It’s been too long since I’ve been able to go out with the WGNSS Botany Group on their weekly Monday outing—a consequence of travel and renovations on top of the frenetic-as-usual insect-collecting season. The result is that my attendance on the Botany Group outings is semi-regular during fall/winter but spotty at best during spring/summer. That may seem exactly the opposite of what would be optimum for studying plants, but as a naturalist to the core I have no trouble finding things of interest no matter the season. Especially when the destination is a place as fascinatingly diverse as Johnson’s Shut-Ins State Park—best known previously for its rhyolite “shut-ins” but now mostly for the gashing scour zone that was ripped across it in Dec 2005 when a catastrophic failure of the reservoir atop nearby Proffit Mountain released one billion gallons of water that tore through the landscape in a matter of 12 minutes. The geology exposed by the scour and the living experiment of biological succession that began afterwards are both fascinating, making the Scour Trail one of the Missouri Ozarks’ most interesting day hikes.
Our chief target for the day was Hamamelis virginiana (common or American witch-hazel), which blooms in November and December and is restricted in Missouri to a few counties in the St. Francois Mountains and the extreme southwestern corner of the state. Interestingly, there is a second species of witch hazel—H. vernalis (Ozark witch hazel), more common in Missouri but much more restricted globally—that occurs here, but as it blooms later in winter (January/February) we did not expect to see it on this trip. We found the former reliably, though not abundantly, and among the last plants we found in bloom were some with the freshest (and best-illuminated by the low-angled sun) flowers. At one point while we were still within the dry-mesic upland deciduous forest uphill from the scour zone, we saw a nice colony of the patch-forming Diarrhena obovata (beak grass). This is an attractive grass that does well in shade and should be utilized more as an ornamental.
Hamamelis virginiana (common or American witch-hazel).
Hamamelis virginiana (common or American witch-hazel).
Diarrhena obovata (beak grass) in dry-mesic upland deciduous forest.
The overlook provided a stunning overview of the scour zone from an elevated vantage—the since rebuilt Proffit Mountain Reservoir rising ominously above it as an almost deliberate reminder of its potential power—before the descent down into the scour zone. It’s an almost alien landscape with an irregular, unweathered floor of exposed bedrock strewn with rocks ranging from pebbles to boulders. Sycamore and willow are the early leaders in the now 17-year-old race to recolonize the barren swath of land, but lack of toeholds for roots to grow is a bigger problem for this future forest than lack of sunlight by taller neighbors. At one point, we spotted a large bush heavily laden with dense clusters of berries atop a pile of rocks. While the more astute botanists in the group recognized it for what it was, I was dumbfounded as to its identity until it was revealed to me to be none other than Toxicodendron radicans (poison ivy)—the largest, densest, most heavily berry-laden “bush” form of the species I have ever seen. So impressive it was that seven botanists gave it much more than just a trifling look.
“Bush” form of Toxicodendron radicans (eastern poison ivy).
Dense clusters of berries on “bush” form of Toxicodendron radicans (eastern poison ivy).
About halfway down the scour zone we encountered the “great unconformity”—previously hidden by topsoil and forest but now exposed. Here, knobs of 1.3 billion-year-old granite are surrounded by 540 million-year-old dolomite deposited atop the granite in the shallow Cambrian seas that once covered all but the tallest of these by then already ancient knobs—mere nubs of the towering mountains they once were but worn down nearly to sea level by nearly a billion years of relentless rain and wind. The exposures of pink granite, their large embedded crystals glistening sharply in the sunlight, contrasted starkly with the dark gray dolomite surround them, representing an incomprehensible gap of nearly 800 million years in the record of Earth’s history preserved in the rocks. The entire history of multicellular life on Earth could be swallowed by such a gap!
Unconformity with 1.3 billion-year-old Precambrian granite (pink rock) surrounded by 540 million-year-old Cambrian dolomite (gray rock) in scour zone below Profitt Mountain
As an entomologist, I cannot ever stop being on the lookout for insects, no matter what the season. Even though temps were well on the chilly side, I still managed to discern a couple of small wolf spiders, and somehow I managed to see a small ant cadaver on a twig that had succumbed to an insect-pathogenic fungus in the Ophiocordyceps unilateralis complex. Even the botanists around me started taking advantage of the opportunity for insect education. Len and Michael noticed a gall on a small Quercus muhlenbergii (chinquapin oak) which turned out to be the work of Disholcaspis quercusglobulus (round bullet gall wasp), and John noticed a colony of Prociphilus tessellatus (woolly alder aphid) on Alnus glutinosa (European alder). Closer inspection revealed an adult Harmonia axyridis (Asian lady beetle) preying upon the aphids.
Small wolf spider (family Lycosidae) on moss-covered rock in dry-mesic upland deciduous forest.
Pardosa sp. (thin-legged wolf spider) on exposed granite in 17-year old scour zone through dry-mesic upland deciduous forest.
Ophiocordyceps unilateralis complex insect-pathogenic fungus infecting ant (family Formicidae) in dry-mesic, deciduous, upland forest.
Disholcaspis quercusglobulus (round bullet gall wasp) on Quercus muhlenbergii (chinquapin oak) in dry deciduous upland forest.
Harmonia axyridis (Asian lady beetle) preying upon Prociphilus tessellatus (woolly alder aphid) on Alnus glutinosa (European alder)
It was as enjoyable an outing as I’d hoped (how can four hours in the woods be anything BUT enjoyable), and I hope not to let so much time pass before the next time I’m able to join the group!
This is the eighth “Collecting Trip iReport”; this one covering a one-week trip to southern Arizona, New Mexico, and California from September 7–14, 2019 with meloid/cerambycid-enthusiast Jeff Huether. Jeff has been a frequent collecting trip partner during recent years, this being our sixth joint outing since 2012. Our initial objective on this trip was to collect cerambycid beetles of the genus Crossidius occurring across southern Arizona/California—part of a larger effort to sample as many of the named subspecific taxa as possible from multiple locations (including type locations when possible) for future molecular studies. We had good success, though we did not collect every taxon that we were after (we were a tad early in soCal). Also, the fact that we had Crossidius as our primary goal did not mean that we would not concurrently be on the lookout for buprestids (me), meloids (Jeff), or other cerambycids (both of us)—and in that regard we were also successful.
Day 1 – Dripping Springs Mountains, Arizona First stop of the trip, and we’re heading east to Safford. As soon as we got east of Superior up into the mountains we saw a place where Heterotheca subaxillaris was in bloom abundantly along the roadsides and pulled over. There were four species of Acmaeodera on the flowers, and I also found a fifth species on the flower of a small white aster. Nice first stop for the trip!
Dripping Spring Mountains.
Acmaeodera gibbula on flower of Heterotheca subaxillaris.
Acmaeodera rubronotata on flower of Heterotheca subaxillaris.
