With the huge losses of biodiversity that we are seeing across the world, a prominent example that became very close to people’s hearts is that of the large pollinator losses and the very important consequences that they could have on the well-being of our ecosystems and ourselves. In this context, a very large movement started seeking to “save the bees,” which has had a number of expected and unexpected consequences. One of the latter is the very significant increase in the adoption of honeybee hives by homeowners with little to no experience in honeybee husbandry, especially with the goal to “help bees” so they won’t go extinct. Although the goal of doing this is very genuine and well-intentioned, there are a number of complexities that come with this decision, which I would like to talk about in this post.
Are the bees dying?
The short answer is yes… kind of. Let me explain. As we mentioned in previous posts, there exists a very large diversity of bees (for example, only in Maryland there are about 400 native bee species!), and it is very clear that trends in biodiversity are negative for bees, as for many other groups of insects, plants and other animals. From that respect, we can say that many native bees are indeed dying, and it is key that actions are taken to provide more healthy habitat for them to survive.
That said, it is important to understand that honeybees are actually non-native livestock in our region (the group of bees that honeybees belong to are native to Eurasia and Africa, not to North America). Honeybees are managed and non-native insects that are reared by beekeepers to produce honey and other materials (e.g., wax, propolis). In places where honeybees are native, local peoples have been using their materials for generations, and in those regions, honeybees have not only been important from a production perspective, but also from a cultural one (read here to learn a bit more about some of these traditional systems).
As for all livestock, honeybees have health issues that need to be treated if they occur. For example, honeybees suffer from serious parasite and viral infections, appear to be negatively affected by certain pesticides applied to the plants they collect pollen and nectar from, and seem to also be affected by environmental stressors such as changes in the diversity of the landscape and the quality of the plants they feed on. All of this increases the real potential to reduce the health of colonies and, if left untreated, decimate them.
Again, the short answer is probably not. As I was saying above, honeybees are non-native to our region, so increasing their populations (for example, by increasing the number of hives) in our region is not likely to positively affect our suffering native species. For example, it has been shown in some studies that honeybees can be pretty competitive in the way they visit plants, displacing native species. Further, and especially if the honeybees are not properly managed (which is, unfortunately, the case for many new unexperienced beekeepers), they can become sick and spread diseases to native bees and other insects, also leading to increasing the pressures on these already-struggling native organisms.
For some reason, I feel that every time I think about what to plant for pollinators, the list of plants that comes to me is one full of herbaceous ones… however, it is odd that this is the case, because it’s not like our region lacks larger plants (e.g., trees, large shrubs) that are both fully able to support pollinators while also supporting other biodiversity and even contributing to flood and rain management! And because if we’re interested in going the large(r)-plant path, we need a bit of planning, in today’s post I would like to present some native shrubs and trees that are great resources for our pollinators. This way, you can start planning where to get them for planting in late winter to early spring.
Why consider trees and shrubs for pollinators?
Large perennial plants such as trees and shrubs have many characteristics that make them very attractive to any pollinator-friendly person in our region. Indeed, while there are many of these plants that act as wonderful food resources for many pollinators (both adult and larval stages), these larger plants represent long(er)-term and abundant resources that can serve different aspects of our ecosystem: they provide shelter and food for birds, they can assist in managing stormwater runoff, retain soil, reduce surface temperatures by their shading abilities, and provide structural complexity to our landscapes. Trees especially are a key component of creating climate-resilient landscapes. In fact, one of Maryland’s climate change mitigation goals is to grow 5 million more trees by 2031!
Planting trees is not necessarily expensive
From a financial perspective, although these plants may be costlier to obtain than the smaller herbaceous ones, there is a multitude of incentives, state vouchers, and programs that strongly reduce or sometimes completely cover the costs of obtaining them. In Maryland, for example, the state provides incentives through the Maryland Department of Natural Resources (discounts to be used at nurseries; all details here), the PG County Rain Check program or the TreeMontgomery program, city incentives, and free tree plantings (e.g., see College Park’s here). In all of these programs, a lot of trees native to our region are covered. If you would like to participate in any of these programs, make sure to check the specific tree lists covered by each (also, see this list of recommended native trees for the state of Maryland). Note that these programs I mentioned here are just a few of the many that exist; if you’re interested in this, make sure to check your city, county, and state resources!
What to plant?
I hope by now I have at least made you curious about the idea of choosing trees and shrubs for pollinators. Below, I made a very small selection of a couple of plants that appear in the native lists, and that are great for pollinators. Let’s take a look at them.
Tulip tree (Liriodendron tulipifera)
Tulip trees are a great native plant that can serve as a great pollinator resource. This tree is in the same family as Magnolia trees. It can reach a large size and it displays stunning yellow and orange flowers. This tree grows fast and is large (considered the tallest native tree in the eastern USA, along with sweetgums), so it can be a good choice for large spaces where a canopy is wanted relatively quickly. The flowers produce a lot of nectar, which attracts a massive number of pollinators. This makes it kind of fun to stand under the tree on warmer days during the blooming time: the buzzing coming from the tree is pretty impressive. Here are some more details on the conditions preferred by this tree.
Tulip trees are among the tallest trees in the eastern USA and have wonderful resources for pollinators that they carry in their stunning flowers. Photo: W. Cutler CC.
American linden or basswood (Tilia Americana)
This tree can reach relatively large sizes, and when it grows to full size it has a very rounded canopy. I personally love this tree, because of the fact that I feel it’s a “social” tree: one can sit with friends under its shade on hot summer days, and just enjoy the life it hosts and the cool breeze it forms under it. Once the season is coming to an end, this tree’s leaves turn a lovely yellow. The flowers of this tree are small and not very colorful, but they are extremely fragrant and full of nectar, which makes them a great magnet for pollinators. You can learn more about the requirements of this tree at Virginia Tech Dendrology.
The American linden has discrete flowers that are very attractive to pollinators. Photo: A. Zharkikh CC.
Hawthorns (Crataegus phaenopyrum and C. viridis)
These are mid-size trees that also sustain a variety of fauna through their flowers, fruits, and bird nest-friendly thorny branches. Their flowers are white, have a typical Rose-family structure (like those of cherry trees), and are attractive to bees, syrphids, butterflies, and hummingbirds. Besides being great for fauna, the two species do well in urban environments, because they both tolerate a wide variety of conditions. Here at pollenlibrary.com and on the Lady Bird Johnson Wildlife Center website you can learn more about each of these species.
Hawthorns have lovely white flower clusters. Photo: F. D. Richards CC.
Fringe tree (Chionanthus virginicus)
This small tree/tall shrub is a great addition to green spaces, and is ideal for hedgerows or just as a stand-alone plant. I am always surprised by the super cool shape of the flowers of this plant, which have very elongated petals that create long white fringes. These flowers attract bees and other pollinators, which come to collect some of the nectar that is produced. This plant is usually dioecious, meaning that one individual plant harbors either male or female flowers, but rarely both. This plant is ideal for areas that receive a lot of sun, because it is under those conditions that it will do best (although it can do fine in less-sunny areas as well). You can learn more about this plant by visiting this website.
The whimsical flowers of fringe trees are not just attractive to us, but also to many pollinators! Photo: 阿橋 HQ CC.
Serviceberry (Amelanchier laevis)
Although all of them can provide very good resources for pollinators, I picked this one to showcase because this species grows relatively fast and does not get too large. This is indeed a larger shrub that has beautiful white flowers, and later on, delicious small berries. Because of all this good stuff, the flowers are visited by many insects, and the fruits are favorites of birds (so you’ll have to win over them if you want to get at the fruits! 😉 ). Here and on the University of Maryland Extension website, you can learn a bit more about this cool plant.
Serviceberries make everybody happy: pollinators in the spring with their flowers, and birds and humans in the summer with their berries! Photo: Henna K. CC.
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!
Even when they look dry and “dead,” our green spaces are full of life. When we think about plants, for example, we can see that herbaceous perennials seem dry but they are actually just retreating underground, while annuals continue their life cycle by spending the winter as seeds in the ground. The same is true for other organisms that live in our green spaces: squirrels become less active, snakes retreat to sheltered spaces, and insects may overwinter as adults underground or in crevasses or as juveniles in their nests or chrysalises. Among these insects, there is a particular group that we seem to take a lot of effort to protect in season, but that we may then forget about in the fall and winter: our pollinators. In today’s post, I would like to talk about some specific ways that allow us to take care of our green spaces in the fall, all while continuing to support these organisms we worked so hard to support throughout the growing season.
Where are our pollinators in the winter?
As we mentioned in a previous post, pollinators don’t disappear in the winter. Instead, they either migrate to warmer conditions (like monarchs do; check out this website to know where they are now!) or stick around and overwinter right here in protected spaces such as crevasses, underground nests, and within plant stems. If we have been enjoying supporting them throughout the season, it may be a good idea to continue to do so also throughout the winter. Let’s see some ways to do this.
