science

“Bugged on the Ozark Trail”

/ Ted C. MacRae / Leave a comment

The Ozark Trail is a renowned resource for recreational activities. Perhaps less well appreciated are the outstanding opportunities for nature study it also offers. Traversing some of the state’s most pristine areas, numerous plants and animals make their homes in the diverse natural habitats found along its length. While reptiles, birds, and mammals may be the most conspicuous animals encountered, they are far from the most diverse or numerous. That honor belongs overwhelmingly to the insects.

The Trail Builder, Late Fall 2008

The above quote is an excerpt from the lead article in the latest issue of The Trail Builder, newsletter of the Ozark Trail Association (click on the banner for a PDF of that issue). Yes, I am the author, and it is purely a matter of coincidence that I ended up authoring the lead article in two different newsletters in the same month (see “Dungers and Chafers – a Trip to South Africa”).

The Mission of the Ozark Trail Association is to develop, maintain, preserve, promote and protect the rugged, natural beauty of the Ozark Trail.–Ozark Trail Association

The Ozark Trail is one of Missouri’s premier hiking resources, stretching from just south of St. Louis southwestward through the Ozark Highlands to the Arkansas border. The vision of a 700-mile through trail connecting to Arkansas’ Ozark Highlands trail is well underway, with almost 550 miles of trail already completed – 350 miles in Missouri. My friend, colleague, and hiking buddy Rich and I began hiking different sections of the Ozark Trail almost 10 years ago, and thus far we have seen 220 of those miles. From the rugged beauty of the Marble Creek and Taum Sauk Sections, traversing the ancient St. Francois Mountains, to spectacular vistas atop towering dolomite bluffs along the Current River and Eleven Point Sections, we’ve experienced the essence of a landscape that Henry Schoolcraft so elegantly described during his 900-mile journey through the Ozarks with companion Levi Pettibone, nearly 200 years previous.

“Bugged on the Ozark Trail” is a short, fun article describing just a few of the insects hikers can expect to see along the Ozark Trail. Missouri is home to perhaps 25,000 species of insects, and many of these are found in the Ozark Highlands by virtue of the diverse natural communities formed within that great landform. Dung beetles, who despite their unappealing diet perform a great service in clearing the trail of waste from horseback riders. My beloved tiger beetles, flashing brilliant green along wooded trails and on rocky glades. Ambush bugs, paradoxically using the beauty of flowers as cover for their deadly intentions. Endangered dragonflies, infuriating deer flies, and endearing butterflies – these are but a few of the insects that can be seen along the Ozark Trail.

Previous issues of The Trail Builder are also available at the Ozark Trail Association website in the archives.

Buppies in the bush(veld)

/ Ted C. MacRae / 8 Comments

In writing an article for the most recent issue of SCARABS, I found myself reliving some long-dormant memories of my trip to South Africa. It was nine years ago right about this time of year when I made what was to become the collecting trip of a lifetime. What a completely different November/December experience compared to the gray skies and bare trees I see outside my window today. Writing that article was a lot of fun – going back through my slides (yep, slides – no digital for me then), reviewing material in my collection, and trying my best to recall some long forgotten details. Using a long-handled tropics net to collect Evides spp. from upper branch terminals of Lannea discolor at Geelhoutbos FarmOf course, scarabs were not my reason for going to Africa – buprestids were! Although I did manage to sneak a few buprestid photos into the SCARABS article, for the most part I was a good boy and kept my focus on the that newsletter’s intended subject. It wasn’t hard, given the gorgeous diversity of “dungers” (dung beetles) and flower chafers that I encountered in that spectacular country. Here, however, I offer a sampling of the Buprestidae I encountered during that trip.

Much of trip was spent in the bushveld (pronounced “bushfelt”) tropical savanna – a mix of grassland and semi-deciduous forest – below the rugged and rocky Waterberg Mountains, their rugged exposures of 2.7 billion year old sandstone and quartzite providing a spectacular backdrop. I’ve already posted a photo of Evides pubiventris, the largest and most spectacular buprestid seen there. A handsome, iridescent green that must be seen to be believed, these elusive beetles spend their days high off the ground on the upper branch terminals of their host trees, Lannea discolor. Success in collecting these beetles comes only to those willing to give it considerable effort. In this photo, I use a long-handled tropics net and tap the rim of the net on the undersides of the branch terminals. The adults are alert and quick to fly but often enough drop from the foliage into the net before taking flight. Many hours were spent during the several days we were at this spot with my neck craned upwards, but my efforts were richly rewarded with several specimens of E. pubiventris and the closely related E. interstitialis.

