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Musings about statistics by a statistics-phobe

By B. Staffan Lindgren, Professor Emeritus

A while back, a paper accepted by The American Statistician entitled “The ASA’s statement on p-values: context, process, and purpose” was posted to the American Statistical Association website. The gist of the paper was that many disciplines rely too much on the p-value as the sole indicator of research importance. Not surprisingly, the paper received considerable attention.

Over my career, I had a love-hate relationship with statistics, knowing just enough to be dangerous, but not enough to really understand what I was doing. Consequently I relied on packaged software and/or colleagues or students who were more quantitatively minded than myself. For example, I generally made sure that a graduate student committee had at least one member with some strength in statistics to make sure I would not leave the candidate stranded or led astray. So if you read my thoughts below, keep in mind that I tread on very thin ice here. I fully expect some disagreement on this, but that is the way it is supposed to be. Ultimately it is your responsibility to understand what you are doing.

The approaches and tools for statistical analysis have changed a lot since my student days, which was at the dawn of mainframe computers for general use, on which we could use a software package called Textform rather than typing the thesis on a type writer as I (read “a secretary I hired and almost drove to depression”) did for my masters. My first visit to a statistical consultant at Simon Fraser University ended with the advice that “This data set can’t be analyzed, it contains zero values.” The software of choice was SPSS, which did not allow for any complexity, so I did a fair bit by hand (which might have been a good thing since it forced me to think about what I was doing, but certainly did not prevent errors). Later in my career it was sometimes a struggle to decide among differing opinions of statisticians what was and was not appropriate to use, but with a little help from my friends I think I managed to negotiate most of the pitfalls (no pun intended) fairly well.

The author with his eponymous insect trap, sometime after struggles doing statistics with room-sized computers. Photo: Ron Long

The statistic-phobic author with his eponymous insect trap, preparing to gather data and test hypotheses. Photo: Ron Long.

One of the issues with our reliance on p-values is that it is tempting to do post-hoc “significance-hunting” by using a variety of approaches, rather than deciding a priori how to analyze the data. Data that show no significance often remains unpublished, leading to potential “publication bias”. In part this may be the result of journal policies (or reviewer bias), which tends to lead to rejection of papers reporting ‘negative’ results. We have also been trained to use an experiment-wise alpha of 0.05 or less, i.e., a significant result would be declared if the p-value is lower than 0.05. There are two problems with this. First, it is an arbitrary value in a sense, e.g., there really is no meaningful difference between p=0.049 and 0.051. Furthermore, the p-value does not really tell you anything about the importance of the result. All it can do is give some guidance regarding the interpretation of the results relative to the hypothesis. I have tried to make students put their research in context, because I believe the objective of the research may dictate whether or not a significant p-value is important or not. I used to work in industry, and one of the reasons I left was that recommendations I made based on research were not always acted upon. For example, pheromones of bark beetles are often synergized by various host volatiles. But whether or not they are may depend on environmental factors. For example, just after clear cutting the air is likely to have high levels of host volatiles, thus making any host volatile added to a trap ineffective. However, a company may make money by selling such volatiles, and hence they would tend to ignore any results that would lead to a loss of revenue. On the other hand, one could argue that they have the customers’ best interest in mind, because if host volatiles are important under some circumstances, it would be detrimental to remove them from the product.

This leads to my thoughts about the power of an analysis. The way I think of power is that it is a measure of the likelihood of finding a difference if it is there. There are two ways of increasing power that I can think of. One is to increase the number of replications, and the other is to use a higher alpha value. It is important to think about the consequence of an error. A Type I error is when significance is declared when there is none, while a Type II error is when no significance is found when in fact there is one. Which of these is most important is something we need to think about. For example, if you worked in conservation of a threatened species, and you found that a particular action to enhance survival resulted in a p-value of 0.07, would you be prepared to declare that action ineffective assuming that it wasn’t prohibitively expensive? If you have committed a Type II error, and discontinue the action, it could result in extinction of the threatened species. On the other hand, if you test a pesticide, would a significant value of 0.049 be enough to decide to pursue the expensive testing required for registration? If you have committed a Type I error, the product is not likely to succeed in the market place. If the potential market is small, which tends to be the case for behavioural chemicals, it may not be feasible to use this product because of the high cost, which has nothing to do with statistical analysis, but could be the overriding concern in determining the importance of the finding.

One area where the sole use of p-values can become very problematic is for regressions. The p-value only tells us whether or not the slope of the line is significantly different from zero, and therefore it becomes really important to look at how the data are distributed. An outlier can have a huge impact, for example (see figure). As an editor I saw many questionable regressions, e.g., with single points driving much of the effect, but which in the text were described as highly significant.

Fig. 1. An example of where a single point is driving a linear regression. Take it away and there is no apparent relationship at all. Figure from http://www.stat.yale.edu/Courses/1997-98/101/linreg.htm

Finally, we need to keep in mind that a significant p-value does not indicate certainty, but probability, i.e., at p=0.05, you would expect to get the same result 19 of 20 times, but that still means that the result could be the result of chance if you only ran the experiment once. (If you run a biological experiment that yields a p-value close to 0.05 a number of times, you would soon discover that it can be difficult to get the same outcome every time). Depending on the context, that may not be all that confidence inspiring. For example, if someone told you that there was only a 5% probability that you would be get seriously sick by eating a particular mushroom, wouldn’t that make you think twice about eating it?? On the other hand many of us will gladly shell out money to buy a 6/49 ticket even though the probability of winning anything at all is very low, let alone winning the jackpot, because in the end we are buying the dream of winning, and a loss is not that taxing (unless you gamble excessively of course). I consider odds of 1:8000 in a lottery really good, which they aren’t of course, evidenced by the fact that I have never won anything of substance! So relatively speaking, 1:20 is astronomically high if you think about it!

Why am I bothering to write this as a self-confessed statistics phobe? I have mainly to emphasize that you (and by « you » I primarily mean students engaged in independent research) need to think of statistics as a valuable tool, but not as the only, or even primary tool for interpreting results. Ultimately, it is the biological information that is important.

