Month: June 2012

West Indian seagrape sawfly

/ Ted C. MacRae / 11 Comments

I spent a few days in Puerto Rico last month. A quick in-and-out for work, there was little chance to do any real exploring. Nevertheless, I booked my return on the last possible flight out so that I would have at least part of a day to look around before needing to go to the airport. I’ve only been to Puerto Rico twice before—once in 1982 on a one-day visit during my honeymoon cruise (with a far-too-rushed guided tour to El Yunque), and again in 1999, also a quickie for work. Given my limited previous opportunities to explore San Juan, you might think I would choose La Forteleza and San Juan National Historic Site in Old San Juan for my day’s destination. After all, they were designated a World Heritage Site by UNESCO (United Nations Educational, Scientific, and Cultural Organization) in 1983. Tempting, but when I looked at the map of San Juan a nice, big, chunk of green immediately caught my eye—Bosque Estatal de Piñones (Pine State Forest). Call me single-minded, but not even a World Heritage Site can match the siren call of 1,500 acres of moist, subtropical forest!

Sericoceros krugii female guarding eggs on leaf underside of sea grape (Coccoloba uvifera) | Bosque Estatal de Piñones, San Juan, Puerto Rico

Mangrove forest covers much of the reserve, accessed by a wide (and annoyingly elevated) boardwalk—an interesting stroll but unsatisfying to me since I couldn’t root around at ground level. One can get only so much enjoyment from distinguishing red, black, and white mangrove before the sameness of the canopy and exclusion from the ground flora/fauna starts to become monotonous. I went back towards the parking lot (photographing a few lizards along the way—more on them in a future post) and had just begun walking the perimeter of a picnic area when I encountered some very large seagrape (Coccoloba uvifera) plants. I’ve seen a lot of seagrape in Florida and have never found any insects on it, so I initially didn’t make much effort to go over and have a closer look at them. However, even from afar I could see that these particular plants had been very heavily damaged by some type of defoliating insect. The first few branches I looked at showed no outward evidence of who the culprit was, but I reasoned it must have been some sort of lepidopteran caterpillar. As I was inspecting the branches, the insect in the above photo caught my eye—at first I thought it was some type of “homopteran” because of the apparent egg-guarding behavior it was showing, but a closer look revealed that it was actually a sawfly! An egg guarding sawfly; who would have thought?!

Female ovipositing her clutch of eggs, which are solid red when first laid.

Predictably, subsequent identification was quite easy as there is only a single species of sawfly in Puerto Rico—Sericoceros krugii in the family Argidae. About 20 species make up this Neotropical genus, occurring from southern Mexico south to Argentina; however, S. krugii is the only species occurring in the West Indies and in addition to Puerto Rico is found in the U.S. Virgin Islands and Dominican Republic (Smith 1992). The species in this genus seem to specialize on Coccoloba spp. (family Polygonaceae) as host plants; however, one species is reported from Triplaris caracasana—also in the Polygonaceae (Smith & Benitez Diaz 2001), and another from Lonchocarpus minimiflorus in the family Fabaceae (Smith & Janzen 2003).

Larvae consume all but the largest veins of the foliage.

Wolcott (1948) describes how this species often defoliates long stretches of seagrape on the beaches of Puerto Rico, leaving “windrows of excrement on the sand underneath the naked branches and leaf midribs…” He also describes its apparent lack of natural enemies (although it has since been recorded as a host for a tachinid fly—Bennett 1999) and the fact that birds do not seem to eat them as possible reasons for its abundance and frequent outbreaks. To me, the screaming red/black coloration of the adult and apparent unpalatability to birds suggest the presence of chemical defenses, and although I couldn’t find any information on this specific to Sericoceros spp., many social species of sawflies are typically well-defended chemically and, thus, aposematic. Despite this apparent defensive capability, the remarkable maternal guarding behavior exhibited by the adult females suggests the eggs still need additional protection from predators and parasitoids. Sericoceros spp. are not the only sawflies to exhibit this behavior, which apparently has evolved across numerous sawfly lineages (see Social Sawflies, by James T. Costa).

This mature larva will soon spin a coccoon on the bark for pupation.

There were only a few, apparently mature larvae still around on the trees that I could find. Wolcott (1948) describes most outbreaks as occurring during the fall and winter months, after which the insects might completely disappear for many months or even a year. I must have caught the tail end of one such outbreak, although the number of females that I saw guarding eggs suggests another wave of defoliation would soon be occurring.

