Silv-E-Blog

In some parts of Eastern Europe it is considered good luck to find a spider or a spider's web on your Christmas tree, and small spiders or spider web ornaments are used to decorate it. A number of stories exist to explain this, including from Ukraine, Germany, and Poland.

The Ukrainian version of the story tells of a poor widow doesn’t have the money to decorate her tree. Her children wake up early Christmas morning to find the tree covered with spider webs. When they open the window, the suns rays touch the webs and turn them into gold and silver. The widow and her children are never poor again. To remember this miracle, trees are decorated with artificial spider webs to bring good fortune in the coming year.

In a German version of the story, the house was thoroughly scoured for Christmas and the spiders had fled to the attic to avoid being swept up during the cleaning. On Christmas eve, the tree was decorated and the spiders decided to have a look at it. Since the spiders were small, they needed to see the tree up close, and because the room was very bright, they had to crawl all over every branch of the tree in order to see the decorations. The spiders left, but their webs remained behind. Later, Father Christmas found the tree covered with webbing, and since he liked the spiders so did not want to remove it, but wanted to please the family so turned the webs into silver.

Polish folklore tells that a spider wove a blanket for baby Jesus, so spiders or spider webs are common Christmas tree decorations, and spiders themselves symbols of goodness and prosperity at Christmas.

Male bees and wasps do not sting. Only females have a stinger, on organ evolved from an ovipositor, an egg-laying organ. Stingers are used to perform a number of functions including defense, attack, food procurement, injecting venom for the purposes of paralysing or controlling its prey, and cutting.

Primitive wasps, such as sawflies including woodwasps, use their serrated ovipositor to saw into plant tissue and insert their eggs into plants. Some species of sawflies also use venom – Sirex woodwasp (aka Sirex noctilio) lays eggs in tunnels that it bores into pine sapwood, and in an adjacent tunnel it injects a phytotoxic mucus along with a white rot fungus, which stress and eventually kill susceptible trees. The mucus and fungus condition the wood for the hatched larvae to feed on.

Sirex woodwasp Photo: Kathleen Ryan

Glands associated with the ovipositor have evolved in parasitic wasp species to produce venom that makes it easier to procure food, by making its prey easier to manage or allowing it to preserve food. Some wasps, such as mud daubers, use venom to paralyse their prey. A female mud dauber leaves several paralysed insects or spiders with its eggs, which the offspring feed on when they emerge from the egg. Similarly, jewel wasps inject a mind-controlling neurotoxic venom into the head of its cockroach prey. The “zombie” cockroach is then led to a chamber where the wasp lays an egg on it and seals both into the chamber. When the larvae hatches, it feeds on the roach. By paralysing the prey rather than killing it outright, it is preserved as a food source.

 Mud dauber wasp Photo: O.P. Sharma, Bugwood.org

More recently, the ovipositor evolved to a stinger which, along with the venom, is used for defense. Most bees use pollen as a food source, so don’t require a stinger for food procurement.  Male wasps do not have stingers, but some do have spikes at the end of their abdomen which they can use to jab their enemies, but it does not inject venom. Otherwise, male wasps can’t defend themselves directly, however, since they look very similar to female wasps, they are protected to some degree.

Yes, you read that right, some insects practice agriculture. Furthermore, insect agriculture began long before we humans established agriculture. Three distinct insect lineages, ants, termites and beetles, independently evolved the capacity to cultivate fungi. Over time, insects became dependent upon the fungi for food and the fungi, at least in some cases, evolved a dependency on insect farmers to sustain it.  

The most commonly known fungus farmers are the leaf cutter ants. There are several species of leaf cutter ants in South and Central America, Mexico and the southern US, but in more northern climes you can see them in action at the Insectarium in Montreal. As with other ant endeavours, fungus farming is a community activity. Specialized forager ants have very large, strong mandibles that they use to cut up leaves, grass or flowers. Lines of foragers can be seen carrying the harvested leaves back to their nests – these trails of ants can move cut leaves over 30 metres across the forest floor, and up and over tree trunks and branches. The ants don’t actually eat the leaves that they harvest, they feed the new plant material to the fungal colony that is nurtured using an antimicrobial secretion to keep the fungus garden free from pests and molds. The resulting fungus is fed to larval ants.

