flies

Bee Fly Parasitism of Tetracha virginica

/ Ted C. MacRae / 25 Comments

I expected to gain a better understanding of insect photography principles and techniques at last weekend’s BugShot insect photography workshop at Shaw Nature Reserve in Gray Summit, Missouri.  I even expected that I would walk away from the event with some new friends.  The one thing I did not expect was the discovery of an apparently unreported host/parasitoid relationship amongst my beloved tiger beetles.  Nevertheless, that’s exactly what happened in a patch of barren soil just outside of the Dana Brown Education Center where the event was being held.

Tetracha virginica 3rd instar larva | Shaw Nature Reserve, Franklin Co., Missouri

I had spied the small cluster of tiger beetle burrows the previous day as we left on our first group hike.  The burrows were unmistakably those of Tetracha virginica (Virginia metallic tiger beetle) due to their size (no other tiger beetle in east-central Missouri approaches the size of this species), and in fact some of the larvae were seen sitting at the tops of their burrows.  Tetracha larvae are easily distinguished from other genera of North American tiger beetles (in addition to their size) by their distinctive white-margined pronotum.  I had to catch back up with the group but came back later in the day and took a few photographs of one of the larvae sitting in its burrow.  Some of the other BugShot attendees were there and wanted to take photographs, but the larvae dropped on their less-practiced approach.  No problem, I just “fished” a larva out of its burrow and let them take their photographs.  When they finished, I began taking my own photographs, but I only got off one shot before the larva suddenly made a bee-line for its burrow and dropped in before I could block its escape.  Oh well, I do already have photographs of the larva of this species from other locations.

Tetracha virginica 3rd instar larva | Shaw Nature Reserve, Franklin Co., Missouri

The next day I passed by the burrows again with Crystal and Lee.  I really wanted them to see the larvae, but they were not active.  No problem, I grabbed a long grass stem, chewed on one end, and inserted it to a depth of about 35 cm before it hit bottom.  A little jiggling to get the larva to bite, then a quick jerk back and out came the larva.  I never tire of seeing someone witness this for the first time—the way they jump back half-startled when they see the otherworldly larva flying through the air and landing on the grass.  I grabbed the larva and placed it on the barren clay to let them take photographs.  Crystal went first, and as she looked at the larva through her viewfinder she exclaimed, “there are wormy-things [the technical term, of course] on him.”  Lee and I looked, and sure enough there were two small “wormy-things” attached to the back of the tiger beetle.  I immediately recognized them as bee fly larvae (family Bombyliidae)—specifically Anthrax analis, the only bee fly known to parasitize tiger beetle larvae in the United States.  I was quite excited by this discovery, as I have never seen these before despite fishing untold numbers of tiger beetle larvae from their burrows over the past decade or so.  We all went camera crazy and took our turns photographing larvae and host, after which I popped it into a vial to keep for an attempt at rearing out the bee flies.

Anthrax analis larvae attached to abdomen of Tetracha virginica larva

It now seems that our find represents more than just a personal discovery, as bee flies—to my knowledge—have not yet been reported parasitizing any species of the genus Tetracha.  Of the 70 Anthrax spp. for which hosts have been recorded (Yeates and Greathead 1997), only three are known to parasitize tiger beetles.  Shelford (1913) gave the first account of A. analis (as Spogostylum anale) parasitzing Cicindela scutellaris lecontei, noting that the adult females lay their eggs by flying backward and downward while thrusting the abdomen forward until it touches the sand near the host burrow entrance.  Hamilton (1925) found Cicindelidia obsoleta parasitized by this species, and Bram and Knisley (1982) expanded its known host spectrum to include C. hirticollis, C. tranquebarica, Cicindelidia punctulata, and Ellipsoptera marginata.  Photographs of larvae (presumably of this species) parasitizing undetermined tiger beetle larvae can be seen in Pearson and Vogler (2001) and in this photo by Chris Wirth.  Anthrax gideon has been recorded parasitizing Pseudoxycheila tarsalis in Costa Rica (Palmer 1982) and Oxycheila trisis in Brazil (Arndt and Costa 2001), while a third undetermined Anthrax sp. has been reared from larvae of Pentacomia ventralis, also in Brazil (Arndt and Costa 2001).  Oxycheila and Pseudoxycheila are related to Tetracha at the tribal/subtribal level (depending on which classification you follow), so the finding of A. analis utilizing Tetracha is not unexpected.