Agelia petalii - South Africa, Limpopo Province, vic. Waterberg Mountains, Geelhoutbos Farm, 30.xi.1999, on Grewia monticolaAnother of the more spectacular buprestids seen on the trip was Agelia petelii, a not too distant relative of Evides (both are in the subfamily Chrysochroinae, containing the bulk of the “classic” jewel beetles). Several individuals of this species were seen here in the Waterberg and also at Borakalalo National Park in North West Province. Their bold markings would seem to make them conspicuous targets for predation by birds but actually serve as protection by mimicking the warning coloration of Mylabris oculata, a common blister beetle in southern Africa that occasionally reaches pest status on leguminous crops and that is – like all blister beetles – largely protected from predation by the cantharidins in its hemolypmph. Many of these blister beetles were seen during the trip, and I had to pay close attention to each of them in order to secure my half dozen or so specimens of the much less common A. petelii.

Meliboeus punctatus - South Africa, Limpopo Province, 8.5 km S of Piesmoor River, 4.xii.1999, on unidentified Grewia-like shrubThis gorgeous little beetle, seen south of the Waterberg near the Piesmoor River, belongs to the enormously diverse but poorly known tribe Coraebini. This tribe – a cousin to the even more diverse genus Agrilus (see this post) – is represented by only a few species in North America but is richly represented in sub-Saharan Africa and Madagascar. Chuck Bellamy – my friend, colleague, and host during this trip – probably knows more about coraebines than anybody alive and has identified this as Meliboeus punctatus. The plant on which the beetles were found remains a mystery – it looks similar to plants in the rhamnaceous genus Grewia on which we saw so many other buprestid species but is clearly not a member of that genus. It is one of the few buprestids I collected on the trip for which I did not obtain host information (I hate that!).

Acmaeodera (Paracmaeodera) viridaenea swierstrae - South Africa, North West Province, Borakalalo National Park, along Moratele River, 24.xi.1999, on Grewia flava blossomThe genus Acmaeodera is another of the hugely diverse groups in the family, having radiated in all the biogeographic realms except Australian. This group is especially well represented in North America, with some 150 species occurring in our desert southwest and many more occurring down into Mexico. The vast majority of these are variously patterned with yellow and/or red markings on a black background. In southern Africa the genus is also diverse but shows greater diversity of form and has, accordingly, been divided into a number of well-defined subgenera. Like our North American species, adults of many African species are frequently found on flowers, where they feed on pollen and petals. I encountered at least a dozen Acmaeodera spp. on the trip, with one of the more striking species being A. (Paracmaeodera) viridaenea. Acmaeodera (Rugacmaeodera) ruficaudis - South Africa, South Africa, Limpopo Province, vic. Waterberg Mountains, Geelhoutbos Farm, 1.xii.1999, on Grewia flava blossomLike other species in this subgenus, adults are brilliantly colored and sexually dichroic, with the individual pictured here (above, left) being a female and the males being greenish brown with coppery sides. Other species are quite somber colored, such as A. ruficaudis in the subgenus A. (Rugacmaeodera) (right). Both of these individuals were found on flowers of Grewia flava.

Discoderoides immunitus - South Africa, South Africa, Limpopo Province, vic. Waterberg Mountains, Geelhoutbos Farm, 1.xii.1999, on Grewia flavaNot all “jewel beetles” do their name justice. This small species – Discoderoides immunitus (another member of the tribe Coraebini) – appears to resemble a piece of caterpillar frass. Several individuals were seen, all sitting on the leaves of Grewia flava like this individual rather than visiting the flowers like Acmaeodera. This beetle reinforced an important lesson I have learned repeatedly about field identification – upon my return to St. Louis, when I had an opportunity to examine these individuals more closely under the microscope, I found one specimen mixed in the batch that was, in fact, not this species, but a species in the closely related genus Discoderes. Moreover, that individual appears to represent an as yet undescribed species. Pity that I found only the single individual, since describing species from such uniques is not very desireable. Regardless, I’m glad I didn’t assume this individual was yet another D. immunitis in the field and pass it by – keeping the species in the still too-swollen ranks of the unknown and unseen.

