A Weakness for Weevils

I was excited to find a new weevil on our property the other day. At least until I identified it.

Meet Otiorhynchus sulcatus—the black vine beetle—pest on a wide range of garden plants, including grapes, black currants and strawberries (all common in my garden).

I admit, I have a weakness for weevils—no matter how much of a pest they are, I think they’re cute. And this one is no exception. She’s lovely, in spite of her diet. And I’m certain she’s a ‘she’, because no males of this species have ever been found. The black vine beetle reproduces parthenogenetically, producing viable eggs without the need for fertilisation by males. 

This ability is the result of a bacterial symbiont in the genus Wolbachia. When researchers in California eliminated Wolbachia in black vine beetles (by giving the beetles antibiotics), the beetles’ unfertilised eggs were no longer viable. It’s a clever little ploy by the bacterium to ensure its own reproduction—only infected insects can reproduce, and they can do so without the trouble of finding a mate (I wrote more about this fascinating relationship in Putting the Science in Fiction and on Dan Koboldt’s Science in Fiction blog).

Another cool feature of the black vine beetle is that it is flightless. It’s not uncommon to find flightless insects and birds here in New Zealand, but it’s a little unusual to see it in invasive pests like the black vine beetle. Native to Europe, the black vine beetle is now distributed all around the world. Pretty impressive travelling for a 6 mm-long flightless insect.

Apparently black vine beetles can cause significant damage to plants. The larvae eat roots in the soil and do the most damage, particularly in potted plants, where root growth is limited. I’ve decided not to worry about them at the moment. I’ve got more damaging pests to worry about, and to be honest, I wouldn’t mind seeing them again. They are awfully cute.

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.

Smells Like Spring

I know, technically it’s still winter. We’re still likely to have icky, cold, wet weather. There will be ice on the water troughs, and frost on the grass in the mornings. There are still plenty of weeks left in the skiing season. And I won’t even think about planting anything out in the garden for at least six weeks.

But yesterday smelled like spring.

That heady combination of lanolin, damp soil, and cut grass.

It sounded like spring, too, with magpies warbling in the trees, swallows chittering overhead, and lambs bawling in the paddocks.

It is not spring. Not yet. But the days are lengthening and the first daffodils are beginning to bloom. It’s time to finish all those indoor winter projects. Spring is on its way.

Here Comes the Sun

After weeks of grey, unending drizzle, we’re finally seeing a bit of sun. Mushrooms abound in the yard, revelling in the dank mist we’ve been swimming through for a fortnight. We are all eagerly awaiting passing of the solstice and the lengthening of the days.

Though it is still pretty dark and drear, and the days will still be short for some time, there are signs of the spring to come.

Lambing has started. This is the time of year when the neighbours grow noisy, with lambs and ewes calling to one another day and night.

The preying mantids are gone, but their egg cases are dotted around the yard, promising a healthy population of my favourite predators come spring.

The daffodils and snowdrops are coming up, and I’ve even seen them blooming in other people’s yards.

And tomorrow is the solstice. Friday, the sun will remain above the horizon fractionally longer than it did the previous day. We’ll be on the upswing.

The Sound of a Story

I sit down at my desk and breathe a sigh of relief. It’s quiet here, in my office. Not like the noisy library where I worked yesterday.

But, no, that’s not true. I hear the roar of the surf in the distance. The trickle of the artificial stream in the garden overlays the sound of the ocean. When I step to the office door, a goat greets me with a maa. Starlings mutter in the treetops, magpies warble on the fenceposts, and a fantail chitters in the shed. A plover’s percussive call is underlain by the chirping of a thousand crickets.

The neighbour rumbles past in his tractor, carrying a bale of silage. I can hear his son in the paddock shouting and whistling at his five barking sheep dogs.

It is far from quiet.

And yet …

Somehow, the sounds here caress my thoughts, rather than intruding upon them like the horrible Muzak from the library cafe, or the screams of tired children, or the drone of the automatic returns machine—please place the item on the trolly.