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Canadian Entomology Research Roundup: June 2015 – September 2015

As part of a continuing series of Canadian Entomology Research Roundups, here’s what some Canadian entomology grad students have been up to lately:

Ecology and Evolution

Rasoul Bahreini (University of Manitoba) found that honeybee breeding can improve tolerance to Varroa mites which can help minimize colony losses in the winter and improve overwintering performance (Article link). Rasoul also found that reducing ventilation may be an effective way to manage Varroa mite infestation in overwintering honeybee colonies (Article link), and that Nosema infection restrained Varroa removal success in bees (Article link).

A setup to study the effects of Nosema on Varroa mite removal in honeybees (Photo: Rasoul Bahreini)

A setup to study the effects of Nosema on Varroa mite removal in honeybees (Photo: Rasoul Bahreini)

A novel method based on agar-polydimethylsiloxane devices to quantitatively investigate oviposition behaviour in Drosophila melanogaster was described by Jacob Leung and colleagues (York University) (Article link).

Paul Abram (Université de Montréal) and his colleagues found that a predatory stink bug has control of egg colouration, depending on whether it is laying on the top or underside of leaves.  The pigment protects developing embryos against UV radiation (Article link). See also a related post on the ESC blog, an article in the New York Times, and a dispatch article in Current Biology.

A spined soldier bug female, with the range of egg colours she is capable of laying (Photo: Leslie Abram/Paul Abram/Eric Guerra)

A spined soldier bug (Podisus maculiventris) female, with the range of egg colours she is capable of laying (Photo: Leslie Abram/Paul Abram/Eric Guerra)

Philippe Boucher and colleagues (Université du Québec à Rimouski/Chicoutimi) found that ant colonization of dead wood plays a role in nitrogen and carbon dynamics after forest fires (Article link).

Did you know that ground squirrels have lice – and males have more than females? Neither did we, but Matt Yunick and colleagues (University of Manitoba) recently published an article in The Canadian Entomologist describing their findings (Article link).

Boyd Mori and Dana Sjostrom (University of Alberta) were part of a group of researchers that found that pheromone traps are less effective at high densities of forest tent caterpillars because of competition for pheromone plumes (Article link).

Parasitoid memory dynamics are affected by realistic temperature stress. As part of a collaboration with the University of Palermo (Italy), Paul Abram (Université de Montréal) and colleagues discovered that both hot and cool temperature cycles prevent wasps (Trissolcus basalis) from forgetting. (Article link).

Trissolcus basalis (Hymenoptera: Platygastridae) parasitizing the eggs of its host Nezara Viridula (Hemiptera: Pentatomidae). These parasitoids can detect their host's

Trissolcus basalis (Hymenoptera: Platygastridae) wasps (left panel) parasitizing the eggs of their host stink bug Nezara viridula (Hemiptera: Pentatomidae; mating couple shown in right panel). These parasitoids can detect their host’s « chemical footprints », and even commit them to memory! (Photos: Antonino Cusumano)

Crisia Tabacaru and Sarah McPike (University of Alberta) studied Dendroctonus ponderosae and other bark and ambrosia beetles and found that competition between the beetles may limit post-fire colonization of burned forest stands (Article link).

Marla Schwarzfeld (University of Alberta) found that tree-based (GMYC and PTP) species delimitation models were less reliable in delimiting test species, and the Nearctic Ophion (Hymenoptera: Ichneumonidae) fauna is much larger than previously thought (Article link).

Where have all the mosquitoes gone? Emily Acheson and colleagues (University of Ottawa) found spatial modelling reveals mosquito net distributions across Tanzania do not target optimal Anopheles mosquito habitats (Article link).

Tyler Wist and colleagues (University of Alberta) found that a native braconid parasitoid (Apanteles polychrosidis) uses host location cues induced by feeding damage on black ash but not on green ash (Article link). Also check out the author’s recent post on the ESC Blog!

Fig. 2 Female Apanteles polychrosidis Viereck (Hymenopetra: Braconidae)

Fig. 2 Female Apanteles polychrosidis Viereck (Hymenopetra: Braconidae) (Photo: Tyler Wist).

Agriculture

Sharavari Kulkarni and colleagues (University of Alberta) discovered that reducing tillage could increase the amount of weed seeds consumed by carabid beetles (Article link).

Physiology and Genetics

Sebastien Boutin and colleagues (Université Laval) are beginning to decode the genetic basis of honeybee hygenic behaviour (Article link).

Investigating the cold tolerance of different Sierra leaf beetle life stages, Evelyn Boychuk and colleagues (University of Western Ontario) found that adults are freeze tolerant, the eggs and pupae are freeze-avoidant, and the larvae are chill susceptible (Article link).

From the Authors:

Shaun Turney, Elyssa Cameron, and Chris Cloutier had this to say about their new article published in PeerJ:

Our supervisor, Prof. Chris Buddle, has always emphasized the importance of voucher specimens for our entomology research. He explained that voucher specimens make our work replicable and verifiable. We wondered how widespread the practice of making voucher specimens among those practicing arthropod-based research. We investigated the frequency of voucher deposition in 281 papers, and the factors which correlated to this frequency. Surprisingly, vouchers were deposited less than 25% of the time! Our paper highlights the need for a greater culture of voucher deposition and we suggest ways in which this culture can be cultivated by researchers, editors, and funding bodies.

Voucher specimens: an important component of arthropod-based research (Photo provided by Shaun Turney, Elyssa Cameron, and Chris Cloutier)

Voucher specimens: an important component of arthropod-based research (Photo provided by Shaun Turney, Elyssa Cameron, and Chris Cloutier)

From Ikkei Shikano, on two of his recently published articles:

Parents that experience a stressful environment can equip their offspring to fare better in a similar environment. Since this can be energetically expensive for the parent, we asked if parents are exposed to two stressors (nutritional stress and a pathogen), would they equip the offspring for both stressors or would they select one over the other? Cabbage looper moths exposed to a pathogen and poor food quality produced offspring that were highly resistant to that same pathogen. Parents that were given poor food produced offspring that developed faster on poor food. When the parents experienced both stressors, they produced offspring that were resistant to multiple pathogens but did not grow faster on a poor diet (Article link).