One of the most exquisite species that I collected was Anadora cupriventris – a very large (by coraebine standards), heavily sculptured species densely covered with curled swaths of gold and brown pubescence. I regret not having the opportunity to photograph the single individual that I found. Another impressive species that I was not able to photograph was Agrilus (Personatus) sexguttatus, surely close to, if not the largest species in the genus and boldly patterned with black and rust red spots on olive green. One last species for which I have no images but is worthy of mention is an undetermined species of the genus Pseudagrilus. Looking like a chunky, brilliant green Agrilus with saltorial (jumping) metafemora, adults would “pop” off the Solanum plants on which they were found as soon as I looked at them. I eventually decided that “Flipagrilus” would have been a more appropriate name for the genus. All told, I collected some 66 species of Buprestidae, including several genera not previously represented in my collection (e.g., Brachmaeodera, Brachelytrium – a few becoming paratypes of new species then being described by Chuck Bellamy and Svata Bílý, Chalcogenia, Galbella, and many of the other above mentioned species). I should mention the assistance of Chuck and Svata for helping me with some of the identifications, as well as Gianfranco Curletti who identified all of the material in the difficult genus Agrilus. I sincerely hope that I have another chance to visit this incredible land of beauty and contrast!

Cicindela limbata – epilogue

/ Ted C. MacRae / 10 Comments

In my Lucky 13 post, I featured Cicindela limbata (sandy tiger beetle) from north of Grand Island, near the easternmost edge of the Nebraska Sandhills. This species is restricted to dry sand blow out and dune habitats away from water, thus its distribution in Nebraska largely coincides with that of the Sandhills themselves. Nebraska populations are assigned to the nominate subspecies, which is characterized by extensively developed white maculations on the elytra, Nebraska, Grant Co., nr. Hyannis, 3.4 mi S Hwy 2 on Hwy 61, 26.ix.2008, coll. T.C.MacRaewith the sutural area and small discal markings metallic green or blue. The whitish areas on the elytra and dense pilosity on the undersurface, along with their habit of digging into the sand during the midday hours, are obvious adaptations for reflecting heat and avoiding the high temperatures that occur in their white sand habitats. In the more eastern areas of the Sandhills, the green sutural areas of the elytra are suffused with a reddish cast (see this photo in Lucky 13), while in populations further to the west no such reddish suffusion is seen. The individual featured in these two photos was found in the western Sandhills (near Hyannis) and is one of the individuals that I dug from their midday burrows (see Sand Hills Success). Had I not been clued into this behavior when I visited this site, I would have left with only the single individual that was seen at the surface. That individual was captured immediately, and further searching for active adults to take photographs of were unsuccessful – until I started digging, that is. Unfortunately, adults that have just been caught or dug out of their burrows aren’t the most cooperative photography subjects, so one of them was kept alive and placed in a terrarium upon my return to St. Louis. (These photos were taken about a week after I returned, and the individual lived for another seven weeks on a diet of 3rd instar fall armyworm and black cutworm larvae. I eventually trained it to grab larvae directly from the forceps – very entertaining indeed! Also, while these photos from the terrarium confines are adequate for illustrating the species, I think they still lack that undefinable spark that is caputured in true field photographs with unmanipulated individuals – compare to this photo).

Cicindela limbata, with its five recognized subspecies1, has one of the more interesting distributions of North American species (see Pearson et al. 2006). In the main area of distribution, the southernmost populations, distributed through most of Nebraska and adjacent areas of Wyoming and South Dakota, are considered nominotypical. A distributional gap to the north separates these populations from Nebraska, Grant Co., nr. Hyannis, 3.4 mi S Hwy 2 on Hwy 61, 26.ix.2008, coll. T.C.MacRaesubspecies nympha, which occurs in sand habitats of northern Montana and North Dakota and further northward into the Canadian Prairie Provinces. Individuals from these populations exhibit even greater development of the white maculations but darker intervening areas. Another distributional gap separates nympha from subspecies hyperborea, which (as its name suggests) occurs even further north in open sand habitats in the pine and poplar forests of northern Alberta and Saskatchewan and adjacent areas of the Northwest Territories. Subspecies hyperborea is characterized by its greatly reduced white maculations (thus, exhibiting expanded dark areas) and overall smaller size, both of which may be regarded as heat conservation adaptations for the far boreal climate in which it lives.

1 Excluding the federally endangered Cicindela albissima (Coral Pink Sand Dunes tiger beetle), which was recently elevated to species status based on mitochondrial DNA evidence (Morgan et al. 2000).

