Sometimes the spider wins

I often see a wasp in summer, dragging around a spider larger than itself, whose legs it has have ripped off the spider’s paralysed body. The wasp places the body in its egg chamber, all nice and fresh for the wasp’s larvae to eat when they hatch. Horror movie stuff, but that’s Nature sometimes. She doesn’t have human morality.

But occasionally it’s the other way around. I found this struggle on my umbrella yesterday.

Huntsman eats wasp; the spider is Holconia immanis, ID courtesy of Samii Lawson, Amateur Entomology Australia Facebook group

The huntsman was about 3 cm from tip of cephalothorax to tip of abdomen – a medium size for our subtropical species. They are great at keeping cockroaches in the house down, too.

This spider would have been fast to catch the wasp, and it is a fast hunter, but perhaps it was inspired by the thought of all its paralysed brethren.

Meanwhile in Cape Town … the spider invasion

Friend Jane says there’s been an influx of Nephila fenestrata, the black-legged golden orbweaver, into suburban Cape Town. Where she lives, the strong webs of these spiders are being strung across walking paths as well as gardens. Luckily, it’s easy to gently reposition them manually, and the spiders aren’t disturbed.

Nephila fenestrata female, ventral view; photo by Jon Richfield, Wikimedia Commons

Female, dorsal view; photo by Jon Richfield, Wikimedia Commons

She says:

It’s only recently that they’ve decided to go suburban but they seem to be in many gardens now, although not in quite such rampant numbers as mine – people are beginning to come and take pictures.

These spiders are native to southern and eastern Africa. You can see a photo of the large and strong web at Biodiversity Explorer, which says:

Nephila fenestrata, the black-legged nephila, occurs over most of South Africa, excluding the arid central and western regions, and is the only species of Nephila to occur in the Western Cape. Since 2002 this species has crossed over the Hottentots Holland mountain range and is now the most commonly seen orb-web spider on the Cape Peninsula. It can be seen from January till the end of June or even to the end of August, usually in forested areas or near areas with trees allowing for suspension of their large orb-webs. In Kirstenbosch and Newlands Forest one can easily see 30 or more of these spiders on a walk.

Wikipedia says of Nephila in general:

The webs of most Nephila spiders are complex, with a fine-meshed orb suspended in a maze of non-sticky barrier webs. As with many weavers of sticky spirals, the orb is renewed regularly if not daily, apparently because the stickiness of the orb declines with age. When weather is good (and no rain has damaged the orb web), subadult and adult Nephila often rebuild only a portion of the web. The spider will remove and consume the portion to be replaced, build new radial elements, then spin the new spirals. This partial orb renewal is distinct from other orb-weaving spiders that usually replace the entire orb web. In 2011 it was discovered that the web of Nephila antipodiana contains ant-repellent chemicals to protect the web.

Typically, the golden orb-weaver first weaves a non-sticky spiral with space for two to twenty more spirals in between (the density of sticky spiral strands decreases with increasing spider size). When she has completed the coarse weaving, she returns and fills in the gaps. Whereas most orb-weaving spiders remove the non-sticky spiral when spinning the sticky spiral, Nephila leave it. …

The circular-orb portion of a mature [US] N. clavipes web can be more than 1 metre across, with support strands extending perhaps many more feet away. In relation to the ground, the webs of adults may be woven anywhere from eye-level upwards high into the tree canopy. The orb web is usually truncated by a top horizontal support strand, giving it an incomplete look.

Adjacent to one face of the main orb there may be a rather extensive and haphazard-looking network of guard-strands suspended a few inches distant across a free-space. This network is often decorated with a lumpy string or two of plant detritus and insect carcasses clumped with silk. This ‘barrier web’ may function as a kind of early-warning system for incoming prey or against spider-hunting predators, or as a shield against windblown leaves; it may also be remnants of the owner’s previous web. At least one reference explains the suspended debris-chain as a cue for birds to avoid blundering into and destroying the web.

Indeed, some webs have captured small birds, but no one’s found that the spiders actually eat the birds.

