The Bumblebee nest boxes have arrived! Two members of HNPNC are participating in a citizen science project led by the University of Nebraska-Lincoln, researching how to build “better bumble bee domiciles”.
The boxes will be placed outdoors at the end of winter, before hibernating queens emerge and start looking for nest sites. We’re excited to get started, although at this point it’s a bit hard to believe that winter will ever come to an end!
The eastern migratory population of monarch butterflies is no more. Lepidopterists (butterfly and moth scientists) confirmed earlier this year, that the once familiar orange and black butterflies are essentially extinct. Their awe-inspiring north-south migrations, linking Mexico, the United States and Canada have ceased.
Most of us are old enough to remember when monarchs were a frequent sight in meadows and gardens. The monarchs’ demise was not unexpected. For decades, people in all three North American countries ratcheted up their assaults on these iconic insects. The monarchs’ overwintering sites in the oyamel fir forests of Trans-volcanic Mountains of central Mexico, while nominally protected, were steadily reduced in size by illegal logging.
Criminal gangs with the tacit assent of corrupt government officials plundered the forests under the cover of darkness.
At the same time, land use practices in North America conspired to reduce milkweed, the monarchs’ larval food plant. Round Up, a potent herbicide was sprayed on thousands of hectares of genetically altered “Round-up Ready” corn and soy, eliminating all of the milkweed in and around agricultural fields.
Homeowners throughout North America could have extended a helping hand by growing milkweed for monarch caterpillars and offering flowers with abundant nectar to the adults. Most people however, in thrall to their lawns, continued to primp and preen those biological wastelands at the expense of birds, butterflies and bugs.
The monarch is dead. No longer will it startle with its beauty. No longer will it inspire with its improbable journey from Canada to Mexico. And no longer will the imaginations of children be carried aloft on its gossamer wings.
In 2006 at a monarch overwintering roost in Mexico I met Lincoln Brower, a pre-eminent monarch butterfly researcher from the United States. He predicted that the eastern North American monarch – our monarch – had “about twenty years left”. I fervently hope he was wrong, but with populations this year at their lowest ebb ever, his dismal forecast may come true.
Where there are abundant sources of food, as is the case well illustrated above, there will be predators. I was amazed when I walked in the woods at night, searching for elusive winter moths, to see spiders on the snow surface at intervals of just a few feet. This was on a mild night (relatively speaking) and their sub-nivean burrows may have been flooded with snow melt.
I discovered that these animals are active all winter, mostly below the snow but also on the surface, and their major food is the snow flea. These spiders seem to have big “boxing gloves” that I thought might help them dig, but they are actually the male’s enlarged palpal tips used for copulation.
People manage their appearance with clothing, jewelry and hair styles to present a particular image of themselves to the world.
Deception is often involved. A muscled, leather-clad, tattooed man may be a powderpuff, but his fearsome exterior projects a formidable – “don’t mess with me!” – presence.
Insects are masters of this bluff. There is a vast array of harmless flies and beetles for example, that have evolved to look like dangerous bees and wasps. This allows them to conduct their business with openness and swagger instead of cowering beneath a leaf or skulking in the undergrowth.
But, like everything in nature, mimicry is complex and nuanced. The viceroy butterfly famously mimics the poisonous monarch butterfly. For years it was assumed that the viceroy was free-loading on the monarch’s distasteful reputation, offering nothing in return.
As is often the case in science, this explanation proved too simple. Research revealed that the viceroy doesn’t taste good either, so the two unrelated species actually reinforce each other’s security.
The bumblebee serves as a common model for mimicry. The snowberry clearwing moth (left), unarmed and likely quite tasty, looks like a large bumblebee and no doubt gains some protection from this resemblance.
Some robber flies also look like bumblebees, but their motives extend beyond mere protection, to the sinister. Robber flies mimic the nectar sipping bumblebees to ambush their prey. They loiter around flowers, waiting for pollinators like bees, wasps and flies to sidle up to the floral bar for a drink.