The fragmented nature of the main limbata population in the upper Great Plains and into the boreal forests is, in itself, interesting enough. Even more interesting, however, are the existence of two small and highly disjunct populations far removed from the main limbata population. One of these is known from Labrador – almost 3,000 miles to the east! Originally referred to subspecies hyperborea, this population was theorized to possibly represent an accidental introduction since individuals appeared to be restricted to open sand habitats within 70 km of the Goose Bay airport (Larson 1986, Pearson et al. 2006). However, careful examination of individuals from this population revealed subspecific differences in maculation (intermediate between hyperborea and nominotypical limbata), lending support to the hypothesis that it is a naturally occurring population and resulting in its description as a distinct subspecies, labradorensis (Johnson 1990). Recent analysis of mitochondrial DNA sequences provided additional support for this subspecies as a distinct entity (Knisley et al. 2008), and newly published field observations by tiger beetle afficionados Dave Brzoska and John Stamatov (2008) conducted 19 years after the initial discovery of the population suggest it is well established in suitable habitats much more distant from Goose Bay than originally reported. This accumulation of evidence seems to increasingly support a historical isolation rather than accidental introduction hypothesis. The fifth and final subspecies is an even more recently discovered and equally disjunct population in the Nogahabara Dunes of northwestern Alaska (Pearson et al. 2006). Although individuals from this population resemble subspecies nympha, morphological and mitochondrial DNA sequence analyses support its status as a distinct subspecies, designated nogahabarensis (Knisley et al. 2008). Such an unusual and fragmented distribution for Cicindela limbata and its subspecies is likely the result of historical changes in climate that have caused expansions and contractions of open sand habitats due to fluctuations in available moisture. The current geographical subspecies may have originated at the end of the mid-Holocene hypsithermal (or Holocene Climatic Optimum) some 5,000 years ago, when previously expansive open sand habitats would have begun shrinking and fragmenting as a result of declining temperatures and increasing moisture regimes.

REFERENCES

Brzoska, D. W. and J. Stamatov. 2008. A trip to Goose Bay, Labrador, Canada. Cicindela 40(3):47-52.

Johnson, W. 1990. A new subspecies of Cicindela limbata Say from Labrador (Coleoptera: Cicindelidae). Le Naturaliste Canadien 116(4) [dated 1989]:261-266.

Larson, D. J. 1986. The tiger beetle, Cicindela limbata hyperborea LeConte, in Goose Bay, Labrador (Coleoptera: Cicindelidae). The Coleopterists Bulletin 40(3):249-250.

Knisley, C. B., M. R. Woodcock and A. Vogler. 2008. A new subspecies of Cicindela limbata (Coleoptera: Cicindelidae) from Alaska and further review of the maritima group by using mitochondrial DNA analysis. Annals of the Entomological Society of America 101(2):277-288.

Morgan, M., C. B. Knisley and A. Vogler. 2000. New taxonomic status of the endangered tiger beetle Cicindela limbata albissima (Coleoptera: Cicindelidae): evidence from mtDNA. Annals of the Entomological Society of America 93(5):1108-1115.

Pearson, D. L., C. B. Knisley and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp.

“My favorite bettle”

/ Ted C. MacRae / 3 Comments

Today’s essay is by guest blogger (and perhaps future entomologist), Madison MacRae. Currently a 3rd grade student at Pond Elementary School, Madison’s interests include ice skating, tetherball, basketball, piano, dancing, singing, and hiking/bug collecting with her dad. Next year they will be something else. Madison would like to be a grade school teacher when she grows up. She would also like to be a nurse… and a fire fighter… and a football player. This is Madison’s second guest contribution to Beetles In The Bush, the first appearing on February 6, 2008 where she discussed the job responsibilities of a professional entomologist. For today’s contribution, Madison will be discussing one of the insects she saw on a visit to Missouri’s sand prairies back in early September [Ed. note: the insect in question appears to be an intergrade population of Cicindela scutellaris, characterized by their green coloration (unicolor influence) with variable maculation (lecontei influence)]. The original article was submitted as school work (with no prompting or prior knowledge by her dad!) and is reprinted here by the kind permission of its author.

MacRae, M. I. 2008. My favorite bettle. Privately published, 1 p., 1 color pl.

“Dungers and Chafers – a Trip to South Africa”

/ Ted C. MacRae / 9 Comments

Those of you who enjoy field trip accounts should check out the December 2008 issue of SCARABS. The lead article – authored by your’s truly – is a scarabcentric travelogue of an insect collecting trip I took to South Africa several years ago. Scarabs?!, you say? Well, even though I focus on bups, ‘bycids, and tigers (some would argue that actually demonstrates lack of focus), I never pass on the opportunity to collect “cool” insects of all types when traveling somewhere as “exotic” as Africa – and scarabs are definitely cool! Still, I did manage to sneak past the editors a few words and pictures about buprestids, one of the more impressive of which I offer here as further enticement. You can also read about heart attacks, flying Tonka trucks, and evil minions.

