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When should a non-aggressive exotic species be demoted to a harmless naturalized resident?

By Dr. Laurel Haavik, US Forest Service

Exotic species that establish, spread, and cause substantial damage are demonized as foreign invaders that charge with menacing force across the landscape. Rightly so; those pests threaten to displace or eliminate native species and alter ecosystem functions. Chestnut blight, emerald ash borer, and hemlock woolly adelgid are all excellent examples. What about invaders that aren’t so destructive? Or, at least don’t seem to be at the moment? At what point do we stop monitoring a seemingly innocuous invasive species, especially one that has proved itself a serious pest elsewhere? To make this decision, it’s helpful to know how much the species has affected its new habitat, and whether this impact already has or is likely to change over time. That is exactly what we set out to do with the European woodwasp, Sirex noctilio, in Ontario.

Nearly a decade after the woodwasp was first found in a trap near the Finger Lakes in New York (and then a year later across Lake Ontario in Sandbanks Provincial Park), it still hadn’t killed pines in noticeable numbers, either in the US or Canada. Native to Europe and Asia, this woodwasp has been introduced to several countries in the Southern Hemisphere, where it has been a serious pest in forests planted with exotic pines. By contrast, in North America, it seems that only the weakest trees, those that are already stressed by something else, are killed by the woodwasp. Would forests with many weakened trees allow populations of the woodwasp to build up enough that they could then kill healthy trees in well-maintained forests? Could we find any evidence that this had already happened or would likely happen in the future?

Our goal was to measure the impact the woodwasp has had in Ontario, and whether that has changed over time, by closely examining the same trees in pine forests every year. First, we had to find sites where the woodwasp could be found, which wasn’t every pine forest, and where landowners would allow us to work. We were not interested in sites that were well-managed, because research had already confirmed that the woodwasp was not present in those forests. We used records of positive woodwasp captures from the Ontario Ministry of Natural Resources trap survey as a guide. We visited 50 potential sites, and eventually selected eight for close scrutiny in our long-term study. These sites were areas where there was likely to be intense competition among trees for resources, with plenty of stressed trees for the woodwasp.

The European woodwasp was probably absent from a well-managed red pine forest (left), but likely to be found in an un-managed scots pine forest (right).

We visited all eight sites every fall from 2012 to 2016, after woodwasps had the opportunity to attack trees. Adult woodwasps mate and lay eggs, attacking trees in the process, in mid-summer. Attack was visible as distinctive resin beads scattered over the trunk. We recorded which trees had been attacked, and later (usually the following year) killed by the woodwasp.

The woodwasp population was considerable at some of our sites, having killed about one-third of the trees within five years. Though at other sites, the population was much smaller, having killed only a small percentage of trees. We’re not exactly sure what caused this variability. It’s possible that the woodwasp arrived at some of our sites years before it arrived at others, and the most vulnerable trees were long dead at the sites it invaded earlier. We have no record of time since woodwasp invasion at any of our sites. It’s also possible that local environmental conditions, which we did not measure, could in some way have affected tree resistance or the woodwasp population.

Most curious, though, was that over the five years many trees attacked by the woodwasp did not die – around 50 to 80%. At least half of these trees were attacked again and again in successive years. We had captured an interesting part of the woodwasp’s ecology, its way of essentially priming trees to become better habitat for its young. When laying eggs, female woodwasps also inject a self-made toxic venom along with a symbiotic fungus into the tree, to help kill it. If the tree is sufficiently resistant to attack, the female may not lay eggs, only the fungus and venom. The fungus and venom then work in concert to weaken (prime) the tree for re-attack – and hopefully successful colonization – in subsequent years.

Female woodwasps sometimes die while laying eggs. Survival of the fittest?

Two-thirds of trees that were attacked by the woodwasp at some point in our study (one or more times) did not die, which shows that most trees selected by the woodwasp as suitable habitat are at the moment resistant to its advances. This also shows, along with the variability in woodwasp impact among sites, that this invader is active in the forest. Should environmental conditions change (say, if a drought occurs), woodwasp populations could quickly rise to outbreak levels, which could kill large numbers of healthy pines. This has happened in other places.

