The puss moth caterpillar’s ‘eyes’ are only for display
A colleague working for Surrey Wildlife Trust kindly guided me to the location of this wonderful puss moth caterpillar (Cerura vinula) yesterday. A pair of them were contentedly grazing on aspen leaves.
Puss moth larvae feed on poplar, willow, or here on aspen
In adult form the furry grey and white moth flies at night between the months of May and July. The larval form looks much more exotic. The gawdy pink ring around its face gives the puss moth a very distinctive appearance.
Head end of puss moth caterpillar
If disturbed the puss moth caterpillar extends two whip-like appendages from its tail end and flails them around to deter attackers. It’s a bizarre and unexpected thing to witness.
Puss moth caterpillar with extended ‘tails’
‘Tail’ detail of puss moth larva
It also has the ability to squirt formic acid from its thorax if further provoked, but I didn’t try that!
Shortly before pupation the caterpillar will change to a fetching shade of orange, and then again to purple.
It spins a cocoon of silk around itself and uses bits of tree bark as camouflage to stay hidden for the winter. The resulting cocoon is one of the strongest constructed by any UK moth.
I will have to return to see if I can find it in its various rainbow stages of development.
Periodically snakes and other animals shed their entire skins, in a process known as ecdysis (or sloughing, or moulting).
Moulting takes up to 14 days to complete. The inner surface of the old skin liquefies, which causes it to separate from the new skin beneath it. By rubbing its skin on hard objects the end nearest the head begins to peel back on itself, until the snake is able to crawl out of its skin, turning it inside-out like a sock.
Head end of moulted adder skin
The ocular scale, or ‘brille’, is discarded along with the rest of the skin. This is essential for maintaining the snake’s quality of vision.
Adder skin showing ocular scale detail
The visually striking process of renewal exhibited by these animals is one reason why serpents have historically been symbolic of healing and medicine in our culture.
Adder skin with side illumination
Snake skin is formed from the remarkably adaptable substance keratin. Some of its properties are best appreciated in close-up:
Backlit adder skin detail
Underside of adder skin showing transparent keratin scales
This particular skin was found on heathland, woven in amongst some dried grasses. We later stumbled across a stunning, newly sloughed, caramel-coloured female sunning herself nearby.
You’d think that arachnids and water was an unhappy combination, but one species of European spider has made boggy ponds their home.
The raft spider (Dolomedes fimbriatus) is the UK’s largest native spider – its body growing up to 2cm long.
It uses the water’s surface like other spiders use their webs – feeling for the vibrations of potential prey with front legs extended. Using this technique it hunts tadpoles, insects and occasionally small fish:
Raft spider eating damselfly
When alarmed, the water repellent hairs on the raft spider’s legs enable it to dive beneath the water, trapping a bubble of air to keep it alive until the coast is clear and it cautiously re-emerges:
The wetland pools favoured by raft spiders are increasingly rare in this country. On the RSPB’s Arne reserve in Dorset their habitat is lovingly preserved, and offers wildlife watchers easy access from the nearby heathland trail:
Boggy pond habitat
On a good day dozens of raft spiders at various stages in their life cycle can be witnessed at the pond’s edge.
The female raft spider is often considerably larger than the male and mating is a dangerous business. He approaches her cautiously, waving his front legs tentatively to judge her receptiveness:
Male raft spider approaches female at her den
She may rush out to scare him off on numerous occasions, after which she retreats and the process begins again, the male edging closer all the while. It’s a nerve jangling thing to watch, let alone participate in.
The female spins a silk bag to contain the fertilised eggs, which she carries about beneath her body, keeping it just warm and moist enough to ensure their survival:
Raft spider carrying egg sac
Then, when the baby spiders are ready to hatch, she lashes the egg sac to vegetation at the edge of the pond and the tiny hatchlings emerge:
Baby raft spiders in nursery web
Mum typically lies in wait nearby to ensure that her young ones don’t come to any harm:
Raft spider guards her hatchlings
This phenomenon of hundreds of spiderlings crowded together for their own mutual safety is only really appreciated up close:
Raft spider hatchlings closeup
But soon the young raft spiders are large enough to fend for themselves and disperse around the pond.
Raft spiders are not fussy eaters. When times are tough and food is scarce, or when too many raft spiders compete for the same local resources, they may even turn to cannibalism: