Categories
book review

The Palaeoartist’s Handbook, by Mark Witton

I’ll start by saying that I’m no artist. And I have no intention of trying to become one in any form, let alone a Paleoartist (specializing in artistic reconstructions of living things known from fossils). That being said, I can heartily recommend this book to anyone interested in fossil animals, ancient ecosystems, or even just beautiful illustrations of both. The truly impressive quality of this book is that I can even recommend it to someone interested in living animals, as there’s much within that describes how living animals look and function and how that’s applied to the past.

The subtitle of this book is “Recreating prehistoric animals in art”, and the book essentially delves into the process of how one can look at fossils and interpret them into a fully realized organism. The first two chapters define Paleoart (= the subtitle of the book, see above), and go through a brief history of the genre. The history was quite interesting, demonstrating how interpretations of fossil organisms, and the methods used to examine and reconstruct them have changed through the years.

Chapter 3 is titled “Researching, Resource Gathering and Planning a Paleoartwork”. At first glance, this chapter seems to be aimed directly at one who is actually going to create Paleoart, and as I said earlier that’s not me! As with this entire book, however, the focus is on the research itself, and the animals themselves and the principles of imagining and portraying extinct life. So this chapter was actually quite interesting for myself, as someone looking for information on how we believe extinct animals looked. Additionally, there’s a table at the end which lists “Paleoart Memes” which was quite fun to read through. From Marine Reptiles being portrayed as almost fully exposed on the surface of the ocean to the constant violence and roaring of prehistoric creatures, this table is a compilation of ideas that are often repeated in Paleoart but are unlikely to be accurate portrayals of the animals involved. Of course prehistoric animals would have occasionally vocalised, and of course ocean-going animals occasionally spend time at the surface, but the constant repetition of these scenarios is what creates a false impression of the prehistoric world. Animals today don’t habitually yell at each other, especially not while pursuing prey. It’s counterproductive for a Lion to keep roaring while it’s chasing down a gazelle, just as it’s unlikely that Tyrannosaurs unleashed a scream every time they burst from cover after some hapless hadrosaur.

The next 5 chapters (comprising about half the book) are titled “Reconstruction Principles” with various subheadings. This section delves into the nitty-gritty of how we know what we know about extinct animals, and how to find out more. I appreciated the fact that these chapters, while dealing with reconstructing extinct animals, continually offered living examples of the principles being examined so that the ideas presented were always backed by living examples. We can’t KNOW what Tyrannosaurus rex exactly looked like and how it moved without a direct observation of the living animal (which isn’t going to happen without some real sci-fi intervention). We can KNOW what living animal bones tell us about their life appearance and behaviour, and so we can work backward from there. One of the big debates out there about dinosaur life appearance is the visibility of their impressively long and intimidating teeth. For so long dinosaurs’ teeth were prominently on display and exposed to the air and viewer. If we look at living animals, however, we can see that even enormous teeth, such as those of monitor lizards (various Varanus species), are usually concealed within lips most of the time. As with many of these ideas, they are speculative, but looking at the extent of features within living species of animals that we can actually observe help us to familiarize ourselves with the diversity of structures and behaviours and enable us to make better speculation about what extinct animals looked like. This is essentially the theme of this book, and it’s a case that is made wonderfully throughout with countless demonstrations of research on living animals’ correlates between bones and life appearance (as well as trackways, traces and even cave art).

Chapter 9 brings the principles we’ve explored through the middle half of the book to their logical conclusions: “The Life Appearance of Some Fossil Animal Groups”. Using the evidence we have from living species (some of which are related/descended from the fossil species in question), and fossils, Witton describes what many groups of extinct animals may have looked like in life. Absolutely fascinating stuff, this was a wonderful tour through an ancient and unreachable world. The groups covered are all Tetrapods (those ‘four-limbed’ vertebrates from Amphibians to Birds), which is understandable given that adding Invertebrates to the list would substantially extend the book. Some Invertebrates are briefly mentioned in the next chapter along with Plants and surrounding environment: “Recreating Ancient Landscapes”.

The final three chapters are the most artist-focused in the book, detailing how a Paleoartist can depict extinct animals and environments in evocative ways while still remaining true to the science involved. As I’ve said a few times now, I’m no artist, but even these chapters proved interesting reading with analyses of some of Witton’s personal reconstructions and how they may be accurate or inaccurate based on the evidence available.