Photos: (above) me standing next to a termite mound near the Waterberg, Northern Province (photo by Chuck Bellamy); (left) Evides pubiventris (family Buprestidae, tribe Evidiini) suns itself on high terminal foliage of Lannea discolor (family Anacardiaceae), Waterberg, Northern Province.

Two new species of Agrilus from Mexico

/ Ted C. MacRae / 4 Comments

ResearchBlogging.orgThe enormous, cosmopolitan genus Agrilus (family Buprestidae – commonly called jewel beetles or metallic woodboring beetles) contains nearly 4,000 described species (Bellamy 2008). With many more still awaiting description, it is perhaps the largest genus in the entire animal kingdom (Bellamy 2003). Agrilus species are primarily twig and branch borers, utilizing recently dead wood for larval development – although there are notable exceptions, e.g. Agrilus anxius (bronze birch borer), A. bilineatus (twolined chestnut borer), and A. planipennis (emerald ash borer), which attack the trunks of living trees and, thus, are of significant economic importance in forest and ornamental landscapes. Host specificity among Agrilus species ranges from highly monophagous – associated exclusively with a single plant species – to rather oliphagous – utilizing several, usually related, plant genera. Adults of Agrilus species are most often found on the foliage of their larval hosts and do not generally visit flowers, as is common in some other genera (e.g., Acmaeodera and Anthaxia). Interestingly, despite the diversity and worldwide distribution of the genus, no species of Agrilus are known to be associated with coniferous plants – a fact that has limited their expansion into the vast northern boreal forests.

Texas, Bexar Co., San Antonio, nr. Fort Sam Houston, em. 25.iv-14.v.1997 ex Phoradendron tomentosum coll. ii.1997, D. Heffern & D. W. SundbergAs can be imagined by its enormity, a comprehensive understanding of the genus will remain a distant goal for many years. Progress will come incrementally, as formal descriptions of new species gradually improve our knowledge of the fauna that exists in each of the world’s main biogeographic provinces. In a recent issue of the online journal Zootaxa, Dr. Henry Hespenheide (UCLA) describes two new species of Agrilus from Mexico. These two species are interesting because of their association with ‘mistletoe’ plants in the genus Phoradendron (family Viscaceae1), obligate hemiparasites that attach to branches and stems of various woody trees and shrubs in tropical and warm temperate regions of the New World. Plants in this genus are known to support a variety of host-restricted insect herbivores, principally in the orders Hemiptera, Coleoptera and Lepidoptera. A single buprestid species has been associated with Phoradendron to this point – Agrilus turnbowi, recently described from specimens reared from dead stems of Phoradendron tomentosum attached to mesquite (Prosopis glandulosa) in southern Texas (Nelson 1990) and pictured here from a specimen in my collection that was reared from dead mistletoe collected at the type locality. At the time of its description, this species was not relatable to any of the other known species in the genus.

1 The Angiosperm Phylogeny Group (2003) includes the Viscaceae in a broader circumscription of the family Santalaceae. However, recent molecular studies suggest the Santalaceae are polyphyletic, with strong support for Viscaceae as a distinct, monophyletic clade (Der & Nickrent 2008).

The two new Mexican species – A. andersoni from Guerrero and Puebla (Figs. 1-3), and A. howdenorum from Oaxaca (Figs. 4-6) – are apparently related to A. turnbowi, which they resemble by their purplish-red coloration and complex pattern of golden setae on the elytra. They are also superficially very similar to each other but differ most notably in size and the overall color and pattern of setae on the elytra.

Figures 1–3. Agrilus andersoni Hespenheide: 1. dorsal habitus; 2. lateral habitus (scale bar indicates 2.0 mm); 3. genitalia of male (scale bar indicates 0.5 mm) (from Hespenheide 2008).

Figures 4–6. Agrilus howdenorum Hespenheide: 4. dorsal habitus; 5. lateral habitus (scale bar indicates 2.0 mm); 6. genitalia of male (scale bar indicates 0.5 mm) (from Hespenheide 2008).

