Author:Anahi

Leave the Leaves, All While Not Making Your Neighbors Mad

Maryland Grows4 Comments

With the fall season we are starting to see a lot of articles talking about the massive ecological and soil quality benefits of leaving leaves, stems, and sticks in our green spaces. As a biologist, I understand why doing so is indeed the right thing to do, but I often face pushback on this topic from people I mention this to through my Extension work or just in my neighborhood. There are of course many barriers to adopting such practices that I have heard people mention, but one that comes up often is the one that involves social or peer pressure. In other words, how to adopt this without making your neighbors mad? In today’s blog, I want to give some pointers to avoid conflict with (and maybe even convince) neighbors who may be less convinced than you on these practices.

Some fall practices that we know are good for biodiversity and your soil

I do not want to talk yet again in depth about these practices (you can read more about it in these other articles if you want to know more):

But I want to just quickly state some of them, so you know what I am referring to throughout this article. I feel that there are three major types of practices that can be adopted for protecting pollinators and other insects during the winter: leaving the fallen leaves on the ground, not pruning certain pithy stems to the ground until the Spring, and making branches and stick piles in sections of your green spaces.

For all these practices, common sense should be used when deciding whether to adopt them or not (e.g., if you are in a fire-prone area, perhaps making huge wood piles is not a good idea), remembering that these are indeed all practices that have been shown to improve biodiversity in our green spaces.

Fallen tree leaves have been spread about fours inches deep in a wide circle around the base of a very large tree in a backyard. Stones are used to create the circular perimeter and contain the leaves.
Piling the leaves around trees is a good way to retain them in the green space, all while giving an impression of “tidiness” to the yard. Photo: D. Mizejewski.

How to avoid “leaving the leaves” look messy?

So, you want to participate in the ”leave the leaves” action, but you still want to make clear that somebody is actually taking care of it. What to do?

  • If you have the option to ignore others’ opinions, you can just leave the leaves where they fell and go on with your life. 😊 That said, this may or not apply to most people.
  • You can pick certain areas of your green space to leave the leaves, but rake other areas. Perhaps you want to have the areas that are less exposed to people’s eyes be those selected for leaving the leaves. This will show that your leaving the leaves is purposeful and not just a lack of care.
  • If you have trees on your space, you can also decide to pile up the leaves around trees. This will provide shelter to insects and other small critters, provide mulch for the tree, and sign active care of your space.
  • A problem I sometimes hear about is leaves blowing over to another person’s yard or space. To avoid this, you can use plants to line/fence your green space. These plantings will have the positive effects of both allowing your leaves to stay on the ground, while minimizing “spill overs”.
  • Explain what you are doing. You can tell your neighbors about what is going on, and even put a sign up to clarify what is happening (if you want to go “fancy”, the Xerces Society has a neat one).
  • A thing NOT to do if you would like to retain arthropod diversity but also make the leaves look “tidier”, is mow them over. This has been shown to kill the insects that were preparing to overwinter in them. ☹
A "Pollinator Habitat" sign is visible in this part of the landscape where fallen tree leaves are spread about four inches deep in a garden bed. The sign explains that the leaves help overwintering pollinators survive the winter.
Displaying a sign that explains that some activities in our green spaces are creating pollinator habitat can go a long way. Photo: C. Corner.

How to leave the stems without issues

Another practice shown to support stem-nesting insects (including several bees) is not trimming pithy stems all the way down during the fall.

  • If you have the option to ignore others’ opinions, you can just leave the stems and go on with your life. 😊 That said, this may or not apply to most people.
  • As for the leaves, you can select sections of your space where you decide to implement this. An extension of this idea is that perhaps you can reconsider where your plantings are, so you have the pithy plants (e.g., brambles) in areas that you know are not going to be looked at all the time.
  • You can also decide to trim the plants down to some extent (about 2-3 ft from the ground) but not completely. This will show that you are taking care of the plants, but that you actively decided not to trim them all the way down.
  • Letting people know what is going on is always a good thing. You can add a little sign to tell people about what you’re doing and why, and/or you can talk to your neighbors to let them know.
2 foot to 3 foot lengths of tree branches and sticks are piled together in an out-of-the way spot in the yard to provide habitat for insects and other small critters. The pile is surrounded and held up four medium-size sticks stuck in the ground vertically at the corners of the pile.
Make your wood and stick piles look “organized” by defining spaces in your yard that you allocate to creating those biodiversity habitats. Photo: Natural History Museum.

Making a pile of sticks and wood without scaring people

Making stick piles is a very good practice to retain biodiversity in green spaces. That said, people can feel like a pile can look untidy, and even some cities may have some regulations about what type of pile may be OK versus not.

  • If you have the option to ignore others’ opinions, you can just make a pile and go on with your life. 😊 That said, this may or not apply to most people.
  • You can restrict the pile clearly to a specific area of your space, and make clear that you have actively decided to make one and are taking care of it. This is to sign that this is not just some brush you left around after you trimmed some plants, but actually a specific green space feature you are trying to build.
  • You can make it look cute. Check out this other blog, A Brilliant Fall Banquet, where some ideas are given.
  • Information, information, information. Let people know what this is and why you are doing it. And also, if there are some afraid of snakes or fires, make sure that the area you live is not known for its high fire or venomous snake danger (you can inform yourself about these topics online or ask an Extension agent; e.g., Venomous Snakes of Maryland.

By Anahí Espíndola, Associate 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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Fear of Insects: Understanding Our Fears to Help Conservation

Maryland Grows2 Comments

Over the years, I have been involved in several initiatives that aim to summarize and translate our knowledge of insects, biodiversity, and some of the ecological services they provide, so that it can be understood by policymakers and the general public to inform decision-making and help ourselves and the living planet. The overwhelming take-home of these works is that insects (and biodiversity in general) are declining at a very fast speed, with very negative consequences on our ability to survive in a less diverse future world. When taking on these knowledge translation activities, however, there is one topic that keeps coming back: people are scared of insects (and wildlife, generally)! Then, how to promote the protection of something we’re scared of and disgusted by? In this blog post, I decided to embark on a mission: to help us understand our fears and recognize how they may be affecting our ability to protect the natural world, and what we can do to turn the wave on this to the benefit of all. Keep reading; I promise I will not shame or judge anybody 😉.

a beautiful collection of colorful beetles on display
Insects (only beetles shown in this picture) are the most diverse and abundant group of animals and play central roles in maintaining ecosystems. Photo: “Insects Unlocked” Project, University of Texas at Austin

The biodiversity crisis – a real problem with real consequences

There is now massive evidence that biodiversity is being lost. This is true for many groups of organisms, but here I want to focus on one in particular: insects. Why? Insects are the most diverse and abundant group of animals and, as such, they are deeply embedded in the running of the natural world. This diversity and abundance turn insects into sorts of ecosystem architects and janitors. They pollinate, feed on other organisms, degrade organic material and make nutrients available for others to consume, disperse seeds, and much more! Beyond the importance of all this to all organisms, these functions, in particular, are central to allowing us to produce food, maintain soil quality and balance, sustain rich ecosystems, and naturally control pests. Promoting insect protection, however, often faces a big challenge: low traction and low engagement, given the fear of insects.

Fear of insects – an encounter between humans and our natural world

Fear and disgust of insects is a very widespread feeling, especially in developed countries and urbanized societies. Although it is understood that the presence of fear or disgust usually develops as a protection system against potential dangers (and there are a few insects that we need to be wary of!), the extent to which fear of insects is present goes beyond what would be needed to properly protect us from a potential danger… And this is starting to have an impact on our ability (and willingness) to protect this important part of biodiversity. How does this work?

People have been studying fear of insects for a while and their findings are really interesting (you can read some neat reviews on this in Current Opinion in Insect Science and Science of the Total Environment). For example, researchers think that this extreme fear of insects may have evolved as a sort of “smoke alarm” (a loud but very non-specific type of alarm). In fact, there is reason to have respect for some insects, since some of them can lead to painful and potentially fatal bites/stings or can carry diseases. The presence of fear against those insects thus makes sense, because they lead to protecting our health. However, there is a balance to be found between responding to a real danger (e.g., hitting a hornet’s nest) or to an inexistent one (e.g., encountering a moth). Because the cost of responding to an inexistent danger is not super high in this case (like for a “smoke alarm”), then an extreme response to any insect can simply appear and spread through human populations. In this case, the only way to “tune” such an extreme response is to learn how to recognize harmful from non-harmful insects, something that many programs (including this blog! 😊) try to do.

Going back to biodiversity conservation, it is illuminating and empowering to realize that the simple action of learning can lead to increased conservation actions… learning when there is reason to stay away from insects or not leads to an appreciation of their huge diversity and more engagement in their protection. Some ways to do this involve using formal learning methods like courses, books, or guides, but also some more interactive ones, such as citizen science projects like iNaturalist or group-specific projects (e.g., the fireflies atlas).

a monarch butterfly
Rearing insects at home (like this monarch butterfly) can be a fun and learning-rich experience through which our appreciation for insects can grow and our fear decrease. Photo: Tim and Selena Middleton (CC)

Another way this fear develops is through social learning. As humans, we can learn through both direct experiences and social interactions. In fact, studies have shown that a large part of this establishment of fear or disgust in humans is learned through interpersonal interactions and not innate. For example, people have discovered that before age 5, most kids are not repelled by most insects or arthropods, and that the level of fear and disgust kids show is correlated with the fear their caretakers have of them. We see this a lot in our work. The Insect Zoo of our Department at the University of Maryland (UMD) is a very popular attraction at outreach events such as UMD’s open house event, Maryland Day. When participating in this event, we see time and time again how kids are not afraid of petting insects or other arthropods, while their parents are grunting and screaming in the background at the simple sight of one. Dealing with this learned fear is a bit trickier because it requires caretakers to become more aware of how they can imprint fear in kids. However, seeking to better understand and recognize insects and their potential (or not) of harm can help break this cycle. Rearing with kids insects like butterflies can be a great positive experience for all, and can happen in pretty much any house. Engaging in learning activities with kids, such as through insect summer camps (UMD has a super-fun Bug Camp!), is another way to restrict the establishment of this type of fear.

a women holds a spider in front of a boy at the insect petting zoo
Petting zoos and other exhibits that feature insects and other arthropods can be a great way to engage kids and adults in healthy and safe interactions with organisms they may fear. Photo: UMD Department of Entomology.

Finally, there is another way this fear may appear. We said above that this sort of fear is more common in urbanized societies. It is thought that a part of the fear may come from a lack of exposure to biodiversity. Under urbanization, there is indeed a removal of contact with natural environments, with people becoming less and less exposed to wildlife. When insects are seen (often in the house), the other two types of fears may pop up and join forces to, on the one hand, trigger repulsion or fear and, on the other, increase avoidance of natural spaces that could contain “bugs.” The good news is that even in cases when there are few natural spaces available close to home, there are indeed many ways people can be exposed and establish positive experiences with insects. Visiting exhibits where insects are featured is one of these ways. You can learn about many other ways in this cool article: Teaching About Insects in a World Afraid of Bugs.

By Anahí Espíndola, Associate 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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Community Partnerships for Pollinators

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When we talk about pollinators and how to help them, we have often focused on what plants can support them, who the pollinators are and some traits of their natural histories, or how to create habitat for them. However, besides individual actions that people can take to help them, other options that are very impactful also exist. In today’s post, I want to present one that involves a combination of community and institutional collaboration: the Bee City and Bee Campus USA certification.

What are Bee City and Bee Campus USA?

The certifications called Bee City and Bee Campus USA are labels that cities and campuses, respectively, can receive from the Xerces Society if they commit and act to protect pollinators and their habitats.

For those who have never heard of it, the Xerces Society is an organization interested in the conservation of invertebrates and their habitats. Over the years, it has not only become recognized as an important conservation organization but also has developed impactful and meaningful ways to support research on the topic and engage the population and institutions (and many other stakeholders!) in conservation actions that are within their reach. The Bee City and Bee Campus certification is one of those initiatives.

How does it work?

Once cities and campuses decide to receive the certification, they need to submit an application and pay an annual fee. By doing this, they commit to taking specific actions that will lead to the conservation of the thousands of species of bees and other pollinators that exist in the USA, as well as their habitats. The certification is revised every year, and if the institution or city is not performing following the set standards, the certification is not renewed. Today, many institutions and cities across the USA have joined the initiative and are actively following their commitments. If you are interested in knowing if your community is a part of the initiative, an online database exists where it is very easy to search for participating members using addresses or names.

The Bee City and Bee Campus USA website has a neat tool to search for current members across the USA.

The commitments that institutions and cities make when they join the initiative involve the establishment and promotion of specific actions. These actions combine institutional and community involvement, which requires the creation of an active committee that will be responsible for running programs that will help the institution reach its goals. Once this committee is created, the group is responsible for proposing and running actions within the reach of the institution. The actions need to be oriented towards promoting the protection of pollinators and their habitats through what can be generally categorized under education, direct action, community involvement, and potential revision of standard operating procedures or policies.

The Xerces Society doesn’t just provide a certification. In fact, it has over the years produced a massive number of tools that help cities or institutions understand how to run the programs. Regular webinars are organized, fact sheets distributed, general manuals and other documentation shared, and a network of participating cities established, allowing for a “hive mind” to develop.

What can some of these actions be?

Education programs involve the distribution of information among the population (for cities) or members of the campus (for campuses). This information can take many different forms but generally educates about the diversity of pollinators, the importance of promoting habitat, the key contributions of pollinators to the well-being of the community and the environment, ways to protect them through individual or joint actions, creating information guides and fact sheets, and more.

Direct actions often require involvement of the institution in establishing habitat for pollinators, distributing resources that will allow the community to protect pollinators (e.g., distributing plants, seeds, other habitat resources), actively reducing the use of pesticides, etc.

Community involvement is promoted by any program that the institution could build to allow its members to come together and engage in projects larger than any individual would be able to take on by themselves. There are many ways this can be done, but some examples are the creation of student-faculty groups that could run research projects that can then be used to inform policies and conservation actions. Others could be the establishment and promotion of institution-wide actions, such as the promotion of months with no or reduced mowing (e.g., “No-Mow Month” initiatives), the running of citizen science projects (e.g., through iNaturalist), establishing days centered around the celebration and recognition of pollinators and their services to humans and the environment (e.g., coordinating Pollinator Week activities), and others.

Finally, one of the unique reaches of this initiative is its ability to promote changes of policies and procedures regularly used by the institution/city. Under this program, the committee should propose and the city or campus implement at least some adjustments in the way the institution in question is run. For example, Integrated Pest Management (IPM) plans should be created and used if they are not already in practice, Code can be adjusted to facilitate the planting of native plants, monetary or other incentives can be offered for the creation of pollinator habitat, and more.

I would like to have my city/campus join; what do I do?

If you’re interested in having your campus or city join the initiative, first go to the Bee City/Campus website and check out the requirements and some of the how-to webinars. Along with this, for cities, you may want to get in touch with representatives and present this as a request. If you’re on a campus, get a diverse group of members together and propose this to leadership. If you still feel overwhelmed by this and feel you still have a lot of questions, reach out to Bee Cities or Bee Campuses in your area and ask them for help! They will be more than happy to explain what their path was and how they came to be, so you can also become part of the national initiative.

By Anahí Espíndola, Associate 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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Heat Waves Affect Pollination Too

Maryland Grows2 Comments

Having grown up in the plains of Argentina, surrounded by large rivers, swamps, hot summers and humidity, I can attest that I am pretty “heat tolerant.” While others complain of the heat, I just enjoy the “embrace” that a hot day gives me. The heat in the last few weeks, however, was even too hot for me! And while I was trying to cool down, I was also worrying about what I was seeing outside: the plants, the insects, the soil… all suffering like me. And because I happen to work on some of these topics, I also knew that it wasn’t just that some plants were drying out; this heat wave (and drought) is also affecting the whole network of interactions that happen around us. So, today let me tell you a bit about how these extreme heat waves affect one of those interactions – pollination – and how what we do in our green spaces can help reduce some of those effects to the benefit of all.

Pollination is affected by heat in more ways than we usually think

Extreme heat waves and droughts such as those we have been experiencing recently affect not only us but also the ecosystems that are exposed to the heat. One of the most evident effects we may see is how much plants suffer. Just look outside and you will see hanging leaves, tiny flowers (if any), and a lot of dry material. As with all organisms, plants also have optimal temperatures at which they can survive; if the temperatures and water availability change, important body functions will not be able to be performed, and even some central parts of their bodies will fail.

In plants, one of those functions is photosynthesis, the process by which plants can make sugar using the energy of the sun, carbon dioxide (CO2), and water. This process is the way the vast majority of plants make their food. If the process is disturbed, the plant will have less energy available to survive, grow, and reproduce. It turns out that extreme heat and water needs affect the ability of plants to photosynthesize. The consequence of this is that, suddenly, the plant has less energy available, needing to enter a sort of “survival mode.” Along with this, the heat affects several protection systems that the plant has, especially those that protect the DNA (the genetic material), as well as the functioning of the machinery that literally “builds” the different parts of the plant. This inefficient protection leads to the DNA being damaged and the plant being poorly “built”, making that part or the whole plant start malforming.

plants with browing stems due to drought
During the heat waves, these beebalm plants had a rough time, with almost no flowers produced and a lot of the plant material simply drying out. Photo: A. Espíndola

In relation to pollination, we know that these changes explain why, under heat and water stress, plants become smaller in size, have tiny or no flowers, lose a lot of leaves and biomass in general, and have parts that start to look “funky.” The changes in the energy availability make the composition of some secretions change as well, such as with nectar, which tends to be less rich in sugars and less abundant (especially when drought is experienced).

a plant with smaller than usual yellow flowers
These black-eyed Susans were able to make flowers this year, but they are significantly smaller than usual! Photo: A. Espíndola

As said before, flowers tend to be small or absent, but even when they are present, the petals and reproductive organs are often misshapen, with the plant becoming unable to produce seeds and fruits. Finally, and super importantly for pollination, a major effect of this is that heat affects pollen quality, reducing the amount that is produced and often making the pollen inviable… meaning that even if the pollen was to land on a stigma, it would likely not germinate, and fertilization would not take place. This latter point is worrisome because it means that even plants that are not animal-pollinated (e.g., plants pollinated by wind or water) will be unable to produce seeds and fruits. 😱

Pollinators suffer the heat, and that affects their survival and pollination

Pollinating insects are also affected by the heat, and some of these effects are related to the same facts we mentioned for plants. On the one hand, like plants, pollinators also have their own DNA and “body-building” machinery that is disturbed by heat. Some of the major consequences of this are that their development can be either interrupted (the larvae or pupae die off) or interfered with. If the development is interfered with, we see malformations in different organs, such as the wings, legs and mouth parts, and particularly in males, of reproductive organs and sperm. Further, extreme heat appears to affect bee neurological abilities, with their behaviors and memory affected, as well as changes in the way they visit and manipulate flowers, which in turn makes pollination more difficult.