Acmaeodera alicia on flower of Heterotheca subaxillaris.
3.6 mi NW Bylas on US-70, Arizona Continuing our way to Safford, Jeff saw some patches of sunflower and wanted to look for Epicauta phoenix. I found the first two (but not in sunflower), and then Jeff found two more. As we were walking back to the car I noticed a Crossidius suturalis sitting on Isocoma tenuisecta that was not quite in bloom, and then another nearby on the same plant. We searched the area again, but the only plants were those few right around the car.
I’ve never seen an orange jumping spider (family Salticidae) before!
5.7 mi NE Safford, Arizona After getting a hotel in Safford, we had time to come back to a spot where Jeff had collected Epicauta phoenix back in July. We found quite a few (see photo) on plants nearby the original collection spot. Looking around more I found an Acmaeodera convicta perched on the tip of a shrub—first time I’ve collected this species! There were several species of tenebrionids crawling on the ground, perhaps prompted to activity by cooling temps as rain whipped up in the distance. I kept one eye on the skies and the other on the plants and eventually found two more A. convicta perched together on the same type of shrub just as rain began pelting my back. We made a quick dash back to the car and called an end to Day 1 in Arizona.
Epicauta phoenix (order Coleoptera, family Meloidae).
Day 2 –1.9 mi S Artesia, Arizona We started seeing Isocoma tenuisecta just coming into bloom as we headed south of town so stopped to see if we could find any Crossidius. I looked at a lot of plants before finding a single C. suturalis sitting on one of the non-blooming plants and in the meantime found one Trichodes peninsularis and a fair number of Zonitis dunniana on the flowers. Looking around on other plants, I found one large Chrysobothris sp. (not C. octocola, but longer and narrower) on the branch of a living Acacia constricta [Edit: this is C. knulli—a new one for me!] and one Acmaeodera disjuncta, several more Z. dunniana and T. peninsularis on flowers of Hymenothrix wislizeni. Finally, I did some sweeping of the bunch grasses in the area and got a nice series of what I presume to be Agrilus rubrovittatus—first time I’ve collected that species!
Crossidius suturalis on pre-blooming Isocoma tenuisecta.
Trichodes peninsularis on Isocoma tenuisecta.
Zonitis dunniana on flowers of Isocoma tenuisecta.
17.7 mi S Artesia, Arizona Another stop with both Isocoma tenuisecta and also Gutierrezia microcephala coming into bloom. We immediately began finding Crossidius pulchellus on the latter and eventually collected a good series of them and also Trichodes peninsularis off the plants When I returned to the first plant we had checked (in fullest flower), a Lampetis webbii landed on it right in front of me! I eventually found C. suturalis on Isocoma tenuisecta, as well as Trichodes sp. and a few C. pulchellus. There was a tall-stemmed malvaceous shrub off which I got a male/female pair of Tylosis maculata, and sweeping produced a couple more Agrilus rubronotata, a few more T. peninsularis, and one Acmaeodera scalaris. I saw a couple of Acmaeodera disjuncta on Baileya multiradiata flowers but missed them both!
Stagmomantis limbata (bordered mantis) on Gutierrezia microcephala.
Lampetis webbii on Gutierrezia microcephala.
1.1 mi N Rodeo, New Mexico We slipped just inside the New Mexico border to visit the area around the type locality of Crossidius hurdi. We found a spot where there were good stands of Isocoma tenuisecta along the roadsides and checked them out. Like the other spots today they were just starting to come into bloom, and rain had just moved through the area. We found perhaps 20 Crossidius individuals total, and honestly they were so variable that I don’t know whether they represent C. suturalis, C. hurdi, or both! [Edit: they are all C. suturalis] I also collected one Sphaenothecus bivittatus and several individuals each of three species of clerids on the flowers of these plants. A male Oncideres rhodosticta was found on the twig of Prosopis glandulosa, and I also found a cool meloid that I’ve never seen before—Megetra punctata!
A particularly well-marked female Crossidius suturalis on flowers of Isocoma tenuisecta.
The coloration of Megetra punctata screams “Don’t eat me or you’ll be sorry!”
Oncideres rhodosticta on Prosopis glandulosa (mesquite).
Mule deerly departed.
Fence row to the Chiricahua Mountains.
Willcox Playa, Arizona We plan to visit Willcox Playa tomorrow (my inaugural visit!), but we had some time at the end of the day and decided to come take a look. There were some stands of Isocoma tenuisecta at the north end of the playa, and I found just a couple of Crossidius individuals on them, presumably C. suturalis, but it looks like they are bedding down for the evening. Also got a couple of Enoclerus sp. on the flowers.
North end of Willcox Playa.
Day 3 –8.4 mi SE Willcox, Arizona On our way towards the Chiricahua Mountains to see if we can find any Crossidius host plant stands. We found patches of Isocoma tenuisecta and Gutierrezia microcephala along Hwy 186 southeast of town—the former was just coming into bloom, but there were plenty of Acmaeodera (scalaris, disjuncta, and amplicollis) on the flowers, including on the unopened heads. We found perhaps a dozen Crossidius suturalis on them as well, and Jeff found one small female that looks like C, hurdi [Edit: it is C. suturalis]. I looked at a lot of Gutierrezia before finding a single C. pulchellus sitting on one of the plants. The same diversity of Acmaeodera as well as a few A. gibbula and T. peninsularis was also found on flowers of Hymenothrix wislizeni, and I took a series of about 10 specimens of what I looks like A. parkeri on flowers of what appears to be Stephanomeria pauciflora. There were also some tiny membracine treehoppers on a thorny shrub (maybe Condalia?) being tended by ants—both adults and young, and I collected a few of the adults.
Acmaeodera amplicollis on flowers of Isocoma tenuisecta.
Acmaeodera disjuncta on flowers of Isocoma tenuisecta.
Acmaeodera scalaris on flowers of Hymenothrix wislizeni.
Jct AZ-186 & AZ-181, Arizona After passing over a small range towards the Chiricahuas we didn’t see any Isocoma tenuisecta until we got to Hwy 181. There were some Baccharis sarothroides at the junction also, so we stopped and looked around. The Isocoma was just barely coming into bloom, but I found two Crossidius on them—one male C. suturalis and one small female that may be C. hurdi [Edit: nope, it is C. sururalis]. Heterotheca subaxillaris was in bloom abundantly, but there were no Acmaeodera on them and the area in general looked quite dry. I did find two A. decipiens on Sphaeralcea sp., and in the way back to the car I spotted a huge Lampetis webbii hanging on Ericameria nauseosa (which we’re not even close to blooming)—surely an incidental record.
Chiricahua Mountains in the distance.
