Every October, shops fill up with fake cobwebs. The real thing is already hanging by your door. The garden cross spider (Araneus diadematus) is one of the most common spiders in towns and gardens, and she is active from June to November, which makes her a Halloween regular. The Wildlife Trusts describe the large white cross on her abdomen, made up of pale spots and streaks on a grey-brown or reddish-brown body. That cross is where her name comes from.
She is also harmless to humans. She spins a spiral-shaped orb web, waits in the middle and feels the vibrations when an insect lands in the sticky threads. The webs are built by the larger females, which is why the spider in the middle of a big web is usually a "she" (Wikipedia, citing the British Arachnological Society).
In this Scan of the week, Pori finds one in her web by the courtyard lamp at dusk and scans her. Both spider photos are real observations shared on iNaturalist; the courtyard, the lamp and Pori are drawn.
The Easter egg flies past the same lamp. Did you spot the bat? It is a common pipistrelle (Pipistrellus pipistrellus), the bat you are most likely to see around a garden. It weighs around 5 grams and usually comes out about 20 minutes after sunset, according to the Bat Conservation Trust. Spider and bat both work the night shift by the lamp, and neither of them needs a costume.
Scan of the week is part of our pilot of short clips that send young people outside, ideally with someone, to find one real species near them.
Found in this clip
- garden cross spiderAraneus diadematus
- common pipistrellePipistrellus pipistrellushidden in the clip
Try it outside
This evening, or on the way home from school, look at the lamps by your door, in the courtyard or in the garden, with your family, friends or your class. Orb webs show up best against the light. Count the webs you find and look for the spider in the middle, or hiding at the edge. Look, don't touch, and leave the web where it is; she needs it for her dinner.
Porini is free for schools.
Start a Porini seasonSources
Illustrations made with AI; the spider photos are real.
All field notes