Since the fungus has been isolated over time, underground within the ant nest where it doesn’t come into contact with other fungi, it has evolved to be completely dependent on the ants to sustain it; the species no longer exist outside of the ant colonies. The ants are also reliant on this relationship, when a new queen leaves the nest, she takes fungus with her to start her own fungus for her colony.

Have you seen carnauba wax listed as an ingredient in your gummy bears, and then noticed its also found in your car wax? Did they add car wax to the candy you ask yourself?

Carnauba wax is the wax from leaves of the carnauba palm tree from northeastern Brazil. The wax is secreted onto the leaf surfaces and functions to protect the fronds from water loss during the dry season. To harvest the wax, fronds are cut, sun-dried, and then the wax is removed by beating the dried leaves. Wax is then melted and filtered.

I saw this tree the other day – burls upon burls. Why does one tree have dozens of burls, while another has none? Let’s start with what a burl is.  A burl is an outgrowth from a tree. It is caused by some sort of stress – for example an injury or a pathogen. The tree’s growth hormones are disrupted by the stressor, and it produces these outgrowths. The burl itself doesn’t seem to harm the tree and the circulatory tissue within the burl still functions, though one would think this might be hindered at least slightly.

Stories of invasive tree-killing insects here in Canada are pervasive. Emerald ash borer, brown spruce longhorned beetle, Asian longhorned beetle and, more recently, hemlock woolly adelgid are just a few. The impact, both economic and ecologic, of many of these insects is, or will be, profound.

In the US, there has been an average of 2.5 new non-native forest insects per year over the past 150 years, and yet the chance of an alien insect surviving and establishing when it arrives here in North America is actually very low. There are few different reasons for this.  Environmental conditions may not be suitable for them - too hot, too cold, too variable - or they may arrive during unfavourable weather. They may not find an appropriate food source - either because there are no suitable food sources, or because they cannot locate it. Or, they may not be able to locate a mate. Alternatively, they may survive and reproduce but their populations remain low and they eventually die off. Even if they do establish, not all insects in a new range will become a problem. Many just join the insect community and never, or rarely, become noticeable. The probability of an insect becoming a successful invader is thought to follow the rule of tens, i.e., about one in ten introductions persist, and about one in ten of those become a problem. So, about one in one hundred introductions are problem insects. However, those problem invasive insects are often inordinately costly both economically and ecologically. Unfortunately, it is difficult to predict which invaders will be successful in establishing.

Most modern-day invasive insects arrive here accidentally. These insects primarily arrive with the importation or movement of materials: wood packaging materials (pallets, crates, spools etc) and live plant material (nursery stock) are the primary pathways, but also shipping containers, firewood, raw lumber with bark, Christmas trees, personal property and vehicles. Wood packaging material has long been an important pathway for movement of invasive insects and likely the source of emerald ash borer and Asian longhorned beetle introductions. Wood packaging is typically made of low quality wood which is often infested by insects. New wood packaging treatment protocols came into place in 2006 to reduce the risk this pathway poses (ISPM #15). These are measures taken in the country where the products are exported, and proof of treatment is required by countries receiving shipments. Since these measures were implemented, fewer shipments are found with infested materials, however some do persist. This could be because some insects survive the ISPM #15 treatment protocols, non-compliance (intentional or unintentional), or because the wood packaging becomes infested after treatment.

Although much of the risk of movement of invasive species is through trade and commercial movement of infested materials, individuals do play a part. Burning firewood where you buy it, and inspecting vehicles and contents for invasive species before you depart from a location play an important role in stopping the spread of invasive species.

Latex is the milky protective fluid found in a number of flowering plants. You may have seen it when you cut a dandelion or milkweed stem. It’s used by the plant as a defense against insects, and is exuded when the plant is injured. Latex is not the same as sap, in trees it is found just under the tree’s bark.

Commercial natural latex comes from the rubber tree (Hevea brasiliensis). Although synthetic rubber is now more commonly used, natural rubber production is still prevalent. Once produced primarily in the Amazon, 90% of latex now comes from Asia.

To harvest latex, a diagonal strip of bark is shaved from the tree (see photo) and the latex flows in to a collecting vessel. Every other day after, a thin shave is made just below the previous cut. This process ends when the shaved area reaches to about a foot above ground. A tree can be tapped when they mature at around 7 years and be tapped for up to 30 years, though more commonly for between 10 and 20 years.