Then they pounce. Imagine the surprise of the victim held firmly in the robber fly’s grasp: “But…but… you’re a bumblebee – you don’t eat meat – lemee go!”
Humans have come lately to the art of deceit. Insects have been practicing it for millions of years.
Late in winter almost every year if one is out and about in the woods, we will encounter an interesting group of tiny organisms on the surface of the snow. These are Snow Fleas (Hypogastrura nivicola). Snow Fleas, a species of Springtail, are very small insect-like creatures that are totally unrelated to true fleas that prey on dogs, cats, humans and other mammals. In fact they are no longer even considered to be insects. At one time, the group called Collembola were considered to be a primitive type of insect. Now, due to recent studies, they, along with two other groups, the Protura and the Diplura (two-pronged bristletails), have each been moved to their own Class equal in status to the insects. Collectively, these four groups make up the Subclass Hexapoda or ‘six-legged’ arthropods.
There are many species of Collembola. They are quite small, about one millimetre in length and most live in the soil where they are seldom encountered, at least knowingly by humans. They can be extremely numerous with populations reaching 250,000,00 per acre. They mostly feed on organic detritus, breaking down leaf litter and the like and aiding in the recycling of nutrients for plants.
The Snow Fleas represent the one Collembolan species that we do see fairly often. They appear in large numbers, and because their dark colour contrasts with the white snow surface, we take note. They tend to aggregate in small depressions such as old footprints in the snow. The depressions likely offer a microhabitat that is just a little warmer, is protected from the wind, and the snow is likely to be saturated with liquid water. In any case, the Snow Fleas appear in large numbers and look much like dust particles. If one looks closely, you can see them jumping about on the surface of the snow.
These photos were taken on April 30, 2013 at a small vernal pool along the Guelph Hiking Trail south of Acton. The masses of Springtails floating on the water looked a lot like globs of oil. It is uncertain if these animals were at the end of their days or if they had trouble breaking free from the surface tension of the water. Some of them were certainly still alive and were jumping about. Nevertheless, the photographs give some idea of the abundance of the creatures.
Although they have legs to help them move about, Springtails are also equipped with an unusual abdominal appendage called the furcula. This structure is what gives the group its name. It folds beneath the body with the loose end tucked into a receptacle also under the body. The furcula is held under tension and when needed, the tension reaches a level that the end slips out of the receptacle. The furcula snaps against the substrate and this throws the Springtail into the air to escape.
Snow Fleas are able to live quite comfortably in the snow and survive low temperatures owing to a special glycine-rich protein that acts as a form of antifreeze. In addition to the important role in recycling nutrients noted above, Springtails have been reported to provide a valuable ecological service by moving spores of mycorrhizal fungi and destroying spores of plant pathogens. Certain species have been blamed for damaging alfalfa crops. They have also been put to use as indicators of soil contamination owing to their sensitivity to certain chemicals in the soil.
by W.D. McIlveen
Halton/North Peel Naturalist Club
Particularly in Spring, a walk in the woods might turn up a very tiny grasshopper among the dead leaves. These are likely Pygmy Grasshoppers, not ‘baby grasshoppers’. They are also known as ‘grouse locusts’ or ‘grouse grasshoppers’ or in one case, a ‘frog groundhopper’. Pygmy Grasshoppers are members of the suborder Tetrigodea and most occur in the Family Tetrigidae. One exception is Tettigidea lateralis that occurs in the closely-allied Family Batrachideidae. The seven species that are known to occur in our area are listed in the following table and samples are illustrated in the attached pages.
These grasshoppers, as their name implies, are quite tiny with adults ranging from about 7 mm to only 14 mm (half inch) in length. Females are slightly larger than males. Because of their small size and generally cryptic coloration, they are easily overlooked. They can be of various colours, browns though gray and mottled, but never green. Their eyes are rather pronounced and the pronotum is often elongated along the back to cover the thorax. The antennae are short and they lack auditory and stridulatory organs. Wings may be long or short.