Closer view of anteriormost Anthrax analis larva

The beetle larva and its unwelcome tagalongs is now in a container of native soil and has accepted the starter burrow that I made for it. Hopefully at least one of the bee fly larvae will complete its development and emerge as an adult to allow confirmation of its identity.  If this host association does turn out to be unreported, we will follow up with at least a short journal communication.  To that end, any literature citations you are aware of regarding bee fly parasitism of tiger beetles that is not listed below would be most welcome.

Congratulations to Ben Coulter, who wins yet another BitB Challenge with 14 points (this guy is a machine!), and Mr. Phidippus came close with 13 points.  Ben and Phiddy were the only participants that figured out the parasites were bee flies of the genus Anthrax, and Phiddy was the only participant to guess the correct genus for the host.  Ben’s win gives him a now commanding lead with 49 points in the current BitB Challenge Session #4 as we enter the home stretch.  Mr. Phidippus and Roy are still in striking distance with 39 and 28 points, respectively.  Is anybody capable of keeping him from his third title?  We shall see.

REFERENCES:

Arndt, E. and C. Costa.  2001.  Parasitism of Neotropical tiger beetles (Coleoptera: Carabidae: Cicindelinae) by Anthrax (Diptera: Bombyliidae).  Studies on Neotropical Fauna and Environment 36(1):63–66.

Bram, A. L. and C. B. Knisley.  1982.  Studies on the bee fly Anthrax analis (Bombyliidae), parasitic on tiger beetle larvae (Cicindelidae).  Virginia Journal of Science 33:90.

Hamilton, C. C. 1925. Studies on the morphology, taxonomy, and ecology of the larvae of Holarctic tiger beetles (family Cicindelidae).  Proceedings of the U.S. National Museum 65 (Art. 17):1–87.

Palmer, M. K.  1982.  Biology and behavior of two species of Anthrax (Diptera: Bombyliidae), parasitoids of the larvae of tiger beetles (Coleoptera: Cicindelidae).  Annals of the Entomological Society of America 75(1):61–70.

Pearson, D. L. and A. P. Vogler.  2001. Tiger Beetles: The Evolution, Ecology, and Diversity of the Cicindelids.  Cornell University Press, Ithaca, New York, 333 pp.

Shelford, V. E.  1913.  The life history of a bee-fly (Spogostylum anale Say) parasite of the larva of a tiger beetle (Cicindela scutellaris Say var. lecontei Hald.).  Annals of the Entomological Society of America 6(2):213–225.

Yeates, D. K. and D. J. Greathead.  1997. The evolutionary pattern of host use in the Bombyliidae (Diptera): a diverse family of parasitoid flies.  Biological Journal of the  Linnaean Society 60:149—185.

Copyright © Ted C. MacRae 2011

T.G.I.Flyday – Triorla interrupta

/ Ted C. MacRae / 5 Comments

Triorla interrupta (male) | Calico Rock, Arkansas

While I was visiting the glades near Calico Rock, Arkansas this past June, I went into town to look along the White River.  With the amount of sandstone bedrock in the area, I thought there I might find sandy loam deposits along the river of the type preferred by Cylindera cursitans (ant-like tiger beetle).  While I didn’t find any of the beetles, I did see this robber fly (managing only this single shot before it flew off), which I take to be the male of Triorla interrupta based on the pattern of abdominal coloration (the first two segments partially black, followed by two almost wholly black segments).  According to BugGuide, this is the only North American species of the genus (a second occurring from Panama to Argentina), and Herschel Raney considers it to be the most common robber fly in Arkansas.