Along with these issues, because of the changes in nectar quality and quantity associated with plant heat stress that we mentioned earlier, the pollinators’ nutrition is also negatively impacted, which further amplifies the developmental, behavioral, and neurological problems mentioned above. Although all insects experience these types of effects when they are exposed to excessive heat, some of them are a bit better at protecting themselves from it. For example, it seems that social bees suffer less from excessive heat than solitary bees, while bees that nest in the ground or in stems tolerate it better than those that nest in cavities.

Here’s what you can do to help mitigate the effects of heat and drought

Although we can’t instantaneously reduce the heat, we can assist plants and insects to better tolerate these conditions. A very effective strategy is diversifying our green spaces, which can lead to local reductions of heat, either through the shade created by the plants and/or the reduction of the excessive presence of bare soil. In particular, this same plant diversification can also increase the amount and quality of foods available to pollinators during these heat events: more diverse plants mean more different types of possible nectar sources available to pollinators, which in turn would increase their chances of survival and boost their health.

If possible, one can also water plants in our green spaces. By doing this, the water stress will be reduced and at least part of the symptoms displayed by plants will also be mitigated. If one were to do this, it is important to water with a slow flow and for a longer period of time, so the water can properly enter the soil. Along with this, using mulch or letting the fallen leaves cover the ground will also help retain some of the soil humidity, all while also providing shelter to insects.

And besides diversifying and supporting our green spaces, it is thoroughly accepted that the current extreme heat and drought events we are seeing are a consequence of climate change. Starting to reduce our and our communities’ emissions is another way to help plants and pollinators, pollination, and at the end of the day, the production of many of the foods we depend on. You can check out this awesome website by Dr. Sara Via and learn about what we can all do, and even sign up for super informative seminars that help you become familiar with and start acting on some of these topics.

By Anahí Espíndola, Associate 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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!


Support Our Insects at Night

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We tend to think about protecting our insects when and where we see them. This is perhaps why we may have a higher propensity to think about protecting pollinators we can see flying around rather than organisms that live in the darkness of the soil or hidden in the leaf litter. In today’s post, I would like to bring some attention to other groups of insects we may tend to forget about but which we can also help protect: insects that are active at night.

Don’t insects sleep at night?

Although many insects are generally less active at night due to the lower temperatures and their inability to move when the temperatures drop below a certain threshold, many insects are adapted to being active at night. For example, if they are pollinators of nocturnal or dusk-flowering plants such as several moth species are, they will be active when darkness falls. Other insects are active at night as predators, or at certain times of the season looking for mates and egg-laying sites. For all these insects, the absence or reduced presence of light is important for allowing them to take on what they need to do to survive and/or reproduce. For this reason, the presence of artificial night lighting in our outdoor spaces, especially in the warmer periods of the season, can interfere with these insects, leading to potentially very negative effects.

How can outdoor night lighting affect nocturnal insects?

Insects can be perturbed in different ways through outdoor night lighting. One of them is its potential interference with their temporal rhythms. In fact, like most animals, insects use light-darkness and the presence of certain night sky cues (e.g., full moon) to regulate their developmental cycles and perceive the progression of the season. The presence of supplementary lights during the night hours can lead to altered developmental cycles, making them longer or mismatching those of organisms belonging to the same species. This can lead to the insects missing their optimal mating times, losing their ability to forage on specific plants, or properly preparing for the arrival of colder nights as the season progresses.

a string of lights is hanging over a a garden firepit area at night
The use of often non-essential lighting, such as light strings and other nocturnal accent lights in our spaces, can negatively affect the development, survival, and reproduction of many nocturnal insects. Photo: P. Danilyuk (CC)

Another issue that artificial nocturnal light can produce relates to the spatial disorientation of nocturnal insects. This can occur when insects are attracted to nocturnal light sources instead of moving towards their optimal habitat. This can lead to increased predation in those areas (the insects become more exposed to being seen), as well as their spending valuable energy by spending time in an inhospitable region. Further, disorientation can happen in a more indirect way by the light’s interference with the patterns present in the canopy. In fact, many insects have been shown to use the contrast pattern of the canopy and the sky to navigate and identify optimal habitats. The presence of nocturnal artificial lights can lead to the disappearance or a stark modification of that contrasting pattern, interfering with their ability to find their way in the ecosystem and decreasing their ability to find a proper habitat for their survival.

two fireflies light up at night
Some insects like fireflies use bioluminescence for inter-species recognition and mating. Photo: T. Ota (CC)

In some cases, the presence of nocturnal artificial light can interfere with mating and intraspecific recognition behaviors. Many groups of insects, such as fireflies and glow worms, use light cues to attract and recognize each other. In regions such as ours, where fireflies represent such an important part of our ecosystem, the use of outdoor nocturnal artificial lighting can interfere with the finding of mates and can potentially lead to much reduced abilities to reproduce and sustain populations.

