DSA 2014 Annual Meeting
2014 Dragonfly of the Americas Annual Meeting in
Wisconsin's North Woods
June 13-15, 2014
ABSTRACTS OF PRESENTATIONS AT 25TH ANNUAL MEETING OF
THE DRAGONFLY SOCIETY OF THE AMERICAS, JUNE 14, 2014
Measuring The Labium Of Aeshna Nymphs: Following In E. M. Walker’s Footsteps
by Robert B. DuBois (Ken Tennessen co-author)
Abstract. The exhaustive studies of nymphs of Aeshna and Rhionaeschna by E. M. Walker (1912-1958) have long guided the taxonomy of these groups and formed the basis for keys still in use today. Uncertainty remains, however, about how he measured the length of the labium, including the varied terminology he used over the duration of his career concerning this structure. This uncertainty has led to confusion about proper application of his taxonomic recommendations. We recalculated ratios of the maximum width/length [W(max)/L] of his illustrations of the folded labium and prementum in publications throughout his career and compared these data with ratios derived from measurement of specimens in our collections. Our results show that from 1912 to 1941, Walker measured only the length of the prementum proper (which he called the “mentum of the labium”), exclusive of the ventrally visible portion of the postmental hinge. In 1941 he excluded the postmental hinge in his description of the nymph of A. verticalis, but included the hinge in his description of the nymph of A. septentrionalis. In Walker’s most recent and influential work (1958), he included the postmental hinge in labium length measurements of nine species, but measured the length of only the prementum for five others. He was consistent with the use of terms, using both “folded labium” (by which he meant the prementum plus the postmental hinge) and “prementum” (by which he meant only the prementum, thus excluding the postmental hinge). We recommend measuring the length of the prementum in future studies because we found less variability when only the prementum was measured than when the folded labium was measured including the postmental hinge. An approximate conversion between the two methods of calculating W(max)/L ratios can be made as follows: ratio calculated when the length of the prementum excluding the postmental hinge is used x 0.88 is approximately equal to the ratio when the length of the folded labium including the postmental hinge is used for species of Aeshna and Rhionaeschna in North America.
In Theory, It's A Great Place To Visit -- But Would I Raise My Kids There? Odonates In A Desert Sinkhole System Experience An Ontogenetic Shift In Landscape Function
by Karen Gaines
Abstract. The Equilibrium Theory of Island Biogeography (ETIB) offers an explanation of how habitat patch size can affect species diversity, with larger patches often supporting higher numbers of species. Studies that explicitly compare patterns exhibited by multiple life stages (e.g., adults and nymphs) of a single taxonomic group are uncommon, however, despite the fact that they may offer additional insight into the general applicability of this theory. Odonates may represent an ideal group for this application because these insects experience dramatic changes in environmental requirements and dispersal abilities during the maturation process from aquatic nymph to terrestrial adult. I examined the effects of water quality and physical habitat parameters on adult and nymphal odonate species diversity in a desert sinkhole complex over the course of three years. As predicted by the ETIB, the species diversity of both life stages increased with increasing sinkhole surface area, but the slopes of the respective species-area curves suggest that the sinkhole complex functions as an island system only for nymphs and as a mainland landscape for adults. Water salinity had more influence on species diversity than did surface area for both life stages, perhaps because salinity strongly affects other site selection cues used by adults and the ability of nymphs to survive until emergence.
Odonate Species First To Colonize Central Virginia Ponds
by Richard Groover
Abstract. A six-year study of lentic sites in Hanover County, Virginia, was conducted. First, a county-wide survey of 26 sites was conducted to identify dragonfly species available for colonization. As a result, seven species not previously reported in Hanover County were found. Eight new or reconstructed impoundments in central Virginia were studied from 2007–2012 to identify which species would be the first to colonize these sites. First colonizer dragonfly species for the lentic habitats studied were Celithemis eponina, Erythemis simplicicollis, Libellula incesta, L. luctuosa, Pachydiplax longipennis, and Perithemis tenera. Seventeen Hanover County species appeared to rarely and possibly never be first colonizers.
