Bees Are Not (Purposeful) Pollinators

Today is World Bee Day, for celebrating our favorite pollinators. I enthusiastically support increasing awareness of bees other than honey bees, but a vague mythology exists. Here is some food for thought, remembering that one out of every three bites of food we eat we owe to the efforts of pollinators.

A tiny sweat bee, genus Lasioglossum, visits a ornamental Amaryllis flower in our Leavenworth, Kansas yard. Bees prefer native plants, though.

There is something of a persistent fairy tale, if only implied, that portrays bees as little agents of plant reproduction, flying flower to flower to effect floral fertilization, like it is their job, or out of the goodness of their tiny little hearts. Nothing could be farther from the truth.

A female mining bee, genus Andrena, pauses to rest and groom between forays for collecting pollen. Colorado Springs, Colorado.

Bees are best described as “pollen harvesters,” or even, perish the thought, “pollen predators.” Female bees actively collect pollen as food provisions for their larval offspring. This definition applies to honey bees, bumble bees, sweat bees, mining bees, mason bees, leafcutter bees, digger bees, all the bees except the kleptoparastic cuckoo bees. Cuckoo bees don’t collect pollen, but lay their eggs in the nests of other bees that do. Cuckoo bee larvae feed on the stolen pollen reserves of their hosts.

Many cuckoo bees, like this one in the genus Nomada, look more like wasps, lacking the "fuzzy" appearance we associate with bees. Colorado Springs, Colorado.

Pollination occurs as a by-product of the bee’s determined, thorough gathering of pollen; and the body form of bees that allows pollen to be shed as frequently as it is foraged. Body plan and behavior therefore make bees effective pollinators.

A male Squash Bee, Peponapis pruinosa, waits in a flower for a potential mate to visit. This bee species visits flowers in the gourd family exclusively. Colorado Springs, Colorado.

Another facet of bee behavior is that some species are oligolectic, meaning they visit only one particular genus, or even species, of flower. This greatly increases the likelihood that pollination will happen. Many bees are generalists, and will visit a variety of flowers, lowering the possibility of compatibility of bee-shed pollen with the flower receiving the bee’s next visit. This is not usually appreciable enough to be negatively significant, but it is still worth noting.

A female sweat bee, genus Halictus, has difficulty reaching pollen and nectar in an ornamental rose flower. Colorado Springs, Colorado.

Flowers and bees have coevolved to take advantage of each other, and it is an ongoing, dynamic relationship. Human interference threatens to upend that in a variety of ways. Some plant cultivars have sterile flowers, and bees therefore waste time and energy trying to “get blood out of a turnip.” Other cultivars, bred for large, complex “double bloom” flowers, result in blossoms too complicated for bees to navigate to find pollen and nectar. Lastly, cultivars may have pollen with a much lower nutritional value than that of the native plant they were derived from.

A worker female honey bee, Apis mellifera, among the first bees active in spring. El Paso County, Colorado.

Honey bees, social bees in the genus Apis that are not native to the Americas or Australia, are the unfortunate poster children for Bee Day, thanks to public familiarity through heavy marketing campaigns by the apiculture (bee keeping) industry. While absolutely vital pollinators for industrial scale agriculture, honey bees in unmanaged, feral colonies have a serious negative impact in natural ecosystems. Honey bees hog floral resources that native bee species, most of which are solitary, need to prosper.

A female Eastern Carpenter Bee, Xylocopa virginica, robs nectar from a hosta flower, throuch a slit she cut at the base of the blossom. Leavenworth, Kansas.

Back to flowers and bees for a moment. There are long- and short-tongued bees. This difference in anatomy means that many bees are restricted to visiting flowers with shallow corollas, such that they can reach the nectar reservoirs. Some larger short-tongued bees, namely large carpenter bees in the genus Xylocopa, are able to cut a slit at the bottom of deep-throated flowers, and “rob” the nectar without dusting themselves with pollen in the process of feeding. Smaller bees follow the carpenter bee, and take advantage of the holes it cuts.

The bumble bee on the left performs proper pollination of a hosta flower, while the longhorned digger bee on the right bypasses the flower's reproductive parts and uses a slit cut by a carpenter bee to rob nectar.