Long-term study of these sites, and hopefully others, is needed so that we can be aware of changes that arise in woodwasp impact. This will allow us to be proactive about what steps to take to manage this invader, should it become a problem. It will also help us better understand and predict what causes exotic species to vacillate on the spectrum between aggressive invader and innocuous resident.

Want to read more? Check out the original article published in The Canadian Entomologist, which is freely available for reading & download until May 14, 2018.

Haavik, L.J., Dodds, K.J. & Allison, J.D. (2018) Sirex noctilio (Hymenoptera: Siricidae) in Ontario (Canada) pine forests: observations over five years. The Canadian Entomologist, 1–14. doi: 10.4039/tce.2018.18

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ESC Blog Classifieds – Postdoc opportunity with Dr. Brent Sinclair

Postdoctoral Fellow – Functional genomics of insect overwintering

Applications are invited for a funded postdoctoral position in insect functional genomics as part of a collaborative project between labs at Western University and the Canadian Forest Service, both in Ontario, Canada.

The project will involve coordinating work between two laboratories to identify and validate candidate molecular markers associated with diapause and cold tolerance in the Asian Longhorned Beetle, Anoplophora glabripennis using a combination of RNA-Seq, high-throughput metabolomics, and RNAi. The ideal candidate will be creative, and enthusiastic, with an ability to work both independently and as part of a team.  We will prefer someone with a background in insect physiology or molecular biology, and with a strong publication record in RNAi (in insects), bioinformatics, transcriptomics and/or metabolomics analyses in non-model systems.  Because of the geographic separation of the CFS and Western labs, excellent oral and written communication in English is a must, as is a valid driver’s license.

The successful applicant will be primarily based in London, Ontario, Canada in the Department of Biology, Western University.  The Sinclair lab at Western is a diverse, vibrant, and globally-collaborative group of low temperature biologists with broad interests in insect ecology, physiology, and molecular biology.  Please visit http://publish.uwo.ca/~bsincla7/ to learn more about the group; informal communication with Dr. Brent Sinclair prior to application is welcomed and encouraged; he will be at the ICE in Orlando, and will be happy to discuss the opportunity in person at the meeting.  The project is in collaboration with Drs. Amanda Roe and Daniel Doucet at the Great Lakes Forestry Centre, Sault Ste. Marie (http://www.nrcan.gc.ca/forests/research-centres/glfc/13459), and will make particular use of the insect rearing and quarantine facility.

The initial appointment will be for one year with opportunity for a two-year extension.

To apply, please send a cover letter, detailing your fit to the position, a CV, and the names and contact details of three referees to Dr. Brent Sinclair bsincla7@uwo.ca by Noon (EST) on Monday 3 October.

We are committed to diversity, and encourage application from all qualified candidates.

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Rassemblement de la recherche entomologique canadienne: Septembre 2015 – Janvier 2016

(English version here)

Cet article fait partie d’une série continue de rassemblement de la recherche entomologique canadienne (Canadian Entomology Research Roundups). Voici ce que les étudiants de cycle supérieur canadiens ont fait récemment:

De la part des auteurs:

Finn Hamilton (University of Victoria)

C’est bien connu que la majorité des insectes sont hôtes à des bactéries symbiotiques qui ont de profondes conséquences sur la biologie de l’hôte. Dans certains cas, ces symbioses peuvent protéger l’hôte contre de virulents parasites et pathogens, même si dans la plupart des cas planent encore un mystère sur la façon dont les symbionts réussissent à atteindre cette défense. Dans cet article, nous avons démontré qu’une souche de la bactérie Spiroplasma qui protège son hôte drosophile contre un nématode parasitaire virulent encode une toxine sous forme de protéine. Cette toxine semble attaquer l’hôte du nématode durant une défense induite par Spiroplasma. Ceci représente, à ce jour, une des démonstrations les plus claires des mécanismes sous-jacents de la symbiose promouvant la défense des insectes. Lien vers l’article

Drosophila

Voici une mouche Drosophila falleni infecté par le nematode, Howardula aoronymphium, dont Spiroplasma  la protège. Crédit phot: Finn Hamilton.

Lucas Roscoe (University of Toronto)

L’agrile du frêne (Agrilus planipennis Fairmaire) est un buprestide ravageur s’attaquant aux frênes d’Amérique du Nord. Dans l’optique du développement de plans de gestion à long-terme de l’agrile du frêne, plusieurs projets détaillant la biologie et l’écologie de parasitoïdes indigènes peu étudiés auparavant ont été amorcés. Un des projets s’intéresse à la séquence de reproduction d’un parasitoïde, Phasgonophora sulcata Westwood. Plusieurs insectes entreprennent des actions répétées avant la reproduction qui sont souvent induites par des phéromones. Les résultats de cette étude sont la description de la séquence de reproduction de P. sulcata et la preuve que les phéromones produites par les femelles sont à la base de ses actions. Liens vers l’article

sulcata

Phasgonophora sulcata, un parasitoïde important de l’agrile du frêne. Crédit photo: Lucas Roscoe.

Marla Schwarzfeld (University of Alberta)

Les guêpes parasitiques du genre Ophion (Hymenoptera: Ichneumonidae) sont presqu’entièrement inconnu dans la région Néarctique, où la majorité des espèces ne sont pas décrites. Dans cette étude, nous publions la première phylogénie moléculaire de ce genre, basé sur les régions COI, ITS2, and 28S. Bien que nous mettions l’accent sur les spécimens Néarctique, nous avons aussi inclus des représentants des espèces les plus connus de de l’ouest de la région Paléarctique et plusieurs séquences d’autre régions géographiques. Nous avons délimités 13 groupes d’espèces, la plupart étant reconnu pour la première fois dans cette étude. Cette phylogénie nous fournit un cadre essentiel qui pourra, nous espérons, inspirer les taxonomistes à divisier et conquérir (et décrire!) de nouvelles espèces dans ce genre qui présente de grands défis morphologiques. Liens vers l’article

Ophion

A parasitoid wasp in the genus Ophion. Photo credit: Andrea Jackson

Seung-Il Lee (University of Alberta)

Seung-Il Lee et ses collègues (University of Alberta) ont trouvé que de larges territoires de rétention (> 3.33 ha) minimisent “l’effet de bordure” négatif sur les coléoptères saproxyliques dans les peuplements boréals d’épinette blanche. Liens vers l’article  Billet de blogue (EN)

beetle

Un coléoptère saproxylique, Peltis fraterna. Crédit photo: Seung-Il Lee.

Paul Abram (Université de Montréal)

La relation entre la taille des insectes et certains traits distinctifs (tel que la longévité, la fécondité, …) a été largement étudié, mais l’effet additionnel de la taille sur les traits comportementales sont moins bien connus. En utilisant le parasitoïde d’oeuf  Telenomus podisi Ashmead (Hymenoptera: Platygastridae) et trois de ses hôtes punaises comme système modèle, nous avons démontrés que la différence de taille était associé a un changement dans la plusieurs traits distinctifs (longévité, masse d’oeufs, taille des oeufs), mais aussi de certains traits comportementales (vitesse de marche, taux d’oviposition, taux de marquage des oeufs). Nos résultats mettent en relief comment la phénotype complet (comportement et traits distinctifs) doivent être considéré quand nous évaluons l’association entre la taille et la condition physique. Liens vers l’article

Telenomus

Le parasitoïde Telenomus podisi parasitisant les oeufs de la punaise Podisus maculiventris. Crédit photo: Leslie Abram.

Delyle Polet (University of Alberta)

Les ailes de insectes ont souvent des éléments directionnels rugueux – comme des poils et des écailles- qui perdent des gouttes d’eau dans le sens des éléments, mais pourquoi ces éléments ne pointent pas toujours dans la même direction? Nous avons proposé que trois stratégies sont en jeu. Les gouttes pourrait être (1) évacuer loin du corps, (2) être perdues aussi vite que possible et (3) évacuer de “vallées” formés entre les veines des ailes. Un modèle mathématique combinant trois de ces stratégies concorde avec l’orientation des poils sur un taon (Penthetria heteroptera) assez bien et pourrait être appliqué à d’autres espèces ou à des matériaux inspirés par la biologie. Liens vers l’article

Winghairs

Poils sur l’aile d’un taon (Penthetria heteroptera). Crédit photo: Delyle Polet.

Résumés bref de recherche

Taxonomie, Systématique, and Morphologie

Thomas Onuferko du laboratoire Packer à York University et ses collègues ont réalisé un vaste étude sur les espèces d’abeilles dans la région de Niagara, Ontario. Onuferko et al. ont collecté plus de 50 000 abeilles et ont découvert 30 espèces qui n’avait pas été rapporté dans la région. Liens vers l’article

Christine Barrie et ses collègues ont signalé que des mouches de la famille Chloropidae sont associés aux phragmites au Canada. Lien vers l’article

Comportment et écologie

Blake Anderson (McMaster University) et ses collègues ont étudié l’hypothèse du découplage du comportement social et de l’activité dans les mouches larvaires et adultes. Lien vers l’article

Susan Anthony du laboratoire Sinclair à Western University, ainsi que Chris Buddle (McGill University), ont déterminé que le pseudoscorpion de Béringie peut tolérer tant les basses températures et l’immersion. Lien vers l’article

Une étude par Fanny Maure (Université de Montréal) démontre que le status nutritionnel d’un hôte, la coccinelle maculée (Coleomegilla maculata), influence le destin de l’hôte et condition physique du parasitoïde. Lien vers l’article

Est-ce que la connectivité est la clé? Des laboratoires Buddles et Bennet à l’Université McGill et du laboratoire James à l’Université de Montréal, Dorothy Maguire (Université McGill) et ses collègues ont utilisé la connectivité du paysage et les insectes herbivores pour proposer un cadre pour examiner les compromis associés aux services ecosystèmiques. Lien vers l’article

 Alvaro Fuentealba (Université Laval) et ses collègues ont découvert que différentes espèces d’arbres hôtes montrent des variations à la résistance naturelle à la tordeuse du bourgeon de l’épinette. Lien vers l’article

Gestion des insectes ravageurs

Rachel Rix (Dalhousie University) et al. ont observé qu’un stress modéré induit par l’insecticide pour augmenter la reproduction et aider les pucerons a mieux se débrouiller avec le stress subséquent. Lien vers l’article

Lindsey Goudis (University of Guelph) et ses collègues ont découvert que la meilleure façon de contrôler Striacosta albicota (Smith) est d’appliquer de la lamba-cyhalothrine de la chlorantraniprole 4 à 18 jours après l’éclosion de 50% des oeufs. Lien vers l’article

Matthew Nunn (Acadia University) et ses collègues ont documenté la diversité et densité d’importantes espèces ravageuses des bleuets sauvages en Nouvelle-Écosse. Lien vers l’article

Physiologie et génétique

Est-ce que l’heterozygositie améliore la symétrie de Xeromelissa rozeni?  Margarita Miklasevskaja (York University) et ses collègues ont testé cette hypothèse dans leur plus récent article. Lien vers l’article

Xeromelissa

Un male Xeromelissa rozeni. Crédit photo: Margarita Miklasevskaja.

Jasmine Janes, récemment graduée de University of Alberta, et d’autres ont exploré les systèmes de reproduction et de structure génétique à petite échelle pour la gestion efficace du Dendroctone du pin ponderosa. Lien vers l’article

Du laboratoire Sperling à University of Alberta, Julian Dupuis et Felix Sperling ont examiné l’interaction complexe de l’hybridation et de la spéciation. Ils ont caractérisé le potentiel d’hybridation dans un groupe de Papilonidae. Lien vers l’article

Marina Defferrari (University of Toronto) et ses collègues ont identifié un nouveau peptide similair à l’insuline dans Rhodnius prolixus. Ses peptides sont impliqués dans l’homéostasie métaboliques des lipides et carbohydrates. Lien vers l’article

Techniques

Crystal Ernst (McGill University) et ses collègues ont collecté des coléoptères et des araignées dans différents habitats du Nord. Ils ont trouvé que la diversité des coléoptères et des araignées par habitat et type de trappes. Lien vers l’article


Nous continuous à aider à divulguer les publications des étudiants de cycle supérieur à la plus vaste communauté entomologique grâce aux rassemblement de recherche. Si vous avez publié un article récemment et souhaitez le divulguer, envoyez-nous un email à entsoccan.students@gmail.com.  Vous pouvez aussi nous envoyer des photos et une courte description de votre recherche dans le but apparaître dans notre prochain rassemblement de recherche.

Pour des mises à jour régulières sur la nouvelle recherche entomologique canadienne, vous pouvez joindre la page Facebook de ESC Students ou nous suivre sur Twitter @esc_students (EN) ou @esc_students_fr (FR).

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Missed Mandate, Missed Biology: The ongoing “Mother Canada” debacle in Cape Breton Highlands National Park

Opinion Piece – M. Alex Smith, Department of Integrative Biology, University of Guelph (salex@uoguelph.ca; @Alex_Smith_Ants; www.malexsmith.weebly.com)

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Like many Canadians, I have been hearing more and more about the so-called “Mother Canada” development in Cape Breton Highlands National Park (CBHNP). Proposed by a combination of private funding in partnership with the federal government, this enormous 10-storey memorial is meant to “… be a place for remembrance and gratitude” to Canadians who have “fallen as a result of war and conflict”. Parks Canada has expressed direct support for this monument through actual monetary donations. The erection of such a memorial within a Canadian National Park has garnered much recent interest in the Canadian and international press.

Beyond any aesthetic concerns people may have about the specific plans, in my opinion, there are two critical problems with this monument. The first was pointed out in a Globe and Mail editorial of June 24 2015: it is redundant. Every town and city in Canada already has a memorial to those who have served and sacrificed. My second objection is a combined biological and sociological one. It concerns the location of a private funded monument within a Canadian National Park, where it appears very unclear what the ramifications of that action will be on the fauna in and around the proposed site. The mandate of Parks Canada is elegantly expressed in its charter, “To protect, as a first priority, the natural and cultural heritage of our special places and ensure that they remain healthy and whole” while fostering “public understanding, appreciation and enjoyment in ways that ensure the ecological and commemorative integrity of these places for present and future generations”. Indeed, 26 former senior Parks Canada managers wrote an open letter to the Minister of Environment Leona Aglukkaq detailing their objections and that such a plan, “is in violation of the site’s Wilderness Zone designation as detailed in the Management Plan for the Park”.

Beyond the effects of the actual physical construction on the park environment, the monument will potentially increase tourist traffic to the area. How will these changes affect the biota (both animal and plant) of the immediate area? Exactly how well known is that fauna? How was the effect on the sites and the adjacent park environment determined?

A detailed impact analysis was completed by Stantec Consulting Limited who concluded that the effects of the development are, “generally predicted to be negligible to moderate in magnitude”. Conclusions regarding the effect of the construction and development on the “wildlife” of CBHNP were based on a single terrestrial field survey of the locality and a consultation of a CBHNP sightings database. (Stantec is actually listed as a Partner and Supporter of the development). In the Stantec impact analysis, “wildlife” is exclusively mammals and birds. As an ecologist whose professional and personal life is replete with instances of being overwhelmed and delighted by the diversity of arthropods living coincidentally (and cryptically) with their better-studied vertebrate relatives, this raised some concerns.

So what can I offer? Well in 2009, I spent a wonderful time collecting arthropods in CBHNP as part of the BioBus program out of the Biodiversity Institute of Ontario at the University of Guelph. In fact, four colleagues and I spent a night collecting insects at a site only 3 km away from the proposed development (Black Brook and the nearby Jack Pine Trail). The Jack Pine trail was particularly beautiful! The trail goes through a forest of Jack Pine that is more than 200km away from the rest of its range and has survived fire and spruce budworm infestation. At any rate, since all the data is publicly available online (dx.doi.org/10.5883/DS-ASCBHNP), I thought this would be an opportune time to explore those records in light of the planned “Mother Canada” development.

 

Figure 1: A high resolution GigaPan panorama taken at the Black Brook collection site (http://gigapan.com/gigapans/29312).

Figure 1: A high resolution GigaPan panorama taken at the Black Brook collection site (http://gigapan.com/gigapans/29312).

 

Figure 2: The collection team earlier in the trip in Terra Nova National Park Newfoundland.

Figure 2: The collection team earlier in the trip in Terra Nova National Park Newfoundland.

