Thursday, October 5, 2017

Apidae in Southern Oregon

Honey bees and a cuckoo bee, cousins in the family Apidae
The family Apidae contains the most well known bees, the honey bees, as well as bumblebees, carpenter bees, and a variety of other types of bees with interesting and diverse lifestyles. There are seven families of bees in the world (six found in the United States, the seventh is endemic to Australia), and of these, the Apidae is the most familiar. The Apidae vary greatly in size, appearance, biology, and lifestyle. The scope of this article is to introduce the reader to a few of the bees in this family found in Southern Oregon. Though the species highlighted here were all found in Oregon, they are representative of apid bees found throughout the country.
Golden paper wasp, Polistes aurifer, and a honey bee
Bees and wasps share a common ancestor. Bees diverged from wasps at least 130 million years ago, probably sometime in the Cretaceous. Wasps at that time were predatory, and were likely found around flowers to hunt for prey. Flowers were already producing protein rich pollen for other pollinators such as flies and beetles, with nectar-like secretions appearing in the Late Cretaceous. It is theorized that in some cases wasps started feeding on pollen as well as their insect prey, and the diets of some evolved to depend solely on pollen. Wasps, like modern wasps, have hair on their bodies, but bees developed branched hairs which are more efficient at holding pollen. This is the main feature that separates wasps from bees. Diet alone is not a reliable method of separating wasps from bees. South American vulture bees (Trigona crassipes, T. necrophaga, and T. hypogea) are members of the Apidae, and feed on carrion rather than pollen. Conversely, pollen wasps (Masarinae) are vespid wasps which provision nests with pollen rather than insects for their young. The eusocial members of the Apidae represent the most highly evolved of all bees and perhaps all wasps as well.
A little Bombus vosnasenskii worker steals honey from a honey bee hive
The genus Apis contains seven recognized species, including the giant honey bee (A. dorsata), the Asian honey bee (A. cerana), and the Western honey bee (A. mellifera). The Western honey bee has around 25 recognized subspecies, often referred to as races among beekeepers. In the US, only a handful of races are introduced, such as the Italian (A. m. ligustica), Carniolan (A. m. carnica), and Caucasian (A. m. caucasia) to name a few. The African subspecies, A. m. scutellata, has hybridized with many of the naturalized Eurasian subspecies, creating the Africanized bees which are restricted mostly to the southern states, limited by cold weather. Africanized bees have traits which help it counter one of the most important of honey bee pests, the varroa mite (Varroa destructor), and may help ensure the economic success of beekeepers in the South who suffer large winter losses from mite infestations.
Honey bee proboscis
Honey bees, as well as all other bees and wasps, have mandibles used for chewing and various other species specific tasks, and a proboscis. The proboscis, the bee equivalent of a tongue, is an assemblage of parts which form the sucking apparatus used to gather nectar or other fluids. The longest part of the proboscis is called the glossa, and it often has specialized hairs at the end. Some bees, such as certain osmiine bees (Megachilidae) have special curved hairs on the glossa used to collect pollen on certain host plants such as those in the Boraginaceae with concealed anthers.
Honey bee corbiculae
Honey bees, bumble bees, orchid bees, and stingless bees have corbiculae, or pollen baskets, which are specialized pollen collecting structures on the tibia of the hind legs of females. The outer hairs are long and curved inwards, while short soft hairs fill the interior. Pollen is mixed with bee saliva or nectar then packed tightly into the corbiculae. This is in contrast to most other pollen-collecting bees which collect pollen in a dry state in long dense straight hair clusters called scopae.
Honey bee sting
The honey bee sting, like the stings of all stinging wasps and bees, evolved from an ovipositor way back in the evolutionary timeline. Ancient female wasps (and many modern parasitoid wasps) laid eggs through the ovipositor. The rise of eusociality is thought to have correlated with the evolution of the sting, and venom, as a means of defense. The possession of a sting and venom may also have enabled wasps and bees to gather resources or hunt for prey out in the open, whereas many parasitoid wasps are relatively obscure and not often seen. The bright colors of many stinging wasps and bees is simultaneously an aposematic defense, a form of Müllerian mimicry (where distantly related species evolve to resemble each other), and in some cases, an example of Batesian mimicry (where generally harmless species resemble other not-so-harmless species).

Beekeepers and many others know that when one is stung by a honey bee, the bee dies. This is because the sting, which is barbed, remains in the victim with a pulsing sac of venom, as well as part of the bees digestive tract. The venom sac continues to pump the entire payload of venom if not promptly removed, best done by scraping. The bee dies, but this is usually of little consequence as the martyr is not a reproductive, that is, does not pass her genes, and is of greater use protecting the colony. This is altruism in the natural world. The vast majority of bees and wasps, however, do not have barbed stings and do  not die after stinging because they retain their sting. The genus Apis, as well as a few South American eusocial vespid wasps (and a handful of stinging ant species), are the only hymenopterans with barbed stings. The myth that bees die after stinging and wasps can sting you til the cows come home turns out to be a fallacy.