4.1 mi SE Willcox, Arizona We came back towards town where things seemed to be further along and found stands of Isocoma tenuisecta in full bloom at the junction of Blue Sky Rd (a classic Arizona collecting locality). Crossidius suturalis were out in numbers on the flowers! Every now and then I got one that seemed too heavily maculated, making me think it could be C hurdi, but in the end I decided that all represented C. suturalis.
Crossidius suturalis mating pair on flowers of Isocoma tenuisecta. Note the difference in antennal length between the male (top) and female.
Willcox Playa, Arizona We went to the Playa to see if there were any tiger beetles to be had. I hiked to the edge of the Playa, and within a few minutes I saw a Cicindela pimeriana—just the second one I’ve encountered (the first was last night at gas station lights)! With that promise of more, I hiked the entire playa edge and never saw another one! I only saw one other tiger beetle—Cylindera lemniscata—seems I’m a bit late in the season for the Willcox Playa tiger beetles. Nevertheless, it’s a cool place and was fun to see. I’ll definitely be back during the summer, not just for here but for nearby Blue Sky Rd. Arriving back at the car, I did find one Moneilema sp. (I think M. appressum) on cholla. There were Crossidius suturalis abundant on the Isocoma tenuisecta, which, like the last spot, was in full bloom, but I’d gotten my fill of them at the previous spot and didn’t collect any.
Stalking tiger beetles.
Jumping spider out in the playa.
Eking out a living.
Cow tracks.
These Gnathium sp. were the tiniest blister beetles I’ve ever seen.
Willcox, Arizona (epilogue) Collecting the insects from the field is only the beginning. Each night they must be processed for storage until they can be mounted once back in the lab.
Processing the day’s catch.
Day 4 – Santa Rita Mountains, Box Canyon, Arizona We passed through Box Canyon on our way to Madera Canyon, so we decided to stop near the dry falls where last year I’d collected such a nice diversity of Acmaeodera spp. on flowers of Allionia incarnata. There was evidence of recent rain, and we found the patch nicely in bloom with four species (scalaris, decipiens, cazieri, and parkeri) on the flowers. Nearby in the wash before it crossed the road was a yellow composite (Xanthisma gracile), from which I collected the first three as well as gibbula, rubronotata, and disjuncta. Euphoria verticalis scarabs we’re flying plentifully around the flowers also—first time I’ve seen the species.
Allionia incarnata (trailing four o’clock) blooming the canyon slope.
Flats below Madera Canyon, Arizona There are records of Deltaspis tumacacorii from Madera Canton at Proctor Rd collected on Croton, so we stopped by on our way south to give it a try. This seems to be a rather hard-to-find bug, so I didn’t have high expectations, and that’s a good thing because I didn’t see the beetle nor anything that even remotely resembled Croton. I ended up checking out the desert broom (Baccharis sarothroides) in the area on which I’d collected Stenaspis verticalisarizonensis and Tragidion spp. (also without high expectations). There were some interesting congregations of Euphoria leucographa feeding at sap flows on the stems and a few Stenaspis solitaria but otherwise litttle of note. I did find one Hippomelas planicauda hanger-on on a low fabaceous shrub (not Mimosa biuncifera), and inspecting the Gutierrezia microcephala plants revealed nothing but a single Acmaeodera rubronotata.
Stenaspis solitaria on Baccharis sarothroides (desert broom).
Peucetia viridans (green lynx spider) feeding on Acanthocephala thomasi twice its size!
Euphoria leucographa and a Polistes paper wasp feeding at a sap flow on Baccharis sarothroides (desert broom).
Euphoria leucographa on Baccharis sarothroides (desert broom).
Taenipoda eques (lubber grasshopper). The striking coloration is a warning to potential predators that it is chemically protected.
Madera Canyon Rd, Arizona We stopped real quick down the road on the way out of Madera Canyon because we saw stands of Isocoma tenuisecta, although they were still just shy of blooming. We looked at quite a few and found a single Crossidius suturalis—probably we are a tad early, and the area looks like it could use a good rain to pop things out and bring the Isocoma into bloom. We also saw low plants that could be the Croton that Deltaspis tumacacorii has been found on [Edit: I do not believe these are the plants, as they are too low]. Would be good to revisit this spot after a good rain!
The author with Ferocactus wislizenii (fishhook barrel cactus)—also called “compass barrel” due to its habit of leaning to the south.
Tumacacori Mountains, Walker Canyon, Arizona Our second shot at Deltaspis tumacacorii, which has also been taken in Walker Canyon. We found thick stands of knee-high flowers that we immediately took to be the Croton—just as described by our contact—on which the beetles have been taken. However, we quickly began doubting that ID and decided the plant must be some type of composite. That would make more sense from a host plant standpoint, as all known host plants for Crossidius spp. are composites (subsequently determined to be Pseudognaphalium leucocephalum, family Asteraceae). We looked at the dense stands for quite some time but didn’t see any beetles (or much of anything else) before deciding that we were probably too early—had the beetles already emerged we would have at least found some stragglers. I did take a few Acmaeodera on the flowers (scalaris and rubronotata), as well as a large cantharid (Chauliognathus profundus). I also took single A. amplicollis and A. rubronotata individuals off of a large helianthoid composite (Viguiera cordifolia) and one A. rubronotata on a small yellow composite (Xanthisma gracile). There were a multitude of darkling beetles crawling in the ground—in one spot I saw five individuals of several species all within a one-square foot area. We’ll have one more shot at D. tumacacorii tomorrow at Kitt Peak.
Pseudognaphalium leucocephalum (white rabbit-tobacco) blooms profusely in the dry wash.
Cantharid vs. cantharid! Chauliognathus profundus (right) feeds on a C. lewisi that it has captured.
Day 5 –Pan Tak, Arizona (road to Kitt Peak) Today’s destination is Kitt Peak to look for Deltaspis tumacacorii and Acmaeodera resplendens, but at the entrance we saw some Isocoma tenuisecta just coming into bloom and decided to check it out. We found a half-dozen Crossidius suturalis but had to really work for them. Alliona incarnata was also nicely in bloom, but I got only one Acmaeodera parkeri? and one A. alicia off of the flowers. There was some Gutierrezia microcephala present, also not quite in bloom, off of which Jeff got a pair of C. suturalis and gave me one. Kinda dry but lots of flowers—wish there would have been more beetles coming to them.
Moneilema sp. on Cylindropuntia imbricata.
Kitt Peak National Observatory, Arizona Our last chance to find Deltaspis tumacacorii, and I also got a tip that Acmaeodera resplendens has also been taken up here. We immediately found several species of Acmaeodera (amabilis, amplicollis, decipiens, and rubronotata) abundantly on several composite flowers—Heliomeris longifolia, Heterotheca fulcrata, Hymenothrix wrightii, Solidago velutina, and Gutierrezia microcephala, and I found a single A. solitaria on a pink malvaceous flower, but no A. resplendens. We also searched thoroughly for any Croton-like plant for D. tumacacorii but found nothing. The Kitt Peak records of that species are older than the Walker Canyon, Peña Blanca, and Madera Canyon records, and most of the records seem to be in August rather than September, so I suspect we are a bit late for both the species and its host plant. My plan at this point is to return sometime during the middle of August and enlist the help of the source of one of the recent records to accompany me.
