Famiglia: AGELENIDAE

Nome comune: Ragno delle case

Nome scientifico: Tegenaria domestica (Clerck, 1757)

Global distribution (WSC 2021): Europe, North Africa, Turkey, Caucasus, Middle East, Russia (Europe to Far East), Kazakhstan, Central Asia, Mongolia, China, Korea, Japan. Introduced to Australia, New Zealand, the Americas

GPS (Neapolis):

37.076328, 15.275567

37.076547, 15.275792

37.076275, 15.276346

Caratteristiche anatomiche: L’ampia distribuzione e la consueta presenza nelle cantine o in altri ambienti bui e umidi delle case hanno reso questo ragno così familiare da attribuirgli un nome scientifico e comune da “coinquilino”. Di aspetto allungato nelle forme del corpo, ha delle zampe anch’esse molto lunghe, in rapporto di circa il 60% del corpo, ricche di peli tattili molto sensibili alle vibrazioni. Il colore va dall’arancione scuro al marrone, con due strisce nere sul (cefalotorace) e screziature giallo e grigio sull’opistosoma (addome).

Comportamento: Abitatori di luoghi bui e umidi formano abbondanti popolazioni se trovano condizioni ideali, non è difficile osservare intere pareti di grotta ricoperte da tele di T.domestica (esempio orecchio di Dionisio). Le ragnatele che costruiscono vengono definite “a lenzuolo”. Fondamentalmente sono costituite da due “ambienti” un imbocco centrale a forma di tunnel in cui il ragno attende la preda, mostrando spesso soltanto il primo paio di zampe utili a saggiare la tela di cattura, e un “lenzuolo” orizzontale, costituito con seta non appiccicosa, sul quale le malcapitate prede, colpendo dei fili di seta verticali, precipitano e spesso divengono il pasto dell’abile costruttore.

Peculiarità: Nelle vicinanze delle tele di T.domestica, si possono spesso osservare delle “sacche” ricoperte di sedimento sospese con un filo di seta. Queste sono i cocoon, in cui sono contenute le uova del ragno: in tal modo, le distanzia dalla parete e quindi da eventuali predatori di uova del micromondo,  mentre il camuffamento, dato dalla copertura con il detrito, le protegge da predatori.

Anatomical features: Its wide distribution and usual presence in cellars or other dark, damp rooms in houses, have made this spider so familiar that it has been given a scientific and common name of 'housemate'. With an elongated body shape, it has legs that are also very long, about 60% of the body, and are rich in tactile hairs that are very sensitive to vibration. The colour ranges from dark orange to brown, with two black stripes on the (cephalothorax) and yellow and grey mottling on the opisthosoma (abdomen).

Behaviour: Inhabitants of dark, damp places, they form abundant populations if they find ideal conditions, it is not difficult to observe entire cave walls covered with T.domestica webs (e.g. Dionysius' ear). The webs they build are called "sheet-web". They are basically made up of two "environments": a central tunnel-shaped entrance where the spider waits for its prey, often showing only the first pair of legs to test the capture web, and a horizontal "sheet", made of non-sticky silk, on which the unfortunate prey, hitting vertical silk threads, falls on, often becoming a meal for the skilled constructor. 

Peculiarity: Near the canvases of T.domestica, one can often observe "pockets" covered with sediment suspended with a silk thread. These are the cocoons, in which the spider's eggs are contained: in this way, it distances them from the wall and thus from possible predators of eggs of the micro-world, while the camouflage, given by the covering with detritus, protects them from predators.

In the context of the global decline in invertebrate (insect and spider) populations and species diversity, we invite you to join us in a collaborative mapping exercise: to notice and become sensitive to spider/web ecologies. Through this shared activity, we hope to map spider/web species richness and diversity within the multispecies ecologies that we share.

Recognising the history of mapping practices in establishing geopolitical divisions and boundaries that exclude and reinforce hierarchical distributions of power and claims to land and natural resources, we imagine these as spider/web counter-cartographies, an attempt to tell the neglected histories of spider/webs. In these counter-cartographies, mapping is engaged as a means of visualising and raising awareness of spider/web habitats as constitutive elements of broader, more-than-human ecologies. Collective mapping allows us to access new scales and new points of view through which to collaboratively think through concepts of multispecies care, extinction, and the possibilities for living together in catastrophic times.

Insect life far outweighs human life: insects make up half of the 2 gigatons of animal life on this planet. It is often hard to reconcile the idea of extinction with creatures that seem so abundant. However, according to recent data, insect populations are declining at a rate of 2.5% per year - suggesting that they might be extinct by the end of the century. A number of scientists have argued that we are now bearing witness to the dawn of a sixth mass extinction. An insect armageddon would be catastrophic for human and other forms of life. Invertebrate animals (insects and spiders) are critical elements of our shared and entangled ecologies: among other things, insects are responsible for pollination of mainstay crops, decomposition of organic material (creating the humus that is an essential component of fungal, bacterial and life cycles), and also providing a critical food source for birds and other higher order animals.

Essentially - the death of insects would trigger a catastrophic ripple effect in the ecologies and systems that support life on Earth; what scientists have called a “bottom-up trophic cascade”, whose knock-on effects would be disastrous for both plant and animal life.

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