BioKIDS home

Kids' Inquiry of Diverse Species

Pholcidae

What do they look like?

Like all spiders, cellar spiders have two body-segments, a cephalothorax in front and an abdomen behind. They have eight legs, all attached to the cephalothorax. Cellar spiders have very long thin legs compared to other spiders. Their legs are many times longer than their bodies. Because of this they are sometimes called "daddy longlegs spiders", though they are not related to the other "daddy longlegs," which are Harvestmen. On the front they have two small "mini-legs" called palps. These are used to grab prey, and in mating, and are much bigger in male spiders than in females.

Different species of cellar spiders have six or eight eyes, and the size and arrangement of eyes is different in different groups. Cellar spiders have fangs that they use to bite their prey with, and have venom glands, but their fangs are very short. Their color varies from light tan to grayish-brown.

Female cellar spiders are often much bigger than males.

  • Sexual Dimorphism
  • sexes alike
  • female larger
  • Range length
    2.0 to 10.0 mm
    0.08 to 0.39 in

Where do they live?

There are hundreds of species of cellar spiders found all over the world. One species in particular, Pholcus phalangioides, is particularly comfortable living in houses and other buildings, and so has been spread all around the world by people moving around. Only a few species occur in Michigan, but they are common in basements and unused buildings.

What kind of habitat do they need?

These spiders prefer to live in dark places: in caves, cracks and crevices in rocks, unused animal burrows, and in the dark and quiet parts of buildings.

How do they grow?

Cellar spiders hatch from eggs, and the hatchlings look more or less like grown-up spiders, though sometimes their colors change as they age. To grow they have to shed their exoskeleton, which they do many times during their lives.

How long do they live?

We don't know for sure how long these spiders live, probably only a few years at most, and very few probably make it that long.

How do they behave?

Most cellar spiders don't move around too much, they usually stay with their web, or raid nearby webs. They often hang upside down while waiting for prey to touch their webs. They are not social animals, they only come together to mate.

How do they communicate with each other?

Spiders in this group probably use touch and chemicals to communicate, though they can see too. They are also very sensitive to vibrations in their webs.

What do they eat?

Like all spiders, cellar spiders are predators. They eat insects, spiders, and other small invertebrates. They spin a large loose, three-dimensional web (not flat like orbweavers) that is not sticky. They use their web as a kind of prey-detection system. When a passing insect bumps into it, they come running out and grab it and bite it, then wrap it in silk. Ants are particularly common prey.

Many cellar spiders also raid the webs of other spiders, eating their prey and the spiders themselves. They sometimes hunt around the edges of the webs of female spiders of other species. Males who come to mate with the female may get eaten by the cellar spider instead.

  • Primary Diet
  • carnivore
    • eats non-insect arthropods

What eats them and how do they avoid being eaten?

Cellar spiders mainly avoid predators by living in dark places. If their web is touched, they sometimes vibrate back and forth very fast. We don't know for sure why they do this, maybe to make themselves harder to see.

How do they interact with us?

These spiders are not dangerous to people, and they sometimes eat insects that are pests to humans.

Are they endangered?

No cellar spider species are known to be endangered.

  • IUCN Red List [Link]
    Not Evaluated

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

carnivore

an animal that mainly eats meat

chaparral

mid-altitude coastal areas with mild, rainy winters and long, dry summers. Dominant plant types are dense, evergreen shrubs.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.

internal fertilization

fertilization takes place within the female's body

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Climbing plants are also abundant. There is plenty of moisture and rain, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

taiga

this biome is characterized by large expanses of coniferous forest, there is an extended cold season and heavy snowfall.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

 
University of Michigan Museum of ZoologyNational Science Foundation

BioKIDS home  |  Questions?  |  Animal Diversity Web  |  Cybertracker Tools

. "Pholcidae" (On-line), Animal Diversity Web. Accessed April 24, 2014 at http://www.biokids.umich.edu/accounts/Pholcidae/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
Copyright © 2002-2014, The Regents of the University of Michigan. All rights reserved.

University of Michigan