IN THE FIELD Downloaded from https://academic.oup.com/ae/article/64/4/218/5232710 by guest on 24 September 2021 A Tale of Two Cliff Dwellings: Parallels Between Humans and Native Bees MICHAEL C. ORR, FRANK D. PARKER, AND S. HOLLIS WOODARD or most of you reading this arti- architectural feats than those going it for which nesting biology remains a mys- cle, your lifestyle defi nes your liv- alone. As if the title didn’t already make tery, singular reports cannot encompass Fing arrangements and vice-versa. it obvious enough, bees can be an excep- the true plasticity of any species. Bees, like Whatever your education or social status, tion to this rule made for exceptions. most animals, are complex, and how they you work in some form to provide safe Bees engage in a number of disparate live is determined in part by the resourc- shelter for yourself and those you care for. nesting strategies across almost the entire es in and challenges of their environ- From cellular phones to robotic vacuums social spectrum, though they don’t yet ments. For instance, Anthophora (Helio- that may one day become sentient and engage in homeowner’s associations, and phila) squammulosa Dours excavates the rule over us all with an iron dust brush, this makes them ideal for studying the deepest nests in the subgenus, perhaps the luckier of us have homes fi lled with dynamic trade-off s between an individ- to shield its off spring from the persistent everything we need and then some. ual’s investment and fi tness. Th e majority degassing of the rather unneighborly vol- Th e living arrangements of most ani- of the ≈20,000 total bee species are sol- cano on which it resides (Erenler et al. mals are rather more spartan. Grizzly itary, and the general structure of their 2016). A less extreme example is seen in bears must settle for hot springs, not hot nests can be summed up (in an over- Anthophora (Heliophila) curta Provanch- tubs, and they don’t make wrap-around simplifi ed way) as an entrance, tunnel, er, which has now been found nesting airplane pillows for giraffes (a prob- and nest cell(s). Branching out from that in desert pavement (Hicks 1934), hard- lem perhaps solved by sheer quantity?). basic design, though, things can get rath- packed silt, and loose, dry soil. Yet, in Insects are often thought of as especial- er wild. Some of my favorites include the working with an undescribed species of ly austere, even further removed from largest bee species in the world (Megachile the same subgenus, I’ve had two more the realm of human luxury. Gary Larson pluto Smith), which nests in active termite females nest within fi ve feet of me as I comics aside, relatively few of us would mounds (Messer 1984), much like Antho- dug up the fi rst bee’s nest. Is this third liken our species to insects. There are phora (Heliophila) braunsiana Friese in species limited to sandy washes, or is exceptions, as one should expect among Africa (Rozen 1969). Of course, I’d also be that just the best nesting substrate for the millions of insect species out there remiss to not mention the beer-drinking this bee at that site? What are the limits (ants, termites, various wasps, and web- bees whose larvae are fed, at least in part, of any given bee’s nesting biology, and, spinners, to name a few). Common to on open-fermented yeasts (Roberts 1971). further, what mechanisms underlie their many examples is a high level of sociality, Although a diverse array of bee nest- choices? Anthophora squammulosa also which makes intuitive sense: individuals ing strategies is known, with Megandrena lives in areas without volcanoes, so why working together may achieve greater being the only North American bee genus would it ever nest in such seemingly 218 American Entomologist • Winter 2018 inhospitable places if it can use other specific system, and fewer than 10 bee that could get confusing, but most of them substrates? (I’m betting on microhabitat species are reported to excavate sand- are magnificent nonetheless, especially limits, as the group generally likes deserts stone nests worldwide (of the aforemen- those hidden at the end of any of the net- and it seems more tied to volcanoes in tioned ≈20,000 total). In contrast, many work of unpaved and often challenging the more tropical parts of its habitat, but species will reuse the tunnels that these roads that reticulate the Colorado Plateau. that’s a study for another time.) two bees excavate, and some appear to In such places, often sheltered beneath We cannot answer these or other ques- simply excavate their relatively small nest overhangs prevalent wherever water his- tions about bee nesting biology without cells directly off of pre-existent, larger nest torically did or