Photo: Manfred Mielke, USDA Forest Service, Bugwood.org

It may sound surprising that flour can be made from tree bark, yet this staple food has been made this way for centuries by the Sami people of Northern Scandinavia. They began harvesting the soft inner bark from pine trees and grinding it into a flour when typical flours were scarce or unavailable - during crop failures, extremely cold weather, or even war. However, more recent findings suggest that the Sami people eventually began using pine flour even when food was plentiful.

The most common tree species used for flour is the Scots pine, so tree bark flour is almost always referred to as ‘pine flour’. However, birch trees may also be used, and are said to provide a beautiful red-ish hue to baked goods.

The process of creating pine flour involves harvesting the bark from already fallen trees or from living trees. The inner bark of a tree (the phloem) used for  flour is a living tissue that transports water and nutrients throughout the tree so harvesting too much of the bark from a live tree would cut off vital nutrient flow and eventually kill it. To avoid this, the Sami people cut very thin, vertical strips of bark off the tree, which looks like a ‘window’ in the trunk once the tree has compartmentalized the wound. After a swath of bark is harvested, the inner bark is peeled away from the outer bark and dried. It is then ground into a powder, and is ready to be used for baking.

Pine flour is not used alone in baking since it lacks the protein molecules found in conventional flours that hold the bread together. By adding pine flour into a baking mixture, the final product is often said to have a sharp but pleasant woody aroma to it.  

Even though pine flour is only used in small amounts, it is extremely nutritious. As stated by food manufacturer Nordic Revolve, 100grams, of pine flour has 84g of carbohydrates, 2.6g of protein, 3.3g of fat, 143 kcal, 400mg of antioxidants, and 55% of it is dietary fiber (2018).

If you are inspired to try making your own pine flour, visit the website Nordic Food Lab (http://nordicfoodlab.org/blog/2015/11/24/tree-bark).  

References  

Anna Sigrithur, A.  M. (2015, November 24). Tree Bark. Retrieved from Nordic Food Lab:  http://nordicfoodlab.org/blog/2015/11/24/tree-bark

Nordic Revolve.  (2018.). Pine Bark Flour. Retrieved from Nordic Revolve:  http://www.nordicrevolve.com/en/product/pine-bark-flour

Bark does a lot for the tree. The outer bark protects the tree from injury, fire, temperature extremes, desiccating wind, intense sunlight, disease, insects and animals. It is also part of the tree’s circulatory system - the inner layer (phloem) conveys nutrients from the leaves through the rest of the plant. The bark of certain tree species is, and has been, used by people for a myriad of purposes. Chemicals from the bark have been used for their medicinal properties – including curare (muscle relaxant used in surgery), quinine (malaria), salicylic acid (aspirin can be obtained from poplar and willow bark). Some bark chemicals are used in the treatment of certain cancers. Bark can have anti-microbial and anti-fungal properties so can be used for food storage. Bark sheets are made into prints, furniture, containers, canoes and homes. Strips of bark are woven into baskets and were used for clothing. We continue to use bark on a daily basis – two interesting uses are corks and spices.

Cork is harvested from the cork oak, native to Mediterranean Europe but primarily found in Portugal and Spain. The outer bark - the “cork” - is harvested every 9-10 years starting when the tree is 25 years old. This doesn’t harm the tree, and the bark grows back. Cork oaks are long-living – up to 250 years. After they are harvested from the tree, the cork bark planks are boiled to soften and clean them, and then flattened. Planks are graded and then are cut into smaller, more workable, pieces. Corks are punched out, high end corks by hand and the rest by machine. Only high-grade cork is used to produce wine corks, the rest of the plank is ground up to make agglomerate cork. Portugal produces 50% of the world’s commercial cork, and Spain just over 30%, the remaining cork comes from Morocco, Algeria, Tunisia, France and Italy.

Cinnamon comes from the inner bark of the evergreen Cinnamonmum species. There two Cinnamonmum species commonly used for commercial cinnamon. Ceylon cinnamon (Cinnamomum verum), most of which is produced in Sri Lanka, but also Brazil, the Caribbean, and India, and Cassia (Cinnamomum cassia) primarily produced in Indonesia, Vietnam, China and Burma. When the cinnamon tree is 2 years old, it is cut back (coppiced) to the stump. This causes numerous new shoots to grow from the stump. The shoots are cut, the bark is stripped, and the inner bark is sun-dried, the bark rolls up in to “quills” as it dries. Depending on the cinnamon tree species and the bark texture, the bark quills may be cut up into sticks or ground into powder. Cinnamon gets it distinctive taste from volatile oils in the bark.