Mated queen marked green
Honey bee colonies are composed of thousands of worker females and a single laying queen. The queen is larger than the others, and it is her sole purpose to lay eggs. When a new queen is hatched, she takes one to several mating flights where she mates with a few to many drones (males) in mysterious drone congregation areas, 50 to 100 feet above the ground. Once the queen has acquired enough semen, she never leaves the hive again and lays eggs until she is either killed, runs out of semen, or the colony swarms. As for the latter, the entire colony, a superorganism, reproduced through the act of swarming. This occurs usually during a time when resources are at their peak (i.e. spring) when the queen and loosely half the workers depart the current hive in search of a new place to call home. The swarm normally clusters on a tree branch, fencing, or any number of structures until scout bees find a suitable cavity or other protected location to build comb. The bees remaining in the original hive will raise a new queen from one of the last eggs laid by the former queen.
Apis mellifera caucasia male (drone)
Although the title of honey bee queen is purely an anthropomorphism, the queen doesn't actually rule anything except for the release of the semen within her ovaries. When an egg is fertilized, it produces a diploid female honey bee. Yet, the queen has the ability to lay an unfertilized bee which will develop into a haploid male, or drone. This trait is known as Haplodiploidy, and is consistent among most of the Hymenoptera (the taxonomic order which encompasses all bees, wasps, ants, sawflies, and horntails). I say most because there are some odd wasps which can produce females from unfertilized eggs. Male hymenopterans, having never possessed ovipositors since only females lay eggs, never developed stings. Honey bee drones, however, die after mating because their male organs are ripped from their bodies after intercourse with new queens. They also become paralyzed, and simply drop from the sky, their penis torn off. My problems aren't so bad, it seems. Most male wasps and bees, much unlike the honey bee drone, can mate repeatedly, and it is often the female which mates with a single male.
Eristalis tenax, drone fly (June) 
Mimicry in the insect kingdom is widespread, particularly among flies. The drone fly, Eristalis tenax, is a mimic of honey bees. It is so named due to its strong resemblance to the honey bee drone. Evolution must know something I do not when it makes one harmless and edible creature mimic another equally harmless and edible creature. Flies, unlike bees and wasps, have only one pair of wings (bees and wasps have two pairs) and a pair of halteres behind the wings. Halteres are small knobbed appendages which allow flies to balance during flight.
Bombus vosnasenskii, the yellow-faced bumble bee
After honey bees, bumble bees (Bombus spp.) are the second most familiar bees. There are 46 species of bumble bees in the United States and Canada, over 200 worldwide. Around two dozen species have been found in Oregon, of which I have observed around five or six. They are quite different from honey bees, though there are also a few similarities.
Bombus vosnasenskii visiting Monardella sp., or coyote mint
Bumble bees are eusocial meaning they form colonies with distinct castes (reproductive and worker castes). Unlike honey bees, a bumble bee colony only lasts for a single growing season. While a honey bee queen can live up to around five years under ideal conditions, bumble bee queens live for one year. At the end of the colonies life cycle, new queens and males are produced and leave the colony to mate. The old queen and the workers of that season all die before winter sets in, while newly mated queens are the only ones to live til the following year, enduring winter sheltered in a protected location.
Bombus huntii
Bumble bees, as well as a handful of other large bees, are able to generate warmth by vibrating their flight muscles. For this reason new queens are able to forage for sustenance very early in the year, often late winter in my region when the earliest flowers are just beginning to bloom (winter heath, Erica carnea, is typically the only thing in bloom in late winter). Newly emerged queens seek out a nesting location which is usually underground (i.e. abandoned rodent tunnels) or within the thick tussocks of bunch grasses. Initially the queen will build a single wax urn and lay one to a few eggs inside. She will forage for nectar and pollen to nourish this first brood. When these first workers emerge as adults they will aid the queen and eventually take over foraging duties while the queen shifts gears to egg laying.
Bombus sp. forcing her way into a closed California poppy, Eschscholzia californica
Bumble bees are important pollinators with unique talents not exhibited by honey bees. First off, many species are larger and stronger than honey bee workers, sometimes with much longer tongues, and thus able to gain access to resources in flowers that are unavailable to honey bees. Additionally, the same mechanism that allows bumbles to warm themselves in cold weather allows them to gather pollen in some plants that is not able to be acquired by honey bees or other small bees. Sonication, colloquially known as buzz pollination, is when a bumble bee (or other bees with this ability) grip onto a flower or the anthers and vibrate their flight muscles to release the pollen. Many plants, particularly those in the nightshade family (Solanaceae) and heath family (Ericaceae), to name a few of economic importance (i.e. tomatoes, blueberries), require sonication for pollination as the pollen will not release from the anthers without it.