Finally, I’d like to mention that the book is (probably unsurprisingly) chock-full of wondrous illustrations created by not only Mark Witton himself but a handful of other amazingly talented paleoartists. In addition to this wealth of beautiful paleoart (which in my opinion is worth buying the book for in and of itself), there are countless diagrams and charts that add so much to the presentation of the material. All in all, The Palaeoartist’s Handbook is a fascinating read, full of information about extinct and living animals and ecosystems and detailing how we know what we know about the past. We may not be able to visit past ecosystems in person, but with a book like this, we can begin to truly imagine what they may have been like.

For Other Norfolk Naturalist Book Reviews, see:

The Social Biology of Wasps, ed. by Kenneth Ross and Robert Matthews

Pterosaurs, by Mark Witton

Flora of Middle-Earth, by Walter Judd and Graham Judd

Categories
Natural Curiosities

Natural Curiosities, Part 1: Emu Feathers

My wife recently ordered me a bag of assorted natural curiosities from a seller on Etsy, Biophilia Supply. They sell ethically sourced nature items for use in decoration or education. In my case, it was for education. I’ve collected the odd natural curiosity myself from time to time (a few insect exuviae, a few dead insects, and a few fossils) and maybe I’ll write about some of those at some point in the future. The excitement of this Biophilia Supply grab bag of items was the variety and rarity of the items themselves. Through this series of posts I’m going to explore the items I received, and the organisms they came from.

Emu (Dromaius novaehollandiae) Body Feathers

Name Discussion: Dromaius novaehollandiae. Dromaius means “racer” in Greek, and the species name “novaehollandiae” is a Latinized version of New Holland, which is what Dutch explorers and sailors called Australia for a while in the 1700s.

Range, Relatives and the Ecology of a Flightless Bird: I have never seen an Emu, except maybe in a zoo, because they live across mainland Australia (though they used to also live on the neighbouring island of Tasmania). There also used to be two other species in the Family Dromaiidae (D. ater and D. baudinianus), but they were both island populations exterminated by humans in the 1800s. Their feathers have “barbs so widely spaced that they give the plumage a loose hairy appearance” (Davies 2002). I’m not exactly sure why Emus have hair-like feathers, but they certainly don’t need them to be stiff like the flight feathers of many other birds because Emus can’t fly. Emus can grow to almost 2 meters tall, and are the second tallest bird in the world, only behind the Ostrich. Emus are nomadic birds, traveling to places that have recently experienced rain and will gather in large numbers at abundant food or water sources. Although they inhabit the edges of deserts, they are always on the move to reach the most productive areas. Another adaptation for their dry and difficult habitat is to eat the richest foods they can find: Emus eat fruit and seeds as well as various species of insects.

Photo By JJ Harrison (https://www.jjharrison.com.au/) – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=92381514

Next up: Bison hair, Porcupine quills or the shed skin of a snake.

Reference:

Davies, S. J. J. F. Ratites and Tinamous, 2002.

Categories
Uncategorized

Swimming Squirrels

We tend to think of animals as “set in their ways”, following the pattern of their species and not varying in their behaviour or ecology on an individual basis. In fact, every species is made up of individuals. And once you start to think about it, of course this is the case.

People are often surprised to hear of diet variation, when wild animals feed upon substances that seem to go against their “pattern”. Crocodiles and Alligators will consume fruit, and could even act as seed dispersal agents (Grigg and Kirshner, 2015). White-tailed deer will eat nestling birds if they happen upon them. Chickadees will feed on dead mammals.

A recent observation reported in The Canadian Field Naturalist journal represents another of these striking behaviours that stands out because it is atypical for the species as a whole. The species concerned is one that many people are very familiar with: the Eastern Grey Squirrel (Sciurus carolinensis). There are already accounts of various Squirrel species hunting and feeding on other vertebrate animals, including birds and even other Grey Squirrels (ie. Cannibalism) (Squirrels as Predators, Callahan 1993). Perhaps more surprising is the recent report of hunting an animal that is outside of its normal environment: namely, a fish. In Guelph, Ontario, a Squirrel was seen to dive from a branch headfirst into a shallow portion of a river. After being underwater for a few seconds “the squirrel swam back to the snag with a fish 3-5 cm long in its mouth” (Sutton et. al. 2020). After feeding on the fish briefly, the Squirrel moved out of view into the woods.

There is so much out there to explore, in your own backyard or neighborhood. Animals are individuals, doing individual things. They are not programmed automatons following rigid beahavioural patterns. Even an animal as familiar and commonplace as the Eastern Grey Squirrel can surprise us if we take the time to pay attention.

