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The Bees in Your Backyard

A Guide to North America's Bees

PRINCETON UNIVERSITY PRESS

INTRODUCTION

Did you know that more than 4000 species of bees live in the United States and Canada? To put that in perspective, there are 4 times more species of bees in these two countries than all the bird species north of Mexico, 6 times more kinds of bees than butterflies, and about 10 times as many bee species as mammal species. Despite their diversity, few people know anything about bees, even the ones in their own backyards. For example, everyone knows that robins nest in trees, that bears hibernate, and that butterflies start out as caterpillars, but most people don't know where bees live, how they spend the winter, or what they eat. This book is designed to introduce you to the bees of the United States and Canada, including their lifestyles and habitat preferences, and what you can do to attract them to your neighborhood. Understanding bees is beneficial not only to the bees, but also to your gardens.

Over 20,000 species of bees have been identified around the world. New species are being found every year, even in places like New York City. Because new species are continually discovered, scientists estimate that up to 30,000 species might exist worldwide. Bees can be found on every continent (except Antarctica), on small islands, on treeless mountaintops, in jungles and deserts, and on top of high-rises in Chicago. They are most abundant in dry and hot environments, like Mediterranean Europe, and the southwestern United States.

Though the drab reddish-brown honey bee is the default image conjured by most when they hear the word "bee," these creatures are in fact diverse and stunning beauties, and the menagerie includes blue and green jewels like Osmia and Agapostemon, fire-engine red Nomada, jet-black fuzz-balls like Anthophora, and zebra-striped Anthidium. Some of the smallest bees in the world are found in North America. Perdita, found in the southwest United States, measure only 0.1 inch, smaller than George Washington's nose on a quarter. At the other extreme, North America is home to giant bumbling carpenter bees (Xylocopa). At more than an inch long, they sound like miniature helicopters as they hover near flowers.

Bees are thought to increase seed set in 70% of all flowering plants, including many of the fruits and vegetables we enjoy. The special relationship that exists between bees and the flowers they visit is not only economically (and gastronomically) important; it is also unique from a biological perspective. Although there are other organisms that are capable of pollination (and are, in fact, good at it), bees are the only ones to actively gather pollen from the flowers they visit, creating an evolutionary dynamic seen nowhere else in the animal kingdom. Despite the particular talents and unquestionable importance of bees, scientists have reason to believe that some bee species may be experiencing widespread population declines. While the specifics are still being assessed, some things are certain: bees are all around us, they enhance the quality of our lives, and they benefit from our improved understanding of them and their needs.

Our hope is that this book will turn amateur naturalists, gardeners, entomologists, and curious souls on to the amazing lives of the bees that not only reside in untamed wild areas, but also flourish in our very neighborhoods. With understanding comes appreciation; in addition to describing the life stories associated with the many bee species of the United States and Canada, we provide examples of ways to encourage these wonderful pollinators on your own plot of land.

1.1 IS THIS A BEE?

Even though bees are common in most neighborhoods, frequently seen on hikes, and ubiquitous residents of city parks, it is hard to tell whether an insect buzzing nearby is a bee or something else. It's no wonder people get confused. Because bees sting, resembling one is a successful strategy for vulnerable insects, and many a bug has evolved the appearance of a buzzing bee; however, a keen eye and a little practice are all you need to see past the ruse.

Bees and wasps are the most similar in appearance, and they are the most easily confused. It is not uncommon to hear complaints about the "bee" that landed on somebody's hamburger at a recent family picnic. Stories of the pesky nest dangling from a branch in the backyard abound. Hikers complain about the horrible buzzing creatures that swarmed from a log they used as a backrest halfway up the trail. And every summer, someone is attacked by "ground bees" while mowing the lawn. In all cases, the annoying insect was probably not a bee but a wasp. Wasps (including hornets and yellow jackets) and bees are close relatives, sharing in common a grandmother 100 million "greats" ago. In some instances the two are so similar that even trained scientists have difficulty distinguishing them. The bee called Neolarra (see section 9.1), for example, was thought to be a wasp by the first researchers to see it. It didn't help that the bee was dead and stuck to a pin, because the most telling differences between bees and wasps are their mannerisms and day-to-day behaviors.