Congratulations to itsybitsybeetle, who showed up late to the party but still managed to pull out the win for Super Crop Challenge #13. Brady Richards came in a close 2nd, while Sam Heads and Mr. Phidippus share the final podium spot. The overall standings remain the same, with Sam leading Brady by a single, slim point and Mr. Phidippus only six points further back. There will be two more challenges in BitB Challenge Session #6, so it’s still possible for somebody to make a late run, especially if one or more of the leaders falters down the stretch. Remember—the top three points earners at the end of the session will get a choice of some loot, so don’t hesitate when the next challenge rolls around.

REFERENCES:

Bennett, F. D. 1999. Vibrissina sp. (Diptera: Tachinidae) a parasite of the seagrape sawfly Sericoceros krugii (Hymenoptera: Argidae) in Puerto Rico: a new record. Journal of Agriculture of the University of Puerto Rico 83(1–2):75–78.

Smith, D. R. 1992. A synopsis of the sawflies (Hymenoptera: Symphyta) of America south of the United States: Argidae. Memoirs of the American Entomological Society 39:1–201.

Smith, D. R. & Benitez-Diaz. 1991. A new species of Sericoceros Konow (Hymenoptera : Argidae) damaging villetana trees, Triplaris caracasana Cham. (Polygonaceae) in Paraguay. Proceedings of the Entomological Society of Washington 103(1):217–221.

Smith, D. R. & D. H. Janzen. 2003. Food plants and life histories of sawflies of the family Argidae (Hymenoptera) in Costa Rica, with descriptions of two new species. Journal of Hymenoptera Research 12:193–208.

Wolcott, G. N. 1948. Insects of Puerto Rico. Journal of Agriculture of the University of Puerto Rico 32(4):749–975.

Copyright © Ted C. MacRae 2012

More on Chalcosyrphus

/ Ted C. MacRae / 2 Comments

Here are two more photos of the fly I tentatively identified as Chalcosyrphus sp. The first photo shows the all-black coloration with no trace of either steel blue highlights (seen in C. chalybea) or red abdominal markings (seen in C. piger). It also gives a better view of the enlarged and ventrally spinose metafemora. The second photo shows the holoptic (contiguous) eyes that make me think this is a male individual (if, indeed, this is true for syrphids as with tabanids).

I’m hoping that posting these will provide any passing dipterists with the information needed for a firmer ID (and possibly an explanation of the purpose of those intriguingly modified hind legs).

Lateral view showing black abdomen with no trace of red (except what appears to be a parasitic mite).

Do the holoptic eyes identify this as a male?

Copyright © Ted C. MacRae 2012

T.G.I.Flyday – Chalcosyrphus?

/ Ted C. MacRae / 5 Comments

When I was an entomology student, I learned that flies in the family Syrphidae are called “hover flies,” due to their habit of hovering in front of flowers, and that the larvae are predators of aphids. As is the case for nearly every other group of insects, I now know that there are exceptions–often many—to the typical rule, and the fly shown in the above photograph is a perfect example of such. Being a beetle-man (and a wood-boring beetle-man, at that), I don’t generally notice flies unless there is something unusual about them. This fly was seen last summer at Sam A. Baker State Park in southeastern Missouri on the trunk of a very large, recently wind-thrown mockernut hickory (Carya alba) tree. I had never seen a fly quite like this before, but everything about it suggested an intimate association with dead wood, including its relatively large, hulking, black form and the way it repeated returned to and landed on the trunk of the dead tree each time I disturbed it. It instantly made me think of robber flies in the subfamily Laphriinae, which includes Andrenosoma fulvicaudum and many species of Laphria that, as larvae, tunnel through dead and decaying wood where they prey upon the larvae of wood-boring beetles. While it was quite obvious that the fly in the photo was not a robber fly, imagine my surprise when I eventually determined it to be a member of the family Syrphidae. For now I’ve provisionally settled on the genus Chalcosyrphus, although it lacks the steely blue cast exhibited by the only all-black species of the genus—C. chalybeus—shown on BugGuide. Another species, C. piger, looks very similar but seems always to have some red on the abdomen, which this individual definitely lacks. Perhaps the related genus Xylota is also a possibility, although the “gestalt” does not seem to quite match that of any shown on BugGuide. Most interesting for me are the distinctly enlarged and toothed metafemora, which along with the correspondingly curved tibiae suggest some predatory function, but the literature that I have seen makes no mention of such, but rather that the adults feed on pollen. My hunch about its association with dead wood does seem to be true, although it now seems the larvae are saprophages rather than predators within the wood, as I first imagined.