Eastern Grey Squirrel at Waterford Ponds, Ontario.

References:

Callahan, J. R. Squirrels as Predators. The Great Basin Naturalist, vol. 53, no. 2, 1993, pp. 137–144. 

Sutton, A. O., M. Fuirst, and K. Bill. 2020. Into the drink: observation of a novel hunting technique employed by an Eastern Grey Squirrel (Sciurus carolinensis). Canadian Field-Naturalist 134(1): 42-44.

Grigg, Gordon and Kirshner, David. Biology and Evolution of Crocodylians, 2015.

Categories
sand wasps

The Sand Wasps, Part 2: The Tribe Alyssontini

The Wikipedia entry for the Tribe Alyssontini reads as follows: “The Alyssontini are a small tribe of small Bembicine wasps.”

And that’s it.

The lack of easily readable information about this group of Sand Wasps reinforces the vast diversity of life, that an entire group of insects with 65 known species (according to the Catalog of Sphecidae.) is so poorly known. To me, it’s exciting. What could each of those species be doing. What might their stories be? There are a few things I can say about this group, entirely gathered from the chapter about this Tribe in The Sand Wasps.

The Tribe Alyssontini are known for being adapted to cooler environments than many other Sand Wasps. Like many of the Sand Wasps, they collect Homoptera (Bug “hoppers”) of various families, mostly Cicadellidae (Leafhoppers). They make their nests in somewhat harder soil than many other Sand Wasps, and have relatively stout mandibles which they use to loosen this harder substrate for nest construction.

Alysson melleus female. Photo taken by Owen Strickland.
Alysson melleus male, photo by Owen Strickland.

For my Introduction to the Sand Wasp Series of posts, go here!

References:

Evans, Howard E. and O’Neill, Kevin M. The Sand Wasps: Natural History and Behavior, 2007.

Categories
sand wasps

The Sand Wasps, Part 1: Introduction

The Sand Wasps is composed from a manuscript left behind by Howard Evans upon his death in 2002, and expanded and completed by Kevin O’Neill (which is what Howard Evans intended with the manuscript). The book is a 2007 update on the natural history and behaviour of the Subfamily Bembicinae, gathering together information published since the 1966 publication The Comparative Ethology and Evolution of the Sand Wasps by Howard Evans.

Howard Ensign Evans was a world-renowned writer and entomologist, focusing on solitary wasps (that is, the wasps that aren’t eusocial). His non-technical books include a book titled Wasp Farm in which he explores the many species of wasps that live on his property at the time, and The Pleasures of Entomology, which describes several insect species and some of the people who studied them. Life on a Little-Known Planet is an excellent overview of just how fascinating insects can be if you take the time to look closer at them, and being published in 1969 contrasts the mysteries of this little-known world against the backdrop of the United States Space Program. In Howard’s opinion, laid out in the book, we would do better to explore the only planet with life because it still contains many mysteries for our curiousity. I couldn’t agree more with this sentiment.

My copy of Life on a Little-Known Planet, an excellent and entertaining book about Insect Natural History.

What are Sand Wasps? Sand Wasps are Wasps of the Subfamily Bembicinae (which is a subfamily of the Family Crabronidae). Most Sand Wasps, unsurprisingly, construct their burrows in sand, or other easily movable soils, but some utilize hard clay. In all cases (except for the brood parasites), they use their mandibles and legs to construct some sort of burrow in which they will raise their young. There are many variations on the nest construction process, which the book highlights time and again. Some species close their burrows, either temporarily while they are away from the nest seeking food for their larvae or eggs inside, and/or as a final cap to their nest. These closures are presumed to be a protective measure against parasites or predators of the vulnerable young wasps within. As a further defense, some species construct false burrows beside the true nest, simple tunnels in the substrate that don’t lead to the prey a predator or parasite may be seeking. Within the true nest, there may be one or several brood cells, offshoot chambers that contain the developing young (egg, larva, or pupa) and the prey provided for the young by the parent. Here there is much variation among species: whether the mother lays the egg in each brood cell before gathering prey for the larva-to-be, or if she places her egg on top of the first prey item, or atop the mass of prey she has gathered. The type of prey, how the prey is carried, and when the prey are brought to the cell all vary according to species.

In the following Posts, we’re going to look at the five Tribes of Sand Wasps, using the book The Sand Wasps as our main guide (it is, so far as I know, the only book like this for Sand Wasps), but utilizing other sources when needed.

References:

Evans, Howard E. and O’Neill, Kevin M. The Sand Wasps: Natural History and Behavior, 2007.

