Categories
book review

Terns, by David Cabot and Ian Nisbet

I remember the first time that I saw a Tern in Southern Ontario, and believed that I was seeing an especially rare sighting. In my head at the time (this was almost ten years ago) Terns were oceanic birds that migrated huge distances across the waves, and were either in the middle of the Arctic Ocean, or amid stormy Southern seas. This idea of Tern distribution and migration was based on the only Tern species that I knew: the Arctic Tern (Sterna paradisaea) and even then only loosely. The Tern I observed flying and diving for fish in Waterford, Ontario was most likely not an Arctic Tern, but rather a Common Tern (Sterna hirundo). Since that perspective-changing observation, I have been looking forward to learning more about these beautiful birds. Thanks to this excellent book by David Cabot and Ian Nisbet, I now have a much greater grasp on Tern biology, ecology, and life history.

Terns is part of a long-running natural history series produced in the UK called The New Naturalist Library. These books are beautiful to look at, both outside and inside and I love having some of this series displayed on my bookshelf. The subtitle of the series is “A Survey of British Natural History” and I will admit to being originally concerned that the content of the books would be not very relevant to a naturalist on the other side of the Atlantic Ocean. For this book in particular, that fear was unfounded. While the focus is undoubtedly British and sometimes very explicitly so, the coverage of this book is extremely valuable to understanding Terns across the world.

The Collins New Naturalist Books are beautiful together on a bookshelf. This is my collection so far.

The book begins with a chapter titled “Terns of the World”, which gives a brief overview of what the authors consider the “true terns” which includes 39 species, and excludes the noddies (genera Anous and Gygis). This brings me to my first complaint in what I consider an excellent book: the use of scientific names (or lack of use). This first chapter is the only chapter to regularly use scientific names when mentioning related terns (ie. genera) or species. Some might find that scientific names break the flow of a book, and I’m sure that’s why it’s written without them later on (for the most part) but I find it incredibly helpful to have the scientific names referenced more often than once at the beginning of a book. I like to remember scientific names of species, it makes finding information about the species a lot easier, and it can even tell you things right in the name itself: members of a Genus are more closely related to each other than members of a different Genus. To use some Tern species as examples: the Arctic Tern (Sterna paradisaea) is more closely related to the Common (Sterna hirundo) and Roseate (Sterna dougallii) Terns (note the same Genus for all three species) than all three are to the Sandwich Tern (Thalasseus sandvicensis) (different Genus). I think the lack of scientific names in most chapters seems out of place given that the text is fairly in-depth and scientific. Even if they didn’t want the flow thrown off for most of the text, I would have liked it if they included the scientific names for the species that were the focused subject of later chapters (see below) even just in the chapter titles for easy reference. In any case, this first chapter does a great job of introducing the terns as a group, offering overviews of the various genera and setting the stage for the following chapters.

The next three chapters continue the theme of giving information on Terns as a whole, and not just the species that are common in Britain and Ireland. They are titled “Food and Foraging”, “Breeding Biology”, and “Migration”. All were full of fascinating information and surprises. “Food and Foraging” described the various ways that Terns find and capture prey (all Terns are predators of mostly aquatic prey except for the Gull-billed Tern (Gelochelidon nilotica) which feeds on mostly terrestrial prey). The chapter conveyed well the foraging strategies of Terns from their perspective, demonstrating how difficult it is for birds to find and catch fish out of water that is often deep. Something I never really considered before is how Terns depend on fish being closer to the surface than fish normally swim. There are various factors that bring fish within the top portion of the water, and thus within reach of Terns (and other aerial predators). One is currents forcing fish to move over shallower sections of a lake or ocean such as sandbars or reefs. But the authors state: “The most widespread factor making prey fish come towards the surface, however, is predatory fish chasing them from below.” Because of this, many Terns follow predatory fish in order to reap the rewards from their attacks on prey fish. This sort of dependence is the sort of behaviour and ecology that I find so fascinating: Terns and Tuna, two utterly different organisms in shape and lifestyle are connected through their use of common prey species. In this sort of way, all species are interconnected and it’s this sort of thing that ecology strives to document and understand. Through the use of photographs, illustrations, and excellent description Tern food acquisition is explored (including the always interesting kleptoparsitism, or food piracy).