If it seems like the myth of the hard-working bee might be falling apart a little, then what about other pollinators like butterflies, moths, wasps, flies, beetles, hummingbirds, and bats? Well, those organisms are not even coming to flowers for pollen, with a few exceptions. They are “flower visitors” that want nectar as sugary fuel for their high metabolism. Setae (hairs), feathers, and fur will accumulate pollen, and shed it, so again, pollination can be achieved, but it is not some kind of selfless mission of the critter.

A female leafcutter bee, genus Megachile, shears a piece from a redbud leaf to use in fashioning a cell in her nest. She can do quite a bit of cosmetic damage, but the shrub will be fine. Leavenworth, Kansas.

All of this is not to say that bees are not loveable, and in need of conservation. Here are some neat facts, tips for helping bees, and resources to investigate:

• There are over 4,000 species of bees found north of Mexico. Hotspots include the Mojave Desert, and Colorado.
• Most native, solitary bees nest in burrows underground, so leave some bare patches of soil in your yard for them.
• ”Bee hotels,” aka bee condos, bee blocks, are for solitary bees that nest in natural cavities in wood. Avoid commercial products, and make your own; or, better yet, leave stumps and solid wood logs in the yard that have obvious holes from beetle borings. Snip old, hollow twigs and woody stems so bees can use those upright tunnels, too.
• Consult online gurus like Dr. Kit Prendergast (“The Bee Babette”) of Australia, and Krystle Hickman (“beesip”) of southern California, for friendly presentations on bees, and tips on how to help them.
• Watch My Garden of a Thousand Bees, a fascinating documentary set in the United Kingdom, but applicable elsewhere in the northern hemisphere.
• Landscape with native plants whenever and wherever you can. Be tolerant of the damage done by female leafcutter bees making their nests by cutting chunks of foliage.

A female sweat bee, genus Lasioglossum, lives up to her name and sips perspiration from my hand. Leavenworth, Kansas.

Enjoy the rest of National Bee Day, and get ready of National Pollinator Week, coming June 22-28, 2026.

The Beetle and the Bee

At the end of February, I finally found a beetle I had been looking for here, for years. Perhaps I had not been scouting for it early enough, but we barely had a winter this year, and I suspect that most years it would have been evident in March. The key was finding an aggregation of its host organism.

Tricrania sanguinipennis is a blister beetle in the family Meloidae. The adult insects measure 9-15 millimeters, but are bright enough, and active enough, that they are easily seen. Their wings, hidden under their red, leathery elytra, are almost vestigial, so they are flightless. Instead they crawl, but rather rapidly, over the surface of the soil, periodically digging where they detect the possible presence of a host.

Kansas is about as far west as this beetle is found, though there are records well north into Saskatchewan, Canada. It occurs over the eastern U.S. to extreme northern Florida, and up into adjacent southern Canada.

The limiting factor is that Tricrania sanguinipennis is a parasitoid of solitary bees that nest in dense aggregations, namely cellophane bees in the genus Colletes.

We have the Unequal Cellophane Bee, Colletes inaequalis, nesting in our yard and/or the adjacent neighbor’s lawn, depending on the year, but those locations are apparently blister beetle-free. It took finding a small aggregation of the bees in a forested park to locate the beetles.

An Unequal Cellophane Bee lurks just inside the entrance to her burrow.

The bees nest in burrows, ideally in sandy soil. The vertical, subterranean tunnels branch into several individual cells, each one an “apartment” for a single bee larva. The grub feeds on a nearly liquid loaf of pollen and nectar. The walls of its room are coated in a type of natural plastic manufactured in glands in its mother’s abdomen, which essentially waterproofs the chamber, and retards mold and fungus.

Back to the beetles. What the female beetles lack in mobility, they more than make up for in fecundity. Each lady can produce hundreds of eggs, over a thousand in some documented instances. How, then, do the beetles gain entry into these tunnels? The answer is that they do not. The larvae do.

The larval stage is unusually lengthy, progressing through six instars. An instar is the interval between molts. It is also strange in that it includes hypermetamorphosis. In this case that means the larval form changes radically in both appearance and behavior from one molt to the next.