Hespenheide speculates that the color and pattern of the golden setae on the elytra may serve to make the beetles less conspicuous by disruptive coloration, noting the similar coloration of the setae to the leaves of Phoradendron as seen in the photograph of Agrilus howdenorum on its host plant (Fig. 7). This form of crypsis may also be enhanced by the purplish-red ground coloration of the adult, which resembles that of the small, darkened blemishes often observed on the foliage of these plants.

Figure 7. Agrilus howdenorum adult on mistletoe host plant near Diaz Ordaz, Oaxaca, México. The golden setae on the elytra are similar in color to the leaves of the mistletoe and may function as a disruptive color pattern. Photograph by C.L. Bellamy (from Hespenheide 2008).

REFERENCES

Angiosperm Phylogeny Group. 2003. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society, 141: 399-436.

Bellamy, C. L. 2003. The stunning world of jewel beetles. Wings, Essays on Invertebrate Conservation, 26(2): 13-17.

Bellamy, C. L. 2008. A World Catalogue and Bibliography of the Jewel Beetles (Coleoptera: Buprestoidea), Volume 4: Agrilinae: Agrilina through Trachyini. Pensoft Series Faunistica No. 79, 722 pp.

Der, J. P. & D. L. Nickrent. 2008. A Molecular Phylogeny of Santalaceae (Santalales). Systematic Botany, 33(1):107-116.

Hespenheide, H. A. (2008). New Agrilus Curtis species from mistletoe in México (Coleoptera: Buprestidae) Zootaxa, 1879, 52-56

Nelson, G. H. 1990. A new species of Agrilus reared from mistletoe in Texas (Coleoptera: Buprestidae). The Coleopterists Bulletin, 44(3):374-376.

A new species of Xenorhipus from Baja California

/ Ted C. MacRae / 4 Comments

ResearchBlogging.orgA few months ago I discussed Trichinorhipis knulli of the tribe Xenorhipidini (family Buprestidae). Members of this tribe exhibit highly sexually dimorphic antennae, with the distal segments of the male antennae highly modified into a very extended flabellate or lamellate condition. The surfaces of the flabellae/lamellae are covered with numerous, presumably olfactory sensillae that are lacking on female antennae (which retain the unmodified serrate condition), strongly suggesting a function involving detection of female sex pheromones. Although chemosensory structures are present on the antennae of nearly all buprestids, the extreme modification exhibited by the males of species in this tribe is not a common occurrence. Nevertheless, similar modifications have evolved independently in a few other genera within the family, including Knowltonia (four species in western North America), Mendizabalia and Australorhipis (monotypic genera in South America and Australia, respectively), and two species of the enormous Australian genus Castiarina. Indeed, males of Knowltonia and the two Castiarina species possess what might be termed ‘bipectinate’ or ‘biflabellate’ antennae due to dual projections from the terminal antennomeres (see Bellamy & Nylander 2007 for a more complete discussion of male antennal modifications in Buprestidae). The tribe Xenorhipidini is the most diverse group in which these modifications have arisen, comprised of the monotypic Trichinorhipis from California and the closely related Hesperorhipis (four species in Arizona and California) and Xenorhipis (until now, 14 species from North and South America and the West Indies).

Xenorhipis bajacalifornica Westcott, 2008 – holotype ♂ (1) & allotype ♀ (2).
Photos by Steve Valley (Oregon Department of Agriculture).

In a recent issue of the online journal Zootaxa, Rick Westcott (Oregon Department of Agriculture) describes a new species of Xenorhipis from the Cape Region of Baja California Sur, Mexico. Although assigned to the genus Xenorhipis, the new species – X. bajacalifornica – seems to bridge the gap between the genera Xenorhipis and Hesperorhipis. As currently recognized, Xenorhipis is distinguished from Hesperorhipis by the shape of the posterior coxal plates, which are scarcely narrowed laterally in the former genus, while in the latter genus they are triangular and with the hind margin strongly oblique. In X. bajacalifornica the posterior coxal plates are somewhat triangular but not as acute laterally as in some species of Hesperorhipis. Xenorhipis bajacalifornica also differs from other described Xenorhipis in its strongly abbreviated elytra, which in males barely reach the second ventrite – similar to species of Hesperorhipis. Other described Xenorhipis exhibit less abbreviated elytra, which cover at least the first three ventrites and in some species almost the entire abdomen. Despite these similarities to Hesperorhipis, a consistent distinguishing character between the two genera was found in the male antenna – in Xenorhipis the flabellar processes begin with the second antennomere, while in Hesperorhipis they begin with the third. It was on this basis that the new species was assigned to the genus Xenorhipis. (The genus Trichinorhipis differs from both Xenorhipis and Hesperorhipis by its rounded rather than quadrate pronotum and its unabbreviated elytra that cover the entire abdomen and has, as a result, been placed in its own subtribe.)

