Month: June 2008

Saving Missouri’s tigers

/ Ted C. MacRae / 8 Comments

For several years now, my friend and colleague, Chris Brown, and I have been studying the tiger beetles (family Cicindelidae) of Missouri in an attempt to characterize the faunal composition and in-state distributions of the included species. Our studies have relied on examination of specimens in museum collections along with several seasons of field work across the state. The data we’ve gathered so far have revealed a fauna that reflects the ecotonal position of Missouri, comprised of elements from the eastern deciduous forest, the southeastern mixed hardwood forests and pinelands, and the western grasslands. These beetles are most frequently associated with disturbed habitats containing sparse vegetation, such as sandbars and erosion cuts, but they also live in other habitats such as along muddy banks, on glades and in forest litter. Since European settlement of Missouri, drastic alterations have occurred in the abundance and distribution of these habitats across the state, and tiger beetle populations have been affected as a result. Dredging and straightening of natural water courses have impacted species that prefer the water’s edge, while fire suppression has impacted those that need dry, open habitats. Grazing has had a profound impact on species associated with sensitive, saline habitats. Conversely, some anthropogenic changes have benefited certain species – road, borrow sand pit and pond construction have increased habitat for species able to utilize such habitats. To date, our surveys have confirmed the presence of 23 species in Missouri (16% of the North American fauna). Some species are common and widespread, such as Cicindela sexguttata (six-spotted tiger beetle) (above, photo taken in a mature white oak forest in Warren Co.). Others have more specific habitat requirements, but their status within the state remains secure. A few are rare and highly localized, primarily representing species at or near the northern or western edge of their distributions that exist in the state as small, disjunct populations. Special conservation efforts may be warrented for these to ensure their continued survival within the state.

One species of potential conservation concern is C. pruinina (loamy-ground tiger beetle), a grassland species normally found in Kansas, Oklahoma, and Texas (left, photo by Chris Brown). This beetle is sometimes treated as a synonym or subspecies of C. belfragei but was most recently considered a valid species by Spomer et al. (2008). When we began our studies, the species was known from Missouri only by a small series of specimens collected in one of the western counties and deposited in the collection of Ron Huber. An additional specimen in the Huber collection labeled “Columbia, Mo.” is considered to likely represent student mislabeling. Several attempts at relocating the western Missouri population were required before we found it, and intensive surveys to determine the extent of its distribution in Missouri were conducted during 2006 using a combination of pitfall traps and direct observation. Those surveys succeeded in detecting the beetle only along one 2.5-mile stretch of county road in Johnson Co. The beetle seems to be restricted to red clay embankments occurring in a small localized area of the county. This season we plan to refine our survey by focusing tightly on promising habitats in this area near the sites identified in 2006 to more precisely define the distributional limits of this population. Regardless of what we find, the flightless nature of the species, its highly localized Missouri occurrence, and the disjunct nature of such suggest that special conservation status is warranted for the species to ensure its continued presence in the state. Despite the relatively low numbers of individuals we have seen, the protected status of the land on which this beetle lives leaves us optimistic about its future.

A Missouri species about which we are far less optimistic is C. circumpicta johnsonii (saline springs tiger beetle) (right, photo by Chris Brown), long known from saline spring habitats in the central part of the state. The Missouri population is highly disjunct from the main population further west and exhibits a uniform blue-green coloration rather than the mix of blue, green, and red colors exhibited by the main population. These features suggest that separate subspecies status might be warranted for the Missouri population. Numerous historical collection records exist from a handful of sites in Howard and Cooper Counties; however, surveys conducted by us during recent years revealed that the populations had suffered severe declines. This appears to be largely due to cattle disturbance and vegetational encroachment of the sensitive saline spring habitats upon which the beetle depends, especially at sites located on private land. Ron Huber, in a letter to me listing the collecting records he had for this species, reported seeing “hundreds of the wary little buggers” at one locality on private land, but in our visit to the site not a single individual was seen around the spring – badly trampled and overgrown with the exotic pasture grass tall fescue (Festuca arundinacea). In all, we were successful in finding the beetle at only one of the historical localities and at one new site located nearby. While both of these sites are located on state protected land, we concluded that the longterm viability of the C. circumpicta johnsonii population in Missouri was in serious jeopardy. Based on our recommendation, the species was placed on the Missouri Species of Conservation Concern Checklist with a ranking of S1 (critically emperiled). While this affords the species legal protection under the Wildlife Code of Missouri, the benefit may be minimal since the Wildlife Code does not address the main threat to this beetle’s survival – habitat degradation. We have not surveyed for this beetle since but plan to make field observations this summer (no trapping!) to check on its status. I sincerely hope we will not have to hang our heads with the realization that we have succeeded in extirpating yet another beautiful and irreplaceable gem.