Several male Unequal Cellophane Bees waiting for females to emerge.

The first instar larva that emerges from the egg is a sleek, streamlined, highly mobile bee-seeking missile called a triungulin. At the time they are active, it is almost exclusively male Colletes bees that are active, buzzing about and frequently landing to investigate a potential site where a female could emerge. It is at these brief moments when a blister beetle triungulin scampers aboard, affixing itself to the hairs on the underside of the bee’s abdomen.

Oops! An overeager male mistakes another male for a female.

When the male bee at last is able to mate, the triungulin transfers to the female bee. In at least a few instances, the triungulin may attach directly to a female bee that it encounters on the ground. She will eventually, and unwittingly, ferry that parasite, and probably several others, to her new nest burrow. Once inside, it disembarks and infiltrates one of the subterranean nest cells.

The beetle larva usually consumes the egg of the host immediately, but not always. The bulk of its diet will be the honey and pollen left by the bee for its offspring in the cell. It may be a frequent occurrence that more than one beetle larva invades a single bee cell. In that event, cannibalism of the competition resolves the conflict.

The meal of the host egg or larva is usually enough nutrition to trigger the beetle larva’s molt to the next instar. This results in a shocking change from that sleek, active larva into the insect equivalent of a couch potato. The second instar is, shall we say….rotund, and boat-shaped. It commences feeding on the pollen and nectar stores in the cell of the now missing bee offspring. The insect retains this form for the remainder of its larval life. The first three instars shuck their old exoskeleton completely, but the fourth and fifth instars retain each molt in its entirety. Think of it as an object inside a balloon (inside another balloon by the fifth instar). Those larvae actually shrink in size to fit inside the shed “skins.” When molting into the pupa stage, the sixth molt is again broken during shedding, and compacted at the rear of the pupa, which is still inside those other exoskeleton balloons.

It takes until late summer or early fall for the life cycle to complete, the adult beetle remaining encased in its final one or two larval exuviae, where it overwinters, still inside the cell in the host’s nest burrow.

You would think that the bee species hosting this diabolical beetle would be decimated by it, but such is not the case. Each spring there are plenty of the adult bees. What is more of a threat is the potential disconnect between the bees and their nectar plants. Colletes inaequalis visits flowering trees almost exclusively, especially Eastern Redbud, and maple trees. As the phenology of the blooming cycles becomes increasingly unpredictable thanks to climate change, the appearance of the flowers may cease to always coincide with the emergence of the bees that pollinate them.

Sources: Messinger Carril, Olivia, and Joseph S. Wilson. 2021. Common Bees of Eastern North America. Princeton, NJ: Princeton University Press. 286 pp.
Parker, J.B. and Adam G. Boving. 1925. “The Blister Beetle Tricrania sanguinipennis - Biology, Descriptions of Different Stages, and Systematic Relationship,” Proc U.S. Nat. Mus. 64(2491): 1-40. This is a wonderfully exhaustive article, with illustrations of all larval instars.

World Bee Day....A Little "Bee"hind

World Bee Day happened the other day, May 20, and it caught me off guard. I had never heard of it, and hustled to make some social media posts for the Facebook groups I founded or administer. I will plan a bigger campaign of celebration next year, but for now....

In fairness, World Bee Day has not been in existence very long. The date honors the birthday of Anton Janša of Slovenia, a pioneer of modern beekeeping in the eighteenth century. The United Nations passed a resolution submitted by Slovenia in 2017 to so honor him. While beekeeping in the northern hemisphere applies only to honey bees in the genus Apis, the U.N. has chosen to use World Bee Day as an opportunity to acknowledge all bee species, the vast majority of which are solitary and not managed by human beings.

North American bees range from giant "large carpenter bees" like this one....

Given the plight of pollinators in general, and the threats to apiculture (beekeeping) from mites, pesticides, industrial-scale agriculture, habitat destruction, and climate....anomalies of increasing frequency, it is easy to be pessimistic and sorrowful on World Bee Day. However, there are signs of hope all around us.

....to tiny Perdita mining bees like this one.

More people are taking up apiculture as a hobby, for example. Even better, many homeowners and small-scale farmers are recognizing the importance of native bees and building simple housing for them in the shape of "bee condos." Now a small movement is building to advocate for allowing those bare patches of soil in your lawn and flowerbed to lie fallow. The overwhelming majority of solitary bees in North America nest in burrows they excavate in the ground. Sometimes many females will nest in close proximity, giving the illusion of a "hive" or a swarm. This is not the case, and unless you step on a bee in bare feet or forcibly grab one, it is not going to sting you. Different bee species prefer different textures of soil, from sandy to clayey.

Leafcutter bees, Megachile sp., using "bee block."

Among the many reasons to celebrate World Bee Day this year is the rediscovery of the world's largest bee, Wallace's Giant Resin bee, Megachile pluto, nesting in termite mounds in Indonesia. It is an important reminder that the natural world is resilient, to at least some degree, and that most species can persist even in unfavorable circumstances.

Female cactus bee, Diadasia sp., entering her burrow.

Colorado, where my wife and I live, ranks fifth in bee diversity in the USA, boasting at least 946 species from huge bumble bees to tiny mining bees in the genus Perdita. California (1,651), Arizona (1,182), New Mexico (991), and Utah (979) rank ahead of us. That makes for a lot of bee species that need conservation if we want to continue enjoying wildflowers and eating everything from blueberries to squash to almonds.

We can encourage bees by....

• landscaping with native trees, shrubs, herbs, and flowers.
• Erecting bee blocks as supplementary housing for solitary bees (and wasps) that normally nest in the dead trees we cut down and logs we haul off.
• Become "weed tolerant" of plants that volunteer in our yards, as long as they are not state-listed noxious weeds. Chances are they are native or naturalized wildflowers instead.
• Leave a few bare patches in the lawn (if you still insist on having a lawn) and flowerbeds so that ground-nesting bees have a place to call home.
• Advocate for changes to municipal and HOA codes and rules that currently discourage eco-friendly landscaping.

It goes without saying that eliminating pesticides and other chemicals from your yard and garden will greatly benefit all life, not just on your property but elsewhere, too, as pesticides drift on the wind and flow in runoff from rain and watering.

Female sweat bee, Agapostemon sp., living up to her name.

World Bee Day is behind us this year, but no worries. You can gear up now to celebrate National Pollinator Week next month, June 17-23, 2019. Tell me how you plan(t?) to respect that designated "holiday." Maybe you need to do what I should do, which is call my governor and ask why Colorado is not yet on the map for it....

Cuckoo bee, Nomada sp., leaving (left), small carpenter bee, Ceratina sp., arriving (right).

Are We Saving Species by Rescuing One Individual Bug?

NOTE: I had to change the original title of this post because, believe it or not, it is a trademarked phrase! The owner of said patent/copyright informed me of this on September 17, 2019 and asked that I remove the title.

Increasingly, thanks to social media, I am struck by how many people attempt to save individual insects they find injured or lethargic. On one hand this empathy for other life forms is encouraging, but on the other hand the energy investment is grossly misplaced.

© Youtube.com

The problem is that the media has painted honey bees and Monarch butterflies in particular as highly vulnerable if not on the brink of extinction. The implied message is that every individual of these species needs protection in every way possible! Consequently, people spend more time "rescuing" individual specimens than in protecting or creating habitat, working to curb pesticide use in their community, or engaging in other strategies that would have a far greater impact on improving the health of the entire species.

Another problem is that most people are not knowledgeable enough to recognize when a given insect really is in trouble. The wrong assessment happens over and over with bees in particular. Bees often become inactive when it gets too cold for them. They rest on whatever object is available and often this is a more conspicuous spot than normal. A good Samaritan human believes the insect is in peril and needs the equivalent of a sugar-water IV, stat! No, it does not.

Further, in late summer and fall, chances are you are saving a male bee, which is even less useful. Male bees live a short life in which their only purpose is to mate with a female. They do not possess pollen baskets, so are less effective pollinators than female bees.