Xenorhipis brendeli ♂Xenorhipis brendeli ♀The photos left show the male (L) and female (R) of Xenorhipis brendeli, the only species in the tribe occurring in eastern North America (west to Minnesota and eastern Texas). Adults of this species are not commonly encountered and have been collected on a variety of deciduous hardwoods but reared almost exclusively from species of hickory (genus Carya). These individuals were reared from dead branches collected in southeastern Missouri – the male from pecan (Carya illinoensis) and the female from shellbark hickory (Carya laciniosa). The male exhibits the scarcely abbreviated elytra that cover almost the entire abdomen (as discussed above). Stan Wellso reported large numbers of males attracted to caged live females in Texas, apparently responding to sex pheromones released by the females.

Xenorhipis osborni ♀Xenorhipis osborni ♂This is another species in the genus – Xenorhipis osborni – known from west Texas. Joseph Knull described the species in 1936 from specimens collected in the Davis Mountains on whitethorn acacia (Acacia constricta), but larval hosts remained unknown until I reared a series of these specimens from dead branches of black acacia (Acacia rigidula) collected above the Pecos River in Val Verde County. I’ve also reared a few specimens from dead branches of catclaw acacia (Acacia greggii) collected in Big Bend National Park, and I wouldn’t be surprised if it breeds in other species of acacia. Again, in this speices the elytra are only slightly abbreviated, though more so than in Xenorhipis brendeli above and also more so in the male (L) than in the female (R). The male of this species is one of the prettiest I’ve encountered in the tribe.

Hesperorhipis albofasciatus ♂Hesperorhipis albofasciatus ♀The genus Hesperorhipis is illustrated here by these photos of H. albofasciatus. These specimens were reared by Rick Westcott from dead branches of walnut (Juglans sp.) – its only known host – collected in Tulare County, California. The elytra in this species are much more abbreviated than in Xenorhipis brendeli and X. osborni but similar to those of X. bajacalifornica – again with the male (L) exhiting greater abbreviation than the female (R). The three remaining species of Hesperorhipis exhibit even more highly abbreviated elytra than H. albofasciatus.

Dr. Charles Bellamy (California Department of Food and Agriculture) is currently revising the tribe. It will be interesting to see how, ulimately, he treats Xenorhipis and Hesperorhipis, given the blended characters exhibited by some species.

REFERENCE

Westcott, R. L. (2008). A new species of Xenorhipis LeConte and of Mastogenius Solier from Mexico, with a discussion of Chrysobothris ichthyomorpha Thomson and its allies and notes on other Mexican and Central American Buprestidae (Coleoptera) Zootaxa, 1929, 47-68

Magnificently Monstrous Muscomorphs

/ Ted C. MacRae / 9 Comments

I suppose tiger beetles have gotten more than their fair share of attention here lately, so for this post I thought I’d highlight insects of a completely different group – flies! Admittedly, as a coleopterist, I tend to view flies with much the same disdain as your average insect non-enthusiast – as pesky, pestiferous vermin worthy of little more attention than a decisive swat. I don’t begrudge them their amazing diversity – at ~100,000 described species worldwide, they are strong contenders with the Lepidoptera and Hymenoptera as the second largest order of insects (of course, you need all three of these orders combined to match the diversity of the Coleoptera). I am also prepared to accept that they may well represent, at least morphologically, the pinnacle of insect evolution (a position that a few hymenopterists I know might argue with) due to their amazing flight capabilities and the morphological adaptations they have developed for such. These include the development of aristate antennae for detecting wind speed, the conversion of the second pair of wings into stabilizing organs (halteres), and the ability to beat the remaining pair of wings at incomprehensible rates – up to 1,000 times per second in some very small midges (even more baffling when one considers that the wing “beat” is actually just a passive result of rhythmic distortions of the thoracic box). I even acknowledge that the vast majority of fly species are not even pests, living their lives innocuously as herbivores, scavenging organic matter that nothing else wants, and preying upon or parasitizing other insects, including important agricultural pests. Still, flies bug me – mosquitoes prevent me from sleeping under the stars without a tent, deer flies drone around my head incessantly while I’m trying to stalk an elusive tiger beetle, stable flies trick me into assuming they are just another house fly (until they bite me!), house flies (the real ones) rudely land on my sandwich with their filthy feet, and eye gnats insist on committing hary kary in my eyes as I walk the trails (I won’t mention their other common name, derived from their habit of clustering around exposed canid genitalia).