View north from Kitt Peak National Observatory.
Multiple species of Acmaeodera visiting flower of Heliomeris longifolia.
Acmaeodera amabilis on flower of Heliomeris longifolia.
Road to Kitt Peak, Arizona We had noticed Gutierrezia microcephala and some other yellow composites in bloom about halfway up the mountain on our way to Kitt Peak and decided then to stop and take a look around on the way down. I took “down” the mountain, Jeff took “up.” I hadn’t walked very far when I saw what I at first thought was the cantharid Chauliognathus profundus (which I had seen yesterday at Walker Canyon preying on another cantharid) on G. microcephala flowers, but something about it gave me pause—it was too cylindrical and robust. I leaned closer to get a better look and realized it was a cerambycid—one that I did not recognize, a beautiful orange color with black elytral apices and pronotal spots! I quickly grabbed it with my right hand, immediately saw another elsewhere on the bush and grabbed it with my left hand, and as I stood there trying to fumble a vial out of my pack to put them in I saw a third individual taking flight from the bush and spiraling into the air and out of reach! I shouted out to Jeff, who came down to where I was, and showed him what I’d found, and together we decided that it must be Mannophorus forreri—a very uncommonly encountered species and more than adequate consolation for not finding Deltaspis tumacacorii earlier in the day. We spent the next hour searching up and down the roadsides, and I ended up with two more individuals from Gutierrezia flowers and two from Heterotheca fulcrata. Jeff found an additional individual on flowers of Thelesperma sp. I also picked up a few black and white Enoclerus sp., one on flowers of G. microcephala and a mating pair on flowers of Acacia berlandieri. We have a long drive to California in front of us now, and it sure is good going into the drive with such a great find under our belts.
Lower slopes of the road to Kitt Peak Observatory.
Thasus neocalifornicus (giant mesquite bugs) congregate on their host plant (Prosopis glandulosa).
Day 6 – Cajon Pass, California Finally made it into California! Once we turned off the interstate, we made a quick stop to look at the roadside habitat where we spotted a good stand of Isocoma sp. in full bloom. We looked at quite a few plants but didn’t find any beetles on them. There were also good numbers of Ericameria nauseosa plants as well (host for Crossidius coralinus), but they weren’t quite yet in bloom yet and the only thing I found on them was a mating pair of Agrilus walsinghami. Moved on quickly to the next spot!
Lancaster, California We met up with Ron Alten and traveled to a classic “Crossidius” collecting site (up to four species have been taken there). We’d stopped at a couple of places on the way there but not found anything—either the host plants were not yet blooming or no beetles were found, so we had the feeling that we might be a week or two early. We had to drive into the habitat a ways before we started seeing host plants—in this case Ericameria nauseosa—but eventually we found a nice large area with the plants in full bloom. It didn’t take long before we found Crossidius coralinus (populations in this area are assigned to subspecies ascendens) on the blossoms. We worked the area for a couple of hours in the heat (97°F) and got a sufficient series for study with some individuals in ethanol for DNA analysis. Males exhibit quite a bit of variability in the degree of development of the elytral markings (thin to moderately expanded sutural marking), while females were quite consistently fully expanded. Males also outnumbered females by 3:1, and all of the individuals I collected were perfect and not damaged—both suggesting that the species is just beginning to emerge. Perhaps that is why we did not find individuals of the other species (mojavensis, suturalis, and testaceus). What I did find, however, was a small trachyderine cerambycid that none of us recognized! It was on the flowers of E. nauseosa—just like C. coralinus—and at first I thought it might be a small, aberrant C. coralinus, but the elytra are completely blue-black and the size was significantly smaller than the smallest C. coralinus male that we saw. I scanned BugGuide and didn’t find anything that matched, so this will have to remain a mystery for now. [Edit: I later determined this to be a heavily marked C. discoideus blandus. In the field I couldn’t see the orange laterals on the elytra.]
Crossidius coralinus ascendens (male) on flowers of Ericameria nauseosa.
Crossidius coralinus ascendens (female) on flowers of Ericameria nauseosa.
Crossidius coralinus ascendens (mating pair) on flowers of Ericameria nauseosa.
Day 7 –Santa Catalina Mountains, Mt. Lemmon, Arizona We decided we were just a bit to early for things in California and decided to come back to Arizona where we’d been having better success. I wanted to take another shot at Acmaeodera resplendens and had been told that Oracle Ridge Trail was a good locality for them, though maybe a bit late. We began seeing them soon after getting out of the car—unmistakable by their brilliant metallic green to copper color. They were not numerous, so I had to work for them and walked the trail about 2 miles out collecting them off a variety of flowers. The majority were on Bahia dissecta, and I also found occasional individuals of them and other species of Acmaeodera (amabilis, amplicollis, decipiens, and rubronotata) on flowers of Heliomeris longifolia, Heterotheca fulcrata, Hymenothrix wrightii, Ageratina herbarea, Achillea millefolium, sweeping, Cirsium sp., and prob. Viguiera dentata. One other beetle I found was a Megacyllene sp. sitting on a plant under a stand of Robinia neomexicana [Edit: this is M. snowi snowi—another new one for my collection!].
View from Oracle Ridge Trail @ 1 mile north of the trailhead.
Acmaeodera resplendens on flower of Heliomeris longifolia.
Acmaeodera resplendens on flower of Heliomeris longifolia.
Scenic Overlook, Santa Catalina Mountains, Arizona A quick stop on the way back down the mountain at a spot where we’d seen Gutierrezia microcephala and Heterotheca subaxillaris blooming along the sides of the road. There wasn’t much going on—a couple of Acmaeodera amplicollis and one A. rubronotata on the flowers of H. subaxillaris, one Enoclerus sp. on Solidago velutina, one A. solitaria on Baccharis sarothroides, and another swept from grasses. I did see Peucetia viridans (green lynx spider) feeding on a very bristly tachinid fly.
A clearwing moth (family Sesiidae).
Peucetia viridans (green lynx spider) feeding on a hairy tachinid fly.
Day 8 –Santa Rita Mountains, Montosa Canyon, Arizona (halfway up) We decided to visit Montosa Canyon to take another shot at Deltaspis tumacacorii and also see if maybe we could find more Acmaeodera resplendens. We didn’t see many flowers along the way up the canyon until about the halfway point. When we did start seeing them we made a quick stop to see what might be on them. I collected some of the more common Acmaeodera (rubronotata, decipiens, and amplicollis) off a few different yellow composite flowers, but we quickly decided to take a look at the higher elevations.