Evans, Howard E. Life on a Little-Known Planet, 1969.

Categories
Uncategorized

Happy Birthday, Norfolk Naturalist!

Inspired by one of my favourite blogs on the internet, Tetrapod Zoology, or TetZoo (http://tetzoo.com/), I’d like to create a birthday article every year- not for the day I was born, but for the anniversary of my blog’s creation. In this post, I’ll summarize the past year of my blog, as well as the story of Norfolk Naturalist leading up to the blog’s creation. So here we go…

My first Tumblr Blogpost featured this twig-mimicking Geometrid Caterpillar, spotted on the Lynn Valley Trail in Simcoe, Ontario.

NorfolkNaturalist Version 1

I’ve tried to start creating blog content many times over the years, but it would usually fall to the wayside of my routine. A few years ago, I created a Tumblr blog in which I wanted to post articles about my own nature observations: norfolknaturalist.tumblr.com. My first post was about Cryptic Caterpillars, and I went on to explore various nature topics through the creatures I had observed myself (usually attempting to do so within a timely manner). Sometimes they were focused on a specific aspect of nature, or a specific animal or plant, and other times they were set up as a slideshow of my trip to a Provincial Park (such as MacGregor Point or Algonquin), giving brief comments about the creatures I observed on my trips. My first tumblr post, Cryptic Caterpillars, was published in March 2018, and it was only a month later that I would acquire my most exciting new tool for nature exploration: a Macro Lens. Up to that point, my nature photos were taken with a telephoto lens, and for insects that meant standing far away and cropping the picture later. Sometimes these pictures hold up, especially for insects like Dragonflies and Butterflies, but my dreams became reality when I was able to photograph Springtails dwarfed by the head of a screw. I had also become a member of iNaturalist at the beginning of 2018. So the ability to photograph the smaller creatures I was so fascinated with, combined with the support and community identification of the amazing iNaturalist website, expanded my horizons as an amateur naturalist.

One of my greatest passions has been learning about the animals and plants and fungi in my own surroundings, and these tools allowed me to do so. My tumblr allowed me to share this passion and interest with others of like mind, and I was excited to be sharing my wonder at the nature that is everywhere.

After a year of posting once or twice a month, I stopped for a while, until in November 2019 I began this current blog as a new platform for sharing my interests and observations. Before we look at Norfolk Naturalist in its current form, let’s take a little detour to Instagram.

One of my most exciting finds ever: a Megarhyssa parasitoid wasp on the Lynn Valley Trail, Simcoe, Ontario. I will have to write a blogpost about this amazing creature sometime.

Observations of the Day

In late 2018 I began to post “Observation of the Day” pictures on Instagram under the profile “norfolknaturalist” (for my Instagram account go here: https://www.instagram.com/norfolknaturalist/). These pictures very quickly became “Observation of the Week” as I really wasn’t that fast at finding interesting creatures to photograph, taking pictures, editing the pictures and transferring them to Instagram. Especially since a lot of my identifications were awaiting confirmation on iNaturalist. These first few pictures (which were titled with their species name and location observed) were then superseded by pictures from my archive of nature photos taken over the years. These photos were posted with a fact about the organisms involved, which grew into my new formula for Instagram: picture of a creature, and a paragraph of interesting information about them. It was really at the beginning of 2020 that I started to post regularly on Instagram, and it was exciting to be doing so. I had accumulated over the years a variety of photos of interesting creatures from local trails in Simcoe, Ontario, as well as various Provincial Parks during camping trips. Reviewing these photos and learning more about the creatures portrayed within them, then sharing that information was quite fun, and I’m really glad I started doing this, and I’m thankful for all the support and interest I’ve received.

A Moose photographed in Algonquin Provincial Park this year. It’s just a nice picture I took of a charismatic animal.

The Current Blog (norfolknaturalist.ca)

I created and posted my first page on this blog, norfolknaturalist.ca, on November 30, 2019. (Welcome to my New Nature Blog) The first post was simply a quick overview of my interests, ideas, and goals with the website: namely, sharing my passion and interest in the amazing animals and plants that provide me with neverending fascination.

One thing I’ve always wanted to do is gather together as much fascinating information about an organism as I can into a post (sort of a mini-review of that creature). I’ve done this twice this past year, once with the Eastern Band-Winged Hoverfly (Ocyptamus fascipennis), and another on the Introduced Pine Sawfly (Diprion similis).

In December 2019, I visited Pinery Provincial Park and had some excellent encounters with some of the beautiful winter birds.