It was a beautiful night in 2009 (Jul-21) at Black Brook where we collected arthropods using two common methods (UV light (which means lots of moths!) and free-hand active search using insect nets). That night, in about four hours of collecting, we came away with 363 specimens from nearly 200 species (191 named and provisional species based on their DNA barcodes). To put this number in context, CBHNP has 200 species of bird – a total nearly matched for arthropods by our single nights work at one location! This diversity is only a small fraction of the diversity of arthropods currently protected by CBHNP. Via these DNA barcodes, (public on BOLD (www.barcodinglife.org, dx.doi.org/10.5883/DS-ASCBHNP) we can compare them to the > 4 million DNA barcode records representing >400,000 species worldwide on this database.

What we find from this comparison is that some of these species may be exceedingly rare. Despite concentrated collections in this and other National Parks before and since this night* there are four species which have been found only once out of these millions of records. While this diversity is currently protected by Parks Canada, it is within 3 km of the proposed “Mother Canada” development. It is unclear how the changes in traffic and construction from the development will affect this protected diversity.

Why bring this up now? What use is a rapid analysis of a single night’s collections? I decided to bring it up to call attention to numerous small and cryptic species in and around the location of the proposed development about which we know very little. Going ahead with an enormous private development within a National Park is a mistake that flies in the face of the mandate of Parks Canada – and does so without good evidence that it would not have negative effects on the diversity of animals that it was created to protect.

 

Figure 3: This neighbor-joining tree is a graphical representation of the diversity of nearly 200 species of arthropods collected at Black Brook in July 2009. The taxa are colour coded and are followed by the number of specimens we caught.

Figure 3: This neighbor-joining tree is a graphical representation of the diversity of nearly 200 species of arthropods collected at Black Brook in July 2009. The taxa are colour coded and are followed by the number of specimens we caught.

John Barber (a freelance journalist from Toronto) closed his recent article in the Guardian newspaper with a marvelous quote from Valerie Bird, a WWII veteran and resident of Cape Breton, “It is vulgar and ostentatious,” she said. “It certainly doesn’t belong in a national park, and I don’t think its going to do a darn thing for veterans.” “I think the idea of this horrible thing offends veterans,” she added. “I find it difficult to find words. This is a monstrosity.”

Not simply a monstrosity – but one contrary to of the principle mandate of Parks Canada, “to protect, as a first priority, the natural and cultural heritage of our special places and ensure that they remain healthy and whole”. Ultimately, this is the essence of the problem. This issue is more than a simple discussion regarding the aesthetics of a >$25 million, >25-metre tall conglomeration of private and corporate citizens (in apparent partnership with our federal government). If a private group wants to erect a memorial on private grounds and can raise the money for their monument – it is certainly their prerogative. This is a critical discussion about the mandate of Parks Canada and specifically how well they protect the natural heritage resident within that Park.

To place this monument in a National Park is not the right of any private group. To consider placing such a monument in a National Park without careful consideration of the most diverse Park residents (insects, spiders and their kin) is not simply poor planning; it’s poor management and should be stopped.

* -Since that evening in 2009, the BioBus has continued to collaborate with Parks Canada in Cape Breton Highlands National Park and now even more is known about the vast diversity of small and important insects from other areas within this National Park. Collections of arthropods have now been made for 3000 species! For more information about those collections visit the reports section at www.biobus.ca. The author has no current association with the BioBus program. All specimens analysed here are publically available via the public data portal of the Barcode of Life Data System (dx.doi.org/10.5883/DS-ASCBHNP).

Useful websites:

Thanks to Morgan Jackson for helpful thoughts on an earlier draft of this post.
Figure 4 – Shareable infographic outlining information & data presented in this article. Please feel free to circulate.

Figure 4 – Shareable infographic outlining information & data presented in this article. Please feel free to circulate.

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Spiders with an identity crisis: a new taxonomy paper

The following is a guest post by Terry Wheeler, from the Lyman  Entomological Museum at McGill University. It is re-posted from the Lyman Museum Blog, where it originally appeared. 

Two wolf spiders, whose names are Pardosa lapponica and Pardosa concinna, run across open ground all over northern Canada. Here’s the problem: these two species of spiders live in a lot of the same places, and they look very similar. Katie Sim, a grad student working with Chris Buddle and me here at McGill, asked the obvious question: are these spiders really separate species? Katie’s insights on that question were just published in the journal Zootaxa.

