Stink Bugs: An Autumn Ritual

This column was published in the Cranbrook Daily Townsman, Thursday October 21, 2010. 
 
Autumn. Time for one of those Kootenay traditions that celebrates warm afternoons and cool nights. That’s right, it’s the season again to patrol the outside of the house and flick stink bugs off the deck, chairs, door, walls and apparently every other possible surface. Those that find their way indoors need to be gently evicted. Careful moving them, they’ve got a loaded rear end to make any warthog or skunk jealous.

For good fun, watch the dog catch one, get a mouthful of the bug’s foul discharge then try to clean it out. A smart pet will only do that once. One of our own spring rituals is to open the deck box that holds our outside chair cushions and shake out the dead stink bugs that have lain entombed and frozen throughout the winter. Deck boxes make a poor hibernation choice for insects.

Stink bugs are more properly called Western Conifer Seed bugs (Leptoglossus occidentalis) and are native to the western United States but have been increasing their range through the last century. They are now found throughout eastern North America as well as accidental introductions into Europe (and probably elsewhere), hitching rides on Christmas trees and other forest products.

They move through a single life cycle each year, overwintering as adults before emerging in the spring to feed on developing seeds in green cones. Females then lay neat rows of eggs on conifer needles as their final act. The eggs hatch and successive larval stages continue to feed on the cones and needles of the trees until the adult stage is reached by late August.

And then the fun begins anew. South and west-facing walls and homes make welcoming places to adult stink bugs looking to keep warm. As the nights cool, the bugs will push farther in their search for warmth. No crack or opening seems to narrow for them to fit through. Their body seems almost two-dimensionally thin and they are able to squeeze through any seal not quite air-tight. Think of them as friendly reminders to check your door and window seals.

There is no need for alarm if they are found inside. They do not bite, for their mouth parts are adapted to sucking tree sap from cones, not biting or chewing. Their only downside, apart from those squeamish about insects in the home, is the foul odour they emit if disturbed. Thus the ‘stink bug’ moniker, one well earned. Crushing them is not advised, even picking them up can result in an unfortunate olfactory experience. Encourage them to move onto a piece of paper, then release them back outside.

The insects are entirely harmless, unless you’re running a tree nursery and trying to gather seeds from conifer trees. They can cause significant losses in seed production by adult trees by feeding on developing cones and occasionally killing the tree itself.

How they find these cones was described by Simon Fraser University biologist Stephen Takács. His team found that growing conifer cones are much warmer than the surrounding vegetation, up to 15º C! (see paper here.) To infrared sensors, a conifer with growing cones appears like a Christmas tree, with each cone brightly “lit” relative to the adjacent greenery.  

Turns out, stink bugs have highly sensitive infrared sensors in their abdomens, directly connected to their brain. When biologists blocked these sensors, seed bugs could no longer find the trees. This attraction to high intensity infrared radiation also explains why the bugs are so drawn to warm, sunlit walls during the autumn.

Ultimately, all the bugs are doing is looking for a place to spend the winter where they won’t freeze to death. As the weather cools and winter looks to set in, that’s something we can all relate to.

Conifer tree under visual and infrared light showing warmer temperature of cones

Appreciating the Urban Wild

This column was published in the Cranbrook Daily Townsman Tuesday October 12, 2010.

Confessing to being a Toronto native to those beyond the 416 area code can be dangerous. Admitting you’re from the city the rest of the country loves to hate, with its smug self-importance, can still elicit reactions from surprise to disdain.

But as time increases from my Toronto address, I’m comfortable enough to go public: I am proud to be a Toronto native. In one of those rites of aging, I recently returned to the big city for my 25th high school reunion.

I had not previously thought of myself as the high school reunion type. I wasn’t exactly the school social coordinator. Most of my youth was spent trying to escape the city in search of a more rural, if not outright backwoods, existence. Summer jobs took me to bush camps across northern Ontario from Algonquin Park to Lake Abitibi, Moosonee and beyond.

So returning to Toronto to reconnect with a few friends and classmates long since forgotten was not something I would have predicted even ten years ago, let alone when I finished high school.

One product of my youthful dreams of a northern idyll was the belief that the only natural world worth experiencing was true wilderness. What exactly constitutes “wilderness” is debatable, but most conclude that it involves a lack of immediate human presence. More strident definitions also require an ‘untouched’ quality where one might indulge the illusion that few, if any, humans have previously visited.

For me, wilderness lay at least two portages removed from overcrowded canoe routes or well off the main hiking trail. Certainly, wilderness wasn’t to be found in suburban Toronto or any other city. But closing one’s eyes to natural areas within urban cities is to miss many wonderful places.

While in Toronto, I found myself with an hour’s wait at my nephew’s high school in the city’s west end. A large old brick school that his grandfather attended set in a typical Toronto neighbourhood of narrow lots on streets lined with mature hardwood trees.

I happened across the “Hillside Nature Garden” at the adjacent Runnymede Public School. Students restored a narrow slope around the school with native trees, shrubs and wildflowers. A trail runs through the strip of natural cover, maybe fifty metres wide at best.