Panoramic view from halfway up the canyon.
Apyrrothrix araxes (dull firetip skipper) on flowers of Baccharis salicifolia.
The larvae of these large skippers feed on oaks.
Santa Rita Mountains, Montosa Canyon, Arizona (entrance to Whipple Observatory) The road was gated past the km-13 point—Jeff took the roadsides, and I took a ridgetop trail off to the south for a little over a mile. The panoramic views were spectacular, and at the southern terminus I stood at the edge amidst gale-force winds admiring the landscape! Acmaeodera were diverse and abundant, though not quite as abundant as yesterday on Mt. Lemmon or a few days ago on Kitt Peak. However, I did get another nice series of A. resplendens, along with decipiens, rubronotata, amplicollis, and amabilis. Host flowers were collected for most of these: Hymenothrix wrightii, Erigeron neomexicanus, Linum neomexicanum, Heliomeris multiflora, Verbesina enselioides, Heliopsis parvifolia, Heterotheca subaxillaris, and Machaeranthera tanacetifolia. I also collected a small series of A. decipiens perching on grass stems and a very cool-looking wasp—black with a bright orange thorax and whitish abdominal apex [edit: I believe this is the scoliid Psorthaspis portiae].
Vista from the southern terminus of the ridgetop trail off Mt. Hopkins Rd at km 13.
Acmaeodera decipiens on flower of Machaeranthera tanacetifolia.
A curious assemblage of bees on this Heliomeris longifolia flower. They were not active, just sitting. [Edit: these are Dufourea sp. (short-faced bees, family Halictidae)].
Santa Rita Mountains, lower Montosa Canyon, Arizona We stopped at a spot near the bottom of the canyon on the way out to see what was going on at the lower elevations. The answer—not much! There were a variety of woody shrubs and other plants in bloom, but the area seemed rather “wilty”. I think this area has a lot of potential, we just didn’t hit it at the right time. I did take an impressively huge tarantula hawk, just because.
Fouquieria splendens (ocotillo) resembles cacti but is not a true cactus. Distantly related to persimmons, blueberries and acacias, it is now placed in its own family (Fouquieriaceae).
Apiomerus flaviventris (yellow-bellied bee assassin) with prey.
The prey is a soldier beetle (likely Chauliognathus lewisi).
Robber flies not only mate tail-to-tail, they fly coupled in the position also. This tandem of giant robber flies (possibly Promachus nigrialbus), flew by me and landed in the bushes. The male (right) tried to take flight again and pulled the female’s hind legs off her perch. She stood firm, however, forcing the male to grab a nearby branch with just his from and middle legs and leave his hind legs dangling also. Note that the female is also feeding on a honey bee—so much natural history going on here!
Flats below Montosa Canyon, Arizona I was a bit disappointed at not finding any beetles at what seemed would be the last collecting stop of the trip. But on our way out we saw a patch of Isocoma tenuisecta in bloom in the lowlands some distance west of the entrance to the canyon—just what we were looking for! Jeff and I each quickly found Crossidius suturalis individuals on flowers of the plants and continued searching up and down along the roadway. We didn’t find any more for awhile but when I got back to the area where I started I spotted another one sitting on a plant on the other side of the barbed-wire fence. I extended my net handle to the max, maneuvered it in position, took an assertive swipe, and got it. Just as I was putting it into the bottle, I saw another one take flight from a plant right beside me. I hadn’t closed the bottle yet but didn’t want the other one to get away, so I capped my thumb over the opening, awkwardly wielded my net into position one-handed, chased after it and took a swing and got it, too! (More often than not these situations end up with me losing both specimens!). There was also a good amount of Hymenothrix wislizeni along the roadside, off the flowers of which I collected several Acmaeodera gibbula, A. disjuncta, and A. rubronotata. This is probably the last collecting locality of the trip, so I’m happy to end up having success with this subspecies of Crossidius (C. suturalis intermedius), which we havn’t found in large numbers on this trip. Just after leaving the site, we saw a bobcat on the side of the road—my first one! Unusual to see one in the middle of the day—it was a small one, must’ve been quite hungry!
Santa Rita Mountains from the highway.
Phoenix, Arizona (epilogue) Bill Warner was kind enough to host Jeff and I for our last night in Arizona prior to returning home tomorrow. What an amazing collection he has built, and his use of flight-intercept traps in recent years has turned up even more amazing beetles. I was happy to also meet Andrew Johnston and Evan Waite, who joined us for dinner.
Bill Warner, an icon among Arizona beetle collectors, sits amidst newly collected I material waiting to be processed.
I was all set to make a “One-Shot Wednesday” post today, but sometimes big news strikes and plans must change. The news today was in the form of a random tweet by Alex Wild:
The link in the tweet led me to the following photo on iStock by Getty:
bedbug has captured worm
I was stunned—the photo depicted a scene almost identical to one that I had photographed back in September while visiting soybean fields in Louisiana. For two months I sat on the photo with no idea what I was looking at, but now thanks to Alex I have my answer! Compare the above photo with mine below, and you’ll see that everything matches perfectly—I had photographed a “bedbug” that had captured a “worm”!
bedbug captures a worm
I considered myself to be fortunate, because there was not just one but two different subjects in the photo, and both of them matched perfectly with the subjects shown in the iStock photo. Gotta love the internet—nowadays names for even the most hard-to-identify bugs are just a click away if you know where to look!
</snark>
Of course, the aggressor in both photos is not a “bedbug” [sic for “bed bug”] (order Hemiptera, family Cimicidae) but a stink bug (family Pentatomidae), specifically Podisus maculiventris, or “spined soldier bug”—perhaps the most common predatory stink bug in North Amerca and ranging from Mexico and parts of the West Indies north through the U.S. into Canada. It is a well-known predator of crop pests and, as such, has been imported to several other countries as part of classical biological control efforts. As for the “worm,” in my photo it is a late-instar larva of Chrysodeixis includens, or “soybean looper, and while I haven’t been able to identify the exact species in the iStock photo it is definitely a lepidopteran caterpillar that appears to related to if not in the same family as the soybean looper (Noctuidae). Now, I concede that “worm” is sometimes used for lepidopteran larvae, but one must also concede that in it’s broadest sense “worm” can refer to members of several disparate phyla such as Nematoda (roundworms), Platyhelminthes (flatworms), or Annelida (segmented worms).