Herbivorous insects unavoidably eat large and diverse communities of non-entomopathogenic microbes, which live on the surface of their host plants. Previous studies suggest that consuming non-entomopathogenic bacteria may induce a costly immune response that might decrease the risk of infection by pathogens. But isn’t it wasteful for an insect upregulate a costly immune response to non-pathogens that it ingests with every meal? Within an appropriate ecological context, we show that cabbage looper, Trichoplusia ni, larvae do not induce a costly immune response, indicating that they are adapted to consuming non-pathogenic bacteria that are commonly found on the surface of their host plants (Article link).

From Kate Pare, on an article published by a group of undergraduates taking the Arctic Ecology field course at the University of Guelph:

Our study focused on changes in ant diversity in the area surrounding Churchill, Manitoba between the historic collections made by Robert E. Gregg in 1969 and collections made by students and instructors of the Arctic ecology field course in 2012. Seven ant species were collected in 2012 compared to the five species recorded from 1969. This increase in species richness in the 2012 collection is more likely a result of cryptic molecular diversity that was overlooked in the collection made in 1969 (Article Link, post on the ESC blog).

Members of the Arctic Ecology Field course 2015 (Photo: Eric Scott)

Members of the Arctic Ecology Field course 2015 (Photo: Eric Scott).


The ESC Student Affairs Committee will be continuing to help publicize graduate student publications to the wider entomological community through our Research Roundup. If you published an article recently and would like it featured, e-mail us at entsoccan.students@gmail.com.

For regular updates on new Canadian entomological research, you can join the ESC Students Facebook page or follow us on Twitter @esc_students.

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Differential parasitism and ash tree volatile organic chemicals

By Tyler Wist  

The ash leaf cone roller, Caloptilia fraxinella (Ely) (Lepidoptera: Gracillaridae) (Fig. 1) started to get noticed in the cities of the Western Canadian prairies in 1998, well, in Saskatoon, SK at least. I know this because that summer the green ash, Fraxinus pennsylvanica (Oleaceae), in my front yard was covered in cone rolled leaflets and had not been prior to that year. I had just started working for the City of Saskatoon’s Pest Management Program that year and one of our mandates was urban forest insects…not that there was any budget to control them, but it piqued my interest in urban forest entomology.

Fig. 1 The ash leaf coneroller, Caloptilia fraxinella (Ely) (Lepidoptera: Gracillaridae) adult, pupal exuvium and cocoon.

Fig. 1 – The ash leaf coneroller, Caloptilia fraxinella (Ely) (Lepidoptera: Gracillaridae) adult, pupal exuvium and cocoon.

The following year, Chris Saunders with the City of Edmonton’s Pest Management Program, contacted us in Pest Management and asked if we had seen this cone roller on our ash trees because they had just noticed it on the ash trees in Edmonton. Greg Pohl had identified this leaf miner/leaf roller that year on all species of horticultural Fraxinus in Edmonton and published the identification and some life history of the moth in a 2004 paper (Pohl et al. 2004) along with a brief identification of several parasitoids that were reared from larvae and pupae. The lone braconid, identified to the genus Apanteles and found to be all one species by Darryl Williams of the Canadian Forest Service in Edmonton seemed to be the dominant parasitoid in this complex, but without a species designation not much else about the wasp could be gleaned from the literature.

Chris Saunders suggested that I study the ash leaf cone roller as a master’s project but I digressed from urban forest entomology for a few years into pollination of a nutraceutical/agricultural crop. By this time, the ash leaf cone roller had spread to every ash tree in both cities and often rolled 100% of the leaflets on a single tree. I finally followed Chris’ advice and started a PhD project in Maya Evenden’s lab at the University of Alberta, which was the only lab in Canada that was working on the ash leaf cone roller problem (Evenden 2009). The Apanteles sp. was still the dominant parasitoid and so, along with studies on the chemical ecology of the moth (Wist et al. 2014), I also studied the third trophic level in this system (Wist and Evenden 2013). Of course, I couldn’t go through my studies without knowing what the species designation was for the dominant parasitoid wasp. Fortunately, Jose Fernandez-Triana had just begun his study of the genus Apanteles at the CNC in Ottawa and once Henri Goulet passed along the Apanteles specimens that I had sent for identification he quickly determined that this parasitoid was Apanteles polychrosidis Viereck (Hymenopetra: Braconidae) (Fig. 2).

Fig. 2 Female Apanteles polychrosidis Viereck (Hymenopetra: Braconidae)

Fig. 2  – Female Apanteles polychrosidis Viereck (Hymenopetra: Braconidae)

Apanteles polychrosidis kills the ash leaf cone roller larvae before they can chew their emergence “window” that they use to escape the cone rolled leaflet as adults. This behaviour gives a fairly reliable visual cue that a cone rolled leaflet without a “window” has been parasitized by A. polychrosidis because the other parasitoids in the complex emerge after the cone roller has pupated and created its escape route “window”. Unrolling the leaflet confirms the presence of A. polychrosidis if its telltale “hammock-like” cocoon is present (Fig. 3). This type of cocoon is thought to be a defense against hyper-parasitism but as we found (Wist and Evenden 2013) it doesn’t always work out for A. polychrosidis!

Fig. 3 Apanteles polychrosidis Viereck (Hymenopetra: Braconidae) adult above its cocoon and beside the leaflet cone rolled by Caloptilia fraxinella (Ely) (Lepidoptera: Gracillaridae). Note the emergence hole in the side of the leaflet that the wasp chewed to escape.

Fig. 3 – Apanteles polychrosidis Viereck (Hymenopetra: Braconidae) adult above its cocoon and beside the leaflet cone rolled by Caloptilia fraxinella (Ely) (Lepidoptera: Gracillaridae). Note the emergence hole in the side of the leaflet that the wasp chewed to escape.