Copyright © Ted C. MacRae 2012

Fathers Day at the Missouri Botanical Garden

/ Ted C. MacRae / 2 Comments

Yesterday my girls (wife Lynne and daughters Mollie and Madison) took me and my father to the Missouri Botanical Garden for Fathers Day. Although I’m an entomologist, I also have a strong botanical bent, and although my wife and father are not scientists like me, they nevertheless find a day at the Missouri Botanical Garden as enjoyable as I do. The girls, on the other hand, will never admit that they like it the way the rest of us do, but I think deep inside they enjoy it very much and, in later years, will look upon these visits as some of their fondest Mothers and Fathers Day memories.

Me and daughters Mollie and Madison.

My father and I have been back together for 20 years now. With my wife and daughters, he has become one of the most important persons in my life. I wrote an essay about my father four years ago that explains how he made me whole—it still rings true today.

Me and Pop.

I have been to the Missouri Botanical Garden many, many times over the years, but one sight have have still never seen is a corpse flower (Amorphophallus titanum). I learned earlier this week that one of their plants is about ready to bloom, so I eagerly looked for this plant as we wound our way through the Climatron. As we came near the end and I still hadn’t seen it, I wondered if somehow I had missed it along the path. Suddenly I caught a glimpse of the giant 3′ tall flower bud near the end of the footpath, and I knew instantly that I had found what I was looking for.

Corpse flower (Amorphophallus titanum) getting ready to bloom.

I will be keeping track of the progress of this flower over the next couple of weeks on the Missouri Botanical Garden Facebook page in hopes that I can see it again when the flower opens fully—a rare botanical treat that few people ever get the chance to experience!

Corpse flower explained.

In my younger years when I had a bit more free time on my hands I was a hobbyist orchid grower. I didn’t have a greenhouse but nevertheless managed to keep a steady supply of plants in bloom by growing them outdoors under shade cloth with heavy watering and fertilizing during the summer and moving them indoors under fluorescent lights and in bright windows during the winter. I don’t have nearly the time for such pursuits these days, but I still enjoy looking at their exquisite and infinitely diverse blooms whenever I have the chance, and the Climatron never fails to disappoint.

One of many epiphytic orchids blooming in the Climatron.

While walking through the Climatron, I noticed a very exotic looking lizard on the trunk of one of the trees. I watched it licking exudate from the trunk and thought such behavior seemed rather odd. I later learned that this was the Standing’s day gecko (Phelsuma standingi), and that it might have an important role in pollinating the double coconut palm (Loidiocea maldivica). Both are endemic to the Seychelles Islands north of Madagascar, with the latter bearing the largest seed of any plant in the world (up to 45 lbs. in weight). The photo below was taken of another individual through the glass of its terrarium and, thus, lacks some clarity, but it shows the vivid colors and markings that distinguish these diurnal geckos from the other more typically nocturnal members of the gecko infraorder.

Standing’s day gecko (Phelsuma standingi).

While not gracing this post in a photo, many thanks to my loving wife, Lynne, who is the best mother my daughters could ask for and who helped make yesterday the special day for me and my father that it was!

Copyright © Ted C. MacRae 2012

Beetle botanists

/ Ted C. MacRae / 16 Comments

Calligrapha spiraeae on Physocarpus opulifolius | Jefferson Co., Missouri

While Dicerca pugionata (family Buprestidae) is, for me, the most exciting beetle species that I’ve found in Missouri associated with ninebark (Physocarpus opulifolius). it is not the only one. The beetles in these photographs represent Calligrapha spiraeae, the ninebark leaf beetle (family Chrysomelidae). Unlike D. pugionata, however, I almost never fail to find C. spiraeae on ninebark, no matter when or where I look, and whereas D. pugionata has been recorded in the literature associated with a few other host plants like alder (Alnus spp.) and witch-hazel (Hamamelis virginiana), C. spiraeae is not known to utilize any other plant besides ninebark as its host.

Beetles in the genus Calligrapha are among the most host-specific of all phytophagous beetles, with most of the 38 species in this largely northeastern North American genus relying upon a single plant genus as hosts (Gómez-Zurita 2005). The genus as a whole is fairly recognizable by its dome-like shape and black and white or red coloration, with the black markings on the elytra varying from coalesced to completely broken into small spots. The species, however, are another matter, with several groups of species that are quite difficult to distinguish morphologically. Fortunately most of them can be easily distinguished by their host plant (although such information is rarely recorded on labels attached to museum specimens). Calligrapha spiraeae, for example, with its reddish coloration and small black spots, looks very much like two other species in the genus—C. rhoda and C. rowena. Those latter species, however, are restricted to hazel (Corylus spp.) and dogwood (Cornus spp.); as long as the host is known, the species can be readily identified in the field.

