Ever wish you could travel back through time and see a west coast Vancouver Island rainforest before industrial logging? To see huge old trees, intact soils and life in a climax ecosystem? You do not have to invent a time machine, you only need to travel about an hour out of Port Renfrew to the spectacular Walbran Valley.
As part of an effort to document the biodiversity of the valley, I traveled with fellow arachnologists Claudia Copley, Darren Copley, Zoe Lindo, and Catherine Scott, along with birders, mycologists, lichenologists and assorted volunteers to spend a day among the giant trees. We were there at the invitation of the Friends of Carmanah-Walbran to lend our expertise to the effort of catloguing the biodiversity of this beautiful, yet still at-risk west coast habitat.
We arrived at the somewhat storied “Bridge to Nowhere”, where in 1991 environmental protesters confronted the logging companies, the RCMP and the government of British Columbia, holding the line against industrial exploitation of a rare ecosystem. What the activists were asking for seems modest: Can’t we have just this one watershed, among all the others on Vancouver Island, be preserved and protected from the clearcutting and degradation that is the fate of every other valley on the Island?
2. Pacheedaht elder Bill Jones walks across the Bridge to Nowhere
While the Friends of Carmanah-Walbran took the other participants deep into the woods on hikes, we arachnologists ventured only short distances into the woods, as our slow and careful sifting through the soil and beating of the bushes is certainly not a thrill ride for everyone. For us, however, it was thrilling, as within 30 minutes of arrival on site, we had found a beautiful and seemingly dense population of Hexura picea, a relative of tarantulas.
3. Hexura picea, a tarantula relative, brought out of its underground silk tunnel complex for a photo shoot.
These little, pretty, but nondescript spiders live in small silk tunnel complexes among the soil and rocks of the forest floor. Each tunnel has a main entrance lined with silk, and several other openings which may facilitate rapid escape or offer alternate exits at which to snare prey. Being members of the suborder Mygalomorphae, they are indeed tarantula relatives, a group of spiders that closely resemble ancient spiders. Many mygalomorphs retain traces of segmentation on their abdomens, unlike the more modern araneomorph spiders. In the Mecicobothriidae (to which Hexura belongs) the terminal spinneret segments bear “pseudosegmentation”
The section of forest we found this spider in was a real “tangled bank”, in fact the scree slope associated with Walbran creek and a small tributary, which has since been covered with a layer of soil and a stand of hardy trees.
4. Erosion is a gentler process in a forested valley, with trees holding on to what would be a talus slope higher in the mountains. The soils beneath these trees support an extensive food web.
Finding these spiders in the Walbran was not unexpected, as they had previously been found in the Carmanah Valley and at Avatar Grove, but their presence on Vancouver Island is somewhat puzzling, as they represent the only known Canadian population, and are seemingly not present on the BC mainland.
Given the dense population in the Walbran, the valley would be an wonderful place to study their behaviour, which so far is undocumented. We would presume that much of the activity of these spiders takes place at night, although Catherine was able to lure one out of its burrow by tickling the silken doormat with a twig.
5. Hexura picea emerges from its silken tunnel and onto its “doormat” to “kill” a vibrating cedar twig.
The litter sampling we conducted will surely yield many more species, although we have to wait until the Berlese funnels have extracted all of the arthropods. The work of sampling and cataloguing biodiversity takes time, and is not totally congruent with the rapid “bioblitz” ethos.
If you are ever in BC, and want a trip back in time (never mind our politics), please do not hesitate to come out to the Walbran Valley. You may just discover something amazing.
6. Darren and Claudia picking up pan traps beside the Malaise flight-intercept trap.
By Staffan Lindgren @bslindgren
Ever since childhood, I have been happiest crawling around turning over rocks, removing bark from stumps and inspecting every potential animal I can see. Early on, I was pretty much on my own, except for encouragement from my parents. At an early age, even before I reached teenage, I started joining various organizations that catered to likeminded geeks. Over the years, I have been involved in, or a member of literally dozens of such organizations. Central to my fascination has always been insects, and my dream was always to become an entomologist.