Another aspect of life that we forget is that insects, like any organism, are prone to developmental problems that cannot be overcome. Improper emergence from a chrysalis will leave a butterfly crippled beyond repair. It happens. Insects reproduce in large numbers to overcome those deficits. Insects are incredibly durable once they mature, and losing half a wing barely slows down a butterfly or a bee. We should be in awe as much, if not more, than in sympathy, let alone pity.

Ok, so last month my wife and I were on vacation in Cape May, New Jersey, and we happened upon a Monarch trapped in a spider web. We intervened. It was a quick fix, simply disentangling the insect and sending it on its way. The whole investment was maybe forty seconds. We understood the insect could collide with a vehicle later that same day. Our expectations for the survival of individual insects are low, given our knowledge of their biology.

Contrast that example with an online video that shows how to mend a broken wing on a Monarch. More than a few such organizations have exploited the "sky is falling" scenarios centered on the Monarch, and one has to question the motives of some of them. Yes, older, established conservation organizations use overly alarming narratives, too, but the best ones measure their tone and can point to historic successes in legislation and habitat protection.

You want to curb insect mortality? Then give up driving. For every insect you nurse back to health, you kill dozens, if not hundreds in the course of operating your motor vehicle. Even bicyclists take their toll. I have seen countless insects mortally wounded, or crushed, on bike paths.

Basically, insects are better served by actions aimed at enhancing habitat health, and planting native vegetation in the landscape of your own property where you are able. Tear out the lawn, or most of it, and do your best to mimic the natural ecosystem where you live. Want to go a step farther? Start a dialogue with city and county officials to restructure weed ordinances and other codes that currently restrict the ability of homeowners to plant for wildlife. Educate your homeowners association to make those communities more wildlife-friendly without compromising safety and property values.

Also, stop insisting that one species is somehow more worthy of our attention than any other. Stop categorizing insects as "friend" or "foe." Such distinctions do not apply to the overwhelming majority of life on this planet.

Be proud of yourself for having empathy for other living things; but, channel that into something that will make a difference beyond the individual insect or arachnid. Do intervene for birds, mammals, reptiles, and amphibians, all of which have far longer lifespans than invertebrates, but make sure you do it legally and correctly. Carry on.

The Wasp Wall

South Cape May Meadows in Cape May, New Jersey is a property managed by The Nature Conservancy (TNC) for birds and other wildlife. Near the parking lot stands a shed that itself is something of a refuge for a whole community of insects. One wall, facing west and with beams that make something of an overhang or trellis, is being worked over by the Eastern Carpenter Bee, Xylocopa virginica. The abandoned nests of these solitary bees are then used by mason wasps, leafcutter bees, and other solitary Hymenoptera.

The shed at South Cape May Meadows, behind the arbor entrance

During our visit this past September 24, we noticed the holes, then soon saw females of the Four-toothed Mason Wasp, Monobia quadridens, exploring some of those cavities. I wrote about this species previously, detailing its life cycle, but this was the first time I had observed them coming and going from nests.

Female Monobia quadridens entering her nest

One female delivered a paralyzed caterpillar during our observations. It was a surprisingly small larva given the size of the wasp, but then she caches several victims in each cell before laying a single egg, putting up a partition of mud, and then starting a new cell along the length of the tunnel inside the wood.

Female cuckoo wasp, Chrysis sp., prospecting for a host

One might think that nests in such solid material would be impermeable to parasites, but not so. We watched a brilliant blue-green cuckoo wasp, Chrysis sp., investigate some of the holes for occupants. Given a nest in progress, she would infiltrate and lay her own egg inside. Her larva would then consume the prey items left by the rightful owner for its offspring. Cuckoo wasps are nearly impregnable, with a very dense exoskeleton that deflects the bites and stings of host wasps. Cuckoo wasps can roll into a ball to further protect themselves.

Female Leucospis affinis ovipositing in a host nest

A less common parasitic wasp also came to the wall. Leucospis affinis is a large chalcidoid wasp. The female is easily recognized by the whip-like ovipositor that curls over the top of her abdomen. The ovipositor is the organ she uses to lay her eggs....by drilling through the solid wood directly into one of the cells of her host. How she divines the location of a host larva through a layer of dense cellulose is a mystery to me, but her aim is usually true.

