entomology

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

Welcome “Baby Damon”!

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”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

Poised for the bounty

/ Ted C. MacRae / 2 Comments

Misumenops pallidus on soybean | Santa Fe Province, Argentina

By mid-April I was near the end of my 8-week stay in Argentina. One of the more enjoyable tasks during this time was to go back out and visit some of the soybean fields that I had seen earlier in the season. I enjoy watching the progression of soybeans over time—both in plant phenology and in the guilds of insects present. Defoliating caterpillars like Rachiplusia nu (oruga medidora) and Anticarsia gemmatalis (oruga de las leguminosas) abound during the late vegetative and early to mid-reproductive stages of growth, feeding day and night on the lush, green foliage. As the days grow shorter and cooler, the soybean fields slowly morph from dark green to tawny-yellow, and leaf-feeding guilds give way to seed-feeding stink bugs like Piezodorus guildinii (chinche de las leguminosas) and Nezara viridula (chinche verde).

Ever present amongst the plant-feeding insects are their natural enemies, with spiders being among the more numerous predators. This small (~10 mm length) crab spider (family Thomisidae) was seen in a soybean field in Santa Fe Province with the plants at R6 stage of growth (pods completely filled). I’m fairly certain it represents Misumenops pallidus based on its close resemblance to the spider in this photo. Piezodorus guildinii stink bugs were especially abundant, and just as the crop of newly hatched nymphs was poised to take advantage of the fat, juicy seed pods, this spider seemed poised and ready to take advantage of the fat, juicy nymphs. In fact, M. pallidus is the most abundant crab spider in soybean agroecosystems in the Humid Pampas of Argentina (Liljesthröm et al. 2002), which as a group comprise nearly half of all spiders in those systems (González et al. 2009). Perhaps one reason for this is their generalist prey selection tendencies, feeding on prey species such as R. nu and P. guildenii when they are abundant and switching to non-pest prey species (except the heavily sclerotized weevils and the large and noxious adults of N. viridula) when they are absent (González et al. 2009).

REFERENCES:

González, A., G. Liljesthröm, E. Minervino, D. Castro, S. González & A. Armendano. 2009. Predation by Misumenops pallidus (Araneae: Thomisidae) on insect pests of soybean cultures in Buenos Aires Province, Argentina. The Journal of Arachnology 37:282–286.

Liljesthröm, G., E. Minervino, D. Castro & A. González. 2002. La comunidad de arañas del cultivo de soja en la provincia de Buenos Aires, Argentina. Neotropical Entomology 31:197–209.

Copyright © Ted C. MacRae 2012

Just published: Cicindela 44(1) March 2012

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Issue 44(1) of the journal Cicindela is now hitting mailboxes. This one-paper issue features an article by Chandima D. Dangalle and Nirmalie Pallewatta (University of Colombo, Sri Lanka) and Alfred P. Vogler (The Natural History Museum, London) reporting the results of a survey of tiger beetles of Sri Lanka and analysis of their habitat specificity. The authors sampled 94 locations on the island representing six habitat types: coastal and beach habitat, river and stream banks, reservoir systems, urban man-made sites, agri-ecosystems and marshy areas, finding ten species in the genera Cylindera, Calomera, Hypaetha, Lophyra and Myriochile at 37 locations representing all habitat types except the last two. The study further revealed that the species of tiger beetles were restricted to different habitat types, with most displaying a high degree of habitat specificity. Statistical analysis revealed significant differences between two or more species in four factors: solar radiation (i.e., sun or shade), soil salinity, soil moisture and wind speed. This suggests that these are the key factors involved in habitat selectivity in Sri Lankan tiger beetle species. Other factors such as temperature, relative humidity, soil type and soil color did not differ significantly between habitats for the different species, suggesting that these criteria are essential for tiger beetle survival in any habitat type.

You may also notice that my photo of Cicindela arenicola, taken last fall in Idaho Falls, graces the cover of this latest issue. Contact Managing Editor Ron Huber to begin your subscription—membership is a very nominal $10 per year in the U.S., a little more elsewhere to cover additional postage.

REFERENCE:

Dangalle, C. D., N. Pallewatta & A. P. Vogler. 2012.  Habitat specificity of tiger beetle species (Coleoptera, Cicindelidae) of Sri Lanka. Cicindela 44(1):1–32.

Dicerca pugionata – safe and sound!