The first entomological society I joined was “Sveriges Entomologiska Förening” in Sweden. Because I grew up in a small northern town, I never really had the privilege of getting to know other members, and before I had much of a chance I was off to Canada. By then I had made some connections to Swedish entomologists through the professors, lecturers, and students of Umeå University, the Royal College of Forestry (now part of the Swedish University of Agricultural Sciences) and Uppsala University. I remained a member of SEF for some years, but once I knew that my planned return to Sweden was not going to happen, I gave that membership up in favour of the societies that I had joined and had closer connections with in North America. I have now been a member in good standing of the Entomological Society of Canada, ESBC, and ESA for more than 35 years, which is almost the entire time I have lived in Canada. I have served each of these societies in executive or other functions, most recently for four years on the executive of the ESC. Through these societies, I have gotten to know many colleagues who I now regard as friends as much as colleagues, I have established research collaborations, and gained a lot of knowledge that I would have missed by only reading what happened to be directly relevant to my own interests. In my opinion, I would not have had what little success I have enjoyed without my engagement in scientific society life.
Due to the unfortunate circumstances of my successor as President, I am currently Acting Past-President. One of my duties is to chair the Nominations Committee, which identifies individuals willing to put their name forward to serve on the ESC Governing Board (If you are interested in putting your name forward for 2nd Vice-President or Director-at-Large, PLEASE CONTACT ME!). In order to help me with this task, I requested a copy of the 2016 membership list. In going through the spreadsheet, I was rather disturbed at the absence of numerous individuals, some of whom have previously served important roles in promoting the ESC (you know who you are!). I know that it is easy to forget to pay the membership dues, but I have a feeling that the reasons for opting out are not always that simple. In the next week or so, memberships will expire, and it is time to once again contribute to your national and regional societies. I know that it seems like a lot of money, but if you think about it, we are talking about sums that are unlikely to break the bank of anyone. The ESC regular membership would be paid off by giving up about 60 cups of Tim Horton’s coffee or 30 cups of Starbucks special coffees. In other words, you would have to forego only about 2-3 cups of Starbucks per month to save enough. It may not seem that supporting the ESC gives you much in return, but if the society is not supported, it would mean that the Canadian Entomologist (one of the oldest journals in the world), the Bulletin, and the Annual meetings would cease to exist. That also means that opportunities to mix with likeminded geeks become more expensive and less frequent. That would be a shame, wouldn’t it?
Please, go to the computer right now and join or renew as a member of the ESC (and whatever Regional Society that is close to you). The ESC needs your support, and I believe you will benefit from being part of the national entomological family of Canada. For me, it has been a privilege to be part of one of the most welcoming and inclusive group of people in science. Please join me!
Last winter, I spent a few months working on insect identifications for the BC Conservation Data Centre, mostly collections of insects made at newly-acquired conservation lands in the Okanagan and Kootenay regions of BC.
As I had no laboratory of my own, and no reference collections to work with, I was working out of the ROM, back behind Antonia Guidotti’s office in the entomology workroom. This place, in midwinter, is usually a little lonely, as Antonia has a lot of work to do all around the collection. And so mostly in solitude, I would sit there at my microscope, stumbling through insect IDs, learning what I could about a vast array of taxa, and listening to an inordinate amount of Leonard Cohen’s music.
Somehow, I feel the mood of Leonard Cohen’s later works lends itself so well to solitary entomology pursuits. The consummate outsider, looking closely and inwardly at the human condition, and yet always so aware of a wider world, Leonard’s music has many parallels to sitting at a scope, baffled by Nature’s diversity and wondering how it all fits together.
(As an aside, when I was going through scads of unfortunate, dead, trapped insects, the song “Who by Fire” seemed morbidly appropriate)
Occasionally, from the lab bench, I would reach out to the other folks online, sharing my discoveries through Twitter (the entomology workroom has a modest wireless connection!).
How excited I was, having lived in BC most my life to discover the wonderful piglet bug Bruchomorpha beameri, a wonderful fulgoroid planthopper that I had no idea even existed before taking this contract!
It was heartening, sitting there alone, singing softly along to Leonard Cohen that people out there on Twitter responded so well to my excitement at discovering these treasures, and offering helpful advice. Terry Wheeler was especially helpful when I was stumbling over some puzzling scathophagids from the Peace District.
Connecting with people like Terry, who encouraged me through my ID struggles made me feel that despite being on the outer edges of my knowledge and what could reasonably be called paid employment in entomology, people cared about what I was doing and were there if I needed them.
With the help of Terry, Antonia, Laura Timms, Lu Musetti, and the great Leonard Cohen, I struggled my way through my contract, and my first eastern winter. Last week, Leonard Cohen died, leaving a huge hole in Canadian songwriting. We still have his recordings and poems to keep us company, though no matter what we are doing.
On Tuesday, I will head back to the ROM as a volunteer, to help sort out some of the ant collection, to the best of my ability. Perhaps I will listen to some of Leonard Cohen’s music, and tweet out some of what I find to connect me and my entomology work to the wider world.
Notre but initial, pour mon superviseur Dr. Brent Sinclair et moi, était de voyager au Yukon pour collecter des araignées. Nous avions entendu du Dr. Chris Buddle, que nous allions rencontrer là-bas, que les araignées étaient nombreuses. Et il avait bien raison ! Cependant, nous ne pensions pas être charmé par le minuscule (maximum 3mm), mais fougueux pseudoscorpion Wyochernes asiaticus et qu’il pique autant notre curiosité.
Notre équipe de recherche a quitté Whitehorse avec tout l’équipement nécessaire (nourriture, réchaud, véhicule à quatre roues motrices et beaucoup de contenants pour l’échantillonage) et nous avons passés les deux prochaines semaines à explorer la tundra, se dirigeant vers le Nord sur la « Dempster Highway ». Cette route est probablement la seule route entretenue au Nord du Yukon et nous permet d’atteindre la région béringienne. Alors que les glaciers recouvraient la plupart de l’Amérique du Nord durant la dernière ère glacière, la Béringie était un des seuls endroits n’ayant pas été ensevelie. Pour cette raison, beaucoup des espècesqui s’y trouvent , telles que W. asiaticus, pré-datent la dernière ère glacière. Bon, cette créature n’est peut-être pas aussi excitante qu’un mammouth ou un castor géant, mais, pour les chercheurs travaillant sur les arthropodes, elle est très spéciale.
C’est Dr. Buddle qui a attiré notre attention sur ces créatures. Il en avait trouvé durant des voyages antérieurs et voulait avoir des échantillons provenant de différentes latitudes (nous avons traversés environ 10 dégrées de latitude durant notre voyage). Il a demandé notre aide pour collecter les échantillons de pseudoscorpions. Ceux-ci vivent sous des roches plates sur les rives des rivières. C’est pendant l’échantillonnage que nous nous sommes demandés ce qu’ils faisaient le reste de l’année. Non seulement ils doivent supporter le froid éprouvant de l’hiver arctique, mais vivent aussi dans une région où il y a des crues périodiques. Nous voulions voir quelle était leur tolérance pour le froid et pour la submersion. Nous allons pris et les avons rapporter vers notre laboratoire à University of Western Ontario, avec aussi environ 600 araignées
De retour dans le laboratoire, j’ai mesuré le point de congélation, les points thermaux critiques minimum et maximum (CTmin et CTmax; les limites de l’activité) des pseudoscorpions. Leur point de congélation, déterminant s’ils survivent ou pas à la congélation, nous a donné une idée de leur habilité à surmonter les hivers glaciaux de l’Arctique. Nous sommes intéressés par le CTmin et CTmax car ils nous permettent d’avoir une bonne idée de leurs limites écologiques, c’est-à-dire s’ils peuvent se déplacer, se nourrir ou se défendre. Nous avons découvert que ces petites bêtes avaient une très mauvaise tolérance au froid. Ils ne survivent pas à la congélation et, aux alentours de -4°C ne peuvent plus bouger. L’Arctique peut atteindre des températures bien plus froides que ça ! Nous pouvons seulement supposer qu’ils recherchent des refuges thermaux très efficaces durant l’hiver ou qu’ils ajustent leur tolérance au froid durant l’année, comme beaucoup d’insectes.
Parlant de changements de saison, nous assumons que leur habitat est inondé de façon saisonnière vu que nous les avons trouvés sur le bord d’une rivière. Est-ce qu’ils se déplacent en amont de la rivière ? Est-ce qu’ils nagent ? Est-ce qu’ils apportent une bulle d’air avec eux, comme les araignées plongeuses ? Au départ, nous pensions qu’ils tenaient une bulle d’air entre leur abdomen et les roches auxquelles ils s’accrochent. Dans nos expériences, ils ont survécu une semaine submergés dans les eaux hautement oxygénées ayant un taux de survie similaire à ceux qui ne vivaient pas sous l’eau. Cependant, ils avaient aussi le même taux de survie que ceux qui étaient submergés dans des eaux peu oxygénées. Nous concluons donc qu’ils tolèrent le fait d’être sous l’eau, mais qu’ils ne se comptent pas sur l’oxygène provenant de l’eau environnante.