Besides Nature Observations and Species Profiles, I want to share my love of reading Nature books, and so I’ve published a few book reviews on my site as well. First was a Book Review of The Flora of MiddleEarth. Many of the books I read are textbook-ish and I’ve found it difficult to find reviews of some of them online because they aren’t designed to be read for pleasure. Sharing my experience diving into some of these books, and some of the fascinating information within is one of my goals with this site, and since that first Book Review, I’ve written two more: one for Pterosaurs by Mark Witton, and one for The Social Biology of Wasps, edited by Kenneth G. Ross and Robert W. Matthews.

And that brings us to the sum total of 7 posts in a whole year. Not very prolific at all. But there’s one very good reason for that.

In April of this year, my son was born. I haven’t been writing as regularly as I might be otherwise, distracted in the best possible way.

My goal for next year’s Birthday Article is that I’ll be able to summarize more than 7 posts, because I hope to write on my blog a little more regularly.

I hope you enjoyed my small tour through Norfolk Naturalist history and I hope you can return soon for some new content! I’ve got a few things in the works: Savvy Squirrels, Sand Wasps, and maybe even Salamanders!

Here’s an Eastern Red-backed Salamander (Plethodon cinereus) that I found this year under a log on the Lynn Valley Trail, in Simcoe, Ontario.
Categories
book review

The Social Biology of Wasps

by Kenneth G. Ross and Robert W. Matthews (ed.)

This book was published in 1991 so it’s certainly not hot off the presses but I’ve recently read it and thought it was worth a Review.

The Social Biology of Wasps is a collection of chapters written by different authors, which can sometimes make the book repetitive but for the most part this volume maintains a consistency of quality and focus that keeps the whole tied together.

The title of this book is key. As much as I would love “The Biology of Social Wasps” this book is more focused than that, instead detailing Social Biology of Social Wasps. The positive side to this focus is that it allows the subject of sociality in the vespids to be explored in great detail, but the negative result is that natural history and basic biology of most species is not discussed in any detail. In this book it allows a more focused discussion, but I would occasionally find it frustrating to find the asnwers to basic questions about the species discussed (what do they eat, what are their nests like, what’s a typical life cycle?) missing or mentioned only in passing in a way that made it difficult to connect some of the arguments of social theory with the species subjects of said arguments/theories.

The first half of the book is called “The Social Biology of the Vespidae”. The chapters in this section begin with two chapters detailing some background on the family tree of Vespidae (where the subfamilies fit) and a very brief overview of the solitary and presocial vespids.

The next six chapters overview the social biology of different groups of vespids. The first, Stenogastrinae, was fascinating to me because it was a group I had never heard of. Stenogastrines are also known as hover wasps and because they’re in the tropics they haven’t received as much study as the temperate wasps. A quote from this chapter will illustrate some of the fascination I felt: “Authors… described with wonder their hovering flight… their shy habits, and their strange, camouflaged nests hidden in the wet and dark parts of the jungle, hanging from roots and threadlike fungi along streams and near the spray of waterfalls.” Another highlight from the chapter on hover wasps was the illustrations of their varied nest architecture, which range from cells lined up in a stack along a stem to cells arranged in a ring, facing inward, creating a donut shaped nest.

There are excellent drawn illustrations through the volume, many done by Amy Bartlett-Wright. Amy is a scientific illustrator and artist who has been doing this now for 35 years. Check out her website: https://amybartlettwright.com/.

These chapters overviewing the subfamilies do well to illustrate what we know and what awaits further study in the social biology of these wasps. They often highlight similarities between strategies but also fascinating differences. One of the comments mentioned multiple times through the book is the influence that ants have had on wasp evolution, as there have been suggestions that they have driven many of the nest designs and defensive strategies of these insects by their relentless ubiquity. A quote that describes this: “There is no potential nesting site in the tropics that is entirely free of ants, many of which readily accept wasp brood as food. It seems likely that the Azteca-wasp nesting associations [an association where Polybia wasps nest inside the nests of Azteca ants, using them as unwitting guards against more dangerous ants] are only the most conspicuous examples of ant-wasp interactions, and that further study will reveal that swarm-founding wasps have as many “words” for ants as Inuit have for snow.”

As I mentioned earlier, these overviews could have done with a little more natural history in my opinion, but as the focus of the book is on the sociality of the wasps, the brevity of such information can be forgiven (the book is already 600 pages long minus the references section).