To assess the percentage of parasitism by this dominant parasitoid I adapted a method that Chris Saunders and I had discussed years earlier for assessing the parasitism of Apanteles sp. on individual trees. For the initial experiment in our paper (Wist et al. 2015) I sampled leaflets to estimate the density of cone rollers on the tree and estimated the percentage of parasitism by A. polychrosidis on two of the common urban species of ash in Edmonton. Apanteles polychrosidis parasitism was higher on black ash, F. nigra, at all sites than it was on green ash, F. pennsylvanica, which can be called differential parasitism and it seems to be common when host larvae develop on two or more host plants, but had not been well studied on trees. When host density and parasitism were graphed, the relationship of parasitism to host density could be visualized by the slope of the regression line, and on black ash, parasitism was independent of host density on black ash, but was negatively density dependent on green ash. In other words, on black ash parasitism is always high but on green ash, parasitism declines as the density of C. fraxinella increases. I ran the same experiment on green and black ash trees in Saskatoon with the same results but we chose to leave them out of the final version of the manuscript.

I was already studying the chemical ecology of C. fraxinella so this was where we looked for an answer to the differential parasitism in the field. I ran a y-tube olfactometer experiment with black and green ash plant material as the attractive source of volatile organic chemicals (VOCs) and this turned out to be rather tricky. I had three treatments that I wanted to test; undamaged leaflets, leaflets damaged by C. fraxinella and leaflets that were mechanically damaged.

First, I tried to bag small seedlings as the source of the plant smell but I couldn’t seal the system well enough to get reliable airflow through the y tube chamber. I had to switch to using leaflets alone which raises the issue of the smell of the leaflets changing once they have been removed from the tree which could be a problem especially in the “undamaged” treatment. I also needed enough female A. polychrosidis hunting for hosts to give me a decent sample size so I had to collect and emerge as many “un-windowed” cone-rolled leaflets as I could in the summer, and hope that they would actually mate and want to oviposit into host larvae at this point in their lives. Another issue was that I couldn’t coax my summer emerged C. fraxinella to lay eggs on ash seedlings to create leaf-mined treatments. Fortunately, a subset of the local population of C. fraxinella had developed a second generation on the new ash leaves that a dying ash tree puts out in July in an effort to save itself. These leaflets became my leaf-mined treatment. Over two seasons with a lot of juggling and timing of three species I was able to gather enough experimental data with the olfactometer to discover that female A. polychrosidis were differentially attracted to the volatile odour cues from each ash species. In green ash tests, they were attracted to the smell of green ash alone but in black ash tests, they were not attracted unless the leaflets were attacked by its host. The “icing on the manuscript cake” was the GC-EAD results by co-authour Regine Gries that showed that 13 compounds in the volatile profile of ash could be sensed by the antennae of A. polychrosidis, and some of them are known to increase in response to herbivore damage.

I’d say that this manuscript is a starting point for further studies on this interesting parasitism system and could accommodate projects from chemical ecology and landscape ecology perspectives at the very least. In fact, Danielle Hoefele and Sarah McPike have already begun projects in Maya’s lab on the FraxinusCaloptilia-Apanteles system. In case you’d like to know more, here is the link to our manuscript published in Arthropod-Plant Interactions.

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Questions About Scientific Publishing? Come to #ESCJAM2015!

This year’s 2015 Joint Annual Meeting in Montréal, Québec includes a free lunchtime workshop sponsored by Cambridge University Press that tackles the topic of publishing scientific papers.

Discussion will be led by a three-member panel examining the publication process through the eyes of an author (J. Saguez), a journal editor (K. Floate) and a publisher (D. Edwards).  Following short presentations by each panelist, the floor will be opened for general questions and discussion.

Send us your questions and we will do our best to address them in our presentations.

What makes for a good paper?  Who should I include as co-authors?  How important is the cover letter?  Why is the review process so long?  How can I best respond to reviewer comments?  What journal should I publish in?  What is hybrid open access?  What are predatory publishers?  Why don’t journals make publications freely available?  Knowing the answers to these and other questions can take some of the frustration out of the publication process.

Our goal is to ensure that everyone leaves with a full stomach and new insights to simplify the publication of their next paper!  You can help us by sending your questions to Kevin Floate (Kevin.Floate@agr.gc.ca) by October 23rd.

See you in Montréal!

Julien Saguez – Independent Researcher/Author

Kevin Floate – Agriculture and Agri-Food Canada; Editor-in-Chief, The Canadian Entomologist

Daniel Edwards – Senior Commissioning Editor, Journals, Cambridge University Press

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From inquiring students to published authors: an adventure in the Arctic

by Amanda Boyd and Kate Pare

The field course in Arctic Ecology (BIOL*4610), offered periodically by the University of Guelph, explores ecological relationships in a sub-arctic environment. Based out of the Northern Studies Research Center, the 2-week course takes place in Churchill Manitoba and the surrounding area. That was what we, the students, knew going into the course. What we didn’t know was that course would be, for many of us, a once in a lifetime experience!

Students in the Arctic Ecology field course learning from Hymenopterist extraordinaire Alex Smith

Students in the Arctic Ecology field course learning from hymenopterist extraordinaire Alex Smith. (Photo by Eric Scott) 

There are only three ways of travelling to Churchill, Manitoba: by boat, by plane or by train. Since we wouldn’t be taking the boat route, two options were left: an hour and forty-minute flight, or a three-day journey by rail. The latter is where most of our adventures began (particularly when some of us didn’t purchase a sleeper ticket). There is much to be learned from a long northward trek, from changing ecosystems and changing cultural environments to increasing price tags. Eventually though, the journey’s end came with a comfortable bus ride and an incredibly delicious meal at the Northern Studies Centre. From there on out, it was down to business.

The first week of our course was spent roaming the rugged landscape, learning about the diverse ecosystems the region has to offer while simultaneously trying to prevent ourselves from being carried off by the swarms of (seemingly) abnormally-sized horse flies. We visited sphagnum bogs, fens, the coast (which may have involved kayaking with belugas), a cranberry-laden moraine and the northern extent of the boreal forest. We explored Krummholtz and bluffs, learned that sedges have edges and learned to always be on the lookout for polar bears (at least 2 bear guards please!). The second week however, allowed us the liberty of designing and conducting our own studies.