In 2005 the European (Sirex) woodwasp (Sirex noctilio) was detected in Ontario. At the time, it caused great concern because it is a significant economic pest in other areas where it invaded and caused extensive mortality to pines. Now more than a decade since it was first detected, and likely much longer than that since it has first arrived, the woodwasp has caused minimal damage and most of its effects have been to trees that were already suppressed, stressed or dying.

Sirex woodwasp (Sirex noctilio). Photo: Kathleen Ryan

So, what makes the woodwasp relatively harmless here, when it is a significant economic pest elsewhere? One of the reasons is community. The woodwasp is native to Eurasia and northern Africa where it is a secondary pest of pine species; it only occasionally becomes an issue after drought or other tree stresses. In this region it has several natural enemies, including parasitoid wasps, nematodes and woodpeckers that help to keep the population in check. It shares the tree with bark beetles and other woodborers which may also function to limit woodwasp populations though competitive interactions. In the southern hemisphere countries where it has invaded, pine itself is not native; introduced pine species are grown in plantations for pulp. Because pine is chemically distinct, there are few native insects of these southern hemisphere forests that can use pine as hosts, so there is virtually no insect community on pine in the introduced range. That is fine, until an invader arrives and manages to exploit the situation, unchallenged by the natural enemies and competitors that are missing from these introduced ecosystems. In contrast, here in North America, there is a well-developed insect community on pine, and natural enemies of native woodwasps that can easily switch to the new host.

There are probably other factors as well - tree resistance, site factors and climate could all impact the woodwasp. A long-term study of pines in woodwasp infested stands in Ontario shows minimal tree mortality in some sites. Overall, two thirds of the pines attacked by the woodwasp survived over the course of the study. The authors point out the changing environmental conditions or events such as drought may change this. Time will tell whether this seemingly invader will cause a problem here. In the meantime though, it is looking relatively harmless.

Eating insects isn’t new, and outside of western countries its actually quite common. An estimated 2 billion people regularly consume insects, and not just when other food is scarce. It has never really taken hold here though. There are a number of reasons why entomophagy, the consumption of insects, never really established in temperate regions of the world – insects are smaller here, they usually occur in lesser numbers, and they are highly seasonal, so they weren’t necessarily available when they were needed. Until recently, insects were harvested from wild populations, now producers farm them to produced food for livestock, pets and people.

Worldwide, the most commonly consumed are beetles (31%), caterpillars (18%),  bees, wasps and ants (14%), and grasshoppers, locusts and crickets (13%). Depending on the type of insect, it may be the larval, pupal or adult stage that is eaten. Insects are consumed whole or processed into powder or paste.

Insects have a very high food value (high protein, fat, vitamin, mineral and fibre content) with low environmental cost. They have a high food conversion efficiency, use less space to rear and rearing generates fewer greenhouse gases and doesn’t require land clearing.  So, it makes sense that raising insects for consumption is now taking off. There a few producers in North America, including Entomo Farms in Norwood Ontario: http://entomofarms.com/

One of the more commonly used insects here for human food are crickets. They can be used whole or powdered and are often incorporated into baked goods. Crickets are high in protein and low in fat. Personally, I find mealworm larvae fried with some garlic are tasty!

Oak wilt is a vascular wilt disease, similar disease to Dutch elm disease, however, is much deadlier. It is a serious threat to oaks, however in many cases can be prevented. Oak wilt was first detected in Wisconsin in 1944 and is found within much of the central and eastern U.S. Oak wilt is not known to be in Canada at present, however its only 574m away - in Belle Isle State Park, Michigan.

Species in the red oak group (leaves with pointed tips - e.g. red, black and pin oak) are at greatest risk and tend to die quickly, usually within a year, and sometimes within a few weeks of infection. Species in the white oak group (leaves with rounded tips - e.g. white, swamp white, bur oak) tend to be more resistant and may show damage on only a few limbs for a time. White oaks can eventually succumb to oak wilt, but this may take a few years. Bur oak is intermediate in its ability to resist infection - some can resist infection, while others die quickly.