Last year we finally succeeded in locating C. cursitans (ant-like tiger beetle) in Missouri (left, photo by Chris Brown). Adults are flightless, and at less than 1 cm in length, are among the smallest of North American tiger beetles. The species has been recorded broadly but sporadically between the Appalachians and Great Plains – a distribution that is probably underestimated due to its small size and general resemblance to ants. A significant distributional gap exists between the eastern and Great Plains records, which Ron Huber believes may be indicative of two disjunct forms and potentially two species. Missouri falls within this gap, and although the species has not yet been formally recorded from the state, a single specimen collected in 1991 “nr. Portageville” is deposited in the Enns Entomology Museum, University of Missouri, Columbia. We had made several attempts over the past few years to locate this species by searching what we thought were promising habitats along the Mississippi River near Portageville, but the species was not located until last year, when I relayed this information to Portageville biologist and tiger beetle enthusiast Kent Fothergill. Kent not only located the beetle at the location I suggested, but quickly found another population on a nearby parcel of land managed by the Missouri Department of Conservation. Hurriedly, we visited the first site and observed a few additional individuals at a nearby location just to the south. The bottomland forest habitat within which all of these individuals were observed is fairly extensive along the Mississippi River in the southeastern lowlands of Missouri, but at this point we can only speculate whether C. cursitans occurs throughout this habitat. Other habitats have been reported for this species, including mesic and wet prairies and meadows (Brust et al. 2005). Such habitats are also found in the southeastern lowlands, and while C. cursitans has not been seen through cursory examinations in such areas, it is possible that the small size, cryptic habits, and narrow temporal occurrence of C. cursitans have allowed it to escape detection. Kent will be helping us this season with additional trapping and direct observation at several selected sites along the Mississippi and St. Francois Rivers to determine whether the beetle occurs more broadly in the southeastern lowlands and whether it utilizes these other habitats in addition to bottomland forests.

I would be most interested in any additional reports of these rare tiger beetles in Missouri (contact me at the email address shown in the left sidebar copyright statement). Remember, C. circumpicta johnsonii is critically emperiled in Missouri – please do not collect it.

My Dad

/ Ted C. MacRae / 1 Comment

My dad had knee replacement surgery a couple days ago. The surgery went off without a hitch, and he’s doing very well. All signs are that he will bounce back quickly and suffer few, if any, complications. I’ve spent much of the past three days here at the hospital – sometimes providing support and encouragement, other times just keeping him company. He should be released tomorrow, and I’ll spend the rest of the week with him at his house – hopefully he’ll be able to get around okay by then.

Some thirty years ago, my dad got an infection that settled in his left hip. By the time doctors found it and figured out what was going on, his left hip socket had degenerated badly, and the only medical option after cleaning up the infection was a year in a full body cast that resulted in fusion of the socket with the femoral head. This left him with a left leg two inches shorter than his right, a bad limp, and a lifetime of pain medications. His right leg became his ‘good leg’ and his left became the ‘bad.’ Decades of walking with a cane and favoring his bad leg put a lot of pressure on his good leg, and at age 73 his right leg had had enough. Now, his good leg is his bad leg, and his bad leg is, well, still his bad leg. This will add a wrinkle to his recovery, since he won’t have a healthy leg to carry the load while his good leg recovers. But I will be there to help, if needed, and in a few weeks his good leg should be good as new.

My dad is not only my dad, but also my best friend. We have a relationship that is based on mutual love and respect, and I don’t know which of us appreciates more what we have with each other. It wasn’t always this way – my dad and I were estranged for 25 years starting when I was 10 years old. My parents married far too young, and each had their own issues – they were but children themselves. Having first me, then my brother and sister, only delayed but could not prevent the inevitable break up that resulted in my fathers absence. I paid a heavy price by not having a father during those crucial, formative years as I finished growing up, but I seem to have turned out okay regardless. It would take many years before I would be ready for something so bold as reconciliation, but maturity and the support of a loving wife eventually made it possible. There were difficult questions to answer, but through it I realized that my father had paid a heavy price as well. Not the selfish irresponsible man I had been taught about, instead I saw a sensitive, deeply introspective man who had lived a life of hard knocks, suffered the consequences, learned from his mistakes and turned his life around.

My dad loves to ride bikes. I do too, but I did not learn the love of cycling from him. My dad is simple yet elegant, with an understated class that people adore. I, too, try to show respect and modesty, but I did not learn these things from my father. We both love classical music (he can live without the metal), listen to NPR, and enjoy humor with more than a touch of irreverance – tastes acquired by each of us before we knew each other. What I have learned from my father during these past 15 years is why I am me – a gift I didn’t know I lacked. I don’t mourn the loss of those 25 years spent without my father, rather I rejoice at the very special relationship that we now have – perhaps possible only because of our separate pasts. My father describes that year in a body cast as the darkest period of his life. I did not know him then, so I could not be there to help him through it. While his recovery from knee replacement will not be near that ordeal, neither will it be easy. But I am here with him, and I know in my heart that whatever difficulties he faces during his recovery, he will look back on this as a small part of the best time of his life.

