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Life: What is it?

I’m going to do something a little bit different with this post. I’ve done a few “Species Profiles” in the past (the Introduced Pine Sawfly and the Eastern Band-Winged Hoverfly), and in those I’ve offered a brief overview of the groups those species belong to before focusing in on the species itself. In future, I’d like to zoom in on a species from a distance. Since all living things, from bacteria to Blue Whales, are part of one huge family tree (species have formed out of species) then all of life is related to a greater or lesser extent. So to start my scope as far out as I can, I’m going to begin with the broadest category of all: Life itself.

What are Living Things? You might be surprised to find that it’s actually quite complicated and difficult to draw lines around living and nonliving things. We can intuitively classify large animals (and by this I mean animals that can be seen without aid of a microscope) as living things. They eat, move and reproduce under their own power. Plants and Fungi are similarly easy to class as alive (though some life stages of Plants and Fungi lie on the border, such as seeds or spores). Although Plants and Fungi don’t behave in easily visible ways in our timescale, they still perform the same functions as Animals: reproducing, metabolizing and growing.

So maybe there isn’t a simple definition for life, but Living Things are still easily distinguishable because of a general sense. It’s just common sense that an Elephant is alive and a rock is not. If we bring the scale downward from the living organisms we can see with our own eyes into the rabbithole of microscopy we find that things are (as always) far more complicated. The simplest and perhaps most relevant example to bring confusion to our general sense of what is alive and what is not is… a virus.

I remember the first time I recognized the difference between a bacterial and a viral infection. The major difference from a patient’s point of view is that Bacteria can be treated (ie. killed) by anti-biotics. Anti-biotics literally means “anti-life”. Because Bacteria are alive they can be targeted by anti-biotic medicine. A viral infection is immune to anti-biotics. Viruses are not killed by “anti-life”. This is because they are supposedly not living. This is where the defining border of Life and not Life gets very very fuzzy.

Viruses come in many shapes and sizes and they affect animals and plants in a myriad of ways, but the reason they do any of that is because they exhibit behaviours which enable them to adapt and react to their surroundings in order to reproduce more of their kind. The description I just offered seems to suggest that Viruses are alive. It really depends on where you draw your lines. My Biology textbook from University states that “the characteristics of life that a virus possesses are based on its ability to infect living cells” (Russell et. al. 2010). So, no living cell, no life. A virus contains some portion of DNA or RNA (the information-coding substance that tells cells what proteins to make and how to make them), and sometimes a protein capsule or container. Again, from my Biology textbook: “They essentially highjack the machinery and metabolism of a living cell in order to reproduce. For this reason, most scientists do not consider a virus alive” (Russell et. al. 2010).

For an alternative view of viruses, here is a quote from a book dedicated to Viruses: “they [Viruses] are highly evolved biological entities with an organismal biology that is complex and interwoven with the biology of their hosting species”(Hurst 2000). In this book, Viral Ecology, the editor also recommends placing viruses within a fourth biological Domain of Life (the other three Domains are Bacteria, Archaea, and Eukarya). He proposes that this Domain be called Akamara which means roughly “without chamber”, describing the fact that organisms within this Domain are non-cellular.

I’m not sure where I sit on the issue of whether viruses should be considered Living or non-Living. The more I learn about them, the more complicated the questions and answers are. I think that intuitively I wouldn’t want to define Life by its components such as possessing a cell, but I also see the value in having strict definitions for labels even labels as amorphous as Life. The point I wanted to make with this diversion into Viruses is that Life is actually hard to define or describe and place within limits, even if on a larger scale it’s intuitively simple.

I don’t think I’ll really be delving into Viral Biology on my blog anyway as I personally prefer learning about organisms I can more easily observe, but it is a fascinating aspect and background for my interests in living things in general.

Next up… Animals, Plants, Fungi. They have to be easy to divide and define right?

References:

Hurst, Christon J. ed. Viral Ecology, 2000.

Russell et. al. Biology: Exploring the Diversity of Life, First Canadian Edition, 2010.

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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.

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Species Profile

Species Profile: Eastern Band-winged Hover Fly

Ocyptamus fascipennis

Ocyptamus fascipennis adult, spotted at Algonquin Provincial Park, August 2019

When you’re interested in insects, you’re always going to be running into something new. There is always one more creature that you have never seen before, one more behaviour you haven’t heard of, and that’s because insects are incredibly diverse. Today, I’m going to pick out just one of the many species of insects to zoom in on, and explore it’s story.