Dragonfly Assemblage Structure In A Northern Boreal Setting: Insights From The 2013 Dragonfly Society of the Americas Annual Meeting Survey
by Dave Halstead
Abstract. The 2013 Dragonfly Society of the Americas (DSA) annual meeting provided an opportunity to gain knowledge of adult dragonfly distribution and biodiversity information in the Boreal Plain and Boreal Shield Ecoregions of north central Saskatchewan. Approximately 50 dragonfly experts and enthusiasts were involved in the seven-day survey. Daily field forms were supplied to each participant for the purpose of data capture. Collation and analysis yielded over 260 separate sampling events involving more than 1600 species occurrences across a latitudinal range of 53.0 to 56.0 degrees inclusive. Two-way cluster analysis was used to gain insight into the natural groupings that help describe dragonfly assemblage structure. This analysis was restricted to 180 sampling events generating six or more species. Indicator species analysis was performed for a variety of cluster analysis groupings to determine maximum indicator value. Six dragonfly groupings were suggested by the analysis. Each dragonfly grouping was tied to one or more statistically significant indicator species. These in turn were tied to six different boreal habitat types. This analysis demonstrates the potential utility of opportunistic surveys, similar to those held in conjunction with the DSA annual meeting, for characterizing dragonfly assemblage structure in a well-defined ecological region.
Duration Of Cold Temperature Affects Hatching Of Overwintering Eggs In Three Related North American Sympetrum Species
by Scott King
Abstract. The aim of the present study was to obtain quantitative information about the length of the diapause period and its effects on hatching in three closely related Sympetrum species. Eggs of Sympetrum rubicundulum, S. internum and S. obtrusum were collected in September 2013 near Northfield, Minnesota, by netting ovipositing females. To simulate diapause, the eggs were placed in bottled springwater and refrigerated in darkness beginning in October. Vials containing one dozen eggs were removed at monthly intervals thereafter for each of the three species and hatching curves determined. Small numbers of S. internum and S. obtrusum eggs hatched after the first interval of cold treatment, while none of the S. rubicundulum eggs hatched during this interval or the following interval. By April, all three species hatched quickly upon being warmed to ambient temperatures. These results suggest that a portion of the eggs for S. internum and S. obtrusum complete their diapause requirements sooner than S. rubicundulum. While this seems counterintuitive for the north-south distribution of these species, the added flexibility of having some eggs ready to hatch earlier might affect the timing and overall period of emergence and therefore contribute to the larger distribution of these two species in general.
Phylogeny of Odonata
by William Kuhn and Melissa Sanchez-Herrera (co-author Dr. Jessica Ware)
Abstract. Jessica Ware’s Laboratory at Rutgers University aims to answer evolutionary and ecological questions about Odonata (dragonflies and damselflies) and Dictyoptera (termites, cockroaches, and mantids) using morphological and molecular methods. Here, we give an overview of the current odonate-related research currently happening in the Ware Lab. Our morphological approach is centered on making automated software tools to extract morphological features from images of specimens. Specifically, we are designing tools that will be able to locate homologous landmarks and extract color and pattern information from images. This information can then be used for species identification, for quantifying color polymorphisms, for identifying objective morphological traits, etc. From a molecular perspective, we utilize mitochondrial and nuclear DNA to explore phylogenetic relationships, biogeographical patterns and population genetics across several families and genera. We use probabilistic methods, Maximum Likelihood and Bayesian Analysis, to objectively reconstruct the relationships and estimate diversification ages among these taxa. We will highlight several exciting applications of our research: (1) a comparison of wing morphology between flier and percher dragonflies in the Libelluloidea, (2) an automated identification system for Odonata, a phylogenetic reconstruction of (3) Petaluridae and (4) Hetaerina, and (5) a morphological and molecular comparison of the highly polymorphic Polythore.
A New Northwestern Range Extension For Rhionaeschna mutata (Spatterdock Darner)
by Ron Lawrenz
Abstract. In early June of 2009, a single male specimen of Rhionaeschna mutata (Spatterdock Darner) was collected as it patrolled the margin of a 2.2 ha raised bog in east central Minnesota, USA. This was the first record for this species in the state. The nymphal habitat requirements for R. mutata are known to be quite narrow, including wooded, fishless ponds with some cover of water lilies, particularly yellow water lily or “Spatterdock” (Nuphar sp.). These key habitat preferences were used to identify two potential breeding sites near the point of capture of the adult specimen. Surveys of these sites during the fall of 2009 resulted in the capture of R. mutata nymphs from both sites (21 nymphs total). Subsets of these nymphs were reared to adults during the winter of 2009-2010 to confirm identification. Adults, nymphs, and exuviae have been observed and collected at both of these sites for the past five years. This population establishes a substantial northwestern extension in the distribution of this species, and it remains as the only known cluster of breeding sites in Minnesota.
Emergence Phenology And Migration In Anax junius
by Michael L. May (J. M. Matthews, J. Gregoire, S. Gregoire, and M. A. Lubertazzi co-authors)
Abstract. Very little published work on developmental phenology of Anax junius has appeared since Robert Trottier, in the 1960s and ‘70s, suggested that migrants and resident A. junius are behaviorally and physiologically distinct. Here we report results that reveal a much more complex life history although, importantly, they support the idea that some individuals in northern populations, even within a single pond, overwinter as diapausing nymphs while others emerge and migrate. Here we examine some selective forces that maintain these two contrasting strategies for avoidance of adverse conditions in A. junius. Nymphal habitats of A. junius typically persist long enough to develop fairly extensive aquatic vegetation but are usually ephemeral and/or isolated enough to be free of predaceous fish. Such habitats often are sufficiently stable to produce annual generations for several successive years, but most eventually become unsuitable through introduction of fish or drought and its attendant abiotic stressors. Even in the absence of identified sources of mortality, emergence success can fluctuate sharply within and among ponds. Emerging adults, therefore, have to balance risks of reproducing in their natal area vs. those of undertaking long distance migration. Here we consider the extent and nature of some of these risks by documenting variation in emergence success at several spatial and temporal scales.
The Migratory Dragonfly Partnership: New Data, New Partners, New Insights
by Celeste Mazzacano
Abstract. The Migratory Dragonfly Partnership (MDP) is a collaboration formed in 2011 among scientists, non-governmental organizations, academic institutions, and federal agencies across North America to better understand dragonfly migration. Effective study of migration requires long-term, coordinated reporting by a large network of people working across a wide geographic range. The MDP is educating volunteers from among nature centers, parks, wildlife refuges, Hawk Watch observatories, naturalists, gardeners, and the general public about dragonflies and their migration, and engaging them in monitoring migratory dragonflies in North America during their fall and spring flights and at local ponds throughout the year. MDP also highlights the importance of conserving vulnerable wetland habitats and dragonfly species. The MDP has already built an international network of more than 600 volunteers who monitor and report on dragonfly migration flights and the seasonal life history of the five main migratory dragonfly species in North America: Anax junius (Common Green Darner), Pantala flavescens (Wandering Glider), P. hymenaea (Spot-winged Glider), Sympetrum corruptum (Variegated Meadowhawk), and Tramea lacerata (Black Saddlebags). I will discuss the current state of MDP monitoring projects and the data gathered thus far, and describe our new partnerships and plans and goals for the future.
A Minnesota-shaped Black Hole – How One Small, Determined Group Can Make a Difference
by Kurt Mead
Abstract. The Minnesota Odonata Survey Project (MOSP), which operated from 2006 through 2012, surveyed the previously unexplored frontier of Minnesota Odonata. Through the activities of the MOSP, nearly 8800 individual records of Odonata were generated, over 6100 of which were museum specimens from collections around the state and 2580 were newly collected specimens. A total of 1881 new county records were produced, and nineteen species were added to the state list during that time, bringing the state total to 150 species. In the seven seasons of the MOSP, 36 citizen training sessions including 29 one-day survey workshops and 7 weekend-long Minnesota Dragonfly Gatherings (MDG) were held. On average, 17 participants attended each event, with an average of 45 people attending the weekend-long MDG events in last two years of the MOSP. Surveys during the last two years of the MOSP targeted 62 counties with the lowest numbers of county records (as low as zero records in the case of one county). Teams of four researchers spent a week surveying for a total of six weeks in 2011-12. The newly formed Minnesota Dragonfly Society is making preparations to continue and expand on this work, as there is still much yet to be learned about the Odonata of this diverse, mid-continental region.
Sympetrum corruptum, A Confusing Migrant
by Dennis Paulson
Abstract. Sympetrum corruptum (Variegated Meadowhawk) has long been thought to be migratory in North America. Its breeding range is primarily western, but individuals turn up well to the east, along the Atlantic coast and especially in fall. Adults overwinter from California to Florida, and it is possible that these individuals migrate north in spring to repopulate higher latitudes. Or, like Anax junius, there are alternating generations each year undergoing northward and southward migrations. It is proving difficult to understand the comings and goings of this species.
Odonata Observed On A Visit to REGUA, Southern Brazil
by Dennis Paulson
Abstract. Netta Smith and I visited the Reserva Ecologica Guapi Açu (REGUA) in southeastern Brazil for 13 days in October 2013 and tried to get to a variety of odonate habitats on the reserve and in the surrounding area. We found 77 species at the end of the dry season, many fewer than the 200 now known from the area but nonetheless satisfying. I will discuss the diversity of the area and show some of the more interesting species.
Life Histories of Two Recently Described Midwestern Ophiogomphus Species (Gomphidae)
by William A. Smith
Abstract. Two gomphids new to science, Ophiogomphus susbehcha Vogt & Smith and O. smithi Tennessen & Vogt, were discovered in Wisconsin in the last 20 years. I determined distribution, nymphal habitat use, emergence patterns and conservation status in Wisconsin and adjacent states. Specimens from various collections and databases were accessed and extensive collecting was conducted in attempts to fill data gaps. All data were compiled into a geo-referenced database maintained by WI DNR Natural Heritage Conservation Program. Ophiogomphus susbehcha is known from only two streams in four Wisconsin counties and three adjacent Minnesota counties. Ophiogomphus smithi has a much wider distribution being found in 19 WI Counties, seven Iowa counties, and two Minnesota counties. Distribution of O. smithi is centered on the Driftless Ecoregion. Distribution suggests a strong tie to sandy soil landscapes. O. susbehcha segments are correlated with high flow levels, low development in the watershed, and mostly forested watersheds on igneous bedrock. O. smithi stream reaches were correlated with medium flow levels, moderate gradient, and with riparian corridors with some forest, grassland/herbaceous cover, and open/non-forest cover; watersheds with some mixed forest, deciduous forest, watersheds with little to no open water, low amounts of carboniferous bedrock, high amounts of riparian zone soil permeability, and very low amounts of fine glacial material. Ophiogomphus susbehcha is among the earliest emerging stream dragonflies in Wisconsin, starting at Julian Date 133 (May 12th). Most emerge within a week with a few stragglers after that. No adults have been recorded after June 24th. This species is likely semivoltine or partivoltine. Ophiogomphus smithi emerges later, with first Julian Date recorded being 144 (May 23rd). A two to three year life cycle is also suggested. Ophiogomphus susbehcha exuviae averaged 0.7 specimens per meter of shoreline sampled based on over 750 samples and suggest a continuous distribution in occupied reaches. O. smithi does not always appear to be continuously distributed. Both species are considered globally to be imperiled by NatureServe. The state of Wisconsin considers O. susbehcha imperiled and legally endangered while Minnesota as vulnerable and legally Threatened. NatureServe and Wisconsin consider O. smithi as imperiled globally and statewide respectively. Iowa and Minnesota have not yet assigned it a conservation rank.