The second half of the volume is titled “Special Topics in the Social Biology of Wasps”. This half of the book is where repetition between chapters occurs, but usually it’s helpful rather than hindering. Most of the chapters take a particular aspect of the wasps’ biology and use it as a lens to view their sociality through it, demonstrating the various pressures or influences that piece of the puzzle has. For excample, three chapters in a row are about Nutrition, Genetics, and Nest Architecture. Each of these chapters looks at the Social Wasps through their particular focal point and illustrates how it could have provided an impetus for these insects to gain sociality, or at least start them on the path they’re on now. Because of this, it can be repetitive, but usually the repetition reinforces the fact that these are distinct, but not mutually exclusive influences on the evolution and maintenance of sociality. They should be looked at as pieces of the same puzzle, rather than all-encompassing explanations by themselves. One of the most intriguing chapters for myself was Robert L. Jeanne’s chapter “Polyethism” which convincingly demonstrated how individual behaviour can lead to sociality and even maintain it in the colonies of these wasps today, mostly through the comparison of direct reproductive fitness and indirect reproductive fitness.

The chapters on the nests of Social Wasps are fascinating as well, because a nest is something constructed not by an individual as in birds, but by a group of cooperating insects (in many cases, several generations of cooperating insects). These chapters are illustrated with some of the more bizarre nest arrangements (as well as the more familiar) and demonstrate some of the ways in which nest types could develop in relation to each other.

The chapter on the exocrine glands was not particularly fascinating to me, and felt somewhat out of place, since no other chapter dealt with physiology/anatomy of the subject species.

The final chapter, “Evolution of Social Behavior in Sphecid Wasps” was an excellent overview of Sphecid wasps’ social biology. This chapter gave plenty of examples of the diverse paths wasps have evolved down, and the many questions that are raised by viewing comparatively wasps and bees.

Because this book was published almost 30 years ago now, I’m sure that much would be updated and edited in a newer edition. Some of the questions raised will have been answered, many would have branched into further questions. I’m not a professional Social Wasp Biologist, and so I can’t say what those answers are, where the questions now lie, of the focus of such studies are now. I can tell you that as far as I know, there is no other overview volume like this one for Social Wasps. So if you’re fascinated by them like I am and can handle dense science writing, then dive in and learn to appreciate the incredible insect societies that blossom and buzz all around us.

Categories
Species Profile

Species Profile: Introduced Pine Sawfly

Diprion similis

Diprion similis larva at Algonquin Provincial Park, September 2019.

Sawflies are a group of insects that many people haven’t even heard of. Part of the reason is because, in appearance and behaviour, they are like a hybrid between two major groups: their larval stages look like caterpillars (larvae of Butterflies and Moths ie. Lepidoptera), and their adult stages look like bees or wasps (Order Hymenoptera). Despite appearances and lifestyle, it is the latter category that they actually fall under: Hymenoptera which also includes the Bees, Wasps, and Ants. The major features that set sawflies apart from their relatives is that they eat plants, and they don’t have the constricted “wasp waist”. You might find this a little confusing, as Bees certainly don’t have an obviously thin waist, but they actually do have a constriction between their thorax and abdomen, it’s just more difficult to see than in many wasp species.

Like many insect Orders, the name Hymenoptera refers to a distinct aspect of the members’ wings (‘ptera’ is derived from the Greek for wing). Hymenoptera doesn’t have an easy translation though, like say Diptera for the True Flies (di = two, ptera = wings). The beginning part of the word is either from the word “hymen” which means membranous, or from the word “hymeno” which refers to the Greek God of Marriage. Hymenopteran wings are membranous, but they also have tiny hooks that link their fore- and hind-wings, meaning that they could be said to be “married” wings as well (Grissell, 2010). Whatever the case, the group is one that includes thousands of species of wasps, bees, ants, and of course, sawflies.

The common name “sawfly” is describing the way the female sawfly lays her eggs. Instead of a stinger or stinger-like ovipositor (egg-layer) at the end of her abdomen (like most of the other Hymenopterans), the female sawfly has a saw-like ovipositor, a cutting tool that she uses to open up plant tissue, and then inserts her eggs within.

This is what the Introduced Pine Sawfly (Diprion similis) does to pine needles. D. similis prefers White Pine (Pinus strobus) as its host plant (in North America), but will lay eggs and successfully grow to maturity on several other pine species. The female lays about 10 tiny eggs inside a pine needle (Cranshaw, 2004). After inserting the eggs, the female seals them in with a secretion that hardens for protection (Wagner and Raffa, 1993). The larvae that hatch from the eggs begin to feed on the pine needles. For the first part of their life, they will remain together but begin to disperse as they grow older. These larvae prefer to feed on needles that are at least 1 year old, probably because the younger needles are full of more toxins (Wagner and Raffa, 1993). As they consume needles, they grow, from 2.5 mm long upon first hatching to almost 3 cm before the larva is said to be “mature”. They don’t grow continuously, but rather have to molt and enter a new size class each time they’ve gained enough nutrients. For female larvae, they have six growth stages between molts and the males have five (CABI, 2020).

During this time, you would be forgiven for thinking they were caterpillars, because they look very similar. The way to tell caterpillars from sawflies is to count the number of legs. Their first set of legs will be six, and jointed for both groups, but they will also have a number of legs behind these called “prolegs”. If the larva you’re looking at has more than 5 pairs of prolegs, it’s a sawfly. Another giveaway is the distinct single eyes of sawfly larvae, as opposed to tiny ocelli (miniature eyes in clusters) in caterpillars.

Once they’ve reached their final larval stage, they spin a cocoon around themselves with silk, and transform within. Diprion similis larvae prefer to form their cocoons in the pine trees where they feed, rather than on the ground like many other sawflies.

In Europe and most of North America there are two generations per year, which means that what happens next depends on what time of the year it is. If the larvae have grown enough and created their cocoons in the summer, they will develop within in about 2 weeks into adults, but if they have reached this point near the end of fall, they will enter diapause (essentially insect hibernation) for several weeks before emerging in the spring (CABI, 2020). When they emerge, the adult sawflies are entirely different creatures, just as butterflies and moths are very distinct from their caterpillar young. The adults have wings, and with these they search for mates.

Adult Male D. similis, displaying the feathery antennae used to track down a female (Photo credit: Scott R. Gilmore.)

Males are attracted to females by pheromones (a chemical signal between members of the same species), as one would guess by the male’s elaborate antennae. The males can be attracted to a female across 61 m of open field, which is a great distance for an insect only a matter of centimeters long (Wagner and Raffa, 1993). Once mated, the female lays eggs in pine needles, and we are back at the beginning of their life history.

One note about mating: it isn’t necessary for the female to mate to be able to lay eggs. She shares with the other Hymenoptera a bizarre (to us) chromosome setup known as haplodiploidy. Females have one set of chromosomes (the mother’s) and males have two (mother and father). What this means in practice is that a female sawfly can lay an egg that will develop into a fully functional male offspring without ever going through the trouble of mating. This has implications for the spread of such organisms, as not all members of the population need to pair up to contribute to the next generation.

Which brings me to my final discussion of this species: they are commonly referred to as the Introduced Pine Sawfly because they were accidentally introduced into North America from Europe, likely in plant nursery stock imported in 1914. They have become well established in North America since then. Thankfully, they only very rarely reach a high enough population density to be considered an “outbreak” invasive species, and though they feed on tree leaves (needles), many predators and parasitoids feed on them (Wagner and Raffa, 1993).

The last time we were camping at Algonquin Provincial Park, I encountered quite a few of their larvae likely because they were in the fairly mobile phase before finding a spot to spin a cocoon (it was the end of September, the beginning of October). They may be an introduced species, and they may feed on White Pines, defoliating some of the branches, but as with any organism, they have a story all their own, and I think it’s worth telling.

Diprion similis larva hanging onto the end of a pine needle in Algonquin Provincial Park.

References:

Wagner, Michael R. and Raffa, Kenneth F. Sawfly Life History Adaptations to Woody Plants, 1993.

Cranshaw, Whitney. Garden Insects of North America. 2004.

Marshall, Stephen. Insects: Their Natural History and Diversity. 2006.

Grissell, Eric. Bees, Wasps, and Ants. 2010.

CABI, 2020. Diprion similis. In: Invasive Species Compendium. Wallingford, UK: CAB International. www.cabi.org/isc.

Categories
book review

Book Review: Pterosaurs, by Mark Witton

Anyone who finds fossil animals fascinating will be delighted by this book by Mark Witton. The science is well-explained, yet in-depth, and the illustrations (photographs of fossils, skeletal reconstructions, and paintings) are incredible.

Pterosaurs begins with several overview chapters to bring the reader up to speed on the basics of pterosaur anatomy and terms, demonstrating some of what we know and what we don’t know about these flying reptiles. The majority of the book details each pterosaur group with a chapter. Here you will familiarize yourself with the ornithocheiroids, pteranodontians, and dsungaripterids. As with many dinosaur names, some of the scientific nomenclature can be a bit tongue-twisting, but by reading this book you will begin to tease apart the differences between pterosaur groups and so become more apt to recognize the names even if you have trouble saying them aloud.