/ Ted C. MacRae / 22 Comments

Dicerca pugionata on Physocarpus opulifolius (ninebark) | Jefferson Co., Missouri

One of my favorite beetle species in Missouri is Dicerca pugionata—a strikingly beautiful jewel beetle (family Buprestidae) found sporadically across the eastern U.S. Unlike most species in the genus, which breed in dead wood of various species of trees, D. pugionata larvae mine living stems of certain woody shrubs—namely alder (Alnus spp.), witch-hazel (Hamamelis virginiana) and ninebark (Physocarpus opulifolius) (Nelson 1975). When I first began studying Missouri Buprestidae (way back in 1982), the species had just been reported from the state based on a single specimen (Nelson et al. 1982). I happened to stumble upon these beetles at what became my favorite collecting spot during the 1980s—Victoria Glades Natural Area, just south of St. Louis in Jefferson Co. For several years while I was visiting Victoria Glades, I found these beetles regularly during spring and fall on stems and branches of living ninebark plants growing within the ravines and along the toeslopes at the lower edges of the glades.

After finding the beetles at Victoria Glades (and nearby Valley View Glades Natural Area), I made it a habit to examine ninebark wherever I found it growing in Missouri. Ninebark is actually rather common in the state along the rocky streams and rivers that dissect the Ozark Highlands. Interestingly, I almost never encountered this beetle on ninebark elsewhere in the state. I’m sure it occurs in other areas, but probably at too low a level to be easily detected. I surmised that the populations at Victoria and Valley View Glades were unusually high due to the non-optimal conditions for its host plant. The ravines and toeslopes where the plants grow are drier than typical for ninebark, and unlike the lush, robust plants found in moister streamside habitats, the plants at these glades are small, scraggly and often exhibit a certain amount of dieback. It seemed likely to me that the plants growing in the glades were less capable of fending off attacks by these insects, thus resulting in relatively higher numbers of beetles at these glades.

After the publication of my “Buprestidae of Missouri” (MacRae 1991), it would be many years before I actually returned to Victoria Glades. When I did return, I was pleased to see that management practices (e.g. prescribed burning, cedar removal, etc.) intended to halt the encroachment of woody vegetation and preserve the glade’s pre-settlement character had been implemented in the area. I was a little bothered, however, by the seeming paucity of insects compared to the years prior to management. I visited the glades again several times afterwards, and not only did insect populations in general seem to be depressed, but I never succeeded in finding D. pugionata adults on the ninebark plants. I began to worry that the prescribed burns, while clearly beneficial to the glade flora, might have had a negative impact on the glade’s insect populations.

I’m happy to report that, at last, I have found the beetles again. I returned to the glades in early May this year and, for the first time since 1987 I found the adults of this species—five in all (a typical number for the many dozens of plants checked) and right in the same areas where I had so consistently found them 25–30 years earlier. This does much to allay my concerns about the ability of these beetles to persist in the face of prescribed burning (though I remain convinced that this management technique should be used more judiciously in our state’s natural areas than it has in recent years), and I’m happy to have these new photographs of the species, which are a decided improvement over the old scanned slides taken nearly 30 years ago!

REFERENCES:

MacRae, T. C. 1991. The Buprestidae (Coleoptera) of Missouri. Insecta Mundi 5(2):101–126.

Nelson, G. H. 1975. A revision of the genus Dicerca in North America (Coleoptera: Buprestidae). Entomologische Arbeiten aus dem Museum G. Frey 26:87–180.

Nelson, G. H., D. S. Verity & R. L. Westcott. 1982. Additional notes on the biology and distribution of Buprestidae (Coleoptera) of North America. The Coleopterists Bulletin 35(2) [1981]:129–151.

Copyright © Ted C. MacRae 2012

Cosmetid harvestman with parasitic/phoretic mites in Argentina

/ Ted C. MacRae / 3 Comments

Metalibitia sp. poss. paraguayensis | Corrientes Province, Argentina

While searching logpiles last month in a relatively intact tract “Selva Paranaense” near Paso de la Patria (Corrientes Prov., Argentina), the most interesting find for me was , a bizarre longhorned beetle that is either amazingly cryptic or a curious mimic (I couldn’t decide). There wasn’t much else to be seen in the logpiles—it had been a very dry summer in northern Argentina, but I did find this interesting species of harvestman (class Arachnida, order Opiliones) huddled together in one of the punkier piles of wood.

Knowing little about harvestman taxonomy (but knowing of several specialists who do), I sent the photos around for expert opinion. Everyone responded with the same opinion—family Cosmetidae, apparently distinguished by its spoon-shaped pedipalps. Marshal Hedin compared them to this similar-looking species photographed in Bolivia, Christopher Taylor (Catalogue of Organisms) thought they might be a species of Metalibitia and Ricardo Pinto-da-Rocha suggested M. paraguayensis as having been recorded from the province of Corrientes (although a specimen would need to be examined to confirm the identification). My thanks to each of these gentlemen for weighing in on a possible ID.