This is the closest encounter I’ve ever had with a Tern, a Black Tern (Chlidonias niger) hovering near me in Long Point.

The following chapter, “Breeding Biology” describes the generalizations and variations on the ways Terns reproduce. Terns use impressive courtship displays both in the air and on the ground to attract and retain mates. I found the description of courtship-feeding (in which the male brings prey to the female) to be especially interesting, summarized nicely by the authors: “Thus, the function of courtship-feeding evolves gradually from advertising the male’s proficiency, through attracting a mate, establishing and cementing a relationship, to provisioning the female and providing the nutrition required for making the eggs.” Once the pair is established, both partners incubate the eggs, feed the chicks and guard them, though males are more likely to provision more often both the female and the chicks (probably because of the continuing courtship-feeding described above).

The final chapter in the broader overview section of the book is all about Migration. My vision of Arctic Terns being exotic oceanic birds crossing the globe is actually not entirely inaccurate. Some populations of Arctic Terns spend the northern summer breeding in the Arctic, and spend the northern winter in the Antarctic, literally crossing from the top of the world to the bottom. It’s mentioned that because of this incredible world-spanning migration: “These birds would experience more daylight in the course of a year than any other animal.” (p 91). Despite these amazing journeys that inspire appropriate awe and interest, we know very little about how Arctic Terns actually migrate, or even their migration routes in detail. This is true of other Terns as well, though the picture is slowly resolving as we gain better technology for tracking bird movements. This chapter explains the current state of tern migration knowledge well and mentions where we are still lacking information.

The chapter following the overview chapters detailed above brings the focus more directly onto Britain and Ireland, as it’s titled “History of Terns in Britain and Ireland”. The chapter delivers on its title, including excellent historical illustrations. Not only does the chapter describe the population changes of the different species of Terns in Britain and Ireland over time, but it mentions some of the reasons (when known) for such changes, as well as various human interactions with these species. Mentioned several times through this chapter is the egg collecting and the methods of scientific collecting in the past (shooting dozens of birds per colony with guns instead of cameras), which obviously had negative effects on tern populations.

The main portion of the book (almost half, if you don’t include the Appendices and References) is made up of five chapters each of which is devoted to a single species of Tern, the five species of Terns that breed in Britain and Ireland. These are: Little Tern (Sternula albifrons), Sandwich Tern (Thalasseus sandvicensis), Common Tern (Sterna hirundo), Roseate Tern (Sterna dougallii), and Arctic Tern (Sterna paradisaea).

These species-focused chapters are thorough and engaging, presenting a detailed account of breeding biology, habitat use, and behaviour. There are specific details included about the populations within the region of focus (the British Isles) such as historical population trends and distribution. Despite this regional focus, the descriptions of tern behaviour and biology is applicable across these species’ range. The Least Tern (Sternula antillarum) is closely related to the Little Tern, and has been spotted in Ontario. Common Terns are widely distributed, also occurring in Ontario. Arctic Terns sometimes occur in Ontario as well. So 2 of 5 species occur both in the British Isles and my own region, and another is very closely related and similar to a local species.

This photo demonstrates better the colouration of Black Terns though it is further away.

Following the species-chapters is a chapter on Conservation, full of case studies and the description of various effects on tern populations in the British Isles, as well as the efforts to alleviate the negative effects.

The final chapter was probably my least favourite, only because I don’t live in Britain or Ireland. Chapter 12: “Vagrants, Passage Migrants, and Occasional Breeders” is aimed very specifically at the British Isles Birder, describing the rare tern sightings within the region.

To round off the book, there are a few Appendices which were good supplementary material on Tern Research and Population monitoring.

Overall, Terns is an excellent book about the biology and behaviour of Terns with a distinct focus on the species that breed in the British Isles. But don’t let your locality deter you from checking out this book if you are interested in diving deep into the world of these fascinating seabirds.

For previous book reviews, see:

Flora of Middle-Earth

Pterosaurs, by Mark Witton

The Social Biology of Wasps

The Palaeoartist’s Handbook, by Mark Witton

Flies: The Natural History and Diversity of Diptera, by Stephen A. Marshall

Categories
book review

Flies: The Natural History and Diversity of Diptera, by Stephen A. Marshall

People are always going on about how Beetles are so diverse, biologists are always explaining to theologians that God must really love Beetles*, and whenever anyone asks “What’s the most diverse group of organisms?” Beetles are always top of the list. UNTIL NOW.

*in case you don’t know the anecdote this is referring to, the earliest source (according to quoteinvestigator.com) runs thus: “There is a story, possibly apocryphal, of the distinguished British biologist, J. B. S. Haldane, who found himself in the company of a group of theologians. On being asked what one could conclude as to the nature of the Creator from a study of his creation, Haldane is said to have answered, “An inordinate fondness for beetles.”” (Hutchinson 1959).

Stephen Marshall proposes in his magnificent volume on the diversity of flies that there are historical reasons why beetles are held up as so diverse when the truth is that they might just be more closely studied than other insect groups… other groups like the order Diptera (true Flies), for instance. And if you read through this 600 page volume loaded with superb photographs and covering every single family of flies in some detail you will come away with the powerful impression that Stephen Marshall is on to something. Flies, a group often neglected because they don’t always photograph well, many look very similar to each other, and a lot of them have distasteful feeding habits, are showcased as the hyper-diverse evolutionary marvel that they are.

Metallic Green Long-legged Fly (Condylostylus sp.), photographed in my backyard, June 2018. I’m just going to post some of the many interesting flies that I’ve photographed myself throughout this article. Stephen Marshall mentions that digital photography is opening up the realms of entomology to amateurs in a way that hadn’t been possible in the past. I wholeheartedly agree!

The book’s first part: “Life Histories, Habits and Habitats of Flies” runs through a sampler of what flies do as larvae and adults. This includes the life cycles of Diptera in general, but elaborates on more specific groups where appropriate. Other sections in this part describe flies interacting with plants, fungi, invertebrates and vertebrates. This entire section comprises about 90 pages and goes into considerable detail on specific guilds* such as the worldwide coastal communities of “wrack flies”, flies that have larvae that feed within decomposing piles of seaweed washed upon shores. Along with the various interactions between flies and invertebrates, this section also includes a discussion of the many human diseases caused or carried by flies such as mosquitoes (Family Culicidae) or house flies (Musca spp.).

*A guild is a group of animals that are united by a common feeding strategy or resource use, but not necessarily united in relatedness. For example, flies from different branches of the Dipteran family tree are considered part of the leaf-mining guild if their larvae produce mines in leaves.

Eutreta novaboracensis, a Fruit Fly of the family Tephritidae, photographed in my backyard, June 2018.

The second part of the book is titled “Diversity” and reading through this catalog of fly families and subfamilies truly does drive home just how incredibly diverse the Order Diptera is. Each chapter covers a large portion of the fly family tree and opens with a diagram of the proposed relationships between the fly groups within. This opening section of each chapter moves from family to family, and describes the basic characteristics of each group detailing subfamilies where possible as well. Within these descriptions are not just lists of characters used to distinguish one family from another but also the basic biology of each group when known. A couple of key things to note here: even when dividing up the flies into smaller and smaller groups it can be hard to generalize because you are still dealing with huge swaths of species in some instances and in others you are simply dealing with species doing very different things despite their close-relatedness. Marshall does a good job of explaining this and I’ll provide an example here from the section on Tipulidae (the Crane Flies, of which there are more than 15 000 described species): “Although most larvae with known biologies are saprophagous and eat microbe-rich organic matter (normally, decaying plant material) in wet environments, some crane flies are predaceous, fungivorous or phytophagous… Some groups have become specialists in extreme environments such as caves, marine intertidal zones and deserts, but most occur in humid forests and wetlands. Most Tipulidae are unknown as larvae.” (Marshall 2012 p. 110).

Crane Fly (Tipula sp.) photographed on the Lynn Valley Trail, May 2018.

The above quote demonstrates the way in which Marshall overviews the lifestyles of the fly groups providing tantalizing glimpses of their diverse life histories, but it also provides an example of something that is rife within the 600 page volume: the overwhelming amount of flies or fly habits that are unknown. To demonstrate, here are some quotes from throughout the book (Marshall 2012):

Valeseguya rieki is known only from a single male specimen” (p 136)

“Larvae and larval habitats of the Lygistorrhinidae remain unknown” (p 141)

“Nothing is known of the biology of these obscure little flies [Ohakunea]” (p 141)

“adults of Oreoleptis (and thus the family Oreoleptidae) have yet to be collected in the field” (p 198)

“The 500 or so species of Acroceridae occur in every part of the world, but most are known from only a few specimens” (p 205)

“Essentially nothing is known about the biology of either Apystomyia or Hilarimorpha” (p 235).

“Even though signal flies [Platystomatidae] are usually conspicuous and attractive flies, many species remain undescribed.” (p 332).

“Larvae are unknown for most species in the family [Lonchaeidae] and little is known about behavior” (p 335).

“The biology of most Pallopteridae species remains unknown” (p 339).

“The truth, however, is that we know almost nothing about the life histories of these bizarre flies [Ctenostylidae]” (p 340)

“Nothing is known about the biology of this group [Nothybidae]” (p 348)

“Despite a worldwide distribution, with about 140 known species spread over every zoogeographic region, not much is known about asteiid biology.” (p 363)

“Nothing is known of the biology of the Neotropical dwarf fly genera [Periscelididae]” (p 365)

The quote list above is not comprehensive, but rather a sampling to show some of the many groups of flies that are mysterious despite their ubiquity in some cases. I don’t want the quotes above to be taken as evidence that the book contains little in the way of information on the flies of the world, seeing as so little is known overall. On the contrary, this volume is chock-full of biological details found nowhere else except the specialized literature and I found myself blown away by many intriguing and fascinating descriptions of fly families and subfamilies. Below are a few of the more interesting groups I had never encountered before reading through this book.

Frog midges (Corethrellidae) are attracted to singing frogs where the females feed on the frog’s blood. Some Phorid flies lay their eggs inside ants, where their larvae consume the ant’s head from the inside. After feeding within, the larvae decapitate the ants and pupate within the armored shelter before emerging as adult flies. These flies are known as ant-decapitating flies, and there are more than 300 species of them in the genus Apocephalus. Vermileonidae is a family of flies known as “wormlions” which are essentially the antlions of the diptera, their larvae constructing cone-shaped pits to trap wandering insects for prey. The Fergusoninidae is a family of flies that “develop only in galls induced by a specialized and codependent group of nematodes” (Marshall 2012, p 366).

Probably my personal favourite are the smoke flies. The smoke flies, platypezid Microsania spp., are attracted to fires (even campfires) but are rarely seen elsewhere. The smoke fly swarms are often followed by the predatory empidid dance fly Hormopeza which “seems to be a specialized predator of smoke flies. Like Microsania, the smoke dance flies are rarely seen except when they appear in plumes of smoke.” (p 298). I feel like the smoke flies, a group of species that can be attracted to something as common as a campfire, and yet are known from basically nowhere else (and thus poorly understood biologically) perfectly encapsulate the mystery and wonder of flies that I have gained from reading this book.

All of this fascinating information is found within the comprehensive and authoritative text, and after going through family by family in this fashion, each chapter in the “Diversity” section has a “photographic guide” portion which covers representatives of most subfamilies with further notes on natural history and significance of genera pictured. The scope of the pictures is mind-boggling and further bring home the diversity of flies, as well as their surprising beauty.

Transverse-banded Flower Fly (Eristalis transversa), photographed in my backyard, September 2018.

The final, shortest section covers collecting, preserving and identifying flies, and contains notes for those interested in starting insect collections of their own (as in, pinned specimens) as well as keys for identifying the major fly groups.

I can honestly say that if this book were published with only the text portions I would buy it because the text is just that valuable in overviewing the enormous diversity of the fly families. And I can also say that if this book were published with only the pictures and captions, I would also buy it for the incredible amount of biodiversity on display, captured in wonderful images of flies from around the world.

I cannot recommend this book highly enough. If you are an insect enthusiast, if you are at all interested in the diversity of life and if you enjoy gasping at revelations about the tiny wonders that flit around the world you have to read this book.

References:

Hutchinson, G. E. 1959. “Homage to Santa Rosalia or Why Are There So Many Kinds of Animals?” The American Naturalist93(870), 145–159. http://www.jstor.org/stable/2458768

Marshall, Stephen A. 2012. Flies: The Natural History and Diversity of Diptera.

For previous book reviews, see:

The Paleoartist’s Handbook, by Mark Witton

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

And for a podcast review, see:

The Field Guides

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.