Life in the Undergrowth


Just like mammals, invertebrates do not always operate alone. In tonight’s episode we meet communal spiders: an arachnophobe’s nightmare. One newly-discovered species even behaves like army ants, marching through the rainforest.

True sociality was the last feature to evolve in invertebrates, as recently as the time of Tyrannosaurus. In this last episode we see the tensions below the surface in some of the great social structures built by insects, and witness the carnage when an ant colony and a termite colony wage war.

LIFE IN THE UNDERGROWTH, Saturday 24th November at 7.30pm


The world of invertebrates is a web of relationships with plants and other animals, and tonight’s episode is full of incredible stories.

There is the Brassia orchid which mimics a spider in its web, attracting spider-hunting wasps – a system that is taken advantage of, though, by a crab spider that lurks on the orchid and eats the duped pollinators, which would normally be their worst enemy. Then there is the newly-discovered blister beetle, whose larvae huddle together on the end of a piece of grass and mimic a female bee. When a male bee attempts to mate with the ‘female’, the larvae grab onto his belly. Confused, he flies away and searches for a real female. When he eventually finds her and mates with her, the beetle larvae hurriedly swap from his front onto her back – and hence get carried back to her nest where they eat her pollen supplies.

Life in the Undergrowth – Saturday 17 November

Silk is the invertebrates’ great invention. From the protective stalks of lacewing eggs to the amazing strength of a silkmoth cocoon, many groups use it. The spiders, though, have taken it to extremes.

The rainbow web spider uses special UV-reflectant silk in the centre of its web, making it invisible to the insects – but beautifully iridescent at the right angle.

Then there is the bolas spider that uses a ball of sticky silk soaked in a copy of moth pheromone to lure them in. The newly discovered Evarcha spider demonstrates the most amazing behaviour yet known, shown on film for the first time.

It feeds on the blood of vertebrates – but does not have the mouthparts to pierce vertebrate skin. So Evarcha singles out and stalks mosquitoes like a cat, then lunges at their blood-filled bellies, sucking them dry at the rate of 20 per minute.

LIFE IN THE UNDERGROWTH, Saturday 10th November at 7.30pm