Tag: insect

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Top 20 Photos 2013-2020

1. The Pale-Painted Sand Wasp (Bembix pallidipicta)

Subject: Pale-Painted Sand Wasp* (Bembix pallidipicta)

*this species doesn’t have a common name, so I created this common name by using the etymology of its scientific name “pallidipicta” which seems to mean “pale-painted”.

Location: Parents’ Farm, Norfolk County.

Date: July 2013.

For an Introduction to this series (my Top 20 Nature Photos of 2013-2020) go here.

The Story Behind the Shot: While growing up, my brother and I discussed several times the idea of a project: to list every single species that occurred on our family’s property. While this project never reached fruition, the idea of it has inspired me throughout my adventures with the creatures in my own backyard and elsewhere. One day several years ago I spent a day just wandering around on my parents’ farm taking photos of every interesting creature that caught my eye. I was amazed to find busy little wasps digging burrows in the sand at the edge of the field. Despite their frenzied activity I managed to capture one at the entrance of its burrow.

The Story Behind the Species: Bembix pallidipicta is one of those Sand Wasps (members of the subfamily Bembicinae) I’ve mentioned once or twice on my blog about a year ago now. The following information on this species is summarized from Evans and O’Neill (2007).

Not all Sand Wasps construct burrows in sand, but B. pallidipicta does, usually selecting large areas of loose sand to begin their burrowing. Nest site selection is fine-tuned in that they require a small amount of moisture in the sand to maintain a fine crust when they tunnel beneath it. The sites where the females emerge and the males mate are often suitable for the females to use for their nest construction, so unless the habitat is disturbed the same site can support a population of sand wasps for multiple generations. B. pallidipicta males gather around sites where adult females will soon emerge, and fly in short hops, which gives the appearance of “aggregations of very small toads” (Evans 1957).

Once their burrow is constructed with a chamber up to 56 cm beneath the surface (the depth is partly determined by the dryness of the sand), the females lay a single egg at one end of the chamber (termed the brood cell). This egg will hatch and the wasp larva will wait within its subterranean chamber for its mother to provide food. B. pallidipicta exhibits what is called “progressive provisioning” which means that the mother brings prey in multiple times to the larva while it is growing and feeding. I’ve always loved this aspect of sand wasps because it’s essentially the same setup as songbirds awaiting worms in their nests. For B. pallidipicta, the prey is all true flies (Order Diptera) of several Brachyceran families, including Flower Flies (Syrphidae), Horse Flies (Tabanidae) and House Flies (Muscidae). When bringing fresh prey to her larva, the mother will push the fragments of partially eaten prey off to the side, and block this debris off with sand. This likely helps prevent parasites or diseases from accumulating within the nest, or it’s possible that it’s a way for the mother wasp to judge how much more prey to provide. Because B. pallidipicta nests in large unrelated groups, females will occasionally steal prey from other females nearby to feed their own offspring. After about 4 days of feeding, the larva pupates and the mother moves on to construct a new nest.

Another view of the same individual Sand Wasp entering its burrow.

My top 20 Nature Photos of 2013-2020 are going to be presented in chronological order of when I took the photos, they aren’t arranged in any other sort of hierarchy. Come back next time for a photo of a much larger animal caring for its young…

For previous posts about Hymenoptera, see:

-Cuckoo Wasps and Carpenter Bees

–The Sand Wasps, Part 1: Introduction

-The Sand Wasps, Part 2: The Tribe Alyssontini

–The Social Biology of Wasps (Book Review)

–Species Profile: Introduced Pine Sawfly

References:

Evans, Howard E. Studies on the Comparative Ethology of Digger Wasps of the Genus Bembix, cited in Evans, Howard E. and O’Neill, Kevin M. 2007. The Sand Wasps: Natural History and Behavior.

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

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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.

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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.

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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

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 its 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 Syrphine 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.

UPDATE NOVEMBER 2021: Near Point Pelee, Ontario, individuals of Ocyptamus fascipennis were observed apparently migrating. The flies were observed moving East to West along with several other insects including tens of thousands of potter wasps (Ancistrocerus adiabatus) (Skevington and Buck 2021). The authors of the paper note that insect migration is a largely understudied phenomenon, especially in North America, so further study is needed to figure out the details.

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.

Skevington, Jeffrey H., and Buck, Matthias. 2021. “The first documented migration of a potter wasp, Ancistrocerus adiabatus (Hymenoptera: Vespidae: Eumeninae)”. Canadian Field-Naturalist 135 (2): 117-119.