If the leaves on your oak tree turn brown and drop early -  in the spring or summer - you should have a closer look at the tree. In red oak, leaves wilt and turn brown starting from the top of the tree and the tips of the branches before spreading down through the crown. Individual leaves brown from the tips and margins inward. Affected leaves start to drop from the branches within about three weeks of infection. Tree decline begins as early as May, through to mid-summer. Infected red oak will die quickly after the onset of symptoms, usually within the same season and in as little as one month. Sporulating mats (pressure pads) develop under the bark of red oak in the fall on trees infected in spring or early summer, or the following spring for trees that are infected later in the summer. Look for bark cracks on the trunk or large branches of newly dead trees. Drumming on the trunk over a pressure pad produces a hollow sound compared to drumming over intact sections of the trunk. Pull off the bark around the crack or hollow-sounding region and look for an oval shaped area of fungal growth that has a fruity smell likened to fermenting apple cider, or Juicy Fruit chewing gum.

If you think you have found oak wilt, contact the CFIA's Plant Health Surveillance Unit

There is no cure for oak wilt, however, it is preventable. Refrain from pruning, harvesting, or otherwise harming oaks from April to August.

Did you know, Quebec is the only province or territory in Canada to have a provincial insect. Selected in 1998 by a public vote held by the Montreal Insectarium, the white admiral beat out a tiger beetle, a damsel fly, a bumble bee and the 12-spotted lady beetle to become Quebec’s unofficial insect.

Do you love cashews? If so, you are not alone - cashews are the most commonly eaten nut in America and Europe. They are expensive though, especially recently.

A cashew is the kidney-shaped seed that projects off the bottom of the cashew apple, the fleshy false “fruit” of the cashew tree. Usually seeds grow inside the fleshy part of a fruit (think applies or pears). So, the cashew apple isn’t actually a fruit, it’s a swollen stem. The cashew apple can be eaten raw or made into jams or juices, but we in North America are more familiar with the cashew seed. Cashew trees are native to the coast of northeastern Brazil, but are commonly planted in other warm, humid climates in Asia and Africa. Several countries export cashews including Vietnam, India, Nigeria, Indonesia and Brazil.

Cashew apples and seeds, photo: William B. Brown Jr, Bugwood.org

Unlike other tree nuts (e.g. walnuts, almonds, pecans, pistachios) cashews are more difficult to harvest and process. The fragile fruit is hand picked, so harvesting costs are higher than for other nuts. Cashews also require more processing than your average nut. The shell of the cashew contains toxins which be removed before the nuts can be sold for consumption, and the nut itself must be heat treated or roasted to remove the toxic residue left over from the shell. So, the “raw” cashews you see in the grocery store aren’t really raw, they have been heat treated during the shelling process. Roasted cashews on the other hand have been cooked twice – once during the shelling and then again when they are roasted.

So, to recap, there are a few reasons why these delicious treats are expensive:

Supply vs demand: There is a high demand for cashews but a limited     supply, so prices are high.

Manual labour: Cashews are harvested manually, so production costs     are higher than for nuts which can be harvested in an automated way.

Processing costs: Cashews require processing to remove toxins.

Emerald ash borer has made its way through much of southern Ontario, leaving millions of dead ash trees in its wake. Now there are two more invaders on our doorstep, that could have a similar impact on other tree species – hemlock woolly adelgid and oak wilt. More on oak wilt in an upcoming post.

Hemlock woolly adelgid (HWA) has been a serious pest in the eastern United States for many years, damaging and killing eastern and Carolina hemlock from Georgia to New York and New England states. Most infested hemlock are killed, in as little as 4 years in the southern part of its range and in 10 years or more in the north. It gets worse, HWA was found in several counties in southwestern Nova Scotia in 2017 and there is considerable hemlock mortality in some of the sites. HWA has been found in isolated locations in Ontario in the past, but all infested trees were removed and the adelgid is not known to be established in Ontario. However, it is very difficult to detect at early stages so it could already be here, or may arrive before long.  Be on the lookout, early detection allows more options for mitigating the insect's impact.

On infested trees, white woolly patches are seen on the underside of twigs near the base of the needles. They are easiest to see in late winter or spring when they are larger (March to May in southern Ontario). Have a look at the underside of the branches especially the younger twigs. Hemlock trees along streams or near bird feeders may be the earliest affected; HWA are often transported by birds. Also have a look at hemlock twigs that have fallen to the ground, you may see the adelgid there as well.

If you think you have found hemlock woolly adelgid, contact the CFIA's Plant Health Surveillance Unit. Because the adelgid can easily fall off infested trees onto you or your pets (or equipment if you are working in the forest), its important that you brush off yourself and your pets as you leave a site and launder your clothing before going out in the forest again, so that you don’t transfer the adelgid.