Argentina represents the southernmost extent of this strictly New World family of harvestmen, while to the north the family extends up to the southern U.S. (genus Vonones). In between, the family is diverse and comprises up to one-third to one-half of the harvestman fauna (Kury & Pinto-da-Rocha 2007). Many species in the family are ornately marked, giving rise to the family name which is derived from the Greek kosmetós (= ornate)—check out this gallery of photos at Flickr to see some truly spectacular examples.

While I was photographing these individuals, and even when I first began processing the photos, I thought that they were quite dirty and debated whether to clean them in PhotoShop. Then I realized that the numerous white spots were not debris, but mites! Whether these represent a parasitic or phoretic relationship is not clear to me, however, and none of the gentlemen I sent the photos to offered any comment about them. Erythraeid and thrombidiid mites are well documented as harvestman ectoparasites during their larval stage, with recorded hosts including Neotropical species of Cosmetidae (Townsend et al. 2008). The tiny, white mites on these individuals, however, do not resemble the large, red erythraeid mites (probably genus Leptus) that I have seen parasitizing our North American harvestman species, and their numbers on multiple individuals is, to me, more indicative of a phoretic relationship. If you want to become thoroughly confused by the tremendous diversity of mites the parasitize harvestmen, see the comprehensive review by Cokendolpher (1993).

REFERENCES:

Cokendolpher, J. C. 1993. Pathogens and parasites of Opiliones (Arthropoda: Arachnida). The Journal of Arachnology 21:120–146.

Townsend, V. R., D. N. Proud, M. K. Moore, J. A. Tibbetts, J. A. Burns, R. K. Hunter, S. R Lazarowitz & B. E. Felgenhauer. 2008. Parasitic and phoretic mites associated with Neotropical harvestmen from Trinidad, West Indies. Annals of the Entomological Society of America 101(6):1026–1032.

Kury, A. B. & R. Pinto-da-Rocha. 2007. Cosmetidae Koch, 1839. Pp 182–185. In: R. Pinto-da-Rocha, G. Machado & G. Giribet (Eds.). Harvestmen: The Biology of the Opiliones. Harvard University Press, Cambridge and London, x + 597 pp.

Copyright © Ted C. MacRae 2012

Holy conglobulation, Batman!

/ Ted C. MacRae / 24 Comments

It’s a pill bug… no, it’s a roach. It’s a pill roach!

Earlier this month I made a quick trip out to California to see my good friend Chuck Bellamy receive his Honorary Membership in The Coleopterist Society. While I was there, I got a chance to spend some time with Chuck’s labmate Martin Hauser. Although Martin is a specialist of flies, he shares my fascination with unusual arthropods of all types and made available for me to photograph this adult female Perisphaerus sp. (order Blattodea, family Blaberidae), or “pill roach”. Seventeen species from southeast Asia and Australia have been described in this genus (Beccaloni 2007), but which (if any) this individual represents remains unknown.

In contrast to ”normal”-looking males, adult females exhibit a ”wingless, half-ellipsoid” morphology.

The most obvious characteristic of species in this genus is the ability of females to roll up into a ball; i.e., conglobulate.¹ Clearly this is a defensive morphotype, but curiously only females possess this ability—males are winged and exhibit the more flattened morphology typical of many cockroaches. Martin and I were unable to get this particular individual to completely enroll (we must not have been scary enough), but when it does the posterior abdomen fits tightly against the pronotal margin, covering all sensory organs and leaving no soft tissues exposed, gaps to enter or external projections to grab (Bell et al. 2007).

¹ I must thank Brady Richards, who, in his answer to ID Challenge #18, used this word to coin the phrase that would eventually become the title of this post.

Adult females apparently exhibit not only maternal protection but also nutrition.

But why should only females and not males exhibit this defensive morphotype? One would think that both males and females are equally threatened by predators. Apparently this is related to their unusual form of uniparental (maternal) care (Choe & Crespi 1997).  Early-instar nymphs in this genus remain closely associated with their mother and cling to her underside until they reach the third instar. These early-instar nymphs are not only blind, but they also exhibit a narrowed head with specially modified mouthparts that fit precisely into two pairs of orifices located on the female underside between the middle and hind pairs of legs. Whether the nymphs are feeding on glandular secretions or female hemolymph remains unknown, but regardless only a limited number of nymphs can be handled by a female at one time. This represents an unusual level of energetic investment in offspring among insects—especially among cockroaches, and thus the female has an interest in protecting that investment. Sealing them up inside an impenetrable ball is certainly one way to protect the nymphs.