This case, of course, just screams for application of the Taxonomy Fail Index (TFI), which scales the amount of error in a taxonomic identification in absolute time against the error of misidentifying a human with a chimpanzee—our closest taxonomic relative. For example, when TFI = 1 the error is of the same magnitude as mistaking a human for a chimp, while TFI > 1 is a more egregious error and TFI < 1 a more forgivable one. In the case shown here, one must go back to the common ancestor that eventually gave rise to all of the worm phyla and noctuid moths (~937.5 mya). In addition, since there are two subjects in the photo, one must also go back to the divergence of the main hemipteran groups that contain bed bugs and stink bugs (mid-Triassic, ~227.5 mya). This results a whopping 1.165 billion total years of divergence between the identifications assigned to the subjects in the iStock photo and their actual identity. Assuming that chimps and humans diverged approximately 7.5 mya, this gives a TFI for the iStock photo of 155! I haven’t searched thoroughly to determine whether this is a record for the highest TFI in a single photo, but surely it is a strong contender!
Cerceris fumipennis nest littered with Neochlamisus sp. beetles
In Working with Cerceris fumipennis Part 1 and Part 2, I talked about the use of this species as a biosurveillance tool for Buprestidae. These wasps are specialist predators of jewel beetles, which they capture almost exclusively and paralyze with their sting to use as food provisions for their offspring in underground nests. I also mentioned that there are other species of Cerceris, each specializing in its own distinct prey group, and at my site in east-central Missouri I found C. bicornis, a weevil specialist, almost as common as C. fumipennis. Thus, when I came upon this particular Cerceris wasp nest, I wondered it I had encountered yet another species in the genus, for littered around it were case-bearing leaf beetles in the genus Neochlamisus.
The bright coppery coloration suggests Neochlamisus platani
I counted 11 beetles lying on the diggings surrounding this nest, and as is typical with buprestids around C. fumipennis nests these beetles all appeared to represent the same species (I’ve done a little collecting of Neochlamisus beetles in Missouri—the especially bright coppery coloration suggests to me N. platani, a species found on eastern sycamore, Platanus occidentalis). I’ve also noted that C. fumipennis nests littered with beetles on the surface also have beetles—usually of the same species—freshly cached underground, so I decided to dig up the nest to see what might be in it. As I inserted the grass stem and started digging, I heard the distinctive buzzing indicating the wasp was still inside the nest, and when it appeared I noted the distinctive three yellow facial markings that identify it as a female C. fumipennis. As suspected, the nest contained another seven beetles of the same species, and I would later learn that C. fumipennis, while specializing on jewel beetles, does occasionally take other prey. Philip Careless and colleagues recorded two leaf beetles, including Neochlamisus bebbiana, and one weevil as hosts for this wasp at their Working with Cerceris fumipenniswebsite. If my species ID of these beetles is confirmed, this should represent yet another non-buprestid host record for C. fumipennis, although I should also mention that out of several hundred observations this was the only non-buprestid prey I observed around or in a C. fumipennis nest.
For nearly 30 years, jewel beetles (family Buprestidae) have been my primary research interest. While some species in this family have long been regarded as forest and landscape pests, my interest in the group has a more biosystematic focus. A faunal survey of Missouri was the result of my initial efforts (MacRae 1991), while later research has focused on distributions and larval host associations of North American species (Nelson & MacRae 1990; Nelson et al. 1996; MacRae & Nelson 2003; MacRae 2004, 2006) and descriptions of new species from both North America (Nelson & MacRae 1994, MacRae 2003b) and South America (MacRae 2003a). Research interest in other groups—especially longhorned beetles and tiger beetles, has come and gone over the past three decades; however, I always return to jewel beetles as my first and favorite group.
In recent years, one species in particular—the emerald ash borer (EAB, Agrilus planipennis) has garnered a huge amount of research, regulatory, and public interest after reaching North America from Asia and spreading alarmingly through the hardwood forests of Michigan and surrounding states. The attention is justifiable, given the waves of dead native ash trees that have been left in its wake. With huge areas in eastern North America still potentially vulnerable to invasion by this species, the bulk of the attention has focused on preventing its spread from infested areas and monitoring areas outside of its known current distribution to detect invasion as early as possible. One incredibly useful tool that has been adopted by survey entomologists is the crabronid wasp, Cerceris fumipennis. Like other members of the family, these solitary wasps dig nests in the ground, which they then provision with captured insect prey. The wasp uses its sting to paralyzed the prey but not kill it, and once inside the burrow the wasp lays an egg on the prey and seals the cell with a plug of soil. The eggs hatch and larvae develop by consuming the paralyzed prey (unable to scream!). After pupation the adult digs its way out of the burrow (usually the next season), and the cycle begins anew. However, unlike other members of the family (at least in North America), C. fumipennis specializes almost exclusively on jewel beetles for prey. So efficient are these wasps at locating and capturing the beetles that entomologists have begun using them to sample areas around known wasp populations as a means of detecting the presence of EAB. Philip Careless and Stephen Marshall (University of Guelph, Ontario) and colleagues have been leading this charge and have even developed methods for transporting wasp colonies as a mobile survey tool and developed a sizeable network of citizen scientists throughout eastern North America to expand the scope of their survey efforts. Information about this can be found at the excellent website, Working with Cerceris fumipennis(please pardon my shameless lifting of the title for this post).
I first became aware of the potential of working with C. fumipennis a few years ago when Philip sent me a PDF of his recently published brochure on use of this wasp for EAB biosurveillance (Careless et al. 2009). My correspondence with him and other eastern entomologists involved in the work suggested that ball fields with lightly vegetated, sandy soil would be the best places to look for C. fumipennis nests, but my cursory attempts to find the wasp at that time were unsuccessful. I reasoned that the clay-soaked soils of Missouri didn’t offer enough sand for the wasps’ liking and didn’t think much more about it until last winter when I agreed to receive for ID a batch of 500+ buprestid specimens taken from C. fumipennis wasps in Louisiana. What a batch of material! In addition to nice series of several species that I had rarely or never seen (e.g. Poecilonota thureura), three new state records were represented amongst the material. A paper is now in progress based on these collections, and that experience catalyzed a more concerted effort on my part to locate a population of the wasp in Missouri. Museum specimens were no help—the only records from Missouri were from old specimens bearing generic locality labels such as “St. Louis” and “Columbia.” Throughout the month of May, I visited as many ball fields as I could, but the results were always the same—regularly groomed, heavy clay, barren soil with no evidence of wasp burrows (or any burrows for that matter).
Near the end of May, however, I had a stroke of luck. I had switched to a flatter route through the Missouri River Valley to ride my bike to work because of knee pain (now thankfully gone) when I saw this:
Practice fields at Chesterfield Valley Athletic Complex | St. Louis Co., Missouri
Those are “practice” fields in front of regular fields in the background, and unlike the latter, this row of nine fields (lined up against the levee adjacent to the Big Muddy National Wildlife Refuge) showed no evidence of regular grooming or heavy human use. Only ten miles from my home, I made immediate plans to inspect the site at the first opportunity that weekend. Within minutes after walking onto the lightly vegetated, sandy-clay soil of the first field, I found numerous burrows such as this:
Cerceris fumipennis with circular, pencil-wide burrow entrance and symmetrical mound of diggings.