Copyright © Ted C. MacRae 2011

T.G.I.Flyday – Andrenosoma fulvicaudum

/ Ted C. MacRae / 19 Comments

Andrenosoma fulvicaudum | Stone Co., Arkansas

First, about the name. T.G.I.Flyday is my contribution to a collusional triad between dipterist Morgan Jackson, myrmecologist Alex Wild, and myself (uhm, beetles).  Although Alex blogs primarily about ants, he has long featured a “Friday Beetle Blogging” series.  I’ve also occasionally stepped on their toes with an ant or fly post, so Morgan and I thought it would be fun to complete the Friday switcheroo with a post about ants on his blog and one about flies on mine. Get it?… Oh well, it made me chuckle when we thought it up.  Anyway, here is my first T.G.I.Flyday contribution.

Among the flies (order Diptera), it is hard to pick anything but robber flies (family Asilidae) as the most charismatic group.  Several subfamilies of robber flies have candidates that vie for the most impressive species, mostly due to their enormous size combined with striking green eyes (e.g., Microstylum morosum, Diogmites neoternatus) or vivid, aposematic / mimetic coloration (e.g., Archilestris magnificus, Eccritosia zamon, Wyliea mydas).  However, my favorite subfamily is the Laphriinae—not because of the amazing bumble bee-like appearance of the nominate genus, but rather the larval food of all species in the subfamily; wood-boring beetle larvae.  Over the years, I have put up hundreds of batches of dead wood for rearing wood-boring beetles in the families Buprestidae and Cerambycidae, and not uncommonly do I find in one of the emergence containers—especially those containing dead pine—an adult of one of these impressive flies. Oftentimes their characteristic pupal cases will be found protruding from the emergence hole, in which case I pin it underneath the fly (just in case some ambitious dipterist examines my collection after I’m gone and finds that the pupal case of xx species is not yet described).  I’ve by now accumulated a rather decent little robber fly collection (especially considering that I’m really a coleopterist), graciously identified for the most part by world robber fly expert Dr. Eric Fisher (California Department of Food and Agriculture).

Last weekend I made the second in a series of trips I’ll be taking to the White River Hills region of north-central Arkansas in an effort to confirm the occurrence there of Cylindera celeripes (swift tiger beetle).  My efforts are focused on the area around Calico Rock, a marvelous system of acidic sandstone barrens interspersed amongst shortleaf pine and oak forests.  The occasional dead pines found in such areas are highly attractive to a variety of pine-associated buprestids and cerambycids (my first loves), and whenever I see a standing dead tree I make a beeline straight for it (the tiger beetles can wait).

This individual was sitting on the trunk of a dead shortleaf pine with a mirid bug for prey.

On this day, sitting on the trunk of the first dead pine that I approached was not a buprestid or cerambycid, but rather this laphriine robber fly.  Based on the reddish posteriodorsal markings of the abdomen and general gestalt, I take this to be Andrenosoma fulvicaudum, a widespread though never very abundant species that occurs across most of North America.  According to Bromley (1934), the species frequents dry, sandy locations where it rests on logs, stumps, or tree trunks exposed to the bright sunlight and is commonly observed preying on small hymenopterans.  These observations are quite consistent with mine, except this one was feeding on a true bug in the family Miridae (perhaps distracting it just enough to allow me these photographs).  Cannings (1998) notes that A. fulvicaudum is attracted to recently burned forests, which will provide a fresh supply of wood-boring beetle larvae on which its larvae can prey.  This is the only species of Andrenosoma occurring in eastern North America; four additional species are restricted to Texas and a fifth occurs only in the western U.S., but the genus reaches its greatest diversity in the Neotropics.

REFERENCES:

Bromley, S. W. 1934. The Laphriine Robber Flies of North America.  Ph.D. dissertation, Ohio State University, 358 pp.

Cannings, R. A. 1998. Robber flies (Insecta: Diptera: Asilidae), In I. M. Smith and G. G. E. Scudder [Eds.], Assessment of Species Diversity in the Montane Cordillera Ecozone, Burlington: Ecological Monitoring and Assessment Network.

Copyright © Ted C. MacRae 2011

Bichos Argentinos #14 – Flies!

/ Ted C. MacRae / 22 Comments

A few miscellaneous fly photos from La Reserva Ecológica Costanera Sur (Buenos Aires, Argentina)  taken last March.  I don’t have IDs except provisionally to family (let’s face it—flies are hard!).

I suppose something in the Tachinidae, based on the black and white striped coloration and distinct abdominal setae.


Definitely a robber fly (family Asilidae), but which one?


I suppose this is some kind of bottle fly (family Calliphoridae).


Nice eyes!


Copyright © Ted C. MacRae 20011

Forgotten Foto Friday: Eudioctria sp.

/ Ted C. MacRae / 2 Comments

Eudioctria sp. | Shaw Nature Reserve, Gray Summit, Missouri

In keeping with my recent theme featuring insects from Shaw Nature Reserve, I present here a long-forgotten photograph that I took back in May 2009.  In fact, not only was this photo taken on the maiden voyage of my Canon dSLR setup, but it is the very first photograph of an insect that I took with the camera—image #19 (1-18 were the initial test shots and a few immediately discarded photos).  It won’t win any awards, but it’s not a bad photo, and the fact that I immediately began attempting shots with the lens dialed all the way up to 1:1 shows I had no qualms about going for broke.

As best I can tell, this is a member of the robber fly genus Eudioctria in the subfamily Stenopogoninae.  Species in this genus are among the tiniest of North American robber flies,  measuring only 6–8 mm in length (compare this with the spectacular 35–40 mm length of North America’s largest robber fly).  They superficially resemble species of the unrelated genus Cerotainia (subfamily Laphriinae) but lack the extra-long antennae. According to Norman Lavers (The Robber Flies of Crowley’s Ridge, Arkansas), Eudioctria can also be distinguished behaviorally, as it prefers flat leaves at the top of small shrubs, while Cerotainia tends to perch on twig-ends.  Eudioctria is primarily a western U.S. genus, although four of its 14 species (albius, brevis, propinqua, tibialis) occur in the eastern states (Adisoemarto and Wood 1975).  I can’t possibly determine which of those four species this individual represents, as to do so requires examination of facial gibbosities and judgements about the degree to which various body parts are pollinose(?)—perhaps I should stick with beetles!

REFERENCE:

Adisoemarto, S. and D. M. Wood.  1975.  The Nearctic species of Dioctria and six related genera (Diptera, Asilidae).  Questiones Entomologica 11:505–576.

Copyright © Ted C. MacRae 2011

Itty bitty tiny little flies

/ Ted C. MacRae / 17 Comments

Saturday was my birthday, and for most of my adult life it has been tradition to take the day off for the Annual-Birthday-First-Bug-Collecting-Trip-of-the-Year™.  At Missouri’s middlin’ latitudes, late April is normally a tad early—at least for the groups that interest me, but it’s less about serious bug collecting and more about kicking off the season in a bit of a special way.  Normally if my birthday falls on a weekend, as it did this year, I’ll take off the adjacent weekday instead (it’s not special if you can’t take off any time from work).  However, this year that wasn’t possible due to events at work far beyond my little sphere of influence (conspiracy #1), thus Saturday itself became the planned day.  My family and I celebrated Friday evening so I could have the whole day on Saturday, and as we ate we watched news reports of suspected tornadoes ripping through St. Louis just to our north and a little further south (conspiracy #2).  Forecasts called for rain continuing well into the following week (conspiracy #3), and for the first time in… well… ever, I had the feeling the ABFBCTOTY might be cancelled due to weather.  Waking the next morning, I turned on the television to see precipitation forecasts across the state (1″ in northwest Missouri to 6″ in southeast Missouri) amidst stunning chopper video footage of neighborhoods destroyed and lives turned upside down.

I stopped counting conspiracies and hugged my girls!

That evening, I turned on the mercury vapor lamp over the garage door for the first time since last year to see if anything might show up.  We live in a heavily wooded area of western St. Louis Co. featuring relatively intact mesic upland forest dominated by several oaks, hickories, and sugar maples that harbor a nice diversity of woodboring beetles and treehoppers (though I didn’t expect to see these on this night).  The night was cool and clammy—nothing but a few moths and flies showing up.  Some of the flies were quite small, and some were extraordinarily small—not more than 1 or 2 mm in length.  Tiny little specks of life!  I thought it might be fun to get in some practice time with the 65mm lens, and the sampling shown below represents a few of those taken with the lens maxed out at 5X (resulting in a frame width of ~5mm):

Male non-biting midge (Chironomidae) | St. Louis Co., Missouri

Female non-biting midge (Chironomidae) | St. Louis Co., Missouri

Moth fly (Psychodidae) | St. Louis Co., Missouri

Same individual as above, chased onto a finished wooden table to highlight its dense pilosity

Copyright © Ted C. MacRae 2011

Bichos Argentinos #8 – “Mosca de la Carne”

/ Ted C. MacRae / 9 Comments


Here is the full-sized photo from which the “super-crop” featured in Super Crop Challenge #4 was taken.  As many of you guessed, this is a higher fly (order Diptera, suborder Brachycera) in the family Sarcophagidae, with the photo crop showing frontal portion of the head and its associated structures.  While dubbed “flesh flies” due to the necrophagic habits of a few of its included species, sarcophagids actually display diverse life histories that include a wide variety of coprophagous and parasitic species (Mulieri et al. 2010).  The fly was one of the many insects I photographed in early March in Buenos Aires, Argentina at La Reserva Ecológica Costanera Sur, where it was found perched on dead wood (I found several individuals of apparently the same species perched on dead wood as well – whether this is significant or chance I don’t know).


The presence of a ptilinal fissure and lunule and a dorsal seam on the antennal pedicel identify this as one of the calyptrate “muscoid” (schizopheran to be more correct) flies.  Within that group, my determination as a member of the family Sarcophagidae is based on its fairly large size, dull gray coloration with three longitudinal black strips on the mesonotum, notopleuron with two strong and two small setae (Calliphoridae have only two setae), and meron with a row of setae (lacking in Muscidae and related families).  Admittedly these characters aren’t visible in the cropped photo that I presented, so guessing the proper family was a bit of a crap shoot.  As noted by (de Carvalho and de Mello-Patiu 2008), species determination of sarcophagid flies is complicated by their fairly uniform chaetotaxy and lack of useful external characters, leaving male genitalia as the only reliable characters for identification.  No suitable key for identifying Neotropical genera yet exists and the elaboration of one will be very difficult without analysis of the male terminalia.  Dr. Luciano Patitucci (Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina) suggested this is perhaps a species of Sarcophaga; however, in a recent faunal study of Sarcophagidae at the reserve, two species – Tricharaea (Sarcophagula) occidua and Oxysarcodexia varia – comprised nearly 90% of the flesh flies encountered (Mariluis et al. 2007).

A single individual is shown in the first two photos, while this mating pair was seen a little later.  Although they seem to represent the same species, I can’t be certain of this, and the photo itself is not the greatest due to the female (bottom) being slightly off-focus.  Nevertheless, I had to show it, because – really – who can resist photographs of fly nookie?! 

REFERENCES:

de Carvalho, C. J. B. and C. A. de Mello-Patiu.  2008.  Key to the adults of the most common forensic species of Diptera in South America.  Revista Brasileiro de Entomologia 52(3):390–406.

Mariluis, J. C., J. A. Schnack, P. R. Mulieri and J. P. Torretta. 2007. The Sarcophagidae (Diptera) of the coastline of Buenos Aires City, Argentina. Journal of the Kansas Entomological Society 80(3):243–251.

Mulieri, P. B., J. C. Mariluis and L. D. Patitucci.  2010.  Review of the Sarcophaginae (Diptera: Sarcophagidae) of Buenos Aires Province (Argentina), with a key and description of a new species.  Zootaxa 2575:1–37.

Addendum:

This challenge concludes the 2nd BitB challenge session, with a record 17 participants in this final challenge.  For a while it looked like HBG Dave would become our newest champion, but Session #1 champ Ben Coulter swooped in, flogged us with terminology (all of it correct and undeniable), and won two of the last three challenges to edge out Dave and, once again, take the overall victory. Make no mistake – Ben knows how to play this game!  Morgan Jackson took second in this challenge and claimed the final spot on the overall podium, while Troy Barlett and newcomer Heath Blackmon tied for third.  Other strong contenders during Session #2 included JasonC and Tim Eisele.  Ben – contact me to claim your loot (and your loot from session #1 is in the mail).

Here is the final points tally for Session #2:

Place Commentor BB#10 IDC#5 Bonus
3/7		 IDC#6 IDC#7 SCC#4 Total
1 Ben Coulter       10   41 51
2 HBG Dave   13 2 4 8 17 44
3 Morgan Jackson   2     4 29 35
4 Troy Bartlett 2 10 2     20 34
5 JasonC   8   4   18 30
6 Tim Eisele 1 8   6 6 8 29
7           20 20
8 TGIQ   2       17 19
9 Christopher Taylor   2       15 17
10 Dave Hubble   15         15
11 James Trager  1 1 2     9 13
12 Gunnar           12 12
13
        1 9 10
14
Dennis Haines 
           9 9
15 Max Barclay       3   5 8
            8 8
17 Charley Eiseman   6         6
18 biozcw           5 5
19 Brady Richards       4     4
  Henry         4   4
21 John Oliver     2       2
 
Mike
           2 2
23 Christy Bills       1     1
  Tucker Lancaster       1     1

Copyright © Ted C. MacRae 2011

Bichos Argentinos #1 – Eristalinus taeniops

/ Ted C. MacRae / 2 Comments

Eristalinus taeniops - a hover fly in the family Syrphidae

It figures that perhaps the most striking insect I saw at La Reserva Ecológica Costanera Sur in Buenos Aires, Argentina would be an introduced species, as the area itself is a man-made reconstruction of the wet Pampas grasslands endemic to coastal areas of the Rio de la Plata.  My identification of this fly as Eristalinus taeniops is based on its great resemblance to the many online photographs that exist from both South America and the U.S. and also the Old World where it is apparently native.  I found no more authoritative sources with which to confirm the ID, so this online comparative will have to do (muscophiles feel free to comment or correct). 

According to BugGuide, E. taeniops is a recent import to the U.S. from Africa, and in fact it has apparently successfully invaded much of the world.  I suppose most folks will be inclined to forgive the fly for all this because of its strikingly patterned eyes, which I would have dearly loved to have gotten in tight for a closeup.  This shot with the 100mm lens dialed in to the max (and only slightly cropped for composition), however, was the only one I managed – the fly bolted as I quickly tried to switch to the 65mm lens, and although I saw two more individuals afterwards, I couldn’t get anywhere close to them in the day’s heat.  Eyes notwithstanding, the species is a near perfect mimic of a honey bee, making one wonder what selective pressures drove the development of these fantastically contrasting eyes.

Copyright © Ted C. MacRae 2011