Although they can tolerate slightly drier sites, most prefer to live on the ground in damp, muddy situations, frequently close to water. They are reported to feed on vegetation debris and microscopic algae that accounts for their preference for moist habitats. Eggs are laid in soil or mud. Because they over-winter as adults, they are likely to be active shortly after the snow melts in the spring. Given the mild winter this year that gives prospects for an early start to the season, we could expect to see these little fellows out and about in the very near future.
by W.D. McIlveen
Halton/North Peel Naturalist Club
Recently, one of the items covered by the news media was the change in distribution of various species owing to climate change. There are other causes for expansions of populations other than climate shifts but this discussion is limited to the global warming phenomenon. The media accounts included the recent appearance of fish species in the ocean much further north than where they normally occur. One species that was mentioned that has relevance to our own area was the Giant Swallowtail Butterfly.
While it is a good thing that the media covered this important story, they unfortunately got it wrong. To listen to what they were saying one was left with the impression the species involved were fleeing from excessive heat in their traditional areas and seeking respite in cooler areas. This is not the case. The geographic range expansion is possible only because the new areas are now offering conditions (slightly warmer) where the cooler conditions had prevented then from surviving before. Giant Swallowtails (Papilio cresphontes) are the largest butterfly in much of North America. Their wingspan ranges from 10 to 14 cm across! (Figure 1). They tend to stay in woodland areas or, in the southern US, in citrus groves. The adults sip flower nectar for food. The larvae of this butterfly are known as the ‘Orange Dog’, not for their colour but for their host in citrus groves. The caterpillars look a lot like bird droppings and can get as big as 4.5 cm long! (Figure 2)
They generally adopt a disguise by looking like bird droppings, an appearance that they retain until they pupate. Another deterrent to would-be predators is the osmeterium. This is a reddish, forked gland located behind the head that is extended when the caterpillar disturbed. The osmeterium exudes a fluid that is considered to smell terrible and deters any attacker.
In years past, Giant Swallowtails were essentially restricted to the far southern parts of the province. They would occasionally wander farther and one vagrant had been reported at Ottawa. Now they are much more frequent in parts of the province where they were seen only occasionally. How much of this recent range expansion is due to climate change is still unclear. Milder winters could certainly assist in the survival of the species over the coldest part of the year. A key limitation in their distribution is the availability of their host plants.
Hosts of the Giant Swallowtail all belong to the citrus plant family Rutaceae. We do not have many groves of oranges or lemons in Ontario to sustain the butterflies but we do have a few other members of the plant family. The list includes Gas Plant (Dictamnus albus), Cork Tree (Phellodendron amurense), Common Rue (Ruta graveolens), Common Hop-tree (Ptelea trifoliata) and American Prickly-ash (Zanthoxylum americanum). The first three mentioned are all introduced or non-native species. They are rarely grown and are thus hardly capable of sustaining populations of the butterflies in Ontario. The Hop-tree is rather uncommon in Ontario and restricted to the Carolinian zone. The main job of supporting the larvae of the Giant Swallowtails then falls to the Prickly-ash that has a much wider distribution than the others though it also tends to grow in more southern parts of the province. Prickly-ash is a relatively inconspicuous species that goes unnoticed unless one needs to cross through a patch of it. Then the thorns on its stems are more than adequate to grab the traveler’s attention. Other than vagrant butterflies that might be carried by the wind, the anticipated range of the butterflies is going to strongly mirror the distribution of Prickly-ash. Perhaps the changing climate will allow that plant to extend its range and thus allow the butterflies to follow further a field. It will be interesting to follow shifts in distribution patterns for these species as well as others that exhibit similar types of range restrictions.
by W.D. McIlveen
Halton/North Peel Naturalist Club
serving Brampton, Georgetown, Milton, Acton & surrounding areas
Meetings are held at the St. Alban's Anglican Church hall,
537 Main Street, Glen Williams (Georgetown), Ont.
Meetings are the 2nd Tuesday of each month from Sept to June at 7:30PM,
unless otherwise noted.