Each pterosaur group chapter has a history of the group’s study, an overview of their anatomy (often highlighting differences and similarities between other groups), hypothesized locomotion (how each group of pterosaurs moved both on the ground and in the air), and ideas about the group’s ecology in the Mesozoic. The history of study was often interesting, seeing how a pterosaur group’s identity changed with new fossils or new ideas about old fossils. The anatomy sections are a bit difficult for myself to get through because I’m not a paleontologist and had to often reference the anatomy overview chapter at the beginning of the book. With the overview diagrams’ help, I was able to comprehend most of what was being described, at the least I was able to recognize the major differences between groups that were being highlighted. The sections on locomotion were fuel for the imagination, conjuring images of how these ancient creatures actually moved through their environments. Witton would often compare each groups’ purported flying ability to a modern group of birds to better convey their distinctive flying style. Of course much of this and the ecology sections are speculation, but Witton provides lines of evidence for and against various flying and feeding modes that have been suggested which brings to light what we know and what we don’t about how these animals lived. The ecology sections are my favourite because I love to imagine the animals as part of the Mesozoic environment, living their lives alongside the plants and animals of their time.

Along with the informatively dense but readable text are the illustrations which are amazing. For each pterosaur group there is at least one skeletal reconstruction of a species along with a fully realized painting of them launching. Besides these, there are photos and drawings of particularly well-preserved fossils. Accompanying each chapter is at least one full-page painting of a scene from the time of the pterosaurs, whether it’s Pteranodon diving into the ocean after a bait-ball of fish, or a Rhamphorynchid investigating a Jurassic snail. These paintings are wonderful at giving life and colour to the fossils and placing these creatures in their setting.

Sprinkled throughout the information-rich text is humour. My personal favourite is a caption for a painting of Azhdarchids which describes them as fleeing the next chapter about pterosaur extinction.

All in all, the book is a wonderfully informative, beautifully illustrated volume, full of descriptions and context for a group that doesn’t get as much press as the Dinosaurs. After finishing this book, you’ll be convinced that pterosaurs were an amazing and unique group of fossil animals as well, that deserve to be treated with the same amount of awe and wonder.

Categories
Uncategorized

Nature Observations: Pinery, Winter 2019

Pinery Provincial Park is a great place to visit any time of the year, and Winter is the season when you can get closest to a few of the bird species that make their home there.

We always bring along bird-seed to Pinery when we go in the Winter, because there are a number of birds that will come very close when presented with a nutritious food supply. Some (Black-capped chickadees and White-breasted nuthatches) can be induced fairly quickly to landing on your hand and feeding from it. This year, we were a bit early in the season and most of the birds except a few brave chickadees were too wary to feed from our hands. Despite this, we were able to feed many birds by leaving out a pile of seeds on the railing on our site (we were staying in one of the yurts they have there). If you’re planning to do this yourself, remember to not leave the birdseed out overnight. During the day, you will attract small foraging songbirds but at night, you’ll most likely be feeding raccoons, who can devastate snapping turtle populations in the park, if they overpopulate themselves.

The first birds we attracted to our food supply were the bold chickadees, ever-eager to exploit any opportunity available.

A perched Black-Capped Chickadee (Poecilie atricapillus)

Next came the nuthatches, with their impressive ‘talons’ which they use to grip bark as they scale down tree-trunks to pry out insect food.

White-Breasted Nuthatch (Sitta carolinensis)

Tufted titmice were quite abundant as well. I’ve never been able to feed one from my hand, but they were quite content to fling seeds about in the pile, picking out the ones they desired.

Tufted Titmouse (Baeolophus bicolor)

The final visitor to our railing was a downy woodpecker. Downys are the smallest woodpeckers in Canada, at approximately 15-17 cm (Backhouse, 2005). Still jabbing as though he were piercing bark, the woodpecker walked awkwardly along the railing. It truly appeared strange to be perched and moving horizontally, as they are so superbly adapted for their vertical orientation on tree trunks.

Downy Woodpecker (Dryobates pubescens)

Although only a few landed on our hands to pick at seeds, we were pleased to see these little birds foraging nearby, bringing cheer to the wintry woods of Pinery Provincial Park.

The view of the seed pile being visited by the winter birds.

References:

Backhouse, Frances. Woodpeckers of North America. 2005.