Cicada Killers

July 13, 2016 / Robinne Weiss / Leave a comment

How can you not love an insect called a cicada killer?

The eastern cicada killer (Sphecius speciosus) is a solitary burrowing wasp. One of the largest wasps in eastern North America, the females top out at about 5 cm (2 inches) in length. These beautiful, large wasps are harmless to humans, but deadly to cicadas.

The female catches and stings adult cicadas. The sting paralyses, but doesn’t kill the cicada. The wasp then takes her immobilized prey to her underground burrow where she lays eggs on them. Male eggs get one cicada each, and female eggs get two or three cicadas (because females are bigger and need more food to reach adulthood). The eggs hatch out, and the wasp larvae eat the cicadas.

Cicada killers, looking a lot like giant hornets, strike fear into most people’s hearts. Their behaviour can be frightening, too. Males defend territories from other males, and can be seen fighting one another, grappling in midair. But males have no stinger, so they’re completely harmless to humans. Female cicada killers can theoretically sting, but unlike the social wasps, they don’t sting to defend their nests. You’re only likely to be stung by a cicada killer if you pick it up and squeeze it.

The cicada killer in this photo is a male. His territory is in my mother’s garden, and he is reliably found on a particular plant in the morning sun, sallying forth to challenge other males who get too close.

Confessions of the Resident Exterminator

June 20, 2016 / Robinne Weiss / Leave a comment

Being the least squeamish member of the household, it falls to me to deal with all members of the animal kingdom on our property.

That means I take care of the livestock, of course (I can’t even imagine anyone else dealing with kidding or mastitis), I dispose of the gifts the cat leaves lying beheaded on the lawn, and I deal with pests.

Though I don’t enjoy killing anything, I have no problem squishing bugs in the garden, and dropping slugs into soapy water (I don’t recommend squishing them—its really slimy). I don’t even flinch at the idea of setting mouse traps or possum traps, either.

But rat traps? *shudder*

I put it off until the rats are so numerous that they’re having loud parties in the attic, keeping me up all night racing around, gnawing on the rafters.

And then I wait longer, until the rest of the family starts to notice the noise in the attic, or a greasy body sliding through the wall cavities.

Then I pull the rat traps out and look at them for a while, screwing up my courage.

Finally, after many excuses, I get out the ladder, prepare some bait (bread with peanut butter is reliable), and make my way to the attic with the traps.

Bait on the trap, set trap in place, pull back the bar to arm it…

SNAP!

Bait goes flying, fingers sting, and I jump, cracking my head on a rafter.

Try again. Bait on the trap, put the trap in place, pull back the arm…

SNAP!

Maybe we can coexist with the rats? I calm myself and try again. Third time’s the charm, right?

Bait, set it in place, hold my breath and pull the arm…

Breathe out slowly. Carefully move my hands away from the trap, willing it not to spring shut.

Get the second trap. Repeat.

The good news…and the bad news is that the traps work. Within 24 hours I’ll have to empty them and reset them. The parties will stop. I’ll be able to sleep.

But I hate setting those traps.

Fabulous Fennel

May 31, 2016May 31, 2016 / Robinne Weiss / Leave a comment

There’s not a lot coming out of the garden at the moment. The summer crops are pretty well finished (though we’re still scrounging the odd pepper or eggplant from the tunnel house), and the winter crops barely had a chance, with the hot dry weather we’ve had until last week. But among the few crops that are available right now is fennel.

This little-used vegetable is versatile and delicious in the kitchen, and attractive and useful in the garden. Leaves, seeds, and bulb are all edible.

Fennel grows year-round here, though the cooler months are when we appreciate it most. I plant it in both spring and autumn, but it seeds in readily, and we eat as many volunteer fennel as we do planted ones.

Fennel has a mild anise flavour that goes well with many other vegetables. When raw, the flavour is refreshing and numbing.

Raw fennel, sliced thin, makes a crisp and refreshing addition to salads. Or it can make a salad all on its own.

It can be braised and eaten as a side dish, or chopped and added to stews or casseroles. It goes particularly well with potatoes in a cheesy gratin, and makes a delightful risotto.

Fennel leaves can be added to salads and stews, even if the bulbs aren’t ready to harvest.

The ground seeds make a zesty addition to burgers, chai, and cookies, too! Or just crunch a few between your teeth after a meal to sweeten your breath.

In the garden, fennel’s big yellow flower heads attract all sorts of beneficial insects that help keep pests in check, and when the plants get too big and rangy, I can feed them to the goats, who love fennel as much as I do.

Promise of Spring

May 27, 2016 / Robinne Weiss / 1 Comment

Tomorrow’s forecast is rather wintery, but I’ve been fortified today. The preying mantises must know their time is short—that one of these storms is going to do them in for good—because over the past couple of days, they’ve been laying eggs all over the place.

There are new clusters on the fence posts, on the rosemary, and even on my office deck.

Though the adults will succumb to the weather, their eggs will rest snug all winter in their cosy egg capsules—a promise of the spring to come.

Predictability

May 19, 2016 / Robinne Weiss / Leave a comment

She’s occupied the same plant for weeks. Her neighbour, on the next plant over, is equally predictable.