Bombus sp. visiting Heuchera sp.
Bumble bees are also very different from honey bees in that they do not communicate the locations of resources of resources as honey bees do (i.e. the waggle dance, a tool honey bees use to communicate the location of favorable flower patches relative to the sun). This lack of communication in bumble bee nests is useful for the use of bumble bees in agricultural settings, particularly greenhouses. While honey bees will forsake a target crop if a more preferred nectar/pollen resource is discovered beyond the farm, bumble bee foragers are all on their own to discover resources. Honey bees may ignore a target crop altogether by means of their communication with other foragers, but bumbles will not. This makes them ideal for greenhouse pollination efforts.
Bombus vosnesenskii on Hypericum perforatum
Bumble bees are adventurers. In my observations they have the most diverse collective palate of any native pollinator. In six years I have not witnessed a single pollinator visiting Klamath weed, Hypericum perforatum, which is a nonnative species from Europe, except for the bee in the above photo. This is just a single example of their dynamic ability of at least some species to adapt to changing conditions.
Bombus vandykei male visiting Echinacea purpurea
Most bumble bees are easily identified by observing which colors are on each tergite, the segments on the top side of the abdomen. In general they are easier for beginners to identify than other native bees due to their relative abundance and larger size. However, a few factors can complicate identification. Natural variability within the same species can occasionally give the impression to the observer that there are more species than the reality. Queens, workers, and males often have different patterns as well. For example, Bombus vandykei males can sometimes be completely yellow while queens and workers have a metasoma that is nearly all black except for a singe yellow band. B. vandykei and B. vosnasenskii females differ solely by the position of a single yellow band being one terga higher in the case of the former, an example of the importance of accurate observations. For most bees, a close look via good photos or an insect net and a hand lens are necessary for accurate identification. Some species are beyond the ability of the enthusiast, and require an expert with a microscope.
Robber fly, Laphria sp.
There are several bumble bee mimics in the region, mostly flies. Robber flies (Asilidae) and tachinid flies (Tachinidae) are the most common of the fly mimics. Not all of them are mimics of bumble bees, but several species bear a strong resemblance. Laphria spp., as well as other robber flies, are predatory and hunt other flying insects, including bees and other robber flies. Tachinid flies are parasitoids, their larvae feed on insect hosts and hosts in other orders including some arachnids (though hosts are species specific).
Xylocopa sp. female, a large carpenter bee, visiting hairy vetch, Vicia villosa
Often misidentified by lay observers for bumble bees, carpenter bees are common and conspicuous. They are the largest bees in Oregon, though unlike bumble bees they are solitary or occasionally primitively eusocial. Not only are large carpenter bees the largest bees in Oregon and much of the United States, but they also have some of the largest eggs of all insects, measuring over half an inch in length, though egg size is probably variable between species.
Xylocopa tabaniformis visiting clary sage, Salvia sclarea
Carpenter bees are similar to bumble bees superficially but several key features can help to tell them apart. The first, perhaps most obvious trait, is that the metasoma of Xylocopa is relatively shiny since the hair is considerable less dense than on bumblebees. Carpenter bees also lack corbiculae, or pollen baskets, and instead possess scopae, dense patches of elongated hairs on the tibia of the rear legs. Though I have observed that when visiting certain plants in the Lamiaceae (mint family) the pollen is deposited on the top of the mesosoma. I suspect that pollen is groomed into the scopae from other parts of the body though I have not observed this directly.
Male Xylocopa perched on a columbine
True to name, carpenter bees nest in wood. Unlike many other bees which nest in premade holes in wood created by beetle larvae or other insects, carpenter bees use their strong mandibles to create cylindrical nests in dead or living wood, occasionally bamboo. They are occasionally considered to be pests for this behavior, though preventing them from nesting in a deck or siding may be as simple as good upkeep (i.e. fresh paint, deck stains, et cetera). Tunnels extend around eight inches, maybe more, with around six or seven partitioned cells. Adult mothers may live two or three years, an oddity for a native bee. Occasionally several females, including a mother and a few of her daughters, will share a nest entrance and provision cells together thus the primitive eusociality. Woodpeckers and other predators and parasites feed on the contents of the cells.
Carpenter bee male, Xylocopa tabaniformis
Male carpenter bees are usually slightly smaller than females. The local species have males with light colored hairs on the thorax while females tend to be entirely black, including their eyes. Males have green eyes, and in my opinion are quite stunning. Males are also territorial and usually claim a patch of flowers as their own. They will chase and grapple with anything that enters their domain, including competing males, other types of bees, flies, falling leaves, pebbles thrown in their general direction, you get the idea. On occasion males even try to ward off humans who get too close, but one should not bother being intimidated because the males, like all male Hymenoptera, lack stingers.