Notre excursion dans le Nord pour l’échantillonnage nous aura donc donné une belle surprise. Un petit pseudoscorpion sur les rives de la rivière a capté notre attention. Cependant, ce n’est pas la seule chose pouvant provoquer un lot de fascination lorsqu’au Yukon. De l’énorme grizzly au caribou aux centaines d’araignées et aux collemboles dont ils se nourissent, l’Arctique est en effet un endroit unique.
By Susan Anthony, PhD Candidate, University of Western Ontario
Our initial aim for me and my supervisor Dr. Brent Sinclair was to travel to the Yukon to collect spiders. We had heard from Dr. Chris Buddle, who would meet us there, that spiders are plentiful. And indeed they were! But what we didn’t expect was to be charmed, and infinitely curious, about the tiny (max. 3mm) but feisty pseudoscorpion Wyochernes asiaticus.
Our research team left Whitehorse with supplies (food, stove, 4WD vehicle, and lots of collecting containers), and spent the next two weeks exploring the tundra heading north on the Dempster Highway. This highway is probably the only maintained road in northern Yukon, and it provided access for us to the Beringian region. As the glaciers swept much of North America during the last ice age, Beringia was the land that was never glaciated. For this reason, many of the species located there pre-date the last ice age, such as W. asiaticus. Now, this creature may not be as exciting as a mammoth or a giant beaver, but to arthropod researchers, it was very special.
It was Dr. Buddle that pointed us to these creatures. He had found them on previous trips, and wanted to collect more from different latitudes (we spanned about 10 degrees of latitude on our trip). He had us help collect the pseudoscorpions: they live on the underside of flat rocks along river banks. It was while collecting them that we wondered what they did for the rest of the year. They would not only have to withstand the grueling cold of an Arctic winter, and they were also in an area that would experience periodic flooding. We wanted to see what their tolerance is for cold and for submergence. We packed them up, and brought them back to our lab at the University of Western Ontario, along with about 600 spiders.
When back in the lab, I measured freezing point, their critical thermal minima and maxima (CTmin and CTmax; the limits of activity) of the pseudoscorpions. Their freezing point, and whether or not they survive freezing, gives us an idea of their ability to survive the frigid winters in the Arctic. We are interested in CTmin and CTmax because they are good ideas of their ecological limits, if they can’t move, they can’t feed or defend themselves. What we discovered is that these little critters have very poor cold tolerance. They don’t survive freezing, and roughly -4°C, they can’t move. The Arctic gets much, much colder than that. Our only guess is that they seek very effective thermal refuges in the winter, or somehow adjust their cold tolerance through the year, much like many insects.
Speaking of seasonal change, we found W. asiaticus along the stream. Undoubtedly, their homes will be flooded seasonally. Do they migrate further up from the stream? Do they swim? Or do they bring a bubble of air down with them, like the diving spiders? It seemed at first that they held a bubble of air between their abdomen and the rocks that they latch onto. They survived for a week in highly oxygenated water (same survival as the ones who weren’t underwater). However, it was also the same survival as those submerged in low oxygenated water. Half of them even survived 2 weeks in the low oxygenated water. We concluded that they can tolerate being underwater, but they likely don’t rely on oxygen coming from the water around their air pocket.
Our trip up North to collect spiders gave us a great surprise. A small pseudoscorpion on the banks of the streams caught our attention. However, there was so much to capture our fascination up North. From the giant grizzly bear and caribou, to the hundreds of spiders and the collembolans they much upon. The Arctic is indeed an unique place.
It is about time I got busy and stared blogging again on this site. Since I am out of practice, I will do what I know best: a photo essay about why I love insects and other arthropods, and how studying them has improved my life!
The following is a guest post by Emma DesPland
Last week the CBC contacted me about an “infestation” of caterpillars near a local sports and community centre, citing parents’ concern that these could be dangerous for their children.
I was surprised.
The pine (Thaumetopoea pityocampa) and oak (T. processionea) processionary caterpillars do have a genuine claim to being a public health hazard: the later instars are covered with barbed setae containing an urticating toxin. These setae break off readily on contact and can even become airborne: if they lodge in the skin, they can cause a rash, but if they contact the eyes or throat the allergic response can be more serious.
Both are Mediterranean species that are expanding their range and causing concern in Northern Europe among people without prior experience. Neither has been reported in North America.
There are several species of hairy caterpillars in Quebec: Eastern tent caterpillars, forest tent caterpillars, gypsy moth and woolly bears among the most common. None have the allergenic properties of processionary caterpillars.
So what were these caterpillars invading the community centre? Forest tent caterpillars (Malacosoma disstria) and gypsy moth (Lymantria dispar). Neither has any history of causing allergies or any other health consequences, except for possibly causing abortions in mares who eat large numbers of them.