The Chrysobothris femorata “problem”

/ Ted C. MacRae / 4 Comments

I found a young cottonwood tree (Populus deltoides) the other day that had recently fallen over in one of the many storms we’ve had this spring. Anytime I see one of these “windthrows” I immediately think – woodboring beetles! Windthrows are attractive to numerous species of Buprestidae and Cerambycidae, and when I find one I try to revisit it often as the season progresses and different beetle species – active at different times and attracted to wood at different stages of dying or death – are encountered. This particular tree was only partially uprooted and so still had fresh foliage in the crown. While death is inevitable, it will be a slow, lingering death as the remaining soil-bound roots try in vain to sustain the fallen tree. This is an ideal situation for attracting species of the genus Chrysobothris, which seem to respond to plant volatiles emitted from trees under duress or recently killed. In the deciduous forests of eastern North America, C. femorata and related species are the most commonly encountered Chrysobothris attracted to these situations. Nursery growers and landscapers know this insect as the “flatheaded apple tree borer” – in reference to the appearance of the larvae as they tunnel under the bark of one of its favored hosts. The species has in fact, however, been recorded breeding in some two dozen genera of deciduous woody plants throughout the continental states and Canada, an unusual level of polyphagy for a genus of beetles in which most species typically exhibit a fair degree of host fidelity.

The problem is, “C. femorata” is not really a species, but a complex of closely related species. Entomologists have recognized this for some time, and while diagnostic characters have been identified for some of the more distinctive members of the group, such characters have remained elusive for C. femorata and its closest relatives. As a result, the species has become sort of a “trash can” for specimens that could be not be assigned to one of these more distinctive species, and in many museum collections large series of specimens can be found labeled simply “C. femorata species complex”. Fortunately, some much needed clarity was provided earlier this year by Stanley Wellso and Gary Manley, who after years of careful, systematic study at last published a revision of the Chrysobothris femorata species complex. In their work, six new species were described and one species resurrected from synonymy under C. femorata. Three of the new species occur in the western U.S., another is restricted to Georgia and Florida, and the remaining two new species and one resurrected species occur broadly across the eastern or southeastern U.S. This brings to 12 the total number of femorata-complex species in North America, with nine occurring in the eastern U.S. and seven in Missouri. The characters used to distinguish the species are subtle but consistent, and available biological data seem to support the species as now defined.

Of the dozen or so Chrysobothris individuals I collected on the fallen cottonwood during this past week, all but one represent C. femorata (as now defined). The photos I share here show some of the characters that distinguish this species from its closest relatives – primarily the straight rather than curved lateral margin on the last third of the elytra and the generally distinctly reddish elytral apices (most easily seen in the full-sized versions of the photos – click to view). Females (first and second photos) tend to show distinct reddish tinges behind the eyes and on top of the head as well. Males (third photo) can be distinguished from females by their bright green face (I tried valiantly but could not get one of these guys to pose in a position showing such). The photos also illustrate some of the typical behaviors displayed by these beetles, with males rapidly searching up and down the trunk looking for mates (third photo), and females probing cracks and crevices in the bark with their ovipositor looking for suitable sites to deposit their eggs (second photo). Of the two dozen host genera recorded for this species, many likely refer to some of the newly described species. In particular, records of this species from oak (Quercus spp.) and hackberry (Celtis spp.) may refer to the new species C. shawnee and C. caddo, respectively. As now defined, this species is still quite polyphagous and occurs throughout the continental U.S., but it is more common east of the continental divide and appears to prefer maple (Acer spp.), birch (Betula spp.), sycamore (Platanus occidentalis), poplar (Populus spp.), and especially rosaceous hosts such as hawthorn (Crataegus spp.), apple (Pyrus malus), pear (Pyrus communis), and cherry (Prunus spp.). Also, of all the species in this complex, C. femorata appears to be the most partial to stressed or dying trees (as with these individuals collected on live, windthrown cottonwood) rather than completely dead hosts. Wellso and Manley note that considerable variation still exists among individuals assignable to their more restricted definition of C. femorata. Thus, it is possible that more than one species is still involved, particularly among those utilizing hardwood hosts (e.g. apple, maple, etc.) versus softwoods (e.g., poplar, birch, etc.). Detailed biological studies will likely be required to identify any additional species that might be hiding amongst these populations.