A diversity of spiders

Written by Lucy Brzoska

If you wish to live and thrive, let the spider run alive 

Enthroned in a Pitch Trefoil flower, the Heather crab spider (Thomisus onustus) had arrayed its legs like a multi-limbed deity.  The colour of raspberry-ripple ice cream, it blended in well with the purple bloom where it meditated, invisible to prey and predator.  Enormous forelegs lay in wait.

It’s always worth getting up close and making eye contact with a Jumping spider. This female Carrhotus xanthogramma was spotted on a Common Smilax leaf.  

Her abdomen has handsome tawny markings.

Shining a torch in a spooky underground chamber in the middle of Collserola’s woods revealed a colony of Meta bourneti – a Cave Spider of the Tetragnathidae family.   The light cast great leggy shadows on the vaulted walls and picked out the prominent black bristles.  Like other Orb spiders, these cave-dwellers rely mainly on these touch sensors to hunt.  They seemed to hang in mid-air, perfectly in tune with the vibrations in their nearly invisible webs.

The Wasp Spider (Argiope bruennichi) adds drama wherever it sets up camp.  There were several alongside Vallvidrera reservoir at the end of summer.  They’d slung their webs low down in the grass where dragonflies cruise.


 

Zooming in on Montjuic Castle (i)

Written by Lucy Brzoska

You barely notice the ants unless they’re lugging some eye-catching, outsize object, such as the remains of a woodlouse.  It was an awkward task, requiring tenacity and strong pincers.

ants-carry-woodlouse

Team effort successfully manoeuvred the crustacean through the crack.  There was barely any flesh on it but woodlice themselves will eat their own or each other’s cast-off cuticles.  The hard, over-lapping armour plating is made of calcium carbonate, a form of calcium we get in dietary supplements.  In any case, ants bring back all kinds of booty to  their galleries, edible or not.

ants-squeeze-woodlouse-through-hole

A jumping spider was darting among the busy ants:  Menemerus semilimbatus, a Mediterranean species often found on sunny walls and rocks.  Upside-down, it surveyed me with a fine set of four bright eyes.

jumping-spider-menemerus-semilimbatus

The other four are located on the carapace, slightly disconcerting until you get used to it.  Two of them are clearly visible here.

menemerus-semilimbatus-jumping-spider-from-above

Salticids are renowned for their visual acuity.  They hunt by stealth and pounce with deadly accuracy.  In their courtship dancing, the males often flaunt brightly coloured parts of their body.  Some species have impressive John Travolta disco moves (click on second image down).

Another movement caught my eye and I was just in time to see a soft downy feather disappear through a hole, as an ant whisked it into the depths of the castle wall.  You can only wonder what use the ants would find for it.

ant-carries-feather