I have handled forest tent caterpillars for years, as have many other researchers, the students in my lab as well as my own children. We have also given hands-on science exhibits, in which countless other children have handled them. Fitzgerald’s classic 1995 book The Tent Caterpillars contains a chapter on “Maintaining Colonies and Suggestions for Classroom Activities”. No-one to my knowledge has had an allergic reaction.
Does this mean that it is impossible that someone be allergic to the hairs on these caterpillars? Of course not, allergies are very diverse, widespread, complex and poorly understood. Some people are allergic to laundry detergent, others to strawberries.
Are there any benefits to be gained by children handling caterpillars? First, it’s hard to stop them. Children are curious and intrigued by the world around them, and caterpillars are ideal experimental subjects: they move and do interesting things, but not too fast. They can be herded and driven across bridges, housed in jars and passed from one finger to the next, but never entirely controlled as they generally manage to escape somehow. This kind of non-directed, curiosity-driven play is just the sort that develops scientific thinking. In addition, spending time with nature calms people, children and adults alike, and helps them recover from stress. Finally, conservation ethics – a feeling that the natural word is precious and deserves protection for its own sake – develops in childhood, through non-directed play in nature. A type of play that is becoming less and less accessible for an increasing number of city-dwelling children.
Instilling fear of the natural world – fear of even something as cute, slightly ridiculous and totally innocuous-looking as a fuzzy caterpillar – cannot be a good way to go, in a world that increasingly needs calm, unstressed people with conservation ethics.
If you are a fan of Canadian neuropteroids, your bucket list should include a trip out west to see one of our best selling points: the Raphidioptera, or snakeflies. The most common of these are in the genus Agulla, and this morning I found several female Agulla when out for a walk at Mt. Tolmie in Victoria.
One of the most surprising things I have learned about snakeflies over the years is that the larvae have a very effective reverse locomotion that allows them to quickly back away from danger. Check it out:
The following is a guest post by Staffan Lindgren
When I was about 10 years old I won a competition in a hobby magazine, which landed me a nice race car track. Since then I have not won anything, really. Yet, I consider myself a lucky person, not only because of a great family life, but because opportunities have always seemed to pop up just when I needed them. But looking back, I would say that my luck was in large part self-made. Over the years, I had made sure I had summer and temporary jobs that gave me appropriate experience, e.g., as a substitute teacher, forest regeneration surveyor, etc.
When I was doing my undergraduate degree in Sweden, the course offerings in the fall of 1973 were not to my liking, so I landed a job as a research assistant to a PhD student studying spiders. But the reason I did, was that I had a longstanding interest in spiders, so I had connected with the student long before that. For example, as a 12-year-old, I wrote to Professor Åke Holm, Uppsala University, after reading a newspaper article posted on a board in my English teachers classroom. Dr. Holm was then Sweden’s pre-eminent spider taxonomist, and had published my first spider book (Holm 1947). His kindness and encouragement has served as a model for me throughout my career. After I graduated with my undergraduate degree, I made a misguided attempt at a PhD in medical endocrinology, studying testosterone secretion in rats. Apart from five small publications (Carstensen et al. 1976, Lindgren et al. 1976, Damber et al. 1977a, Damber et al. 1977b, Bergh et al. 1982), I came away with a bruised ego and a severe allergy to rats.
After my failed 2-year forage into mammal reproductive physiology, I realized that I needed to re-focus on my first love, which was entomology. The first thing I did was to contact (by which I mean that I wrote a letter ) Dr. Bertil Lekander, professor of forest entomology at the Royal College of Forestry, Stockholm, Sweden. He offered to take me on as a special interest student in the two forest entomology courses offered to future foresters. To make a long story short, this led to a life-long association, albeit informal, with Swedish forest entomologists. For example, I published my Master of Pest Management Professional Paper as a Forest Entomology report (which also has a long story associated with it, the main lesson of which is the old adage “It’s not what you say, but how you say it”), and I had the privilege of spending 6 months as a visiting scientist at SLU in Uppsala in 1993 thanks to the connections I made there. Nevertheless, a few courses did not lead to a specific job, so once that was done I was once again without a firm direction in life. Because I had made many friends and connections in the Department of Ecological Zoology at Umeå University, in part through the spider job, but also through volunteering every spring and fall on an annual 4-day microtine rodent survey (Hörnfeldt et al. 1986) I got wind of a 4-month Teaching Assistant position in the Department of Health and Environment, which I was offered (notably in competition with another future entomologist, Anders N. Nilsson, who became a world authority on aquatic beetles). This position involved leading a class trip to the Soviet Union, among other things.