As taxonomists, we can use multiple kinds of evidence to determine species limits. This includes things like morphology, genetic sequence data, geographic distribution, and ecology. These two species were originally described from widely separated areas: P. lapponica from Lapland, and P. concinna from Colorado. But since then they’ve been found in many more sites and we now know that their ranges overlap in northern North America.

The other long-accepted way of distinguishing between these two species was a small morphological difference between their reproductive structures (many closely related arthropods look very similar externally, but if there are differences, we often see them in the genitalia. “Why?” is a topic for another post).

As Katie collected spiders as part of our Northern Biodiversity Program fieldwork in northern Canada, she realized that the morphological differences between the two species weren’t that clear-cut, once you take variation into account. Based on careful measurements of specimens from all across the north, Katie found overlap in almost all morphological characters, even genitalic characters that had been used in the past. There was only one small piece of the complex male mating structures (the terminal apophysis, for the spider fans reading along) that seemed to hold up as a difference between the species (and only the males, obviously). Question marks started to appear.

sim-et-al-fig-3

Katie’s next step was to delve into the genetic differences between the two species. Even though species can look very similar externally, DNA sequence data sometimes uncovers fine differences between them. This is especially helpful with closely related, or recently diverged species. Katie used the DNA barcode, a section of the mitochondrial gene CO1, which has proven pretty useful for distinguishing animal species. And the DNA results showed some interesting patterns, some of which were unexpected.

sim-et-al-fig-5

The figure above is a haplotype network. Each circle is a little island of genetic similarity, connected to other islands by the lines. We’d expect different species to be part of separate “islands”, but that didn’t happen here. Pardosa lapponica (in light gray) and P. concinna(in black) sometimes share the same haplotype, and each of the two has multiple haplotypes. That means there’s more genetic variation within a “species” than between them. But wait! There’s more!

After a suggestion from one of the reviewers on an earlier version of the paper (this back-and-forth of suggestions is one of the strengths of peer-reviewed science), Katie looked at the CO1 barcode sequences of P. lapponica specimens from northern Europe, where it was originally described. Unexpectedly, the Russian specimens (the dark gray circles without numbers in the figure above) were genetically distinct, by a good margin, from the North American specimens of P. lapponica.

So what does this all mean, taxonomically? First, the spider we call “Pardosa lapponica” in North America seems not to be the same species as “Pardosa lapponica” from northern Europe (which “owns” the name, because it was described from there first). Our North American P. lapponica may, in fact, be the same species as the spider we’ve been callingPardosa concinna, but before we can make the final decision on that, it would be necessary to study additional North American specimens, especially from Colorado (the “type locality”, or collection site of the original P. concinna), to confirm this.

And that’s how taxonomy often works: good, careful research will answer one question, and in the process, new questions pop up. Sometimes, you think you know a spider, and sometimes, you realize you really don’t.

Reference

Sim, K.A., C.M. Buddle, and T.A. Wheeler. 2014. Species boundaries of Pardosa concinna and P. lapponica (Araneae: Lycosidae) in the northern Nearctic: morphology and DNA barcodes. Zootaxa: 3884: 169–178.

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How to get a spider to drink blood

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Spiders may not bite, but that doesn’t mean you can’t get them to drink your blood! All you need is a sunset at the beach, hordes of mosquitoes, a spider, and some frustration to take out.

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The other night, I was unwinding with an evening of wasp and bee photography at Iona beach, but the flight conditions were great for mosquitoes. They kept interrupting my shots of this lovely Tetragnatha laboriosa, so I decided to share the wealth.

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Trapping the mosquito against my skin, I released it in the sweet spot of the web.

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You can see the movement of the wrapping action, as I was also dragging the shutter to get some light in the darkening sky.

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I was looking forward to a great splash of blood as the spider bit in!

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This is about as good as it got however, but I am sure the spider will appreciate the extra protein already in liquid form.

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This one is pretty cool too…

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The mozzies kept biting, so I kept tossing them into the web.

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I kept the spider busy wrapping up her gifts for quite a while.

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When we both had had enough, I headed home, feeling itchy, but satisfied that I had at least achieved the fattening up of a cool tetragnathid.