Nest closure of mason wasp or carpenter bee

A completed nest of a mason wasp is usually identified by the mud plug that closes the entrance to the hole in the wall. Because the soil at Cape May is essentially all sand, it was difficult to tell if we were looking at a sand closure or a sawdust closure that would be the work of one of the carpenter bees.

Nest closure of leafcutter bee, Megachile sp.

Easier to identify was the completed nest of a leafcutter bee, genus Megachile. Leafcutter bees snip oval pieces from leaves of living plants and fashion those clippings into barrel-shaped cells that they stack along the length of a tunnel in wood, or underground in the case of a few species. The female bee then cuts at least one perfectly circular leaf fragment that serves as a "lid" for the completed cell.

Nest of grass-carrier wasp, Isodontia sp.

We found one hole filled loosely with bits of grass, and we surmise this was the work of yet another kind of wasp, the grass-carrier. These solitary wasps, related to mud daubers in the family Sphecidae, use dry grass to fill, and/or partition, and plug their nest tunnels. Near Cape May Point State Park we did witness a female Isodontia mexicana select and bite off a dry grass stem to take back to her nest, so we know these insects were active.

Female grass-carrier wasp, Isodontia mexicana, cutting a piece of grass

Ironically, one other kind of wasp was tearing the wall down one mouthful at a time. Workers of the Bald-faced Hornet, Dolichovespula maculata, would alight on the wall and begin chewing off wood fibers to mix with their own saliva. This creates a pulp that they use to make durable paper nests. Looking more closely at the wall we realized that the scores of yellow streaks on the otherwise weathered gray wooden surface were where yellowjackets (of which the Bald-faced "Hornet" is just another species) had stripped fibers for use in building their nests.

Bald-faced Hornet gathering wood fibers to make paper

No doubt, earlier in the season there would be even more activity around this wall. The shed is still standing, sturdy as ever, so the insects are not doing much, if any, structural damage. Please consider that if you find that your own shed is becoming home to carpenter bees and other insects. You may find yourself as enthralled as we were by the little ecosystem started by carpenter bees.

Female Monobia quadridens exiting her nest

Sources: Evans, Howard E. 1963. Wasp Farm. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 178 pp.
Buck, Matthias, Stephen A. Marshall, and David K.B. Cheung. 2008. “Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region,” Canadian Journal of Arthropod Identification No. 5: 492 pp. (PDF version).
Krombein, Karl V. 1967. Trap-nesting Wasps and Bees: Life Histories, Nests, and Associates. Washington, DC: Smithsonian Press. 570 pp.
Krombein, Karl V., et al. 1979. Catalog of Hymenoptera in America North of Mexico Vol.2 Apocrita (Aculeata). Washington, DC: Smithsonian Institution Press. Pp. 1199-2209.

White Prairie Clover: An Awesome Blossom

I am not a botanist by any stretch of the imagination, but I am pretty sure that the insect magnets in the shortgrass prairie field up the hill from my home here in Colorado Springs, Colorado, are White Prairie Clover, Dalea candida. What follows is a sampling of the many bees, wasps, butterflies, flies, and other insects that come to the flowers of this plant; and a little information on Dalea in general. Much of the pollinator enhancement literature touts Purple Prairie Clover, D. purpurea, so one has to dive deeper.

A cuckoo bee, Nomada sp., forages while a male sweat bee, Lasioglossum sp., approaches

Prairie clovers are in the pea family Fabaceae. White Prairie Clover in Colorado occurs from 3,400-7,200 feet in elevation, and blooms from June to August. It is a low-growing plant, flowers on stalks up to two feet tall, but the ones I see are no more than one foot tall and sometimes difficult to discern among the tall grasses, cacti, and yucca they share the prairie habitat with. This species is widespread from the Front Range across the Great Plains, north to Saskatchewan and Wisconsin, and as far east as Tennessee, Georgia, and South Carolina.

Common Checkered-skipper, Pyrgus communis

The flowers are arranged in a cone, and bloom from the bottom to the top. The cycle can last up to a month, providing insects with pollen and nectar over a longer period than most flowers, and often at a time when few other plants are blooming. The down side to this plant, from the perspective of the photographer/entomologist is that insects quickly move to the side of the flower opposite the photographer, where they are hidden from view, then fly to another florescence and repeat. I missed a good number of opportunities because insects move across the flowers so speedily.