As a real world example of scientific research in action, the first day of week-two was spent sampling in the footsteps of Robert E. Gregg and collecting ants from his original 1969 study sites (Gregg 1972). Armed with basic instructions on the identification of the 1969 sampled ant species and genera, we visited a total three sites: Cape Merry, the Churchill Welcome Sign, and Goose Creek Bog. At each site, we spent approximately three hours actively searching for ants, breaking open woody debris and digging into moss hummocks. This was true for all but the Goose Creek site where our (brand new bus) tire sprung a leak and we had no choice but to wait there (which may have resulted in a thoroughly sampled population of Odonates) until Alex Smith, one of the instructors walked into town to radio the Churchill Northern Studies Centre for Plan-B transportation. From there it was back to the lab for a crash course on identifying ants to morphospecies, and for many of us, a valuable lesson that all individuals of a species do not look the same (due to individual variation and cryptic diversity). The rest of week-two was spent with groups of students at every site chasing a variety of six-legged, sub-arctic mysteries. Of course, as students of the natural world, no curiosity was overlooked and no opportunity for fun either! Many an hour was spent bluff jumping, polar bear sighting, investigating the Ithaca shipwreck, and in the case of some students, completing a partial reconstruction of an arctic fox skeleton. Needless to say, it was a very short two weeks that passed with discovery and awe.

One of the many species collected - an ant in the Leptothorax muscorum complex, collected at Cape Merry (Photo by Chelsie Xavier-Blower)

One of the many species collected – an ant in the Leptothorax muscorum complex, collected at Cape Merry (Photo by Chelsie Xavier-Blower)

Going into our field course, I’m not sure any of us thought we would come out of it as published authors. For many of us that participated, the Arctic Ecology field course provided the first real opportunity to actively participate in research outside of the university. The idea that a few days’ worth of collections could be turned into a scientific paper was almost unimaginable. The resulting paper was the first publication that any of us had contributed to. It was exciting to receive the manuscript drafts, and then paper proofs and to know that even aspiring researchers like us could contribute to the knowledge of the scientific community.

During the course, we took high-resolution panoramic GigaPan photographs of the areas we sampled (Smith et al 2013) – you can explore those here. All the DNA barcodes we generated during the course are publicly available for download and exploration. Finally, we wrote about using GigaPans in our Churchill adventures in an article for GigaPan Magazine.

Members of the Arctic Ecology Field course 2015

Students of the Arctic Ecology Field course (now published authors!)(Photo by Eric Scott)

Acknowledgements

We would like to thank LeeAnn Fishback and the staff of the Churchill Northern Studies Centre (https://www.churchillscience.ca/) for all their hospitality and help in Churchill. Support from the CREATE Lab Outreach Program at Carnegie Mellon University, the Learning Enhancement Fund of the University of Guelph (http://www.lef.uoguelph.ca/) and the Fine Foundation helped provide funds for GigaPan-ing and DNA barcoding during the course. Support from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI) to Alex Smith and Sarah Adamowicz provided support and infrastructure.

References

Gregg, R.E. 1972. The northward distribution of ants in North America. The Canadian Entomologist, 104: 1073–1091

Smith, M. Alex, S. Adamowicz, Amanda Boyd, Chris Britton-Foster, Hayley Cahill, Kelsey Desnoyers, Natalie Duitshaever, Dan Gibson, Steve James, Yurak Jeong, Darren Kelly, Eli Levene, Hilary Lyttle, Talia Masse, Kate Pare, Kelsie Paris, Cassie Russell, Eric Scott, Debbie Silva, Megan Sparkes, Kami Valkova (2013) “Arctic Ecology” GigaPan Magazine Vol 5 Issue 1. www.gigapanmagazine.org/vol5/issue1/  (students ordered alphabetically)

Smith, M. Alex, Amanda Boyd, Chris Britton-Foster, Hayley Cahill, Kelsey Desnoyers, Natalie Duitshaever, Dan Gibson, Steve James, Yurak Jeong, Darren Kelly, Eli Levene, Hilary Lyttle, Talia Masse, Kate Pare, Kelsie Paris, Cassie Russell, Eric Scott, Debbie Silva, Megan Sparkes, Kami Valkova S. J. Adamowicz  (2015) The northward distribution of ants forty years later: re-visiting Gregg’s 1969 collections in Churchill, Manitoba, Canada. The Canadian Entomologist. http://dx.doi.org/10.4039/tce.2015.53

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Entomologist Survey: Life & Living in Academia

This is a guest post by Dr. Laurel Haavik, post-doctoral researcher in the Department of Entomology at The Ohio State University.

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I am a post-doc. I’ve been one for nearly six years. Like many other post-docs, I have been working for over a decade towards my goal: a tenure-track position at a research-intensive academic institution. I enjoy research and teaching, and so a career including both seemed like a logical pursuit. I must be good enough to succeed in this pursuit, otherwise someone would have told me to opt for a different path by now. After all, only a small percentage of Ph.D.s actually become professors. I must be pretty close to achieving this goal, because lately I’ve had several interviews – no offers yet. By now, most of my peers have secured permanent positions, although some have gone on different paths. It must be my turn soon. I had faith in the system; confidence in myself.

Earlier this summer, I was invited to give a talk at a conference, in a session on women in science. I accepted willingly; the subject seemed challenging and relevant. As I began to prepare, I realized I knew nothing about it. So, I did what any scientist would do: I turned to the primary literature on women in science. What I found changed my whole perspective on academia, my career, and most importantly: my life.

I learned that the tenure system is outdated, and filters out many creative and talented people. It was established ca. 1940, when those entering academic careers were mostly men. Assistant professors were expected to live on campus, and work intensively, around-the-clock, on establishing themselves until achieving tenure. Sounds a lot like graduate school, or a post-doc, doesn’t it? There’s not much room in that scenario for having a life outside of this pursuit. It turns out that not much has changed about this in the intervening 70+ years. To make it worse, there are now few jobs and too many of us with graduate degrees competing to fill them. It turns out that women, more often than men, are willing to forgo their academic dreams because of this ridiculousness, in favor of something better – probably a happier life. It seems that there are two issues. One: is it even possible? Women are confronted with the complications of basic biology at the very same time as they would be embarking on a demanding academic career. Most of us are well into our thirties, near the end of our child-bearing years, by the time we’re on the job search. Two: they’re exhausted, wondering if an academic career is akin to never-ending graduate school. In the academic atmosphere, there is intense pressure to do more; for example, publish or perish, fund or famish. Talent and creativity that science badly needs is undoubtedly lost as women and men continue to opt out of this outdated system, and for very reasonable grounds.