presently does cut the more information about where and how tunnels. More never excavate, instead sim- terrain, they made their homes. Where bees live. Successful nesting is fundamen- ply nesting in the tunnels themselves. In the bees bore through sandstone, the tal to bee survival, and therefore bee con- total, roughly 20 insects are now known Ancestral Puebloans instead built up walls servation, but this work is not easy and to reuse tunnels within the A. pueblo sys- with sandstone blocks. Though humans few fully recognize its importance. At the tem alone. Given the putative benefits of and bees differ in their methods, both most basic level, the effort a bee must sandstone and the demonstrated ability humans and bees use a mortar of sorts Downloaded from https://academic.oup.com/ae/article/64/4/218/5232710 by guest on 24 September 2021 expend to successfully produce each of of other species to exploit pre-existent to improve the structural integrity of their its offspring will determine its fitness and, tunnels, more of these freeloaders likely homes; the bee uses secretions to close its ultimately, the persistence of its species await discovery. nest cells, and to line them to better main- at a given site. It makes intuitive, economic sense that tain relatively consistent environmental Although talk of busy bees may at first more species would exploit the efforts of conditions. The hard work of the Ances- evoke the rowed metropoles of honey sandstone excavators than would excavate tral Puebloans remains even today, those bees, or perhaps the resinous megastruc- nests themselves. Even if the benefits of ruins evincing the structural strength of tures of stingless bees, many solitary bees living there offset the costs, it makes sense sandstone. It is this durability, this bene- are also suitably busy for the old adage, to avoid the costs altogether when possi- fit to either group, that I’ve focused on so especially on a per-bee basis. For example, ble. Why work when you could choose not far and will return to, but there are other Andrena haynesi Viereck and Cockerell to (says the Ph.D. candidate pursuing an meaningful parallels. will excavate nest burrows in sand that academic career and the manic lifestyle Ever since learning that A. pueblo had are up to three meters deep (Parker and that entails)? Nonetheless, there remains nested within the sandstone blocks of a Griswold 1982). Anthophora (Anthopho- one sandstone-inhabiting animal, a true ruin at Mesa Verde National Park (at Site roides) pueblo Orr might initially seem ecosystem engineer, that is indisputably 3 in Orr et al. 2016), I’d been thinking lazy in comparison, because their nests better known by both researchers and the about the confluence of bee and human are scarcely found more than a handful general public: humans. More specifically, lifestyles. How often were bees and people of centimeters below the surface. I think I refer here to the Ancestral Puebloans (a found at the same site? What about at the that it gets a pass, though, given that what term preferred over “Anasazi,” a Navajo same time? As with many other questions, a bee nests in can also cause some hard- word for the group that roughly means these were sequestered away, waiting ship. Sandstone is a bit harder to deal “ancient enemy”). for an opportunity to be answered while with than sand, after all. There are a number of ways in which I worked on my dissertation. Needless Why would a bee, or anything else, one may draw parallels between human to say, I jumped at the chance to visit a really, ever choose to chew through sand- and bee uses of sandstone, but this dis- ruin site where Curtis Frazier (Utah State stone to make its home? (I encourage you cussion has largely focused on the bees University Eastern) had found sandstone to try this at home if you don’t already so far. Although you probably know more bee nests. agree that it’s generally a bad idea.) This about humans than bees, in general, some As with all others I take, the trip was question drove our recent paper, in which additional background information on this multipurpose. It started in Grand Stair- we described A. pueblo and explored specific topic might prove valuable. First case-Escalante National Monument in the selective forces which appear to act off, what little we know about the Ances- Southern Utah, where I found a few dozen upon it (Orr et al. 2016). We found that tral Puebloans is based upon archaeolog- new sandstone nest sites, gave two pre- the energy, time, and wear costs incurred ical work on the ruins they’ve left behind, sentations, and heard of several more in excavating sandstone may be offset because they’re believed to have aban- sites from attendees.