I’m particularly fond of the species name for this spider as it is a Latin version of my surname 🙂

Jane says it’s on for young and old in a small patch in her garden:

I would never have thought 4 square metres could have held such variety. I was out in front chatting to my neighbour about how one of the nephila orbs had caught a gecko lizard and sucked out all its juices, leaving the dehydrated corpse in the web, which she’s still fiercely guarding. ‘Look,’ says Louise, and lo and behold behind that orbweaver a praying mantis is stalking a white butterfly – such drama – but the butterfly did escape.  Some butterflies have flown smack into the orbweaver’s curtain, but a surprising number manage to avoid it. A gorgeous black bumble bee managed to duck and dive, as do most of the damsel flies. Mind you, a little white eye bird (a tiny passerine) nearly copped it, but seemed to have rebounded off the web and got stuck in one of my sheets, which was hanging out to dry. I come indoors from the dazzling display to make a cup of tea and a triumphant jumping spider staggers across the kitchen counter with its trophy, a fly bigger than itself. Go spider! I’m having to move strands of orb nearly every morning or I’d be trapped in the house – great colonisers, these ladies.

Tiny treasures: the invertebrates

Some of the many enjoyable activities on the Hinterland Bush Links course involved the invertebrates of the subtropical rainforest. Our fearless leader was the enthusiastic Michelle Gleeson (of Bugs Ed and author of Miniature Lives).

Michelle Gleeson showing one of her bug boxes

 

 

 

 

 

These bug boxes, which Michelle uses for her educational presentations, contain a selection of impressive beasties not just from Australia but from all over the world.

Michelle led us to likely spots to catch bugs. First was the important occupational health and safety chat. Then we were shown how to use various pieces of equipment.

Then heads down and bums up …

Bugging in the blackbutt

Bugging in the rainforest (tutor and herpetologist/naturalist Tony Bright on the right)

 

 

 

Cat, polar bear guide extraordinaire, was pleased with her earwig larva …

Well, it’s white like a polar bear!

 

Here’s the famous bush-tucker, witchetty grub, wood-eating larva of one of several moths.

Witchetty grub

 

Don’t lean against a tree with the web below on it. Underneath the web is the highly venomous northern tree funnelweb (Hadronyche formidabilis). You can see the silk triplines that alert the spider to things crawling over the surface – then it will rapidly leap out and grab its meal, retreating under the web in a split second.

Web of the tree funnelweb, Hadronyche formidabilis

 

If you looked under that web, you would probably see one of these …

Male (left) and female (right) northern tree funnelwebs (Hadronyche formidabilis); photo Toby Hudson, Wikimedia Commons

The Australian Museum says:

Most funnel-webs are ground dwellers but a few live in trees. The largest of all funnel-webs is the Northern Tree Funnel-web Spider, Hadronyche formidabilis, reaching 4 cm – 5 cm body length. These spiders live in the wet forests of northern New South Wales and southern Queensland and have been found over 30 m above ground. While many have their retreats in surface-opening branch rot-holes, some spiders appear to live and feed entirely inside the deadwood pipe of large forest trees like Tallow-wood, feeding on beetles and other insects inside this rotting wood habitat.

That tree was alive, though.

There were a lot of spider holes in the ground. Tony Bright thought they’d belong to trapdoor or wolf spiders (not all trapdoor spider holes have trap doors). Sometimes they can go as deep as a metre.

This trapdoor was very well camouflaged by moss on top.

While we’re on the subject of spiders, there’s a good article on Australian huntsmen here.

Among other finds were the egg case of a praying mantis …

Praying mantis egg case (Orthodera ministralis)

 

and a case moth’s larva case …

Case moth larva case

 

Setting up a light trap at night did not attract many insects, perhaps because it was too cold …