Most important among these behavioral differences is that bees are pollen eaters. Wasps, in contrast, are meat eaters. While both visit flowers for nectar (the "energy drink" of the insect world), bees also visit flowers in order to collect pollen for their young. On the contrary, wasps pursue other insects and drag them back to the nest for their offspring to devour. This one dietary difference has resulted in very different bearings. To aid in the gathering of pollen, bees are usually hairy (pollen sticks to hair), and many species look like cotton candy with wings. Rooting around in flowers is messy business, and a few minutes rummaging among floral parts leaves a bee coated in hundreds of tiny grains of pollen. Using her many legs, the bee grooms herself, wiping all the pollen to the back of her body, where she stuffs it into the spaces between special stiff bristles on her legs or belly. These tufts or masses of special hairs are called scopa. Quite the opposite of the furry bee, wasps look like Olympic swimmers, devoid of all hair, skinny-waisted, and with long spindly legs.

There are exceptions to every rule, of course. Some bees have scant hair on their bodies and are wasp-thin. In these cases, look for silvery or golden hairs on the face; wasps tend to have glistening mugs, while bee hairs don't shimmer from any angle. Behavior, as mentioned above, can be telling, too. Bees spend more time on flowers than wasps do; wasps in contrast are more likely to raid your backyard barbeque in search of animal proteins accidentally left on a plate.

Since bees and wasps are difficult to distinguish, many stung victims often blame the hapless bee for crimes not committed. The culprit in these cases is likely a paper wasp, a hornet, or a yellow jacket. All live socially in hives. Ever the opportunists, these wasps take advantage of the many resources found in urban environments, often building their homes along fences, under eaves and decks, attached to windowsills, or in various holes or cavities. All three will collect fibers from dead wood and plants and then use their saliva to make a papier-mache house of sorts. These nests often bear a strong resemblance to the honey bee hives depicted in Winnie the Pooh books, and it is thus not surprising that many people think these wasps are bees. These kinds of wasps also enjoy taking a bite of your grilled chicken back to the nest to feed their offspring, or stopping on the lip of your glass of root beer for a sugary sip. The gangly, thin-waisted, and hairless body gives them away as wasps and not bees, however. In addition, the wings of these wasps in particular are folded in a distinctive way. Rather than lying flat across their back (thorax) so they overlap over the abdomen, their wings run as parallel dark strips on either side of the thorax.

Though not close relatives of bees the way that wasps are, many flies mimic the bee look. For a fly, the advantages to playing copycat are huge. Bees have spent millennia evolving stings and every creature on land has learned that they are not to be messed with. For a fly, looking so painful can save them from becoming the lunch option of hungry birds, reptiles, and other potential predators. For a predator, of course, being able to tell the difference between a bee and a fly increases the number of options at the insect buffet. Over time, the discerning eye of the predator has therefore weeded out the not-so-good fly look-alikes, leaving behind flies that at first glance seem identical to bees — down to "pretend" pollen-collecting hairs on the legs!

Flies have several important characteristics that can help separate them from bees. First, flies have only two wings, while bees have four (a fore and a hind wing on each side). Second, flies usually have two short, blunt antennae that emerge from nearly the same place on their faces; bee antennae are longer (often much longer) and more widely spaced. Third, fly eyes are usually bigger and closer together than typical bee eyes, often almost touching at the top. As they do not carry pollen, flies have no dense tufts of stiff hairs on their bellies or legs (though a few species mimic this look with bright spots on their abdomens near the back legs). And finally, if you've actually captured a specimen for your collection, flies are much squishier, and piercing them with a pin is like piercing Jell-O. Bee bodies are much more resistant to the insect pin.

Even when a bee is properly identified as such, there are many common misconceptions about how it lives. Because of the importance and abundance of honey bees, we are most familiar with their life cycle. It is often assumed that all bees follow a lifestyle similar to that of the honey bee, when in fact honey bees are the exception rather than the rule for the habits of bees as a whole. Though extraordinary creatures, they are poor representatives of their fellow bee kin. First, honey bees live in hives, but 70% of all bees live in the ground. Second, honey bees are social and work together to build their hive nest; in contrast most other kinds of bees work alone. Third, honey bee mothers meet their offspring; the majority of bee mothers never encounter their young. And finally, honey bees make and store honey to eat in the winter, which few other bees do. We delve into each of these topics in more detail in the following sections.

1.2 BEE NAMES

If we are to talk about bees, we need to be able to distinguish between those that are bees, and those that aren't. This is trickier than you might think, and scientists have classified and reclassified bees and their relatives many times over the last 300 years.