What can we do to reduce this type of nocturnal pollution?

The obvious answer to this question is that if we want to reduce this type of pollution, our best bet is to turn off non-essential outdoor night lights, in particular during times of the year when insects are active. Doing this may actually save us some money, but also will allow us to support a higher diversity in our area, all while potentially letting us appreciate even more the nocturnal activity that may be present in our region. For example, doing this may make it easier to support fireflies and participate in their conservation, but can also support the reproduction of plant species that depend on nocturnal pollinators.

If leaving lights on is unavoidable, one should consider the intensity that is being used. Can the light be dimmed to a lower intensity? Could it be filtered to display a color that is less disruptive to insects? The Xerces Society has put together a really neat guide on this (Firefly-Friendly Lighting Practices – PDF), and I strongly encourage you to consult it if interested.

Finally, another way we can contribute to reducing unnecessary night lighting is by engaging in our communities. Initiatives such as DarkSky can help with this, both promoting best practices at the community level and engaging in conservation through community certification programs that are conservation-effective. You can learn more about these nocturnal conservation programs here.

By Anahí Espíndola, Associate 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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

The Shared History of Wasps and Bees, And How Bees May Have Become Vegetarian

Maryland Grows3 Comments

We may have all found ourselves in that situation in which we see an insect on a flower and we wonder whether it is a wasp or a bee, and we may have also seen people panic when they encounter a bee, thinking that it is indeed a wasp. Although the two groups are very distinct and there are several ways of telling them apart (check out this previous post to see how to do it), this difficulty is in part a signature of the shared evolutionary history that the two groups have. In today’s post, I want to tell you about the evolutionary origin of bees, how it is interwoven with that of wasps, and how evolutionary studies can help us understand and explain the diversity of our charismatic bees.

Evolutionary histories and the big family we are all part of

Before jumping into the main topic of this blog, please bear with me so I can give you a bit of context for what I’ll tell you, and so you can fully appreciate the power of the discoveries I will tell you about in just a second. One of the foundations of today’s biology and the way we understand life is that living organisms share a common ancestry and that evolutionary processes such as natural selection, mutations, dispersal, and random processes have led to the establishment of new lineages that can evolve into new species and new groups of organisms. What this means is that all the living organisms we know can be placed in a sort of genealogical tree, where more closely related species and groups appear placed on branches of the trees that are also closer to each other (we call these trees “phylogenies” or “phylogenetic trees”). Also, this means that if we were to take these trees, and we were to follow the evolutionary process “backward” (from the tips to the internal branches; that is, from the present into the past), we would be able to identify branching points, which represent the now extinct ancestors of species we know today.

a diagram of a family tree
A phylogeny can be compared to a genealogical tree we may want to build for our family. In this tree, the most closely related members of our family share recent ancestors (marked with diamonds), but are still connected with more distantly related members of the family with longer branches and other more ancient shared ancestors. In the same way, a phylogeny represents the relationships between species or groups of species, with branches connected by their shared ancestors. Image: University of Iowa

Although this may sound like a biological nerd moment of mine, I hope that you will appreciate the enormity of this principle. This simple concept indicates that each of us and all species that exist on the planet have shared ancestors at some point in our history. We are all related to each other, like a huge family… and as for all families, the study of our history can teach us fun and interesting things about who we are, helping us understand and explain things we observe today. Let me tell you what the study of these phylogenies has taught us about wasps and bees (and their shared history) and why this excuses us in part from not always being able to tell them apart 😉.