But this cute little moth did appear …

Michelle told the intriguing story of the interaction between cycads and their pollinators, certain thrips, which eat the pollen. Science Daily writes about it here. Cycads come in separate male and female plants, and the males produce pollen for up to four weeks a year (depending on the cycad species). During this time, the male cone, in which the thrips live, heats up in the morning to something like 25 degrees above the air temperature, up to 38 degrees C (100 degrees F). This causes the thrips, with accompanying pollen, to leave as they can’t take the heat. The male cones also emit an airborne chemical toxic to thrips, making sure they go. The thrips float around and head for a female cone, which has emitted a pollen-like odour to attract them, and pollinate them with the pollen they’ve carried over from the male cone. (This is known as push-pull pollination.) The male cones cool down and stop emitting the toxic chemical later in the day, attracting the thrips back for another shot at the pollen, and round and round it goes for the pollination period. Cool, huh? Or hot, depending on the time of day. 🙂

Despite contracting scrub itch (aka chiggers in the USA – perhaps allowing your study subjects to get a little too close to you?), I have to wholeheartedly endorse Michelle’s message …

 

Lugging the luckless legless

Why are we not overwhelmed with insects and other small greeblies? Some would say we are, but think how many more there would be without them all preying on one another.

Birds eat spiders and wasps, which eat spiders, which eat … and I haven’t even mentioned ants. It’s not so much a food chain as a food web, with many, many links.

This time of year, lots of wasps are in action. The spider-eating wasp behaves like it eats spiders and it does, but in a round-about way. The adults actually eat pollen and nectar. The female builds a nest and chases down a spider, paralyzes it, cuts off its legs, places it in the burrow and lays at least one egg on the body of the spider. The hatchling wasp then has a ready food supply the moment its born – a fresh, living spider.

These wasps move very fast, with constant twitching of antennae. This one was trying to move the spider upward. It was having a hard time and kept falling down.

Fabriogenia species with de-legged and paralysed huntsman

It was having trouble with the size and weight, and eventually tried to take off …

… but fell to the decking and moved quickly out of sight, spider still in tow.

Brisbane Insects has a lovely shot of a spider wasp and huntsman in flagrante delicto, before the paralysis and de-legging.

It really is a jungle out there and there’s a lot going on, mostly out of range of our human ‘radar’. We may get bugged by all those spiders and insects, but there’d be a lot more of them without that tangled food web.

The silence in the forest

Walking along the tracks of Lord Howe Island’s palm forests was a strange experience. All I could hear was the wind through the palm leaves, the sea and the occasional rustle. At home when I hear rustling, it’ll be a brush turkey, a goanna, a snake, maybe a frog or three, or one of many, many birds. In the same month (November) at home, there’s also the ear-splitting stridulations (love that word) of cicadas en masse.

Lord Howe native kentia palm forest

Insect days

The warm and sunny autumn days of the last couple of weeks (until yesterday) have brought out the insects. The birds were probably very pleased when the rain stopped and they could get a decent feed.

I found a stick insect of my very own. This one ([update] a spur-legged stick insect, Didymuria violescens – thanks to Denis for the suggestion; see the comments below) was smaller than the last one – the length of the body about 90 mm, compared with 150 mm for the other one.

Stick insect

A bookish spider

Indulge my anthropomorphism for a moment …

“Know thyself”, wrote Plato, and this little spider is perhaps taking it to heart, trying to read a scientific tome.

"So many insects, so little time!"

But it’s reading the wrong book – the CSIRO’s “The Insects of Australia”. Perhaps I’ve misread its intentions, and it’s really trying to research its lunch!

The thing on the ceiling

Luckily for me, any spider phobia was nipped in the bud at an early age by my Dad. He used to laugh (not unkindly) when a small me confessed to being frightened to go to the outside toilet when the family were at our beach holiday shack. It was a classic Australian ‘dunny’ – wrought iron, blazing hot in summer, freezing in winter, a long-drop type with seat over a hole that Dad added lime to occasionally. When it filled up, he’d just knock fill  up the hole, dismantle the ‘building’, dig a new hole and re-erect the iron sheets. He was a plumber by trade and knew how to do these things, but most of the men who had shacks with their families on the beachfront in Australia (the ones that are left are still iconic Australian architecture) would have just done it themselves. Simple to construct and fairly ecologically sound for 10 shacks on the foreshore with no running water or electricity. Now those holiday villages have expanded and MacMansions, septic tanks, electricity and even running water are in evidence. Ah, progress!