Small carpenter bee, Ceratina sp.
Close relatives to the large carpenter bees, small carpenter bees (Ceratina spp.) are quite dissimilar to their large cousins. Many species of Ceratina are so small they are likely to be missed altogether, or mistaken for small flies. Rather than nesting in wood, they nest in broken pithy stems of woody plants, usually those in the Rosaceae (i.e. roses, blackberry). The small bees also have an affinity for flowers of plants in the rose family, though they visit a wide range of plants in many families.
Small carpenter bee, Ceratina sp., on Monardella villosa
Small carpenter bees are lightly haired, with sparse white scopae on the hind tibia. Many species are actually a dark metallic green, though by casual observation it's not always easy to notice. Females have bluntly pointed abdomens. Some species have white markings on the lower part of the face. Similar insects are other small bees, particularly masked bees (Hylaeus spp., Colletidae), and small aphid wasps (Pemphredoninae, Crabronidae).
Long-horned bee male, Melissodes sp.
Long-horned bees are named for the very long antennae of the males, as seen in the photos. The common name actually represents several genera in the Eucerini tribe including Eucera, MelissodesTetraloniella, and perhaps a few other less common genera as the males are all endowed with very long antennae. Melissodes, and others, nest in the ground. Species in my region in Southern Oregon are active in late summer. They are very fast and difficult for me to photograph, though this only adds to their allure. I caught and chilled two males for the purpose of identifying them, allowing them to warm up and fly away after I had taken a few photos.
Long-horned bee male, Melissodes sp.
Male Melissodes have two-toned antennae which are dark on top and buff colored on the bottom. They don't seem to be territorial, as many males and females are often found in a particular flower patch. In my observations males attempt to mate with females while they are foraging, and both males and females will attempt to mate repeatedly, if the males don't get bucked off by the females. I have not seen long-horned bees attracted to gardens, rather they seem to prefer specific patches of plants. I have observed them visiting Madia elegans in the middle of summer, normally in the morning before the heat sets in. The other plant I have seen them visit en masse is pennyroyal, Mentha pulegium, a nonnative from the Old World. I wonder if their floral preferences are influenced by the closeness of the floral resources to their nesting sites, often congregations of many nests in a relatively small area.
Digger bee, Anthophora urbana (2017)
A common digger bee, Anthophora urbana is native to much of the West. These fast flying bees are active for much of the growing season so long as there are floral resources to their liking available. I captured and chilled this female visiting vinegarweed, Trichostema lanceolatum (Lamiaceae). Like the long-horned bees, they collect dry pollen with scopae and nest in the ground. The genus Habropoda, related to Anthophora, are also found in this region but I have only observed them earlier in the year when the fruit trees are in bloom. These bees are able to sonicate, like the other large bees of the Apidae.
Cuckoo bee, Nomada sp.
The Apidae contains a vast group of upstanding citizens, those which contribute to pollination and demonstrate what we would call ethical guidelines. But what do bees know of ethics? A handful of bees in the Apidae are kleptoparasites, meaning they steal the nests of other bees for their own brood. These are known as the cuckoo bees. Kleptoparasitism is known to several bee families, and even within genera that are mostly not kleptoparasitic. The genus Ceratina, for instance, has a few kleptoparasitic species. The most notable feature of cuckoo bees is that females lack any mechanism for collecting or carrying pollen, as the nest they steal is already provisioned with the necessary pollen by the host bee. Cuckoo bees, thus, do not make a large contribution to the pollination effort. They are, anyway, interesting and beautiful, often wasp-like due to their lack of hair.
Cuckoo bee, Nomada sp.
Cuckoo bees enter the nests of other bees usually solitary bees like digger bees, and lay an egg in one or more cells prepared by the host. The cuckoo eggs typically hatch before the host egg, then the larva kills the host egg or host larva with a pair of over sized mandibles. Development the happens as expected, but what emerges from the host cell is not the host species, but the parasite. Fret not, for the presence of such bees indicate a strong population of host species, which is good overall.
Virgin honey bee queen
Are there more? Absolutely! There are over 1,000 species in fifty genera in North America, and well over 5,000 species worldwide in at least 200 genera. That is a lot of bees. So, when someone mentions bees it might be prudent to ask them to be more specific. The word bee is used colloquially to talk about honey bees, which do not accurately represent the family as a whole but are rather more of an oddity. Not to say that honey bees shouldn't be appreciated, but rather I think one should appreciate them for how they serve us and what they represent evolutionarily as the most advanced of all bees. I don't mean to say they are better than other bees, just different. I love all bees, and I think you should too. That is my message. (And wasps, now read this.)

(Photos taken with my trusty Nikon COOLPIX B700 and Samsung Galaxy S7 Edge. Some photos taken with the S7 through the eyepiece of a dissection microscope courtesy Old Sol Enterprises)

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