Tag: hymenoptera

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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.

Categories
June 2021 Observations Nature Observations

Cuckoo Wasps and Carpenter Bees

Probably the most commonly observed insect group in my backyard (at least observed with my camera) is the Order Hymenoptera (the Bees, Wasps, Ants, and Sawflies). Partly this is because they are one of my favourite groups, and partly it’s because they make good subjects for photography, what with the bees and wasps having a tendency to land and sit still (momentarily) on colourful flowers. These are some of the pollinator visits I’ve captured this month: 

Unidentified Bee visiting my garden flowers.
Bee in the Genus Andrena.
I’m not sure what kind of Bee this is, but it’s coated in Pollen!
This is a Chrysis cuckoo wasp, which gets its young into other Hymenopterans’ nests, much like the Cuckoo Bird does in other bird nests.

This next backyard visitor looks like another Hymenopteran, but is actually a convincing Bumblebee Mimic, a Robber Fly Laphria thoracica pretending to be a Bumblebee. This mating pair zipped through the garden up into a tree, so I had to use the telephoto lens rather than attempting a macro shot.

Mating Pair of Bumblebee Mimic Robber Flies.

Not all Hymenoptera were zipping through the garden from flower to flower. Some were setting up their homes there. One such home was the thriving Pavement Ant (Tetramorium immigrans) colony under a large rock in the middle of our flowerbed. Whenever the rock is lifted, the exposed larvae are whisked away by frantic workers. The flurry of activity is like a living explosion of insects when the colony is uncovered.

Pavement Ant colony in my backyard garden, larvae and workers exposed under a rock.

The other fascinating Hymenopteran homebuilding was the infiltration of leftover dried stems by Small Carpenter Bees (Ceratina). I watched one digging into the middle of the stems and was able to get some decent pictures of the process. Unlike the Ants, these Bees don’t work together in a colony, each female constructs her own nest and provisions it with pollen. Despite this lack of cooperation, there is parental care within the Genus. Ceratina females guard their developing young by waiting at the nest entrance and will even open up sealed nest chambers to check on them (Wilson and Carril, 2016). Looks like I’m going to have to take a second look at those stems…

  • Small Carpenter Bee excavating her nest in a dried and broken twig in my garden.

References:

Wilson, Joseph S. and Carril, Olivia. The Bees In Your Backyard. 2016.

For other June 2021 Observations, see:

–Flies Falling to Fungi and Other Dipteran Observations

–Fuzzy Flies and Song Sparrows

–The Wonders of Wrens

–A Visit to Big Creek, Part 1

–A Visit to Big Creek, Part 2

And for other posts focused on Hymenopterans, see:

–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\

For more nature observations, photos and natural history facts, follow me on instagram at norfolknaturalist.

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.