At the end of that position, I had started the proceedings to go to Canada, which ultimately led me to where I am today. Again, this was not something that happened by accident. In 1968-69, I spent a year in central Michigan as a high school exchange student. This was an extremely formative experience for me. It made me confident that I could succeed in an English-speaking environment, and it shaped me politically (it was the height of the Vietnam War, two political assassinations , Martin Luther King, Jr. and Robert F. Kennedy, Jr., had happened earlier in 1968), and there were significant racial tensions throughout the US. Anyway, I had become convinced that applied science was the only worthwhile pursuit in terms of education (see my earlier post here), and had found the Centre for Overseas Pest Research, a British organization. (Remember that there was no Google or internet, so all of this was done through libraries and by asking for information by mail). I received a letter back that they could only offer employment to “British subjects”, but they passed on a brochure about the Master of Pest Management program at Simon Fraser University. This seemed like the ticket to my future, so I wrote to SFU. The response was positive, so I decided to apply. But I needed funding. Fortunately for me, I managed to land a fellowship from the Sweden-America Foundation, and in combination with the relatively generous student loans from the Swedish Government, I all of a sudden found myself in a position to go to Canada! And the rest is history, as they say!
What does this history of my formative years have to do with luck? I truly believe that some people have more luck than others. When you buy a lottery ticket, the odds are fixed. But in the job market, including academia, you can change the odds in your favour, at least to some degree. The points I take home from the experience I have accumulated over my career are:
- If people know you, they will pass on information that may lead to your big break.
- Treat people with respect, i.e., treat them the way you wish to be treated. If you are well liked and respected, it will make a difference when you are looking for references or recommendations. This is particularly important when dealing with workers. I found that by showing an interest in, and respect for, their experience and knowledge rather than acting superior, you gain their trust and respect, and they will welcome your opinion.
- Don’t hesitate to seek help or advice from professors, no matter how eminent or important they are. In entomology in particular, I have been amazed at the kindness and generosity I have encountered from people really had nothing to gain by responding or talking to me. The worst that can happen is that you don’t get a response, or one that makes you steer clear of that individual (which has yet to happen to me).
- We all have weaknesses. Work on them. I used to shake like a leaf when having to address an audience. Some of the best scientists and public speakers I know suffer from extreme nervousness, but they have learned to cope with it. If you suffer from nerve problems, seek help, or at least give yourself experience. There are tricks to help you, and you’d be amazed how experience helps!
- Never, ever pretend you know something you don’t. Honesty always pays off in my experience.
- Finally, and most importantly, follow your heart. If you are passionate about what you do, you are more likely (and able) to build experience, which in turn becomes as important, or more so, in a job interview.
These are some ways to “make you lucky”. Just like an athlete has to put time and effort into achieving their goals, we do as well.
Best of luck!
Bergh, A., J.-E. Damber, and S. Lindgren. 1982. Compensatory hypertrophy of the Leydig cells in hemiorchidectomized adult rats. Experientia 38:597-598.
Carstensen, H., S. Marklund, J.-E. Damber, B. Näsman, and S. Lindgren. 1976. No effect of oxygen in vivo on plasma or testis testosterone in rats and no induction of superoxide dismutase. Journal of Steroid Biochemistry 7:465-467.
Damber, J.-E., H. Carstensen, and S. Lindgren. 1977a. The effects of barbiturate anesthesia and laparotomy on testis and plasma testosterone in rats. J. Ster. Biochem. 8: 217-219.
Damber, J.-E., S. Lindgren, and B. Näsman. 1977b. Testicular blood flow and oxygen tension in unilaterally orchidectomized rats. Experientia 33:635.
Holm, Å. 1947. Svensk spindelfauna. 3, Egentliga spindlar. Araneae Fam. 8-10, Oxyopidae, Lycosidae och Pisauridae. Entomologiska Föreningen, Stockholm, Sweden.
Hörnfeldt, B., O. Löfgren, B.-G. Carlsson. 1986. Cycles in voles and small game in relation to variations in plant production indices in Northern Sweden. Oecologia (Berlin) 68:496–502
Lindgren, S., J.-E. Damber, and H. Carstensen. 1976. Compensatory testosterone secretion in unilaterally orchidectomized rats. Life Science 18:1203-1205.
© Copyright – Entomological Society of Canada