Bees and wasps, and the vegetarian wasp

As you may know, bees and wasps are both insects that belong to the order Hymenoptera. Despite the fact that people knew they were related but distinct from each other, it was not until relatively recently that people understood what that relationship was. In fact, because they share a lot of common traits, scientists were for a long time confused about what the most closely related group of Hymenoptera was for bees, wasps, and ants. Some years ago, with the development of new methods that allow for more detailed studies of phylogenies, researchers found strong evidence that ants are a group of organisms that is related but distinct from another group formed by bees and by a particular group of solitary and usually ground-nesting wasps called crabronids. Besides the taxonomic and purely conceptual importance of this discovery, what this meant biologically was on the one hand, that bees are evolutionarily extremely closely related to wasps, to the point that we could consider them “non-carnivorous wasps”. On the other hand, this discovery showed that all bees we know today would have evolved from a wasp-like ancestor that was solitary and ground-nesting, like the crabronids we know today.

a family tree of bees and wasps - showing evolutionary relationships
In 2017, Branstetter and collaborators used phylogenies to demonstrate that all bees and a group of wasps (crabronids) shared a common ancestry, indicating that bees can be considered a type of “vegetarian” wasp. In the figure, the position of the common ancestors is shown with arrows and stars. The main groups are labeled on the left. Image: modified from Branstetter et al., 2017

If you’re like me and find this fun, keep reading because it gets even more fun! 😊 So, after this discovery, the people who work on these topics wanted to know more. For example, can phylogenies tell us more about how the transition from a meat-based diet (wasps are carnivores) to a pollen-based one (bees feed mostly on pollen and nectar) could have happened? To investigate this, researchers ran a similar analysis, but this time considering a lot more species of both bees and crabronids. Constructing phylogenies using genetic information, they figured that when the evolutionary relationships of these groups were studied, it appeared that bees were the most closely related to a particular group of crabronids that is known to predate on thrips (a family called Ammoplanidae).

a closeup of a small black bee
Bees have been shown to be very closely related to a group of tiny wasps in the family Ammoplanidae which are known to hunt on thrips. Photo: CBG Photography Group (CC).

Besides confirming the discoveries of the previous study, this one provided a logical and interesting biological and ecological context for the transition from carnivory to pollinivory in bees. Thrips are a group of insects known to feed on plant materials, often found on flowers, where they feed on pollen. This new study proposed that a possible evolutionary opportunity may have appeared when a lineage of thrip-predating wasps evolved the ability to not only digest thrips meat but also the pollen they contained in their guts (!!). This transition could have set the evolutionary foundations to eventually transition to a diet fully based on pollen, which opened opportunities to the newly emerging lineage to feed on a new dietary resource not already in use by other wasps. If this is true, this transition would have provided an important evolutionary advantage (e.g., reduced competition for food), which would have led to the huge diversification of bees, leading to the extreme diversity we see today.

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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Research Update from the Serpentine Grasslands: Pollinators in a Rare and Endangered Habitat

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Did you know that before European colonization and thanks to native land management, the area that is now northern Maryland was home to thousands of acres of sprawling prairie-like grasslands? It’s a pretty cool thing to imagine, right? Instead of dense urban centers, highways, farms, and patches of forest, most of Baltimore County would’ve been a nearly treeless ocean of swaying grasses and wildflowers! Instead of cars, shopping carts, and the hustle and bustle of people, you’d see majestic herds of deer and elk, a horizon dotted with flocks of birds, and the busyness of bees and butterflies. You can read more in a previous blog post about these eastern ‘Serpentine Grasslands’. Sadly, these grasslands no longer exist in the formerly massive extent they used to occupy, but several preserved remnants still endure here in Maryland to tell the tale of their former glory!

a view of the Maryland Serpentine Grasslands on a cloudy day
A stormy summer evening at Soldiers Delight Natural Environment Area, Baltimore Co. – one of Maryland’s Serpentine preservation areas. Photo: Justin O’Neill

What is the current status of the Maryland Serpentine Grasslands?

Many historic and contemporary human-driven environmental changes have caused these special ecosystems to dwindle to the point of concern; it is currently estimated that only 1.6% of their historic area in the region remains. This precipitous decline of eastern Serpentine Grasslands is concerning because they support many special plant species that are considered threatened or rare in Maryland. Luckily, several private and governmental organizations have taken to conserving and studying these ecosystems in Maryland and elsewhere (check out some of them here: Soldiers Delight and Lake Roland). Although eastern Serpentine grasslands have attracted considerable scientific research interest in terms of their rare and unique plant life, the animals that call these critically imperiled habitats home are virtually undocumented (with the exception of some rare butterflies and moths). Could there be special Serpentine associated species that we have yet to even notice?

a purple wildflower found in the Maryland Serpenine Grasslands
Phemeranthus teretifolius, the Quill Fameflower, is one of the special plants that makes its home on the dry and rocky soils of Serpentine habitats. The flower is only open during a few short hours in the afternoon, during which it is abuzz with small solitary bees. Photo: Justin O’Neill

The mission of knowing what lives there to better protect it

To address this knowledge gap, our team at the EspíndoLab, have set out to start documenting the insects present in Maryland’s Serpentine Grasslands. Our current focus is on flower-visiting insects that could act as pollinators, specifically bees and hoverflies. Given the many rare and threatened plants documented in these areas, we figured it was important to first know what insects might be helping most with Serpentine plant reproduction. 