I took a long, hard look at my career so far. I’m on my third post-doc. I’ve had two failed relationships and a third that might not make it if I have to move again. I’m not married. I don’t have children. I’m in my mid-thirties, meaning that if I want to have children, I better get situated and do it soon. Maybe academia isn’t for me after all, even though my interests, teaching and research, are so well-aligned with the academic mission. I realized that my adult life so far, 90% career and 10% life outside of work, is a direct product of what I like to call our broken academic system. We need to better understand and voice our discontent with the broken academic system, or it won’t change.

I wondered if others feel the same way. In my field, had others thought of leaving science? And if so, why? Has the disparity in numbers of women and men graduates vs. those occupying professional positions actually changed in recent decades? Most importantly, what allows people to cope with such a rigorous career? I’ve been lucky to have had some great mentors, support from my family, and support and encouragement from the scientific community in my field. Have others had the same kinds of emotional support systems?

My study pursues these questions among three related fields: Forestry, Entomology, and Forest Entomology. In all three of these fields women are not historically well-represented, but this has changed in recent years, especially in Entomology. There are still few women in Forestry. Forest Entomology is a small field with a very inter-connected community, which I hope will provide an interesting contrast to its two larger, sister fields.

Please follow the link below to participate in my study, by completing my survey.

I invite men and women at all stages in their careers, as well as those who are no longer in science, to participate. Please forward this invitation to anyone you know who is no longer in science, but completed graduate school (M.S. or Ph.D.). The results of this study will be published in the primary literature.

Please follow the link below to complete the brief, 28-question survey by September 30, 2015

https://www.surveymonkey.com/r/forestry-entomology

It may take 10-15 minutes to complete. I apologize for any cross-posting of this survey. No personal identifying information will be collected as part of the survey, and your participation will be completely anonymous. Answering questions in the survey will indicate consent. Participation is voluntary and you may withdraw at any time without penalty, and there are no incentives to participate. Participation will have no effect upon your relationship with the Entomological Society of Canada. This study has been determined Exempt from IRB review.

Please contact me if I can provide any additional information regarding the aims of or your participation in the survey (Laurel Haavik, 479-422-4997, haavik.1@osu.edu). For questions about your rights as a participant in this study or to discuss other study-related concerns or complaints with someone who is not part of the research team, you may contact Ms. Sandra Meadows in the Office of Responsible Research Practices at 1-800-678-6251 or hsconcerns@osu.edu.

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Student opportunities at the 2016 International Congress of Entomology

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Next September, the largest-ever scientific meeting of entomologists will take place at the International Congress of Entomology (ICE) in Orlando, Florida. For graduate students and early-career entomologists, it will be a fantastic opportunity to meet your peers from all over the world, present your research in a high-profile setting, and scout out potential study or career opportunities.

While you might be thinking that it’s an awful long time from now, and that there’s that pesky thesis that you have to get written, there are two important deadlines coming up soon that you should be aware of:

1. Travel Awards for Students and Early-Career Professionals

The international branch of the Entomological Society of America is giving a total of $50,000 worth of awards to students from outside the USA to attend ICE 2016.

Find detailed information about these awards here. Note that you need to be a member of the ESA to apply, that and membership will cost you between $50 and $150. If you plan to apply, you need to act fast – the deadline for application is September 1st, 2015.

Also note that the Entomological Society of Canada will also have a student and early-career professional travel awards program to assist with attendance at ICE. Information about these awards will be available soon!

2. The International Graduate Student Showcase (IGSS)

The Graduate Student Showcase, which has become a staple of ESC annual meetings, is coming to ICE 2016! Don’t miss this opportunity to present your finished research project alongside the top graduate students in entomology from around the world.

To apply, you need to be defending your MSc or PhD thesis between September 30, 2015 and September 30, 2016.

Find more information about the IGSS here.

The deadline for IGSS applications is October 31, 2015.

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The flight of the backswimmer: dispersal behaviour in a freshwater insect

By Celina Baines

Have you ever thought about what a pond-dwelling insect might do if it doesn’t like the pond it lives in? People generally assume that these insects are stuck where they are, but actually, many freshwater insects have wings and can fly. This movement between ponds is an example of a process known as dispersal.

Backswimmers, for example, are insects that live in ponds and streams (and sometimes even swimming pools!). Backswimmers have a characteristic way of swimming – on their backs, just under the surface of the water, using their hind legs to propel themselves. It makes them look a little like they are doing the backstroke (hence their common name!). But they also have wings, and can fly between ponds.

A top view of a backswimmer swimming. Backswimmers can often be seen swimming just under the surface of the water, ventral side up. Photo credit: Shannon McCauley.

A top view of a backswimmer swimming. Backswimmers can often be seen swimming just under the surface of the water, ventral side up. Photo credit: Shannon McCauley.

We know from observing these insects that not all backswimmers make the same decisions about whether to disperse. Some individuals spend their whole lives in the ponds they are born in, and some individuals move to new ponds. So why do some individuals stay and some leave? One factor that could influence dispersal decisions is the quality of the pond. Pond “quality” could depend on many things, including the risk of being eaten by predators like fish. Dispersing can be a great way for organisms to avoid habitats that will be bad for them or their offspring.

Once a backswimmer has decided that it wants to disperse, it then has to decide whether it is strong and healthy enough to fly. This could be another factor that determines whether an individual decides to stay or go.

In the summer of 2013, I conducted a field experiment to learn more about how backswimmers make dispersal decisions. I wanted to test whether dispersal was induced by fish. I also wanted to test whether body condition (basically, the general strength and health of an organism) influences dispersal decisions.

I started by collecting backswimmers from a pond at the Koffler Scientific Reserve. That’s a research site owned by the University of Toronto, where I’m a graduate student.

This is me collecting backswimmers from a pond at the Koffler Scientific Reserve. Photo credit: Chris Thomaidis.