At this point you may be wondering why the species name refers to the plant genus Spiraea rather than Physocarpus. In fact, ninebark was already known as the host plant when Say (1826) described the species, but the name spiraeae was given because at the time ninebark was included in the genus Spiraea (Wheeler & Hoebeke 1979).

REFERENCE:

Gómez-Zurita, J. 2005. New distribution records and biogeography of Calligrapha species (leaf beetles), in North America (Coleoptera: Chrysomelidae, Chrysomelinae). Canadian Field-Naturalist 119(1): 88–100.

Say, T. 1826. Descriptions of new species of coleopterous insects of North America. Journal of the Academy of Natural Sciences of Philadelphia 5:293–304.

Wheeler, A. G., & E. R. Hoebeke. 1979. Biology and seasonal history of Calligrapha spiraeae (Say) (Coleoptera: Chrysomelidae), with descriptions of the immature stages. The Coleopterists Bulletin 33:257–267. 

Copyright © Ted C. MacRae 2012

Damon diadema—Tanzanian giant tailless whip scorpion

/ Ted C. MacRae / 21 Comments

Damon diadema, Tanzanian giant tailless whip scorpion (adult female)

I’ve reared more than my share of arthropods over the years—from easy ones like Madagascan hissing cockroaches to hard ones like certain tiger beetles (in fact, I’m the only person to have ever seen the larva of Cylindera celeripes, much less reared them from egg to adult) to the innumerable tarantulas, scorpions, millipedes, hickory horned devils, darkling beetles, etc. that fall somewhere in between. And that’s just as a hobby entomologist—nevermind that it has often been my job over the years to rear dozens of species of insects and other “critters” as part of my professional duties. One group of arthropods, however, that I have not yet tried to rear are tailless whip scorpions or whip spiders. Members of the arachnid order Amblypygi, they are not scorpions, not whip scorpions, not even spiders, but rather something else. Like other arachnids they have eight legs and the combined head and thorax (cephalothorax); however, more than any other arachnid, tailless whip scorpions have stumbled upon a most insect-like body plan—the first pair of true legs are modified to long, thin, sensory appendages that mimic in form and function insect antennae, leaving—again, like insects—only three pairs of walking legs, and as predators they have the anteriormost pair of appendages (pedipalps) modified into grasping,  jaw-like structures analogous to the toothy mandibles of predaceous insects.

Adult males have the pedipalps extending past the ”knee” of the first pair of walking legs…

Of course, any resemblance to insects ends right there—tailless whip scorpions look like they belong not only to another class, but another world! Flattened, scuttling sideways at blinding speeds, and with legs all asplay at odd angles, they are as frightful and menacing in appearance as the hairiest, jaws-dripping-with-venom spider imaginable. However, nothing could be further from the truth. Lacking the sting of a scorpion, the venom of a spider, the powerful bite of other “jawed” creatures, or even defensive chemicals of any kind, tailless whip scorpions have only their speed and ability to hide in the slimmest of crevices to prevent them from becoming easy meals for the vertebrate predators with which they share their world.

…while in females the pedipalps are distinctly shorter.

The male and female Damon diadema, or Tanzanian giant tailless whip scorpion, featured in these photos belong to Martin Hauser, a dipterist with the California Department of Food and Agriculture in Sacramento who I had the pleasure to spend some time with last month. Like me, Martin is a fan of invertebrates as pets, but unlike me he has strayed into unusual taxa that I haven’t yet tried—these tailless whip scorpions being perhaps the most impressive of these odd groups. Hailing from east Africa (eastern Tanzania and Kenya north to Ethiopia and Somalia), this species has gained some popularity in recent years among hobbyists due to their adaptability to culture, relatively docile nature, and—of course—their terrifyingly impressive size (body length up to 30 mm according to Prendini et al. 2005, although some hobbyist forums state as much as 2 inches, and with “whip” spans many times that). In this species males and females are immediately distinguishable by the relative length of the pedipalps—highly elongate in males and with the “elbow” extending past the “knee” of the first pair of walking legs, while shorter in females and not reaching the knee. Damon diadema is the largest of the East African Damon variegatus species-group, and while there are other amblypygids in the world that are larger (e.g., Acanthophrynus from Central and South America, with up to 10″ leg-span and nearly 20″ whip-span), none are so tolerant of captive rearing as this species. There seems to be some confusion about identification of Damon spp. among hobbyists, and even Martin wasn’t sure which species his represented; however, according to Prendini et al. (2005) all of the species are easily distinguished morphologically. Damon diadema is one of only two species in the genus with two spines rather than one on the ventral surface of the pedipalp trochanter, the other being D. brachialis from southern African and unknown in captivity. In the closeup face shot of the adult male below, two spines can be seen on the right pedipalp trochanter, just visible between two of the pedipalp apical spines.

