Hunting the Hunter (Part 1)

You would think that a spider as robust (and venomous) as a huntsman spider (Sparassidae) would be pretty safe from predatory and parasitic insects. But not so. This article is the first in a series on the insects which make a meal of large spiders.

A few years ago I witnessed a titanic struggle taking place on a window at the front of our house. A large spider hunting wasp (or ‘spider wasp’) was pulling a huntsman spider backwards up the window glass.

Wasp and huntsman

This spider is a female of the species Cryptocheilus bicolor of the order Pompilidae. These gorgeous black and orange wasps find a large spider and sting it to paralyse it.The female spider wasp doesn’t feed on the spider herself – the spider is food for her offspring.

Earlier that day I had seen our wasp digging a nest hole in the sand bank at the rear of our house. Many species of spider hunting wasps place their prey in a nest in the ground (one spider per cell) and lay a single egg on it. The hatching wasp grub feeds on the live but immobilised spider.

I saw her trying to fly with the spider but she could barely lift it off the ground – her wings were damaged as you can see from the image above. Dragging the spider was her best option and she was attempting a shortcut up over the house rather than going all the way around!

The glass was slippery and the spider was heavy and down down down she would slip – sometimes all the way to the ground. Each time she fell down she started the climb again. I have no idea why she insisted on going up glass rather than up the house bricks where she would have had more grip.

Eventually after about half an hour of this frustrating struggle she gave up and began hauling the spider around the house – a distance of about 50 meters. She accomplished the task of dragging the spider to her nest in just a few minutes. After about an hour she emerged from the nest and flew away. I assume she had laid her egg and had no more interest in the nest.

When spider wasps move around on the ground they move in a jerky ‘stop start’ manner and constantly flick their antennae and wings. The video below shows typical spider wasp behaviour (featuring a different individual to the one described above).


There are about 230 species of spider hunting wasps (Pompilidae) found in Australia. This is only one of the groups of insects which attack spiders – there are many more. The image below shows some insects from one such group. What are they? You’ll have to wait for the next ‘one minute bugs’!



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Simply irresistible

The Grampians region of Victoria is one of Australia’s richest and most diverse flora areas. One third of Victoria’s flora is represented here so it is no surprise that the region was once dubbed “the Garden of Victoria” by the great botanist Ferdinand von Mueller.

Spring is an excellent time to see wildflowers throughout the region, especially terrestrial orchids such as the Mantis Orchid (Caladenia tentaculata) pictured below. It is one of the green-comb Spider Orchids and is common throughout the Grampians region. The colourful and flamboyant flowers of this orchid may be pleasing to the human eye but they are simply irresistible to certain male insects.

Caladenia tentaculata

The Mantis Orchid is one of many sexually deceptive orchids. Orchids such as these don’t have nectar to reward pollinating insects so they must attract insects some other way.  The orchids lure male insects to their flowers with scents that mimic female insect sex pheromones. The labellum of the flower where the male insect lands is hinged and swings the insect against the sexual organs of the flower. During its struggles to mate with the flower the insect will either pick up pollen, or deposit pollen that it has acquired from another flower.

The insect pollinator of the Mantis Orchid is a thynnine wasp of the family Tiphiidae. These wasps are the most important insects which pollinate Australian terrestrial orchids by pseudocopulation. The wasps are also remarkable because males are winged and females are wingless. A female wasp finds a mate by advertising her presence with pheromones, the male picks her up and mating occurs in flight. It is quite common to see mating pairs flying around our property. A mating pair of thynnine wasps is pictured below.

Thynnine wasps

All this flying around while mating means the wasps stay in a coupled position for a prolonged period of time. To facilitate this, both sexes have evolved unusually shaped genitalia that include spines, grooves and other structures, so that they don’t accidentally disengage. But why don’t the females have wings? Some female flower wasps are parasites of beetle larvae and mole crickets located underground. Winglessness allows females to dig underground and hunt for prey without risking damage to delicate wings. This probably sounds exotic and unusual, but wasps of the family Tiphiidae are common in Australia, in fact we have about 700 native species.

Thynnine wasps are not the only insects lured into pseudocopulation with native orchids. I think I have space for one more story which should be titled “How not to photograph a pseudocopulating insect“. One November some neighbours showed me Large Duck Orchids (Caleana major) flowering on their property. As you can see below they are spectacular flowers that resemble flying ducks, so I grabbed my camera for some shots.

Caleana major

Within minutes of me starting to shoot the orchids an insect arrived and landed on one of the flowers. “Holy cow”, I thought. “It’s the pollinator!” Heart racing I tried to capture the insect but in my excitement I tripped over my tripod and almost flattened the orchid! By the time I got myself organised the insect, a type of sawfly, was trapped inside the orchid and was barely visible. I did get a couple of shots of the insect emerging but they are pretty terrible (see below).

Duck Orchid pollinator

How did the orchid trap the insect? The ‘head’ of the duck is the lid of a trap which swings down by the ‘neck’ trapping the insect inside the ‘body’. In it’s struggles to escape the insect is covered with pollen and will transfer that to the next flowering Large Duck Orchid it is attracted to. Hopefully one day I can have another crack at these shots and try not to be overwhelmed by the occasion!

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Insect Architects

After a few months off for house painting one minute bugs is back!

I was prompted to write this post after completing an article for Hort Journal Australia on a similar topic. My argument in the Hort Journal piece was that insects are not mathematical or engineering geniuses, and that their behaviour is dictated by the instincts they have evolved with. All very scientific and anti-anthropomorphic. The post here is a bit different. Let’s marvel at the exquisite perfection of some of the structures that insects build.

Our first architects are moths of the family Psychidae – the case moths. These are harmless creatures found in most gardens throughout Australia. Cases are spun by caterpillars from silk to which twigs, sand, moss, lichen, leaves or bark are attached. The cases can open and close at each end, the front end for feeding and the rear end for ejecting droppings. I believe the species illustrated below is Lepidoscia arctiella – look at how precise those little bits of twig are!


Continue reading Insect Architects

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