Despite first impressions, six legs and a very ”cockroach-ish” head belie its true identity.

Conglobulation has actually arisen several times amongst arthropods. Obviously pill bugs (a.k.a. roly-poly bugs) are the first group that comes to mind in this regard, but Eisner & Eisner (2002) illustrate nearly identical morphology in two oniscomorph millipedes as well as isopods and Perispharus and also describe strikingly similar behavior by the larva of Leucochrysa pavida  (family Chrysopidae).

Many thanks to those of you who participated in ID Challenge #18. As of now, the comments for that challenge are closed, and I will reveal the comments and award points shortly. My sincere thanks again to Martin Hauser for allowing me to photograph this most interesting insect!

Edit 5/28/12, 12:55 a.m.: For the first time ever, we have a 3-way tie for a BitB Challenge win—Sam Heads, Brady Richards, and Mr. Phidippus all earned 12 points to share the top spot in this challenge. Since these three gentlemen were already the three leaders in BitB Challenge Session #6, there is no change to the leaderboard in the overall standings (44, 42 and 37 points, respectively). However, Dennis Haines (34 points) is hanging close, and Tim Eisele (25 points) still has a shot at the podium. Any number of others following closely behind could also find themselves on the podium if any of the three leaders should falter down the stretch.

REFERENCES:

 Beccaloni, G. W. 2007. Blattodea Species File Online. Version 1.0/4.1. World Wide Web electronic publication. <http://Blattodea.SpeciesFile.org&gt; [accessed 27 May 2012].

Bell, W. J., L. M. Roth & C. A. Nalepa. 2007. Cockroaches: Ecology, Behavior, and Natural History. The Johns Hopkins University Press, Baltimore, Maryland, 230 pp.

Choe, J. C. & B. J. Crespi. 1997. The Evolution of Social Behavior in Insects and Arachnids. Cambridge University Press, Cambridge, U.K., 541 pp.

Eisner, T. & M. Eisner. 2002. Coiling into a sphere: defensive behavior of a trash-carrying chrysopid larva Leucochrysa (Nodita) pavida (Neuroptera: Chrysopidae). Entomological News 113:6–10.

Copyright © Ted C. MacRae 2012

Science Outreach in Action

/ Ted C. MacRae / 5 Comments

This evening I had the distinct pleasure of presenting to the Missouri Master Naturalist™ program, a community-based natural resource education and volunteer service program for adults whose mission is to “engage Missourians in the stewardship of our state’s natural resources through science-based education and volunteer community service.”  The purpose of this organization is to develop a corps of well-informed volunteers to provide education, outreach and service to benefit natural resources and natural areas management within the community. Master Naturalists receive training and contribute volunteer service to become a certified Master Naturalist™.

There are several chapters serving different areas of the state—my presentation was made to the Miramiguoa Chapter serving Franklin County in east-central Missouri. My talk was titled, “Tiger Beetles of Missouri,” and, as an “expert” in my chosen field, attendees received advanced training credit in addition to the basic training they receive in more general aspects of Missouri ecosystems. It is tempting to think that attendees were there just to get the credit, but what I found was one of the most engaged and interested audiences to which I’ve had the pleasure to speak in quite a long time. Naturally, it is not difficult for me to show a lot of passion when I get to present on something as dear to my heart as tiger beetles, but as a presenter I feed off audience enthusiasm as well. As a result, the combination of subject and audience engagement made for a fun discussion, and I only hope the audience enjoyed the 90 minute session as much as I did.

I write about this because I see Science Outreach by practicing scientists as critical to advancing appreciation of and participation in science by the general public—not just because I think they will have fun, but because a science-friendly community tends to make community and policy decisions favorable to and based on science. You might call it my brand of politics! I’ve been heavily involved in science outreach for many years now, talking to everyone from pre-schoolers to secondary school science classes to natural history organizations. The specifics of my message are tailored to the audience, but the underlying principle is the same—to help the audience gain appreciation of entomology in particular and science in general. I think I will chalk up tonight’s presentation as another win!

For those interested, here is a link to a PDF version of the presentation, which provides the best ‘snapshot’ look at the tiger beetle fauna of Missouri available so far:

Miramiguoa – May 2012 – TB of Missouri

Copyright © Ted C. MacRae 2012