There isn’t a huge body of research on why people don’t like insects and spiders, but the studies that have been done have concluded that one of the main problems people have with creepy crawlies is their unpredictability. They could jump, bite, sting, run, fly…and most people can’t predict what an insect will do next.

But I’ve come to realise that insects and spiders are, in fact, highly predictable.

For three years (its entire adult life) there was a metallic green ground beetle underneath the goats’ water barrel. It was there every time I looked, and I came to depend upon it to be there for Bugmobile programmes (along with two or three others whose ‘addresses’ I knew).

Until age and winter claimed her, I had an Australian orb weaver who I would pluck from her hiding place in the morning, take to a bug program, and return to her home in the afternoon—day after day, week after week.

A bee or wasp will always be the first insect to fly out of a sweep net, so you can quickly let them go before seeing who else you’ve caught.

If you put two adult male crickets together in a cage, they will always chirp.

A ladybug will always climb up an object, and fly away when it gets to the top.

A bee will not sting unless it feels threatened.

Most spiders will quickly rappel to the floor when frightened.

In fact, because insects and spiders behave largely out of instinct, they are incredibly predictable.

But, of course, you have to spend time with them to know that. You have to pay attention to them, instead of just stomping on them when you see them. You have to learn their ways. You have to behave predictably around them, in order to note that they are predictable themselves.

Somewhere, there is an insect research project going on to try to figure out why insects are so frightened of people. I suspect the bugs will find it’s because we’re so unpredictable.

I’ve Got This Bug

May 11, 2016 / Robinne Weiss / Leave a comment

Pseudocoremia leucelaea

“So, I’ve got this bug?”

I grimaced into the phone. It was going to be one of those calls.

One of those calls where the caller expects me to identify an insect over the phone. An insect they didn’t really look at terribly closely and didn’t bother to collect.

“It’s sort of brown, with long feelers. What is it?”

I try to help. I try to tell people where and how they can get their bug identified, but sometimes I think I’m just talking into the wind. Most of the time I’m sure they hang up thinking, “Well, she didn’t know much, did she?”

Here’s the thing.

Even in New Zealand, which has a very limited number of insects, compared with other places in the world, there are 10,000 species of insect to choose from.

Some are iconic, to be sure. Some are easily recognisable.

Many are not. Many look different as an adult than they do when young. Sometimes males and females look very different. Colours and markings can vary from individual to individual. Some features are only visible under a microscope. And verbal descriptions are less than useless.

So when a person says an insect is brown, I wonder whether it is a dark chocolate sort of brown, a reddish brown, a light brown…because “brown” could be anything.

When they say it’s “about a centimetre long” I wonder whether it is closer to 9 millimetres or 11 millimetres, because it might matter.

When they say, “It looks sort of like a huhu grub” I wonder what features make them say that. Is it legless? Is it a creamy white colour? Or is it just that they’ve seen pictures of huhu grubs and it’s the only thing they can think to compare it to?

When they say it’s got long feelers, I wonder whether those antennae are filiform, moniliform, pectinate, capitate, or serrate.

When they say it has clear wings, I wonder whether it has two or four. And whether those wings are fully clear, tinted, or partly covered in scales.

I wonder how many tarsal segments its legs have.

I wonder whether it has setae on its tibia. And if so, how many, and what size they are, and how, exactly, they are arranged.

I wonder what the shape of the marginal cell on the front wing is. Or whether the wing venation is reduced, or whether the wing is fringed at all.

Sometimes, someone can describe an insect in detail to me over the phone, and I am baffled. Then they bring me the insect, and I can immediately identify it, and it looks nothing like I imagined from the description they gave.

I’m always happy to try to answer people’s entomological questions, but sometimes I feel like one of the three blind men trying to identify an elephant by feeling just a small part of it’s body.

Mosquitoes, Disease, and Environmental Change

May 2, 2016 / Robinne Weiss / Leave a comment

With Te Waihora/Lake Ellesmere just a few kilometres away, we’ve always had mosquitoes at our house. But since we installed a small pond, the mosquito population of our property has gone up (in spite of the fish, which do eat a lot of them).

Though mosquito identification is not my forte, most of the mosquitoes appear to be Culex pervigilans, the common house mosquito, or vigilant mosquito. Like most of our mosquitoes, this species is endemic to New Zealand.

Because of the isolated nature of New Zealand, few of the world’s nasty mosquito-borne diseases have ever arrived here, and no human diseases have managed to arrive and spread. But that doesn’t mean they couldn’t, if given the opportunity.

Whataroa virus is an Australian bird virus, which may also produce flu-like symptoms in people. In New Zealand, it has been found only in the area around the small West Coast community of Whataroa. It was first detected in 1962, and recent surveys show it has not increased in prevalence since then. In New Zealand, it is vectored by Culex pervigilans, which is common throughout the country.

So why hasn’t it spread?

Well, we don’t know for certain, but to get a clue, it’s worth looking at why other mosquito-borne viruses spread. Most emerging diseases come on the heels of environmental change—when the habitat changes, mosquito populations may increase (many mosquitoes do well in disturbed habitats), or the virus’ other hosts may increase or move around, spreading the virus. Environmental changes can be natural, like seasonal flooding; or human-induced, like cutting native forest (or digging a pond…).