Mayflies, shadflies, fishflies. What you call them may depend on where you grew up. They should never be referred to as June bugs though, even though they appear in June, because that’s a different insect entirely. I grew up calling them fishflies, aptly named because the giant heaps of them that appeared under streetlights in the morning smelled like, well, rotting fish. The proper common name is the burrowing mayfly.

Mayflies are aquatic insects, living most of their life in the sediments at the bottom of lakes. We typically see them only when they emerge as adults. They have a very short adult lifespan – a day or two – they emerge, mate, lay eggs and die. They don’t eat as adults and don’t even have mouthparts. So the good thing is that they will never bite you.

Burrowing mayflies tend to hatch synchronously resulting in a mass emergence, so in a good mayfly year, numbers can seem overwhelming. The downside is that they can make roads slippery, and clog drains and gutters, and they don’t smell all that great. That’s it though, remember when I said they don’t have mouth parts? They don’t bite or eat your plants. Lots of mayflies are a good actually a good thing – mayflies are an indicator of the health of the lake bottom – if its clean and well oxygenated mayflies thrive, but low oxygen levels at the lake bottom, pollutants, invasive species and habitat destruction all impact the mayfly population.  

 Mayflies in the news:

Canadian town overrun by fish flies

What is a bite and what is a sting?

Insects bite or sting when they, or their colony or nest, is threatened. Or in the case of blood-feeding insects, they bite when they seek a blood meal. Insects bite with their mouthparts. Stinging on the other hand, is quite different. The stinger is found at the opposite end of the insect – at the end of the abdomen. When it stings, the insect injects a venom which can be quite painful. The stinger itself is a modified ovipositor (egg laying organ), so only females can sting.

Most stinging insects are in the Hymenoptera taxonomic order, i.e., bees, wasps and ants, but not all species in this group sting (at least not in the traditional sense, more on that in another post). In Ontario, insects that commonly sting include bees (honey bees, sweat bees, and bumble bees), wasps (yellow jackets, bald faced hornets (yes hornets are a type of wasp), and paper wasps) and European fire ants.

Some stinging insects, for example honey bees, have barbed stingers and can only sting mammals once since the barbs get caught under the skin of their victim and are torn off. More often, stingers are smooth, and can be used repeatedly even on the same victim. This is the case with wasps and most other bees including bumble bees; some wasps such as yellow jackets have barbed stingers, however the barbs are small and can be withdrawn from the victim without damage.

Insects that sting: bees, wasp and ants

Bees: Bees have fine hairs covering all or part of the body, though sometimes it is difficult to see this from a distance. They tend to have a more compact shape than wasps, and often (but not always) carry pollen on the outside of their bodies. Honey bees and bumble bees are social insects and live together in central nest where they cooperatively rear and defend the queen’s offspring. Honey bees and bumble bees are not aggressive but will sting if they are handled. Sweat bees have a range of social behaviours and can be solitary, social or something in between. There are several species of sweat bees, some metallic as in the photo and others non-metallic. Sweat bees are attracted to salt so will land on people on hot days. They will sting if handled.

Wasps: Wasp are smoother bodied and shiny, and generally more elongate in shape than bees. Although they do feed on nectar and pollen, they are primarily predators. There are three primary groups of wasps that commonly sting people: yellow jackets, hornets and paper wasps. Like honey bees and ants, these wasps are social insects and live together in a central nest where they cooperatively rear and defend the queen’s offspring. Wasps are typically more aggressive than bees, and all have smooth stingers allowing them to sting repeatedly. If the hive is threatened, they will sting en masse.

 Ants: Ants evolved from wasps, although most have since lost their sting. A few ant species, such as fire ants, retained their stinger. Similar to wasps, ants may be solitary or social, though the fire ants are social insects living in a central nest. The more aggressive Solenopsis fire ants originating from South America are not found in Canada, however the less aggressive (and less painful) European fire ant is found in eastern Canada. Like bees and wasps, they will sting when their nest is threatened.

Solitary vs social stinging insects.

Some stinging bee and wasp species are solitary (ie. they don’t live in a hive or nest), for example mud-daubers. Solitary stinging insects are typically not aggressive, although will sting if handled.

Social insects are typically more aggressive and will attack if they perceive that the nest is threatened.