Effects Of The Proximity And Density Of Human Habitation On The Survival And Diversity Of Select Odonata In A Northwest Indiana Set Of Three Moraine Lakes
by George Smolka
Abstract. The Valparaiso Chain of Lakes is a set of more than 40 small lakes and ponds left over from the Wisconsin Ice sheet. I studied three large lakes, Wauhob, Long, and Flint, to see if the density of human habitation affected Odonata diversity. I studied a large set of invertebrates, including nymphs of Odonata, to determine the effect of herbicide use in the lakes (human incursion) but report only effects on Odonata here. The lakes form a ragged north/south line. Human shoreline population densities increase from northernmost to southernmost whereas Odonate and other aquatic invertebrate population densities and diversity decrease from north to south (the inverse of human population densities). Very roughly, 90% of the overall Odonata species that inhabit this set of moraine lakes exist in the northernmost lake, whereas only about 10% exist in the southern. Direct effects such as those caused by pesticide and herbicide run off, can be directly measured, as can the abuse of herbicides to control invasive Eurasian watermilfoil ,but the ecological effects seem to be a more complex problem, involving not only the toxicity to biota, but abiotic and human behavioral components too.
A Taxonomic Review of Amphiagrion (Now, Which Species Occurs In Wisconsin?)
by Ken Tennessen
Abstract. Species classification status within the widely ranging genus Amphiagrion has been uncertain for decades. Two species, A. abbreviatum (Western Red Damsel) and A. saucium (Eastern Red Damsel), have been recognized for over a century, but whether one, two or three species exist is uncertain. To test the practical utility of the taxonomic characters that have been used to separate the two species in traditional keys such as Walker (1953) and Westfall & May (2006), I examined 190 male specimens from various collections, generating data for 18 morphological characters (16 structural and 2 color pattern). My main objectives were 1) to see if morphological characters indicate how many species of Amphiagrion exist, and 2) to determine which species occurs in Wisconsin. My data suggest that two species are involved. The three published key characters are of limited use, especially thoracic length. Several new characters which I believe are more reliable were discovered and will be detailed, among them the ratio of hind femur length to abdomen length, setal color, and hind femur color pattern. Based on this morphological study of adult males, I determined that the species occurring in Wisconsin is A. abbreviatum.
Phylogeny And Systematics Of Somatochlora Based Upon Mitochondrial DNA
by T.E. Vogt (M.J. Mahoney, J.R. Purdue, and E.D. Cashatt co-authors)
Abstract. The dragonfly genus Somatochlora comprises approximately 40 species and is the most diverse genus in the family Corduliidae. The genus is primarily Holarctic and restricted entirely to the northern hemisphere. Prior infrageneric classifications include Walker (1925), Schmidt (1957), Belyshev (1974) and Ishida (1996). Only those of Schmidt and especially Belyshev were largely global in scope. Belyshev extensively discussed the biogeography of the genus. Walker's scope of study was North America plus western Europe while Ishida addressed only Japanese taxa. Taxonomic characters utilized included adult male terminal appendages and female vulvar lamina (Walker and Belyshev), adult male terminal appendages (Schmidt), and middorsal abdominal hooks and lateral abdominal spines of nymphs (Walker and Ishida). Molecular sequence data (mtDNA, ND3, 542 bp) were obtained for comparing genetic based phylogenies with historical morphological classifications. A variety of analyses were employed to produce phylograms. The molecular phylogenies, when using different outgroups, were largely concordant. Walker’s species groups were the most consistent with the molecular data. A total of ten species groups were inferred from the phylograms with corroboration of adult and nymphal morphological characters.