The fantail flits in and out of the story I’m writing without knocking over my coffee. The goats and sheep graze beside me without barging across the keyboard. The crickets keep to the grass. The tractor rumbles along without leaving tire tracks on my manuscript. The ocean doesn’t even wet my toes.

But somehow, I’m certain these sounds end up in my stories, caught up in the weave of plot and characters. The fantail is there, in the flick of a character’s fingers. The ocean is the relentless sound of the plot line. The tractor is the rumble of disaster bearing down on my protagonist. The goats’ deep maa is the voice of wisdom, and the crickets’ chirping lightens the mood.

Market Smells

I brought seven dead-ripe rock melons in from the garden yesterday afternoon. The smell in the kitchen was overpowering, and took me directly to Roots Market, a large farmers’ market in Lancaster County PA, on a hot July day.

For me, the smell of ripe melons = Roots. I’m not entirely certain why—there are many competing smells at the market. Perhaps because in the mid-1980s a melon grower had a stall at the entrance where my family always arrived, so it was the first smell I experienced every time. Whatever the reason, that smell will forever be associated with that market in my mind.

I’ve been to many farmers’ markets since the mid-80s. Memorable smells accompany many of them.

In Ann Arbor, Michigan, it was basil, which my housemates and I bought by the grocery-bag for pesto.

In Panama, the market in Penonome was where my husband and I shopped every week or two. The meat-sellers’ area was screened from the flies, but the screen didn’t stop the smell of beef, pork, chicken and fish on display in the tropical heat from wafting through the market.

In St. Paul, Minnesota, I remember the smell of flowers and sweet corn.

I haven’t been to many farmers’ markets here in New Zealand, because I grow all our vegetables, but as a seller in Leeston, I remember the smell of my friend Cris’s homemade bagels.

Pretty cool how smell can act as a teleportation device, spanning distance and time in an instant.

Pheasants: Honorary Natives

We’ve had a lot of pheasants around the house this spring. The common pheasant (Phasianus colchicus), also known as the ring-necked pheasant. Is a curious bird…or rather, our relationship to it is curious.

The common pheasant is native to Asia, but has a long history in Europe. It was probably introduced by the Romans, and the first printed mention of the bird in Britain was in 1059.

Who knows what ecological impacts the pheasant had in Britain? I doubt anyone paid attention at the time. By the time people began to worry about conservation, in the early 1800s, it was the pheasant they worried about, as its numbers declined with land-use changes and the introduction of firearms for hunting.

The pheasant was first introduced to North America in the 1770s, and has naturalised in many areas. As in Europe, it has become a popular game animal and is the focus of conservation efforts, in spite of its non-native status.

Many years ago, I applied for a job with a ‘conservation’ organisation in Minnesota. Though I was ultimately offered the job, I turned it down, because its sole focus was on the maintenance of pheasant populations for sport hunting. I struggled to view that as conservation in a place where pheasant habitat was incompatible with habitat for threatened native animals, and where maintaining a pheasant population required captive breeding, because winters are simply too harsh for it to survive, even with appropriate habitat.

Even in Hawaii and New Zealand, where introduced species are almost universally considered pests, the pheasant is fussed over and cared for as a native—bred in captivity and released to keep its numbers up for the benefit of sport hunting.

A search for information on the ecological impact of pheasants is curious. Many sources presuming to address the ecology of pheasants deal only with the threats to pheasants themselves, not pheasants’ impact on the native ecology around them. It is as if even researchers have turned a blind eye to the fact pheasants are non-native over most of their current range. In truth, their impact is undoubtably small compared with non-native predators like stoats, cats, and rats. They tend to prefer disturbed, agricultural habitats (though they have been recorded as competing with native prairie birds in North America) and feed primarily on cultivated foods, weeds, and insects.

Yes, they feed primarily on crops. They’re crop pests. They particularly like grains and small fruit crops, and can cause significant losses in grape vineyards and in small holdings.

So, why do we embrace the pheasant so unreservedly? Let’s face it, most of us don’t eat pheasant, so we get no benefit from the bird. But it seems its long historical association with people and the agricultural landscape have made it almost a domesticated species. And, as we put up with the chickens occasionally wreaking havoc in the garden, so we put up with the pheasants, too.