This is me collecting backswimmers from a pond at the Koffler Scientific Reserve. Photo credit: Chris Thomaidis.

I brought the backswimmers back to a lab at the University of Toronto. Because I wanted to test the effects of body condition on dispersal, I first had to manipulate the backswimmers so that they had different levels of body condition. I did this by carefully controlling how much food each backswimmer got to eat.

Backswimmers are carnivores, and they aren’t very picky. For this experiment, I fed them fruit flies, because it’s really easy to get lots and lots of fruit flies. So, in what turned out to be one of the most back-breakingly tedious jobs I’ve ever performed for science, I (and many uncomplaining assistants) counted out thousands of individual fruit flies to feed to the backswimmers. Each backswimmer was housed in its own little cup, and received a specific (and carefully counted) number of fruit flies to eat every day. Here’s what the hundreds of drink cups looked like, colour coded and full of bugs.

Left: Cups housing backswimmers at the University of Toronto. Right: A backswimmer in its cup.

Left: Cups housing backswimmers at the University of Toronto. Right: A backswimmer in its cup.

After a few weeks of controlling the backswimmers’ diets, it was time to bring them outside to see if they would fly. I set up some artificial ponds in a big field. These “ponds” are actually just watering tanks that farmers use for cows and horses, but I added algae and artificial plants to make them more like natural ponds. Since I also wanted to test whether backswimmers are scared away by fish, I added a fish to half of the tanks. I put the fish in cages, and that way, the backswimmers could tell there was a fish in the tank (they could see and smell the fish), but the fish couldn’t actually eat the backswimmers.

This is me, checking the artificial ponds for backswimmers. Photo credit: Betty Dondertman.

This is me, checking the artificial ponds for backswimmers. Photo credit: Betty Dondertman.

Then I put the bugs in the tanks, and waited. After a couple days, I went back to the tanks and checked to see which backswimmers were still in the tanks, and which ones had flown away.

Firstly, I found that backswimmers are scared away by fish; they are more likely to disperse when a fish is in their pond.

I also found that the backswimmers with high body condition are more likely to fly, probably because they are strong fliers and have the best chance of successfully finding a new pond.

Both of these results were really cool and answered some questions for us about how backswimmers make dispersal decisions. But they might also tell us a little about how other organisms move around in natural ecosystems. Dispersers are the only individuals that can find new ponds and start new populations. If dispersers tend to be the strongest and healthiest individuals, that’s great for native species that we want to encourage to start new populations. But having strong, healthy individuals from exotic species start new populations is probably bad news. Dispersal can therefore have important consequences, which is why we need to understand more about how and why organisms disperse.

For more information about my study, check out the recent publication:

Baines, C. B., McCauley, S. J., & Rowe, L. (2015). Dispersal depends on body condition and predation risk in the semi‐aquatic insect, Notonecta undulata. Ecology and Evolution 5(12): 2307–2316

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Canadian Entomology Research Roundup: April – June 2015

As a graduate student, publishing a paper is a big deal. After spending countless hours doing the research, slogging through the writing process, soliciting comments from co-authors, formatting the paper to meet journal guidelines, and dealing with reviewer comments, it’s nice to finally get that acceptance letter and know that your work is getting out there. The ESC Student Affairs Committee is happy to be posting a fourth roundup of papers authored by Canadian graduate students. Stay tuned to the ESC blog for some full length guest posts from some of the students below in the coming weeks!

Have a look at what some entomology grad students in Canada have been up to recently! Articles below were published online from April through June 2015.

Forestry

Seehausen et al. found that parasitism of hemlock looper Lambdina fiscellaria (Guenée) (Lepidoptera: Geometridae) pupae was significantly reduced in plots with high partial cutting intensities (40%). To sustain parasitism rates in forest stands vulnerable to hemlock looper defoliation at naturally high levels, it is recommended to refrain from high intensity partial cutting. Article link

Apechthis Ontario parasitizing a hemlock looper pupa (Photo credit: Lukas Seehausen)

Apechthis ontario parasitizing a hemlock looper pupa (Photo credit: Lukas Seehausen)

During its recent outbreak starting in the early 2000s, the mountain pine beetle destroyed huge areas of lodge pole pine forests in BC and Alberta while also expanding its geographic range east and north. More recently, the beetle has been confirmed to be attacking and reproducing in a novel host, jack pine, which is distributed from Alberta to the Atlantic coast. New research by Taft et al. looks at how specific chemicals in jack pine trees that affect mountain pine beetle vary in jack pine across its range. Article link

Another study from the Erbilgin lab at University of Alberta by Karst et al. revealed that stand mortality caused by prior beetle attacks of mature pines have cascading effects on seedling secondary chemistry, growth and survival, probably mediated through effects on below-ground mutualisms. Article link

Physiology and Genetics

Proshek, Dupuis, et al. found the genetic diversity of Mormon Metalmark species complex are more diverse than traditional morphological characters. Article link

A Lange Metalmark butterfly (Photo: Wikimedia Commons)

Oudin, Bonduriansky, and Rundle at the University of Ottawa found the amount of sexual dimorphism present in antler flies is condition-dependent. Article link

Nearby at Carleton University, Webster et al. studied the edge markings on moths to show they can provide camouflage by breaking up their body outline. Article link

Another study from Carleton University, from Hossie et al., showed that predator-deterring eyespots tend to appear on larger-bodied caterpillars and that smaller species are better off remaining undetected. Check out the detailed blog post about this study on the lead author’s blog, and a great photo gallery of caterpillars with eyespots! And here’s the link to the Article.

Jakobs, Gariepy, and Sinclair established that adult phenotypic plasticity is not sufficient to allow Drosophila suzukii to overwinter in temperate habitats. Article link

Insect Management

Part of the PhD work of Angela Gradish focused on the White Mountain arctic butterfly (WMA), a very rare butterfly occurring only on the alpine zone of Mts. Washington and Jefferson in New Hampshire. Despite its threatened status, little was known of the WMA’s population structure, distribution, and behaviour. So Gradish grabbed a net and headed up Mt. Washington, where she spent part of two summers collecting WMA samples for genetic analyses while performing a mark-release-recapture study on the population. She was the first to use genetic analyses to study the WMA, the results of which are presented here.  Find the results of the mark-release-recapture study here.