How do we do this?

To document these flower-visiting insects, the lab crew has undertaken 5 years (2019 – 2023) of observations and insect collection in three of Maryland’s most intact Serpentine Grassland conservation areas. Because different flowers bloom during different parts of the growing season (spring to fall), we had to visit these conservation areas many times each year to observe the full range of flowering plants and their insect visitors. So, once every two to three weeks across each season, the Serpentine squad would head out to visit our many field study sites and systematically capture bees and hoverflies seen interacting with flowers. Currently, we are working on the meticulous process of examining each captured specimen with a microscope to determine its species identity using taxonomic guides.

a student researcher collecting insects at the Maryland Serpentine Grasslands
Nets at the ready! The Serpentine squad carefully captures bees and hoverflies seen visiting flowers at several study sites across three of Maryland’s Serpentine conservation areas. Photo: Justin O’Neill

With this information we can begin to catalog the insect species that make up Serpentine pollination communities. This allows us to explore if the communities present in the Serpentines are different from those in nearby habitats and if they possess any rare or unique species. This information will also give us insight on how the plant and pollinator communities interact with one another; informing us about key species that contribute vitally to pollinator persistence or plant reproduction. Ultimately, the knowledge we gain will provide a baseline understanding about the dynamics of pollinator diversity in the grasslands and inform the organizations that conserve and restore these ecosystems.

What are we learning?

So far, the EspíndoLab’s efforts in the grasslands have revealed quite a bit about the broad array of insects that visit these unique plant communities. Notably, among the myriad of beetles, butterflies, flies, and wasps that visit Serpentine flowers, native solitary bees and hoverflies are consistently observed to be the most abundant – and perhaps most important potential pollinators. Interestingly, social bee species, particularly honey bees, that are commonly observed in many pollination communities, were infrequently encountered in our collecting efforts until late in the season, if it all. This suggests that they may pass on the relatively sparse floral resources of the grasslands until the Fall, when dense and attractive patches of goldenrod and aster bloom – potentially providing them an important source of resources as pickings become slim late in the season.

Most excitingly, our collections have revealed 39 unique genera of bees and hoverflies in the grasslands, so far – with more likely to be found as we continue to identify the many insects from our collections. Our efforts have also found several rare bee and hoverfly species; some of which are insects that have never been observed in Baltimore County! Among these rare and interesting finds are two bees and a hoverfly that are particularly special.

The hoverfly, Trichopsomyia litoralis, is relatively new to science – having only been described in 2019. Not much is known about the ecology of this species, but its larvae are known to feed on economically important pests. Encountering this species in the Serpentine grasslands is interesting not only because it is rarely observed, but also because it is currently thought to only inhabit an eastern coastal range (likely associated with sandy sites)! This information could extend our understanding of this hoverfly’s distribution or suggest that these flies undertake long migrations during their life cycle.

On the other hand, we have found two rare bee species that are really cool: the mining bee, Andrena gardineri; and the nomad bee Nomada seneciophila. These bees are what we call specialists: they have very specific ecological requirements. For example, A. gardineri is known to preferentially forage for pollen on plants from the genus Packera (ragworts or groundsels) – it is considered a Packera specialist. Even though A. gardineri is quite rare in the region, we find it commonly during our spring grassland collections. This is because almost all the conserved grassland areas provide good conditions to host lots of Packera anonyma.

close-up of the face of a bee found in the Maryland Serpentine Grasslands
A close-up shot of a fluffy male Andrena gardineri specimen. Photo: USGS Bee Monitoring Lab / Brooke Alexander. CC 2.0

The other notable bee we observed, the nomad bee, Nomada seneciophila is a vanishingly rare cuckoo bee (see here what these bees do and why this is fascinating). These bees wander (nomadically so) around in search of other bee’s nests so they can hijack them for their own young to develop in! N. seneciophila, as it turns out, is a specialist of our specialist friend, A. gardineri. That is, this nomad bee species has a very strong preference for stealing the nests of our other rare bee, A. gardineri!

another bee found in the Maryland Serpentine Grasslands
The waspy-looking Nomad bee: Nomada seneciophila. Photo: Justin O’Neill

From these interesting encounters, it is becoming increasingly clear that these grasslands not only support remarkable plants; they also provide critical resources and nesting habitat for rare bee and hoverfly species. Although these once expansive ecosystems might not exist on the grand scale they once did, their remnants are unique contributors to the region’s biodiversity. Taking the time to document their floristic and faunistic wonders is important for understanding the historic role they played in shaping regional biodiversity today, and how that biodiversity may respond to the changing environments of the future!

By Justin O’Neill, Ph.D. student, and Dr. Anahí Espíndola, Assistant Professor, EspíndoLab, Department of Entomology, University of Maryland, College Park.