Although we may love them with all our hearts, it is true that every one of our most beloved friends and family have sides that at times make us mad… and that’s no reason for us to love them less. I feel our relationship with pollinators and other beneficial insects is similar to that which we have with our loved ones: pollinators pollinate and play an important role in native plant reproduction and food production… and sometimes can become a nuisance if not properly managed. As for our loved ones, the fact that pollinators can become a nuisance shouldn’t stop us from supporting them; we just need to learn how to sustain our relationship while controlling its negative aspects. In today’s post we’ll talk about one pollinator in particular, with which our relationship can sometimes become complicated. Let’s talk about carpenter bees.
What are carpenter bees?
In our area, carpenter bees are large bees belonging to the bee genus Xylocopa. If you enjoy being outdoors, I am pretty sure you have already seen them. A very common species in our region is the eastern carpenter bee, which is about the size of a bumblebee, has a “dot” on its back and dark wings, and when exposed to the sun, has a shiny abdomen. These bees are very common in our area, and are very regular floral visitors of many ornamental and food-producing plants.
The eastern carpenter bee (left), a native to the mid-Atlantic, has a shiny abdomen, while bumblebees (right) have fuzzy and hairy abdomens. Photos: J. Gallagher, Wikimedia: R. Hodnett.
Because they are about the same size as bumblebees, carpenter bees are often confused with them. To differentiate them, a look at their abdomen will quickly allow us to know who’s who; carpenter bees have shiny abdomens, while bumblebees have very fuzzy and hairy abdomens.
The life cycle of a carpenter bees
It’s not random that carpenter bees are called that way. Their life cycle is tightly linked to wood, in which females dig holes to build their nests. Carpenter bees have impressive mandibles that they can use to chew soft wood to dig galleries in it. Although they may seem impressive, these are peaceful bees that sting only if physically and aggressively disturbed. In the spring, males of these bees establish and defend their territories, a strategy that will win them a female to mate with. During this defense, they “chase away” other males but also people who may be close to what they consider their spaces. These males are harmless, however, since they have no stingers and thus can’t sting.
Life cycle of a carpenter bee. Photo: NC State Extension.
The life cycle of these bees goes hand-in-hand with the season. In the early spring the hibernating adults emerge, mate, and the females build their nests in the wood. These nests consist of galleries, at the end of which the females lay eggs and store food (nectar and pollen) for the developing larva. The larvae develop throughout the spring and summer, and by the end of the summer emerge as adults. These adults are the carpenter bees we usually see flying in the early fall. Once the weather starts becoming chillier, at the beginning of the winter, these adults return to some of the cavities and overwinter there, emerging the following spring, to restart the cycle.
Why can carpenter bees become a nuisance?
As we saw above, carpenter bees nest in wood. If a house or any structure is built of wood, they may pick it to build their nests. When this happens, these bees have the potential to affect the integrity of our wooden buildings. So, we see that while these bees are very important pollinators native to our region, this particular aspect is the one that can be problematic in our relationship with them. The good news is that there are solutions for this!
Carpenter bees nest in wood, which sometimes can be a part of human buildings. Knowing how to proactively protect wooden structures is the best way to manage this helpful native pollinator, while protecting our buildings. Photo: H. Jacoba.
If there are no nests yet in the wood
The best solution is of course not the reactive, but the proactive one. If we have important wood structures that we don’t want to see occupied by these bees, the best we can do is first to use hardwood (which these bees tend to dislike) and/or to treat the wood. The treatment consists in painting or varnishing the wood, which will deter the adults from nesting in it. A very good treatment is coating the wood with almond oil in the spring, which will deter the bees from choosing that section to nest.
Another proactive action that can be taken along with wood staining is to distract the bees from the wood that we want to protect. To do this, one can use pieces of wood that one may not be interested in keeping, and displaying them in other parts of the open spaces so that females choose to nest in those surfaces instead of in the wood we want to protect. Besides protecting the wood, this also allows us to support these important native pollinators from our region, all while reducing the potential negative impacts on our buildings.
If bees are already established in the wood
If carpenter bees are already established, there are several options. First, if the number of nests is really low, and if the structure can be removed and replaced, then this should be done and the new wood structure should be stained to protect it. If possible, the piece of wood that is removed can then be placed elsewhere in the green spaces around the property, which will provide nesting resources for this pollinator, and will simultaneously protect the house and support native pollinators.