Angela Gradish collecting

Collecting butterflies on Mount Washington (photo credit: Angela Gradish).

Marshall and Paiero, from the Marshall lab at University of Guelph, gives a new record of a Palaearctic leaf beetle, Cassida viridis, which has been present in Ontario since 1974. Article link

Maguire et al., from the Buddle lab at McGill University, found destructive insect herbivores can positively or negatively impact ecosystem services depending on outbreak conditions. Article link

Biodiversity

Ernst and Buddle discovered that the diversity and assemblage structure of northern carabid beetles show strong latitudinal gradients due to the mediating effects of climate, particularly temperature. Article link

Behaviour and Ecology

The Luong lab at University of Alberta observed that ectoparasitic mites have deleterious effects on host flight performance of Drosophila species. Article link

Therrien et al. from the Erbilgin lab at the University of Alberta found that bacteria can influence brood development of bark beetles in host tissue. Article link

Desai, Kumar, and Currie from the Currie lab at the University of Manitoba conducted the first major baseline study of viruses in Canadian honey bees to show that deformed wing virus has the highest concentration among worker bees. Article link

Baines, McCauley, and Rowe from the Rowe lab at University of Toronto showed that dispersal is a positive function of body condition in backswimmers, but not interactive with predation risk. Article link

Backswimmers can often be seen swimming just under the surface of the water, ventral side up (Photo credit: Shannon McCauley).

Backswimmers can often be seen swimming just under the surface of the water, ventral side up (Photo credit: Shannon McCauley).

Strepsiptera is a peculiar and enigmatic insect order. All are entomophagous endoparasitoids. Unusually for parasitoids, they possess a very broad host range, encompassing 7 orders and 34 families of insects, in various habitats worldwide. Despite their broad host range, and cosmopolitan distribution, surprisingly little is known about their biology. The gaps in knowledge of this group has led to many generalizations about their biology and behaviour. Only recently are studies beginning to uncover a hitherto unforeseen diversity in reproductive strategies. In this review, Kathirithamby, Hrabar, and colleagues discuss the reproductive biology of Strepsiptera: what is known, and what mysteries remain to be solved. Article link

In the Sargent lab at University of Ottawa, Russell-Mercier and Sargent investigated herbivore-mediated differences in floral display traits and found that they impacted pollinator visitation behaviour, but not in female reproductive success. Article link

Techniques

Can you use gut content DNA analysis of a staphilinid beetle to track predation of spotted wing drosophila? Here’s what Renkema et al. found.

Rosati et al., from the Vanlaerhoven lab at University of Windsor, discuss using ImageJ software to quantify blow fly egg deposition in a non-destructive manner. Article link

We are continuing to help publicize graduate student publications to the wider entomological community through our Research Roundup. Find the previous edition here: http://escsecblog.com/2015/05/04/canadian-entomology-research-roundup-march-2015-april-2015/. If you published an article recently and would like it featured, e-mail us at entsoccan.students@gmail.com. You can also send us photos and short descriptions of your research, to appear in a later edition of the research roundup.

For regular updates on new Canadian entomological research, you can join the ESC Students Facebook page or follow us on Twitter @esc_students

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Emerald Ash Borer – marking 10 years of research

Emerald Ash Borer. Credit Debbie Miller, USDA Forest Service. Bugwood.org

Emerald Ash Borer (Agrilus planipennis). Credit: Debbie Miller USDA Forest Service, Bugwood.org.

To mark the publication of the Emerald Ash Borer special issue from The Canadian Entomologist, guest editors Chris MacQuarrie and Krista Ryall from Natural Resources Canada have co-authored this blog post about the issue.

In 2002, residents of Detroit, Michigan noticed something was killing their ash trees. Ash trees in North America are susceptible to some diseases that can result in decline and mortality, so a forest disease specialist was dispatched to investigate why these trees were dying. It was soon determined that the culprit was not a disease, but an insect: a shiny, metallic-green, buprestid beetle not previously known from Michigan, or anywhere else in North America. Authorities in Michigan notified their Canadian counterparts who soon discovered numerous ash trees dying in Windsor, Ontario from damage caused by the same beetle. Eventually, with the help of a European systematist the insect was determined to be the previously described (and previously rare) Agrilus planipennis. Today, this insect is better known by its common name:  the emerald ash borer.

To commemorate the discovery of emerald ash borer in North America, we organized a symposium and workshop at the 2013 Entomological Society of Canada’s and Ontario’s Joint Meeting in Guelph, Ontario. The timing and location of this workshop seemed appropriate because 2013 marked 10 years of research on the emerald ash borer and Guelph is located only a few 100 kilometres from where emerald ash borer was first found, and is now well within the insect’s Canadian range. Our goal with this symposium was to review the state of knowledge on emerald ash borer after ten years of research, and look ahead to the questions that researchers will be asking as the infestation continues to grow and spread. We were fortunate that many of the researchers who have contributed so much of what we know about emerald ash borer were able to participate.

We were quite pleased with how well the symposium turned out. However, information presented in a symposium is ephemeral and fades away as soon as the last talk is over. To prevent this, we imposed upon our presenters to also prepare written versions of their presentations. It took some time, but now these papers are all complete, and have been put together to form a special issue of The Canadian Entomologist dedicated to the emerald ash borer.

Emerald Ash Borer

Emerald Ash Borer.  Image credit: Chris MacQuarrie

Ten years is a long time in research. We estimated that over 300 papers on emerald ash borer had been produced over that period, with more being produced every month. It is our hope that this special issue can serve as an entry point into this literature for researchers new to the field. We also hope that this issue can be valuable to more established researchers as well, to use as a resource and a touchstone in their own work. This special issue can also serve as a reminder of how much effort is required (in both research and by people) to understand a new pest. What we have learned about emerald ash borer over the past ten years (well, 13 years now) is immense. There is still much to learn though.”

The Emerald Ash Borer special issue is the free sample issue of The Canadian Entomologist for 2015.

Access the special issue for free until 1st January 2016 here.

Main image credit: Debbie Miller, USDA Forest Service, Bugwood.org