The species I’ve chosen is Ocyptamus fascipennis, or the Eastern Band-winged Hover fly. Let’s start from the top: Ocyptamus fascipennis is a “True Fly”, a member of the Order Diptera, which is a division of the Class Insecta. Diptera means “two wings” which gives you the easiest way to identify this group of insects when you encounter them. Almost all insect groups have 4 wings (two pairs) but these pairs of wings have been modified into very different structures in different lineages of insects. For the True Flies, one pair of wings still provides lift and flight, while the other has been reduced into tiny knobs known as halters. These reduced wings act as stabilizers, giving the flies the ability to perform aerobatic feats of agility (as I’m sure we’re all familiar with in House Flies (Musca domestica)). The halters of Diptera are more than just balancing beams, they’re actually sending complicated signals to the fly about its aerial position.

Ocyptamus fascipennis is part of a Family of True Flies called Hover Flies, or Flower Flies (Family Syrphidae). The Syrphids are common insects in gardens where they feed on nectar and pollinate flowers. Because of this habit, many species of Syrphids have taken on the appearance of more conspicuous flower visitors such as bees and wasps, in order to gain some protection from the classic warning colours of black-and-yellow stripes. O. fascipennis in particular seems to mimic solitary wasps or types of parasitoid wasps with its elongated and narrow abdomen.

So far, we’ve been talking about adults of these flies, but all insects go through multiple life stages, some more dramatically varied than others. Diptera undergo holometabolous growth which is a fancy way of saying that they have life stages that look very different from each other and one of those stages is a transformation phase which is mostly immobile. When young hoverflies (larvae) hatch from eggs, they look very different from the adults landing and lifting from flower petals in gardens. Larval O. fascipennis have no wings, and no legs, and are sometimes known by the name that many fly larvae receive: maggots. O. fascipennis larvae don’t consume garbage or dead animals, but instead are active predators, squirming across leaves in search of their prey: aphids.

Stephen Marshall, in his incredible book about Insects describes Syrhpine larvae hunting as this: “at night they move blindly among the aphids, grasping victims using typical maggot mouth hooks, then holding the doomed aphids up off the surface to consume the body contents.” (Marshall, 2006).

A Syrphine larva hunting a herd of aphids (photo credit: Christine Hanrahan)

It seems then that Flower Flies are very beneficial insects to have in the garden. They provide pollination for flowers, and their larvae consume plant-eaters such as aphids and related scale insects.

While I was unable to find very much information pertaining to Ocyptamus fascipennis specifically, one other member of the genus deserves special mention because of its interesting larval habitat: tank plants (Bromeliaceae). The Central American and South American species of Ocyptamus that inhabit these confined aquatic habitats (pools of water within the plant itself) ambush and consume other aquatic insect larvae that live in the plants alongside them. The larvae are even thought to use a paralyzing venom to subdue their prey (Rotheray et al, 2000).

All in all, Ocyptamus fascipennis and its relatives are fascinating flower flies with intriguing habits. I hope you’ve enjoyed taking a closer look at them today.

References:

Rotheray, G. E., M. Zumbado, E. G. Hancock and F. C. Thompson. 2000. “Remarkable aquatic predators in the genus Ocyptamus (Diptera, Syrphidae).” Studia Dipterolologica 7: 385-98. (full text available here: https://repository.si.edu/bitstream/handle/10088/17095/ent_FCT_89.pdf?sequence=1&isAllowed=y )

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

Marshall, Stephen. Flies: The Natural History and Diversity of Diptera. 2010.

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Welcome to my new Nature Blog

If you’re interested in the living things that inhabit this world with us, then you’ve come to the right place. I’ve always found it fascinating that there are so many different kinds of creatures, living out lives in different ways to us humans. In some cases, it’s difficult to believe that we share the same planet, let alone the same backyard. There are countless species that surprise and delight in your own neighbourhood, and there are many more around the world. I’d like to explore this diversity, and try to share my own excitement about these creatures, whether they are insects, fungi, plants, birds, mammals, or any of the other species that crawl, fly, swim, run or grow across the planet.

To do this, I’m planning on producing posts detailing a specific species or group of species to get a taste of what sort of creatures are out there. I will also occasionally post about my own observations (and photos) of species that I’ve encountered in my own travels in Southern Ontario. Another thing I’d like to do is review books that are relevant to learning about nature, as I have a personal library stocked with some great books about the diversity and wonder of life.

I hope that when you visit this blog you learn a little something, gain a greater appreciation for living things, and get inspired to pay a little more attention to the world of nature that’s all around us.