Pedipalps modified as raptorial ”claws” make these arachnids formidable predators.

I visited Martin at a good time, for not only did he have these marvelous monsters available for me to photograph, but one of the females had just recently produced a brood of young. All of them had reached 2nd instar by the time of my visit, with one or two already at 3rd instar. It was interesting to note the tendency of the juveniles to aggregate under the adult female, as if they needed/wanted her for protection. While seemingly obvious, this is actually quite interesting because most amblypygids are considered to be solitary and intolerant of conspecifics (Walsh & Rayor 2008). Damon diadema, however, is known to live in prolonged subsocial groups, apparently aided by kin discrimination abilities. I find this fascinating, considering the extraordinarily limited neural capacity of these creatures—there are only so many brain cells available for conducting the business of life without diverting any of them to the ability to recognize unrelated conspecifics, much less their own kin. It is the reason so many spiders and other predaceous invertebrates tend to live solitary lives and have evolved elaborate courtship dances to convince a potential partner that they are, in fact, a mate and not a meal.

Two ventral spines on the pedipalp trochanter distinguish Damon diadema in east Africa.

I was so impressed by these creatures that after returning home from California I set about finding a source from which I could purchase one of them—or better yet a male/female pair. Sadly, I could not find any sources—my dream of seeing these fantastically fearsome-looking fellows in an aquarium in my office would have to wait. I happened to mention this in passing during correspondence with Martin about other matters, and although it was not intended as a suggestion (or even anticipated that it could be interpreted as such), Martin immediately offered to send me a couple of his juveniles. How could I refuse?! We corresponded a little more about preparations for and timing of the shipment, and on Friday last week the package arrived. Neither of us were completely sure how well the little guys would handle a 3-day transcontinental journey, so it was with a blend of anticipation and trepidation that I opened the package. Imagine my surprise when I found them not only alive and well, but all six of them were alive and well! Well, for now they are all going under the name “Baby Damon,” but I suppose as they grow and (hopefully) develop some distinctiveness I can start giving each of them their own, unique name. It may take awhile—individuals of this species don’t mature sexually until around 12-15 months. Martin was also kind enough to include some small, temporary containers that will provide better confines until they are large enough to move into the large terrarium that I readied for them, and just as Dave has been  doing with his tarantulas, it will be fun to monitor the progress of each individual through their molts. This will continue to provide entertainment even after they reach adulthood, as amblypygids continue to molt and increase in size all of their life. Their lives could also be long ones—I’ve read of people maintaining this species for 10 years or more as adults, so it looks like I am in this for the long haul. A formidable challenge it might seem, but in addition to the invertebrates I mentioned above, I’ve also spent the past several decades being responsible for cats, dogs, rats, salamanders, and—most recently—two hominine juveniles (and females at that). Now that’s a challenge!

This 2nd instar youngster can already handle crickets its own size.

REFERENCES:

Prendini, L., P. Weygoldt & W. C. Wheeler. 2005. Systematics of the Damon variegatus group of African whip spiders (Chelicerata: Amblypygi): Evidence from behaviour, morphology and DNA. Organisms, Diversity & Evolution 5:203–236.

Walsh, R. E. & L. S. Rayor. 2008. Kin discrimination in the amblypygid, Damon diadema. The Journal of Arachnology 36:336–343.

Copyright © Ted C. MacRae 2012

Welcome “Baby Damon”!

/ Ted C. MacRae / 9 Comments

”Baby Damon”—one of six 2nd instar Tanzanian giant tailless whip scorpions that now call me Papa!

Just a quick post to formally introduce “Baby Damon,” who arrived last Friday with several siblings courtesy of my friend Martin Hauser in California. Damon represents the species Damon diadema, or the Tanzanian giant tailless whip scorpion. It will take at least a year for Damon to reach maturity, and he may live as long as ten years or more, so it looks like I’m in this for the long haul! When I visited Martin in California a couple of weeks ago I had a chance to photograph Damon’s terrifyingly impressive mother and father as well—look for those pics soon!

Copyright © Ted C. MacRae 2012