these actions have value and are appreciated! I plan to document my first-year adventuring after fireflies this spring and summer and hope you will join me!

  • Action Plan | Join the Firefly Atlas

    • sign up for Xerces/ FFA e-newsletter
    • create a FFA account
    • watch the FFA training video, “How to do a FFA survey”