Male Hunt's Bumble Bee, Bombus huntii

Bees of all stripes seem to enjoy White Prairie Clover, and male bees may visit not only for nectar but for mating opportunities with foraging females. I saw far more male sweat bees, Lasioglossum (subgenus Dialictus), for example, than I did females. Even male bees can be sufficiently hairy enough to perform pollination services, even though they are not gathering pollen to feed to offspring. This is especially true for bumble bees and longhorned bees.

Sweat bee, family Halictidae

Female mining bee, Calliopsis sp.

Male longhorned bee, tribe Eucerini, family Apidae

Cuckoo bee, Triepeolus sp.

A second species of Triepeolus

Butterflies visit the flowers, too, mostly for nectar, but the caterpillar stage of some species feeds on the foliage of Dalea. This is the case for the Southern Dogface, a rather scarce species here in Colorado. In addition to the butterflies shown here, I also spotted a Variegated Fritillary making a brief stop on a blossom.

A "crescent" butterfly, Phyciodes sp.

Two Reakirt's Blues, Echinargus isola

At least one moth visited White Prairie Clover during my two separate observations: the Jaguar Flower Moth, Schinia jaguarina.

Jaguar Flower Moth, Schinia jaguarina

Wasps were highly diverse and plentiful visitors, but made some of the shortest refueling stops of all the insects observed.

Great Golden Digger wasp, Sphex ichneumoneus

Thread-waisted wasp, Ammophila pictipennis

Female Ammophila procera

Male Ammophila procera

Ammophila ferruginosa

Black & Yellow Mud Dauber, Sceliphron caementarium

Male sand wasp, Bembix sp.

Male beetle-killer wasp, Cerceris sp.

Male beewolf wasp, Philanthus ventilabris

Male thynnid wasp, Myzinum sp.

Female thynnid wasp, Myzinum sp.

Cuckoo sand wasp, Stizoides renicinctus

Flowers that are attractive to pollinators are also attractive to their predators and parasites, and that was certainly obvious during my watch periods. The bee assassin, Apiomerus sp., was somewhat surprising because the bug is so conspicuous atop such a small flower. I suspect it was having little or no success. Meanwhile, the odd, cream-colored ambush bug, Phymata sp., could achieve proper concealment, even to the point that I recall seeing only one when there were surely many.

Bee assassin bug, Apiomerus sp.

Thick-headed flies accost bees or wasps in mid-air and ram an egg between the victim's abdominal plates. The fly larva that hatches then feeds as an internal parasite. This often kills the host, but not always.

Thick-headed fly, Zodion sp.

Thick-headed fly, Physocephala sp.

My personal experience is that white flowers, or at least pale flowers, attract a far greater diversity of insects than red, blue, or purple flowers, and even more than yellow flowers in some cases. It is puzzling to me that few pollinator advocates bother to reveal that fact. Maybe because everything is bee- and butterfly-centered, and still color-intensive in the landscaping sense, white flowers get short shrift in recommendations for the garden.

Grasshopper wasp, Prionyx atratus or Prionyx subatratus

It may be worth it to harvest seeds from wild plants, but please do not dig up mature White Prairie Clover. The plant has a deep taproot. One may also wish to consult their state's Native Plant Society for potential sources of seed. The plant flourishes in full sun and dry soils, requiring only a medium quantity of water.

Green-eyed wasp, Tachytes sp.

I will try and produce more floral-themed, pollinator-rich posts in the future to help readers in making landscaping decisions that support native plants as opposed to exotic ornamentals and inappropriate cultivars. Feel free to make suggestions as to additional resources.

Mason wasp, Euodynerus sp.

Sources: Holm, Heather. 2017. Bees: An Identification Guide and Native Plant Forage Guide. Minnetonka, Minnesota: Pollination Press LLC. 224 pp. Useful mostly for Upper Midwest U.S.
Mader, Eric, et al. 2011. Attracting Native Pollinators. North Adams, Massachusetts: Storey Publishing. 372 pp. A Xerces Society guide.
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