Carpenter bees can sometimes establish many nests in structural materials. If this affects the integrity of the building, more extreme actions may be needed. Photo: JoeyZ51.
If the piece of wood can’t be removed and, in particular, if the nests appear to jeopardize the integrity of the building, a more radical action should be taken. In that case, the use of insecticides can be considered. If this path is taken, it is important to not perform insecticide applications without proper knowledge, meaning that this should be done by an expert applicator. This point is really important, because non-targeted and improper insecticide treatments can lead to a lower efficiency of the treatment on the carpenter bees, and the death of other non-target beneficial insects (e.g., other bees, beneficial pest control insects, etc.) that may become in contact with the treated region.
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!
With the fall very clearly upon us, we tend to think more about falling leaves than flowers. Indeed, the big flower boom is ending, with all early-season flowers well past flowering. However, fall is a very important season for many pollinators, which still require food and shelter in preparation for the winter. In this blog, I would like to take a little bit of time to go over the importance of fall resources for pollinators, and what you can do to make sure they are available in your green spaces.
Why is fall special in nature?
The end of summer/fall is a special time for many organisms in our temperate regions. This is usually the last chance these organisms have to gather energy and resources to get ready for the winter. In the case of pollinators that are active during this period, the fall is key for collecting sufficient pollen (=food) for their nests, and for finding appropriate overwintering spaces for the adults and/or the offspring (take a look at this post to learn more about this), all of which will impact survival until the following year/season. If we want to help these pollinators, making sure that these resources are available is the best we can do!
Providing food for pollinators in the fall
Several native plants in our area flower in the fall and act as wonderful resources of pollen and nectar (and more!) for our late-summer/fall pollinators. These plants are easy to grow and once established provide abundant (nutritional) resources for our local insects.
Goldenrods
This group (Solidago spp.) consists of many species which flower in the late summer/fall. These plants are perennials that will create patches once established in an area. For this reason, they are easy to grow, although for this very same reason may usually require a bit of containment, since otherwise, they will easily spread everywhere. If the latter is a problem, plants can be grown in pots, where the containment issue is more easily resolved.
These plants support a large community of many different types of bees (many of which are specialists that can use only specific types of pollen and can be rare), as well as butterflies, flies, and wasps. In fact, more than any other herbaceous plant studied by Fowler/Droege, goldenrod (species in the genus Solidago) supported the most specialist bees (39 species). Importantly, because these plants create tall hollow stems, they can also act as nesting resources for stem-nesting bees. This way, these plants are great fall resources for many of our pollinators.
Goldenrods develop numerous flowers that provide support to a very large number and diversity of pollinators. In this picture, goldenrods stand out of a background of other yellow Asteraceae in a home garden. Photo: A. Espíndola
Two easy-to-grow species that one can find in several native nurseries are the tall goldenrod (Solidago altissima) and Canada goldenrod (Solidago canadensis). Both species have long stems that end with many yellow inflorescences. Both of them flower in the late summer and fall and can be easily grown in green spaces, especially drier sites that are exposed to the sun. As said before, although these plants are great pollinator magnets and resources, they tend to spread readily, so, unless that is wanted, they require some control once they start spreading in an area.
Asters
Asters are another group of plants native to our region that acts as a great pollinator resource in the fall. These plants are also perennials and can be small or become shrub-like, depending on the species. Unlike the goldenrods we were talking about just above, these plants tend to display a larger variety of floral coloration, with flowers going from white, to pink, and purple, depending on the species. Like goldenrods, these plants provide both food and nesting sites to many pollinators. Their flowers attract a very large variety of pollinators (bees, butterflies, flies, beetles, wasps) during a time when there is little else to feed on. The flowers of these plants are also known to support specialist and often rare bees, which depend strongly on its pollen for survival, as well as many butterflies, including Monarchs. Their stems are also great sites for stem-nesting bees. Finally, their leaves support the larvae of many local butterflies.
New England asters can be obtained from native plant nurseries and are able to support a very large diversity of pollinators, including rare and specialist bees, as well as adults and larvae of many butterflies. In this picture, we can see a Monarch adult feeding on the characteristic purple/blue flowers. Photo: Glenn Marsh
A lovely species that can be grown in our green spaces and provides hundreds of blue/purple flowers is the New England aster (Symphyotrichum novae-angliae). This perennial herbaceous plant can be obtained from nurseries and will grow three to six feet tall in the summer (but it can be cut back in mid-summer if you want to keep it shorter). The plant requires at least some sun and does well in a variety of soils we find in Maryland. I love watching the lovely cute flowers, and all the activity they attract. This is really one of my personal fall garden highlights!
