In a Flash: How You Can Help Fireflies

Growing up in Argentina I remember the summer nights coming home from visiting my grandparents in the country, and looking out into the darkness of the fields, briefly lit up by fireflies. I remember that even though the drive was long (for my child-time perception), I was always looking forward to it and wanted it to never end… Those lights were so magical! How was it even possible that small little insects could create such a whimsical view?

I grew up and moved to other places where fireflies were not present… until I moved to Maryland. My first summer here (and all the following summers, really), I would look forward to those night lights, and then sit outside and just watch them again and again. The excitement I had when traveling back from my grandparents’ is still fresh in me, and I wonder every time at the little insects, no matter how many times I have seen them. In today’s post, I wanted to share some cool resources that will help you find another excuse to continue watching them, learn to recognize the different species and protect them through a variety of ways.

Fireflies from here

North America harbors a very large number of species of fireflies. Among the over 150 species present across the continent, about 15 are known to occur in Maryland (on iNaturalist you can see more details). Although most species prefer relatively humid conditions (e.g., close proximity to creeks or moist areas), they all differ by when they are actively producing light (for example, dusk vs. the night) or their flashing patterns (you can learn a lot more about their biology and behavior from  Mass Audubon).

images of the different fireflies in Maryland
Several species are known to be present in Maryland. Photo:

Love watching fireflies?

Today, the diversity, ranges, and even conservation status of many fireflies in North America are not well understood. This is problematic because studies appear to show that many species may be declining. However, without clear information on where the different species occur and when they are active, it is really hard to know whether species are likely in need of conservation or not. However, given how large the continent is and how fireflies appear to be present in many regions of the country, it is challenging for scientists to get this information efficiently… or is it?

To address this need, some groups of scientists started a set of projects that rely on what we call citizen science. Here, citizens from around the country can voluntarily sign up, go outside in the evening and watch for fireflies, and then submit their observations to the projects. Anybody can participate in these projects, so we can all actually help the scientists help the fireflies, just by taking part in the studies! The projects that are currently happening in our area are slightly different in scope. Let’s see what each one is trying to do.

This project receives both incidental observations (e.g., you were walking and saw a firefly) and information from structured surveys that are geographically restricted to specific targeted areas (one of which includes most of Central and Eastern Maryland). This project is also seeking to gather information in particular about specific species that are suspected to need conservation or need more data in that particular region. Although participation in incidental observations is simpler than in one of the targeted surveys, both are really useful to the scientists. Either way, the project offers a lot of resources to learn how to identify fireflies and will also help you confirm the identifications once they have been submitted. For both participation types, one has to register and create an account, so all submissions can be properly identified and databased. To get to know about this project, and access its resources, visit the Firefly Atlas website.

This project seeks to understand the population trends of fireflies and the potential reasons for those changes. This project is open to anybody who would like to participate and receives observations from any region of North America. Participants engage in performing 10-minute-long surveys once a week during the firefly season. These observations can be done from anywhere (e.g., your backyard, a forest) and even not seeing any fireflies is useful information! To participate, interested people need to create an account, and then become familiar with the number of flash patterns that they may encounter (a neat chart is shared to learn this). Finally, they need to implement a very easy-to-do protocol and submit their results. To earn more about how to participate, check out the Firefly Watch website.

I want to help the fireflies, but I don’t have the time or ability to take on these projects

Although many things are left to understand about firefly biology, scientists already know that some threats exist. If we want to help them, and while we learn more about their ecologies and needs, we can do so by acting to address these threats in our everyday lives.

As for other insects and biodiversity, habitat loss and pesticide use are important threats to their survival. Increasing the diversity of habitats in our green spaces and choosing non-pesticide solutions when possible are great ways to help them! Another threat that is particularly important for fireflies is light pollution. Because fireflies use light to communicate with each other, if we have a lot of lights on during the night, we can prevent them from finding each other, interfering with their reproduction and thus reducing their ability to sustain their populations. Turning off all unessential lights (e.g., accent lights, light strings) present in our green spaces at night can go a long way, while even saving us some money.

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

Anahí also writes an Extension Blog in Spanish! Check it out here,, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

How climate change works

In my last post, I addressed some common questions that farmers ask about climate change. Although I considered why the scientific information documenting climate change is trustworthy, I didn’t actually explain how climate change works. A savvy reader picked up on this and was dissatisfied that I didn’t present the relationship between increasing CO2 and global warming. In this post, I’ll correct that omission.

The CO2-temperature connection occurs through the “Greenhouse Effect”, a process that almost everyone has heard about but surprisingly few people can explain.

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Are Stink Bugs Bugging You? Are Wasps the Solution?

project stink-be-gone logoSummary: Learn how University of Maryland researchers and University of Maryland Extension (UME) Master Gardeners collaborate on research to reduce brown marmorated stink bug populations in Maryland. Project Stink-be-Gone, by Rebeccah Waterworth

As temperatures cool, many of you probably have had to share your homes with bugs. One of the most notorious of these squatters is brown marmorated stink bug (BMSB) (Fig. 1). It is also a serious pest of many economically important crops. Paula Shrewsbury and I are interested in developing sustainable pest management practices for BMSB, particularly biological control using small wasps (Fig. 2). These critters are also known as parasitoids, and they lay their own eggs inside a stink bug egg. The baby wasp (larva) inside the stink bug egg eats the developing stink bug. After about 10 days, the wasp larvae have become adults, chew their way out of the bug eggs, and fly off to look for new bug eggs to parasitize! Stink bugs do not hatch from the eggs where wasps emerged (see the video at the end of this post).

brown marmorated stinkbug adult
Fig. 1  An adult brown marmorated stink bug, Halyomorpha halys. Photo by David R. Lance, USDA APHIS PPQ from

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