There is, however, one group of flies that possess “cool factor” rivaling that of even the most popular insect groups – robber flies and their kin. I’ve always picked them up as an aside, even sending them off for authoritative ID and constructing an inventory of the species in my collection. The brute of a fly pictured here is not a true robber fly, but in the related family Mydidae. Mydus clavatus can be recognized easily in the field by its large size and distinctive black coloration with red/orange on top of the 2nd abdominal segment. Presumably this is an example of Batesian mimicry modeled upon spider wasps (family Pompilidae) in the genus Anoplius. This mimicry allows them to fly rather boldly in the open and is so persuasive that it can not only fool the casual observer, but even the most knowledgable of entomologists might be loathe to handle it despite knowing better. Although common across the eastern U.S., aspects of its life history are poorly understood. Adults have been reported to be predators of other insects, but apparently there are some doubts about the veracity of such reports. Patrick Coin of BugGuide has observed adults (males?) taking nectar from flowers and has suggested that reports of predation by adults might have been an erroneous assumption due to their relation and resemblance to robber flies. Larvae are reported to be predaceous on woodboring beetle larvae, and I have reared adults of this species from a dead sycamore (Platanus occidentalis) stump in southern Missouri that was infested with mature larvae of the large buprestid species, Texania campestris. This habit is similar to robber flies of the genus Laphria, which mimic bumble bees and carpenter bees.

In Greek mythology, Promachos (Προμαχοε) was “the champion” or one “who leads in battle” – an appropriate generic name for the so-called “giant robber flies” of the genus Promachus. These large flies are dominant and fearless predators that will capture just about any flying insect – even adult dragonflies. There are three species of Promachus in the eastern U.S. that exhibit the yellow and black tiger striping of the abdomen seen in this individual, identified as a female Promachus hinei by Herschel Raney at BugGuide due to its reddish femora and occurrence in the central U.S. Promachus rufipes is similar but has black femora with distinctly orangish tibiae and is more common in the southeastern U.S., whereas P. vertebratus has more muted two-toned legs with smaller dark areas dorsally on the abdominal segments and is more common in the northern states. Additional species occur in the region but lack the tiger striping of the abdomen, and even more species occur in the western U.S. Members of this genus generally lay their eggs on the ground near grass roots, and the larvae burrow into soil after hatching and feed on soil insects, roots, and decaying matter before pupating within the soil in an unlined cell.

During my recent trip to Nebraska I encountered this related robber fly genus Proctacanthus, also determined by Herschel provisionally as P. milbertii. These large robber flies with a prominent beard are similar in habit to Promachus species, laying their eggs in crevices in soil and the larvae feeding on soil insects, roots, and decaying plant matter. Proctacanthus milbertii is a late season species that occurs across much of the U.S. and reportedly loves butterflies. However, Joern & Rudd (1982), in studying predation by this species in western Nebraska (where the individual pictured here was photographed) found that grasshoppers made up 94% of the prey captured by this species. Interestingly, nearly all of the remaining prey captures were other P. milbertii, which was carefully verified as such since mating postures can be easily mistaken for prey handling positions. Grasshopper prey species taken by this species were most strongly influenced by availability rather than size, suggesting that even the largest grasshopper species could be captured as easily as smaller species – a testament to the ferocity of this robber fly.

Another family of flies modestly related to robber flies and also ranking high in “cool factor” are the bee flies (family Bombyliidae). The scaly bee fly, Lepidophora lepidocera (ID confirmed by Joel Kits at BugGuide), is a particularly attractive member of the family. The distinctive, hunch-backed shape of this southern U.S. species is shared with the more northern L. lutea, from which it is distinguished by having pale scales only on the 5th abdominal segment and not on the 4th also. Most bee flies are presumbably mimics of – yes – bees; however, the species in this genus might actually be mimics of robber flies instead. Adults are most often seen taking nectar from flowers – this individual was taken on flowers of tall boneset (Eupatorium altissimum). Larvae are characterized by Sivinski et al. (1999) as kleptoparasites on the provisions of solitary wasps in the families Vespidae and Sphecidae – meaning that the larva does not parasitize wasp larvae directly, but instead usurpes the nest provisions on which the wasp larvae were supposed to feed. The little thieves!