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!
A Silver-spotted Skippper on wild bergamont flowers in Maryland, observed recently by iNaturalist user Andy Wilson
I have been writing blog posts for Maryland Grows on a regular basis for a while. To do this, I usually meet with Christa, the blog manager, every 6 months and plan on the topics I will cover over the next few months. When we do this, we seek to cover the needs we see from readers, but sometimes the topics come to us as a result of our discussions. This is exactly what happened for today’s topic. Today, let me tell you the story of how this came to be, and at the same time show you a great free tool available at our (literal) fingertips!
The story
Picture myself and Christa on Zoom, planning dates and topics for the next few months. It is February and it is cold outside. We have been making our way through the upcoming months, thinking of what each one will look and feel like, and what will be growing and buzzing around in each of them. August comes. How is August in Maryland? What do we usually see around? What issues are common in green spaces in August?
I think of August and in my very pollination-biologist-biased way start thinking of the pollinators we see in August… And what comes to me is “butterflies!” I remember writing about butterflies in the past, so maybe butterflies are a bit redundant as a blog topic. However, I don’t remember writing about a specific group of butterflies called “skippers,” which are common in Maryland. So, sure, let’s write about skippers, but what skippers are around in August? As we discuss and try to narrow down the topic, I open this incredible tool I use very regularly to learn about local species, report observations I make, and do research in my lab. This magical incredible tool is called iNaturalist.
So, there I am, opening iNaturalist’s website, and doing a quick search to find out the most common and most abundant skippers we find in Maryland in August. I am doing this, and Christa is intrigued; what am I doing? How am I figuring this out? I decide to share my screen to show her what I’m doing. Christa is amazed. You can do all that with iNaturalist?! The world needs to know! So, there we have it. Our blog topic showed itself to us. Today’s blog will be about what iNaturalist is, how to use it, and what type of information we can share with and learn from it. I hope that this blog will motivate you to start using it as well, and, like me, every time learn something new about species here and elsewhere in the world.
iNaturalist; ever heard of it?
We live in the times of social networks, like Twitter, Instagram, and Facebook… And as it turns out, social networks are really useful to science too! iNaturalist is one of those networks!
iNaturalist is a global social network that allows people to submit, find, and explore biodiversity observations from around the world. What does this mean? This means that through this network, every time a person observes an organism anywhere in the world, they can take a picture of it, upload it to iNaturalist, and then have the network help them identify what it is through its picture (using image recognition software), its location, its date, and the input of other members. This information is then stored in a public database, which can then be explored easily by anybody, including scientists, you, me, kids, conservation agencies, and more! At the end of the day and using all these data, the network can output maps and other information of any species ever added, allowing for the reported localities to be found, and, if the user wants to, visited to try to see the organism in question. Today, iNaturalist has over 5 million users worldwide, with over 109 billion observations of over 380,000 species!
OK. But how does iNaturalist work?
To explain this, let’s come back to my skippers story. I am talking to Christa and want to know what the most abundant skipper in Maryland may be, and whether it is present in August. To do this, I first go to the iNaturalist website (if on a computer; otherwise, I would open the app on my phone). This is what the page looks like.
The last full week of July is National Moth Week, and I encourage everyone to take a closer look at the vast diversity of moths that fill our natural world. Butterflies and moths belong to the same insect group, but moths far outnumber butterflies in species diversity. Since many moths have muted colors or fly at night, we’re largely unaware of this bounty. Let’s take a whirlwind appreciation tour of the group to illustrate the amazing, bizarre, and quirky features of this major insect order.
Rosy Maple MothCoffee-loving Pyrausta Moth
Moth adults come in all shapes and sizes, and like butterflies, wings are their most prominent feature. There are “micro-moths” whose wingspans are less than an inch, and giant “silk moths” up to 6 inches, making them the largest moths in North America. (Our native silk moths are not closely related to true silk moths, but they got the name because people thought they could be farmed for silk.) The wings of some moths look like mere slivers, seemingly insufficient for flight, while others are tucked around their body so they look fairly cylindrical. Some lay so flat at rest with their wings spread that you’d swear they were two-dimensional.
