Nifty Nematodes

Nematodes under the microscope. Image: CSIRO

A week or so ago, during a writing break, I spent some time peering through the microscope in my ongoing quest to find tardigrades in our yard. I had no luck on the tardigrades, but as usual I came across lots of fabulous little invertebrates.

Perhaps the most common creatures under the microscope were nematodes. No surprise, really. Nematodes are the most common multicellular organisms on earth; there are several million in every square metre of soil here in New Zealand. Most are tiny (less than 3 mm). But not all are so minuscule; the largest, a parasite of sperm whales, can grow to 8 to 9 metres in length.

Nematodes can be free-living or parasitic on animals and plants. In fact, most animals (vertebrate and invertebrate) and plants are host to at least one specialist nematode parasite. Free-living nematodes eat bacteria, fungi, or small invertebrates (including other nematodes).

As you can imagine, nematodes are of huge importance ecologically, economically, and from a human health perspective.

Humans are host to about 60 species of nematode. Diseases caused by nematode parasites in humans include: ascariasis (an intestinal infection that can cause growth retardation and a variety of intestinal and other problems), hookworm (causing anaemia and developmental problems),filariasis (a lymph infection, causing swelling in many body parts, including elephantiasis of the legs), trichinosis (an intestinal infection causing diarrhoea, fever, and other symptoms). Many nematode infections are asymptomatic, and it’s likely most of us play host to nematodes for most of our lives.

The control of nematodes is important in agricultural systems. Worldwide crop loss to nematodes is estimated to be 12.3 percent of production (US$157 billion). Livestock and domestic pets are also susceptible to nematode infection, and millions of dollars annually are spent to control nematode infections including lungworm, hookworm, trichinella, heartworm, and many others.

But nematodes aren’t just doom and gloom. They’re integral parts of natural ecosystems, and critical components in nutrient cycling (especially nitrogen) and food webs. They regulate the bacterial population in the soil, and provide food for many organisms (including some fungi, which catch nematodes with lassos, like tiny cowhands). They can be useful, too. Some insect parasitic species are bred to help control insect pests—a highly species-specific, organic control method.

And like the tardigrade, nematodes are tough. A culture of live nematodes aboard the Space Shuttle Columbia were the only organisms to survive the re-entry breakup of the shuttle, making them the only organism known to survive unprotected atmospheric descent.

Fabulous Flatworms

Australian flatworm

One of the common animals in my yard and garden is the flatworm. Strictly speaking, “the” flatworm here in New Zealand is actually multiple species—possibly up to a hundred—but they have been poorly studied, so it’s unclear just how many species there are.

Flatworms are some of the most impressive predators in the garden, able to consume prey up to 55 times their own size. That’s the equivalent of your house cat taking down a female elk. They eat snails, slugs, and earthworms, digesting them externally before sucking them up with one or more mouths located midway along their bodies.

I love to find flatworms around the yard. They come in striking colours, and some have lovely brown stripes—the orange Australian flatworm (Australoplana sanguinea) is most common in my garden, followed by the relatively nondescript brown New Zealand flatworm (Arthurdendyus triangulatus). Like the slugs they eat, they prefer damp places, and they protect themselves with a layer of mucous. Flatworm mucus is stickier than slug mucous, and they use it to attach themselves to their prey during feeding.

New Zealand is full of non-native invasive organisms, but New Zealand flatworms are one of the few organisms that have turned the tables and become pests overseas. They are easily transported in potted plants, and have successfully invaded Ireland and Scotland. Though there was widespread panic at first about their potential to threaten the local ecology, they appear to have caused little damage to earthworm populations in the UK. Like most cold-blooded animals, their appetites are small. Far from being a devouring hoard, each flatworm can manage, on average, just one earthworm per week. And if they don’t manage to find an earthworm every week, it’s not a problem—they can go a year without eating.

Weeding Therapy

You know it’s been a good therapy session when it leaves a clear weeding front.

I make no secret of the fact I have a weeding problem. I’ll ignore hunger, thirst and bodily pain to pull just a few more weeds—fill the wheelbarrow, finish the garden bed, never mind the cost.

But in spite of my obsession, I believe there is a place for weeding therapy, even for me.

Today, when the temperature hit a sweltering (for mid-winter, at least) 18 degrees (64ºF), I had no interest in my usual lunchtime walk. No. Today, after weeks of inactivity in the garden, I needed to weed.

I grabbed my gloves, and hove to. A sweaty half-hour later, I was refreshed and ready to get back to work.

The key to good weeding therapy (to avoid it becoming a weeding marathon) is setting limits—I give myself half an hour, and set a timer so I’ve no excuse for running over time. It helps to choose the therapy weeding job well; I go for places that have been irritating me, places that are desperate, or places where the weeds are big and easy to pull. It gives me a greater sense of accomplishment in a short amount of time, so I feel I can quit when my time is up.