 

Hillside Garden Project (outlined in red) at Runnymede
Public School, Toronto. Ursula Franklin Academy & Western
Tech High Schools are in upper right corner. from Google Earth



Hardly wilderness by anyone’s definition, it likely supports little more than a few bird nests, the odd raccoon and a few voles. But here, sumac, sycamore and sassafras trees provide shade and cover to a piece of ground that otherwise be mowed lawn, a weed source or a cement retaining wall littered with lunch wrappers and unfinished homework.

More importantly, it provides a wonderful natural classroom to the school’s young students. To many, that small patch of green likely serves as an introduction of the world beyond concrete and computers.

Statistics Canada state that 80% of Canada’s population lives in an urbanized centre of more than 1000 people. By that measure, Sparwood, BC, (population of roughly 4000) is as urbanized as Toronto. But nonetheless, the measurement indicates the degree to which our population lives in developed centres. Urban-rural splits are becoming major political wedges (witness the recent longun registry ballyhoo) with the main complaint of the rural and small community dwellers being that urban folk don’t understand the non-synthetic world beyond city limits.

Natural areas, even small ones like the Hillside Nature Garden can serve as an introduction to city children who may not otherwise have an opportunity experience nature first hand. Through planting and caring for native species rather than nursery-bred exotics, hopefully a better appreciation for our natural world may also be sown and fostered.

Even in smaller urban centres like Cranbrook, with true wilderness at our doorstep, many children have no introduction to the natural world. School programs like Wild Voices for Kids and trips to the Blue Lake Centre should be required curriculum components. The objective isn’t to turn everyone into a wilderness loving environmentalist, but broaden overall experience and appreciation of our world.

Trouble for the Food Supply

This column was published in the Cranbrook Daily Townsman Tuesday September 21, 2010.



So how did your garden do this year? Generally cool temperatures have kept many tomatoes green and not helped many crops, especially berries. On the other hand, cool and regular showers has our lettuce still going strong when it is normally virtually toasted by early August. We’re enjoying a second go-round of peas and were enjoying a bumper crop of beans until the frosts of early September took them out.

But more than just good weather and careful tending is required to pull off a successful garden. Many crops, wildflowers and other plants are reliant on insects for pollination in order to successfully bear fruit and viable seeds. Bees provide the vast majority of these pollination services to agriculture and natural ecosystems. Honey bees can increase yield in 96% of animal-pollinated crops and insect pollination in general (mostly bees) is necessary for 75% of human crops worldwide. If you like berries, coffee, nuts and other foods, you want bees.

But recent declines in bee populations around the world raises significant concern for the future for both agricultural productivity and wild plant communities. The majority of agricultural and apicultural (bee keeping) scientists now agree that significant declines have occurred in honey bees world wide. Some estimates suggest a 59% loss of honey bee colonies in the USA between 1947 and 2005.

And domestic bee populations decline, what is going on in wild bee populations are also thought be suffering widespread losses. Recent work in Illinois found half the bumblebee species there were either extirpated (no longer existing in certain areas, but present elsewhere) or had suffered declines. The trouble is we don’t know much about wild bees. To document a decline you need both current population estimates and from some time in the past. We just don’t have much of that data. Where the data are available, the news is not good.

A recent review of pollinator declines, published in the journal Trends in Ecology and Evolution, reports on evidence of the decline and what is driving it. Habitat loss is indicted as a key driver of wild bee declines. As natural ecosystems are urbanized or otherwise altered, most native bees suffer along with other wildlife species. Hand-in-hand with bee declines are losses of plant diversity. In some cases this becomes a chicken-and-egg scenario. Many plants rely on bees for pollination and reproduction and vice-versa. If one is removed from the ecosystem the other also fails. Trying to figure out which declined first is difficult and not always

Electron micrograph of Varroa destructor mite on a honey bee

Intensified agricultural activity is another driver. Insecticides in particular kill bees directly, while herbicides and fertilizers are implicated as reducing food availability to bees and other pollinators.

One cause of bee declines that has received media coverage is the introduction of a parasitic mite from Asia. The Varroa mites latch on to bees and feeds on the insect’s hemolymph (essentially insect blood). Further weakening the bee are various viruses transmitted by the mite so that entire bee colonies can be wiped out. Some estimates suggest that all feral honey bee colonies in the Europe and the United States have disappeared as a result of Varroa mites.

Varroa mites on honey bee pupae.

Climate change may also impact bees. Mismatches in bee emergence and plant flowering can result in reduced productivity for both bee and plant. All these drivers may act independently or in an additive effect that combine to drive local declines farther and faster. The consequences for agricultural and food production are significant, though they can rent travelling honey bee colonies at the time when pollinated is needed most.

Most home gardeners can’t justify that level of cost. Worrying about late and early frosts is enough of a challenge. Adding in doubts about whether your garden will be pollinated is just one more uncertainty.