Traditionally, scientists have used a system of classification known as taxonomy to group organisms together according to the way they look, and they use the same conventions across all living organisms. At the most inclusive and "highest" level of classification is domain, followed by kingdom, phylum, class, order, family, genus, and species. For example, all insects fall into the same class (Insecta) because they have a hard exoskeleton (rather than a soft skin like mammals), three distinct body parts (a head, a thorax, and an abdomen), six legs, compound eyes, and antennae. Within that large class, all butterflies are grouped together in the same order Lepidoptera, all flies are in the order Diptera, all bees are in the order Hymenoptera, and so on, according to certain characteristics that are shared in common by all members of the group. Each grouping in the taxonomic hierarchy is more exclusive than the one before it, until all the organisms in a group are considered the same species. For most purposes, these levels of organization suffice; however, bees require some additional divisions. Tribes and subfamilies are both smaller than the level of family, but larger than the level of genus. We use tribe and subfamily divisions frequently in this book. Subspecies are also discussed in this book; they are distinctive, often regional, variations of a species.

Together, the combined genus and species name of an organism is entirely unique, and no other organism that has ever lived shares that combination of names. These two names are usually underlined or italicized (as we have done in this book). The genus name is always capitalized, and the species name is always in lower case. Quite often the scientific names of organisms are strange-sounding, as they are based on Latin or Greek roots that indicate something distinctive about the group. They are frequently unfamiliar words, and learning to pronounce them may seem overwhelming. Take comfort in knowing that you likely recognize, and are probably undaunted by, many scientific names. The common names of many flowers are the same as their scientific names: Chrysanthemum, Hibiscus, Petunia, and Echinacea are all scientific and common names. You probably also aren't intimidated by names like Rhinoceros or Hippopotamus even though they are scientific names. Dinosaur names, too, are scientific, but every six-year-old can rattle off his five favorites without a stutter. With practice, bee names are just as easy.

A note on scientific pronunciation. Scientific names are based on Latin or Greek and often use unusual combinations of letters. They also involve an abundance of syllables, and it seems that the emphasis is not always where a native English speaker might be inclined to place it. Nonscientists are often daunted by the strange-looking words and avoid saying them at all costs. Here is a secret: scientists are often daunted by the same words. What's more, even among scientists who study these bees (or plants, or butterflies), there are many different pronunciations, all approximating the same word. When Latin was a living language, there may have been an appropriate pronunciation, but today there is no one right way. Hylaeus may be pronounced "hi-/ee-us", or "hi-/ay-us" depending on who is saying the word; neither is more correct. With that in mind, take your best guess. If you are saying the word out loud, it is likely in conversation and you and your audience will together come to a common understanding with no harm done. We have provided one possible, popular pronunciation below each bee's summary information box in the following chapters.

We recommend reading the scientific name first, then reading the pronunciation slowly, one syllable at a time, and then piecing them together. For clarification on our pronunciation guide, please see the appendix.

Why don't we just use common names, the way others do for most birds and mammals? First, the common names that exist for bees are not unique to different groups. For example, the name "long-horned bee" is a common name frequently used for more than 200 bee species in North America. These individual species have different life histories and geographic ranges and are not all closely related to each other. It is impossible to know which particular long-horned bee is meant without its scientific name. Second, even without the overlap in common names, there are more species of bees than there are birds (or mammals), and common names don't exist for most of them; also troublesome, because there is no standard set of rules, a few species have several common names (e.g., Colletes are known as cellophane bees, plasterer bees, or polyester bees). And finally, bee names based in Latin and Greek do not always translate well to common names.

Because all bees belong to the same order, bee classification takes place at the family level and below. Seven bee families have been identified in the world, six of which occur in the United States and Canada. Each chapter in this book contains all of the bees in one family (with the exception of the parasitic bees; they occur within three of the other families, but we have pulled them together into one chapter). Within each chapter, we have divided the bees further by subfamily, tribe, or genus depending on the size of the group; small genera (plural of the word genus) are put together in one section with other rare genera of the same subfamily or tribe. Genera with many species and those that are commonly seen are given their own sections.

You can tell whether someone is talking about a family, subfamily, tribe, or genus in one of several ways. The family name always ends in -idae, often abbreviated in conversation to -id, as in, "This plant has a lot of megachilids visiting it." A subfamily name always ends in -inae, and a tribe with -ini. Both tribe and subfamily names are abbreviated in conversation to "-ines," as in "You have a lot of beautiful anthidiines in your bee collection." This can be a minor source of confusion, though the rank can usually be understood by the context. Unlike the higher levels of classification, the genus name has no definitive suffix. In print, it will begin with a capital letter and be in italics.

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Excerpted from The Bees in Your Backyard by Joseph S. Wilson, Olivia Messinger Carril. Copyright © 2016 Joseph S. Wilson and Olivia Messinger Carril. Excerpted by permission of PRINCETON UNIVERSITY PRESS.
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