Only a few more minutes passed before I found an occupied nest, the wasp sitting just about an inch below the entrance to its pencil-wide burrow. The three yellow markings on the face indicated it was a female (males have only two facial markings), and in short order I found numerous other burrows also occupied by female wasps. Some were just sitting below the burrow entrance, while others were actively digging and pushing soil out of the burrow with their abdomen. I flicked a little bit of soil into one of the burrows with a female sitting below the surface, which prompted an immediate “cleaning out” of the burrow—this explains the dirty face of the female in the following photo, but the three yellow facial markings are clearly visible:
Cerceris fumipennis female removing soil from burrow entrance.
After finding the burrows and their occupants, I began to notice a fair number of wasps in flight—leaving nests, returning to nests, and flying about as if searching for a ‘misplaced’ nest. A few of these were males, but most were females, and I also caught a couple pairs flying in copula (or at least hitched, if not actually copulating). Despite the number of wasps observed during this first visit, I didn’t see a single wasp carrying a buprestid beetle. This puzzled me, because all of the Louisiana beetles I had determined last winter were taken by standing in the midst of nests and netting those observed carrying beetles. Finally, I had confirmation that I was truly dealing with this species when I found a couple of beetles lying on the ground near the entrance to a burrow. These would be the only beetles that I would find on this visit, but subsequent visits during the following few weeks would show “ground picking” to be the most productive method of collecting beetles. Across the nine fields, I found a total of nearly 300 nests, and the wasps showed a clear preference for some fields over others—one field (P-6) had about 150 nests, while a few others had less than a dozen. The photo shown in ID Challenge #19 shows a sampling of ground-picked buprestids from P-6 in a single day, and occasionally I would find a real prize like Buprestis rufipes:
Buprestis rufipes laying near Cerceris fumipennis nest entrance.
Coincident with the appearance of large numbers of beetles laying on the ground near nest entrances, I also began to see wasps carrying their prey. Wasps carrying large beetles are easily recognized by their profile, but even those carrying small beetles look a little more “thick-thoraxed” (they hold their prey upside down and head forward under their thorax) and exhibit a slower, more straight-line flight path compared to the faster, more erratic and repetitively dipping flight of wasps not carrying prey. Learning how to discern wasps carrying prey in flight from the more numerous empty-handed wasps prevents a lot of wasted time and effort netting the latter. Nevertheless, there does appear to be some bias towards larger beetles when netting prey-carrying wasps in flight, as evidenced in the photo below of beetles taken by this method, also in field P-6, on the same date as the ground-picked beetles shown in ID Challenge #19. This could be a result of visual bias towards wasps carrying larger beetles, as in later visits (and presumably with a more refined search image) I did succeed in catching larger numbers wasps carrying smaller beetles (primarily in the genus Agrilus).
Buprestid prey of Cerceris fumipennis: L–R and top to bottom 2 Dicerca obscura, 2 D. lurida, 3 Poecilonota cyanipes, 2 Acetenodes acornis, 1 Chrysobothris sexsignata, 1 Agrilus quadriguttatus, and 1 A. obsoletoguttatus
All told, I collected several hundred beetles during my twice weekly visits to the site from late May to the end of June. Beetle abundance and wasp activity began to drop off precipitously in late June, which coincides precisely with the end of the adult activity period for a majority of buprestid beetles in Missouri, based on my observations over the years. This did not, however, spell the end of my activities in using C. fumipennis to collect buprestid beetles, which will be the subject of Part 2 in this series.
Congratulations to Joshua Basham, whose efforts in ID Challenge #19 earned him 12 points and the win. Morgan Jackson and Paul Kaufman were the only others to correctly identify the Cerceris fumipennis connection and take 2nd and 3rd, respectively. In an unexpected turn of events, BitB Challenge Session #6 overall leader Sam Heads did not participate and was leapfrogged by Brady Richards, whose becomes the new overall leader with 59 points. Sam now trails Brady by 5 points, while Mr. Phidippus lies another 3 points back. With margins this tight, the overall standing can still change in a single challenge, and there will be at least one more in this current session before an overall winner is named.
MacRae, T. C. 1991. The Buprestidae (Coleoptera) of Missouri. Insecta Mundi 5(2):101–126.
MacRae, T. C. 2003a.Mastogenius guayllabambensis MacRae, a new species from Ecuador (Coleoptera: Buprestidae: Haplostethini). The Coleopterists Bulletin 57(2):149–153.
MacRae, T. C. 2003b.Agrilus (s. str.) betulanigrae MacRae (Coleoptera: Buprestidae: Agrilini), a new species from North America, with comments on subgeneric placement and a key to the otiosus species-group in North America. Zootaxa 380:1–9.
MacRae, T. C. 2004. Notes on host associations of Taphrocerus gracilis (Say) (Coleoptera: Buprestidae) and its life history in Missouri. The Coleopterists Bulletin 58(3):388–390.
MacRae, T. C. 2006. Distributional and biological notes on North American Buprestidae (Coleoptera), with comments on variation in Anthaxia (Haplanthaxia) viridicornis (Say) and A. (H.) viridfrons Gory. The Pan-Pacific Entomologist 82(2):166–199.
MacRae, T. C., & G. H. Nelson. 2003. Distributional and biological notes on Buprestidae (Coleoptera) in North and Central America and the West Indies, with validation of one species. The Coleopterists Bulletin 57(1):57–70.
Nelson, G. H., & T. C. MacRae. 1990. Additional notes on the biology and distribution of Buprestidae (Coleoptera) in North America, III. The Coleopterists Bulletin 44(3):349–354.
Nelson, G. H., & T. C. MacRae. 1994.Oaxacanthaxia nigroaenea Nelson and MacRae, a new species from Mexico (Coleoptera: Buprestidae). The Coleopterists Bulletin 48(2):149–152.
Nelson, G. H., R. L. Westcott & T. C. MacRae. 1996. Miscellaneous notes on Buprestidae and Schizopodidae occurring in the United States and Canada, including descriptions of previously unknown sexes of six Agrilus Curtis (Coleoptera). The Coleopterists Bulletin 50(2):183–191.
Eriopis connexa adult on soybean | Buenos Aires Province, Argentina
Congratulations to those of you who correctly guessed the identity of the “subject” in ID Challenge #16 as the ladybird beetle Eriopis connexa (family Coccinellidae). This is one of the most common ladybird beetles in Argentina, and during the past few weeks I have seen large numbers of these beetles in the soybean fields that I have been visiting. Coccinellids in Argentina are among the easier the groups to identify to species thanks to the excellent website Coccinellidae of Argentina. Identifying the “meal,” however, proved to be a little more difficult. Most people guessed aphids, a natural choice, but soybean aphids have not yet made it to the soybean fields of South America (thankfully!), so the victims of these predaceous beetles must be something else. There was a clue in the challenge photo that at least one person picked up on (but didn’t make the connection) in the form of small black globs stuck to the hairs of the plant on which the beetle was sitting. These are actually the fecal deposits of the bean thrips, Caliothrips phaseoli (order Thysanoptera, family Thripidae) (which I covered a year ago in A thrips is a thrips…), which for the past two seasons now has built up large populations on soybeans in Argentina. In fact, an adult bean thrips (yes, “thrips” is the correct singular form) can be seen in the above photo (which I did not notice while I was taking the photo). I’ve not yet witnessed these beetles actually feeding on a thrips, but the large numbers of thrips and beetles and near absence of any other suitable prey item makes the association almost a given.