Which brings us back to Whataroa, which hasn’t changed much at all over the past 50 years. There’s been no great increase in mosquito habitat, and little development that would favour the non-native blackbirds and thrushes that appear to be the reservoir for the virus. So the Whataroa virus has simply languished in place.

If the Whataroa virus had arrived at another location, it might have already spread far and wide (as avian malaria has done over the past 40 years). If a developer had come into Whataroa and built golf courses or fancy subdivisions, it might have spread. When the next big Alpine Fault quake happens, the resulting destruction will likely create new disturbed habitat for mosquitoes, blackbirds, and thrushes, and Whataroa virus might spread with them.

All sorts of variables determine whether and when a mosquito-borne disease becomes a problem. Some of these are known, and under our control, but many are either not understood or are out of our control. Sometimes, the only thing we can do is to react when trouble strikes.

Which is, of course, my excuse for swatting this mosquito when it landed on my arm this morning.

Rocket Spider

May 1, 2016 / Robinne Weiss / Leave a comment

One of my favourite spiders here is an Australian invader. Officially known as the Australian ground spider Nyssus coloripes (formerly Supunna picta), but at Crazy Corner Farm, we invented a more colourful name, the rocket spider.

Rocket spiders have colourful orange front legs and white spots down their sides, making them stand out wherever they are.

They are in a group of spiders known as the fleet-footed spiders, and they are most definitely that. They are active daytime hunters, and race around as though they are rocket-propelled.

There is a female rocket spider who lives in my office. She’s been there for the better part of a year now, and zips over my bookshelves, desk, and walls as I work. She’s not shy—I sometimes have to shoo her off the keyboard, and once she skittered across my face.

I’m sure the rocket spider finds plenty of flies to eat in my office, but these spiders have unusual tastes. Though rocket spiders don’t build webs to catch food, I’ve seen them in the webs of Australian orb weavers—eating the orb weaver.

It’s a spider eat spider world, after all.

An Unusual Moth

April 29, 2016 / Robinne Weiss / Leave a comment

One day last week I was folding the laundry, which had been hanging out on the line all day. As I shook a t-shirt to fold it, up flew a tiny moth. When it landed again, I noticed that it looked odd. It sat with wings wrapped around it, a bit like a grass moth. But it held its spiky back legs high in the air, unlike any moth I’d seen. I took a couple of photos, none of which came out great—the iPhone just wasn’t made for macrophotography.

Still, even with a grainy photo, I was able to identify the moth to the genus Stathmopoda.

That’s where it started to get weird.

Everyone knows that butterflies and moths start off their lives as caterpillars, and that caterpillars eat plants, right?

Not so, in the genus Stathmopoda. Instead of munching leaves, the caterpillars of Stathmopoda eat other insects.

Yes, they’re carnivorous caterpillars.

They prey primarily on scale insects, so some species are actually used as biological control agents to help control these pests.

They are not the only carnivorous caterpillars. Though carnivory is rare among butterflies and moths, it has evolved separately several times in at least eight different lineages. Most carnivorous caterpillars eat small, slow-moving or sedentary insects, as you might expect from an animal that is neither speedy nor particularly formidable itself. As far as we know, there is only one moth that is carnivorous as an adult—the ‘vampire moth,’ Calyptra eustrigata, which feeds on the blood of ungulates.

I’m quite happy that this little Stathmopoda is carnivorous. Our currants suffered a bad case of scale insects this summer, so I hope there are lots more Stathmopoda out there. Here’s wishing it great reproductive success in the garden!

The Aphipocalypse

April 9, 2016 / Robinne Weiss / Leave a comment

It has been years since I’ve seen an aphid infestation quite this bad, and rarely at this time of year.

As I’ve mentioned before on this blog, I usually have aphids in early spring, and then the predators and parasitoids knock them back to almost nothing through the summer.

But somehow, the predators and I all missed the aphids on the pumpkins. I expect the warm dry summer was perfect for their growth. I rarely take note of the pumpkins from December to April—they need little weeding, and are generally pest free.

So when I went to harvest, it was a bit of a surprise to find millions of aphids on the underside of nearly every leaf in a back corner of the pumpkin patch.

All summer, the aphids have been cloning themselves, producing dozens of replicas every week—an army of little green girls. Only girls. It wouldn’t have taken them long to build up the population level out there right now. Some of the generations of aphids had wings (you can see some on the left side of the leaf in the photo), and dispersed to other plants, but most stayed put, slowly spreading across one leaf after another.

But, as big as the population is today, they will all die over winter. About this time of year, the females will start producing a few males—also genetically identical to themselves, with the exception of a missing sex chromosome. Only in the fall will females mate and produce eggs. The eggs will overwinter, hatching out in spring (all female) to start the cycle over again.

I think I won’t wait for these girls to lay eggs. I’m afraid that, now that the pumpkins are gone, the infested vines will be dunked in a bucket of soapy water and buried deep in the compost pile. No sense in letting them get a head start on next spring!