And if I do quit before exhaustion, pain or hunger set in, I can return to other work in a focused state of mind, ready to bang out the next chapter or tackle the next editing job.

And the best part is that, with so much garden area here, there will always be more weeds, so therapy is always available when I need it.

Appreciate the season

Drizzle-soaked hebe.

It’s another grey, damp day in a string of grey damp days. We’ve had little rain, but almost no sun, either. Though my last blog was about spring, this weather reminds me it’s still winter.

I’m itching to get out into the garden, to plant seeds, to get on with the business of springtime. The weather hasn’t been cooperating.

In a way, that’s good. It is too early to plant, to early to turn the soil. The weather reminds me to appreciate what winter has to offer—the excuse to stay indoors and sew, the opportunity to play board games and read books, a reason for a mid-afternoon cup of tea. I forget to value these things when I have them, instead looking forward to the next season of frenetic activity. Sometimes I need a week of fog and drizzle to remind me.

Red Currant Orange Muffins

I’ve occasionally noted how alike in smell, flavour and texture red currant jam and cranberry sauce are. And since I’ve got a freezer full of last summer’s currants, I decided to use them in a recipe calling for cranberries.

The result was a lovely red currant orange muffin. Even better than the cranberry version, because the fruit came from our own garden.

2 cups all purpose flour
1 c. whole wheat flour
1 Tbs baking powder
3/4 tsp baking soda
1/2 tsp salt
3 eggs
zest of one orange
juice of 1 orange, plus enough yogurt to make 1 1/2 cups
1/2 cup brown sugar
125 g (8 Tbs) melted butter
1 cup fresh or frozen (thawed) red currants

Combine flours, baking powder, baking soda and salt in a large bowl. In another bowl, whisk together the eggs, orange zest, orange juice, yogurt, sugar and butter. Combine wet and dry ingredients, stirring just until evenly moist. Fold in the currants.

Fill well-greased muffin cups—for me, this makes 21 muffins.

Bake 15 minutes at 210ºC (400ºF). Allow to cool in pan 5 minutes before removing.

Still Life with Insects

I’ve written and discarded half a dozen blog posts over the past week. Nothing seems to be quite right. Out of ideas, I resorted to the book of 500 writing prompts I created for my daughter. A random stab at the non-fiction section of the book brought me to the question: What objects tell the story of your life?

I tried to encapsulate everything in four objects:

The fiddle: made by a neighbour in Panama, given to me for my birthday by my husband. The fiddle not only tells the story of our years living and working among the incredible, resourceful people of Panama, but also tells the story of my lifelong interest in learning to play the violin…an interest which always ended up being pushed aside for other interests. Because I’m interested in learning so many things, there simply aren’t enough hours in the day.

The beetle puppet represents my insatiable curiosity about arthropods, and how that curiosity has bled into my other interests. Peanut butter jars full of bugs on my dresser when I was a kid led to the entomology degree, which led to teaching about insects at Penn State University, and then starting the Bugmobile. And the puppet is only one of many insect-themed and inspired artistic projects I’ve done over the years, as art and science mingle in my brain.

The gardening gloves speak of my weeding addiction and my love of growing food. The gloves are never more than a month or two old, because I wear through them in that time. I think that says it all about gardening for me.

The rock represents adventure, the natural world, and the wild places I have visited and lived in. Like me, the rock has traveled far and has been changed by the stresses it has experienced along the way.

Salt-preserved Green Beans

I always struggle with what to do with too many green beans. I can (bottle) some, but none of us really like the taste of canned beans, and their mushy texture leaves a lot to be desired. I don’t freeze any, because freezer space is at a premium, and I prefer to fill it with sweet corn and peas instead.

So this past summer, I preserved some green beans in salt. The recipe I used claimed that the flavour and texture of salt-preserved beans is far superior to canned or frozen.

I pulled out the crock of salted beans the other day to test them out.

At first glance, they didn’t win any beauty contests, especially the yellow wax beans, which came out of the salt a sort of dead-flesh colour.

I rinsed them and soaked them for two hours, as directed, and then tossed them into a green bean and potato charcharis.

Cooked into a flavourful Indian dish, the beans most definitely had better flavour and texture than canned beans. Almost as good as fresh, even.

Unfortunately, they were so excessively salty, they made the dish almost inedible. Even my salty-olive-loving family couldn’t choke them down. Most of the dish ended up on the compost pile, and I expect an epidemic of high blood pressure in the local sparrow and mouse population who dine at chez-compost.

There are still some beans left. I’ll try using them again—small quantities in otherwise unsalted stews or soups might work well (sort of like a salty ham hock in bean soup). Maybe.

But I’m thinking I’ll just give away the extra green beans next year.