Eriopis connexa larva on soybean | Buenos Aires Province, Argentina
Not only are the adult beetles numerous on the plants, but eggs and larvae as well. Larvae are every bit as brightly colored as the adults, with a color scheme that leaves little doubt regarding their association. In the case of this larva, I watched it roam back and forth across the soybean leaf, pausing momentarily and apparently eating something—thrips eggs I presume.
Congratulations to Mr. Phidippus and Dennis Haines, who tie for the Challenge win with 14 points each, while Gustavo and Dave tie for the final podium spot. Mr. Phidippus, however, easily takes the overall win in BitB Challenge Session #5 with a whopping total of 57 points. Mr. Phidippus—contact me for your loot! Dennis Haines and Tim Eisele take 2nd and 3rd overall honors, and full standings for BitB Challenge Session #5 are shown below.
I happened upon a rather interesting scene last week in a soybean field in northern Argentina (Chaco Province). This assassin bug (family Reduviidae) had captured and was feeding on an adult stink bug of the species Piezodorus guildinii—an important pest of soybean in Argentina and Brazil (where it is known by the common names “chinche de la alfalfa” and “chinche verde pequeño”, respectively). Assassin bug predation is always interesting enough itself, but what made this scene especially fascinating was the large congregation of flies surrounding and even crawling upon the predator and its prey. I had not witnessed something like this before, but it seemed clear to me that the flies were engaging in kleptoparasitism—i.e, stealing food. I’ve gotten into the habit of keeping a full set of extension tubes mounted on the camera with my 100mm macro lens—this not only provides the most useful (for me) range of magnification but also serves as a convenient and easy-to-use field microscope. Through the viewfinder I could see that there were at least two markedly different types of flies involved—more abundant, small, brown flies that I presumed (incorrectly, as it turns out) to be some type of drosophilid (vinegar fly), and a few larger, black flies that were completely unfamiliar to me. The flies were apparently feeding on fluids from the stink bug prey but also crawled all over the assassin bug as it fed. The assassin bug seem unencumbered in its feeding by the presence of the flies, but periodically it would slowly wipe its forelegs over its head to dislodge flies that had settled onto it. Just as quickly as they flew away, however, they crawled back.
The assassin bug, on the other hand, I recognized as very likely a species of Apiomerus—a large, exclusively New World genus known in North America as “bee killers” for their habit of sitting on flowers and ambushing visiting bees for prey. The prey selection behaviors of these insects, however, are more generalist than the name implies, as can be seen by these photographs. To verify my generic ID and possibly obtain a species ID, I sent some of these photos to Dimitri Forero at the Heteropteran Systematics Lab at University of California-Riverside. Dimitri is revising portions of Apiomerus (e.g., Berniker et al. 2011) and working on a general phylogenetic hypotheses for the genus. In the past he has been quite helpful in fielding questions from me about these bugs, and within a few hours Dimitri replied to inform me that the assassin bug was, indeed, a member of the genus Apiomerus, likely representing the common, widespread species A. lanipes (ranging from Panama to Argentina), based on its coloration, locality, and relative size. Update 12 March, 3:07 pm—After seeing the last photo in this post (which I did not send to him initially), Dimitri wrote to say the ventral abdominal pattern was not characteristic of A. lanipes. He asked about its size, to which I replied that it was about the same length but maybe a little less robust than A. crassipes (eastern North America).He later added, “I now think that this is A. flavipennis Herrich-Schaeffer, 1848. It is very similar to A. lanipes, but a lot smaller (lanipes is really robust), and with the abdomen with black and white patches, whereas in lanipes the abdomen is always black. I checked some series of specimens that I have here and, I am pretty sure now of the ID. I have material from Argentina as well. In some specimens that coloration of the corium varies, but the original description says it is yellow with a “hairy” pronotum, which fits very nicely your photos.” Apiomerus flavipennis is known from Argentina and Southern Brazil only.
Quite unexpectedly, Dimitri also noted that at least some of the flies could belong to the family Milichiidae. He first became aware of these flies after seeing a photograph of Apiomerusshowing something similar and suggested Milichiidae online as a possible source for more information. This remarkably informative website by milichiid expert Irina Blake, who dubs species in the family as “freeloader flies”, is a model for how websites dealing with obscure insect taxa should be organized and populated (and features on the home page a great photo of ant-mugging flies taken by our favorite myrmecophile). At any rate, I forwarded my photos to Irina and within minutes received her response that the bigger black flies most probably represent the cosmopolitan Milichiella lacteipennis and the smaller flies a species of the family Chloropidae (of “dog pecker gnat” fame) in the subfamily Oscinellinae, noting that she has seen similar (or the same?) chloropids in other photos as well engaging in kleptoparasitism.
Not long after receiving the first reply from Dimitri, I got another message from him with a link to a very interesting paper by Eisner and colleagues (1991), who recorded freeloader flies in Florida preferentially attracted to stink bugs and leaf-footed bugs (family Coreidae) being preyed upon by the orb-weaving spider Nephila clavipes. Olfactory stimuli were already suspected to be involved in attraction of milichiids and also chloropids (Sivinski 1985); however, Eisner et al. (1991) experimentally demonstrated that milichiid attraction was tied to specific components of defensive sprays in several pentatomid and coreid species (including P. guildenii, the prey species in this series of photographs). The defensive sprays of the bugs were generally ineffective at preventing predation by the spiders (and apparently this is the case for A. lanipes and other reduviids as well), thus serving as a signal to milichiids and chloropids not only of the presence of a food source but perhaps also assisting search for mates in a density dependent fashion (Sivinsky 1985). Milichiid attraction to hymenopteran prey, richly endowed with integumental glands themselves, has also been documented; the Eisner study raises the question whether these types of prey are also detected from chemical cues.
Eisner, T., M. Eisner & M. Deyrup. 1991. Chemical attraction of kleptoparasitic flies to heteropteran insects caught by orb-weaving spiders. Proceedings of the National Academy of Sciences of the United States of America 88:8194–8197.
Sivinski, J. 1985. Mating by kleptoparasitic flies (Diptera: Chloropidae) on a spider host. Florida Entomologist 68(1):216–222.
Beetles In The Bush 