biology

List of endangered spiders

List of endangered spiders is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand List of endangered spiders rather than just read about it. In short: An endangered species is "a species at risk of extinction because of human activity, changes in climate, changes in predator-prey ratios, etc., especially when officially designated as such by a governmental agency such as the U.S. Fish and Wildlife Service".

Key takeaways

List of endangered spiders belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect List of endangered spiders to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of List of endangered spiders from memory before moving on to harder problems.

Reference excerpt

An endangered species is "a species at risk of extinction because of human activity, changes in climate, changes in predator-prey ratios, etc., especially when officially designated as such by a governmental agency such as the U.S. Fish and Wildlife Service". A spider is a member of the order Araneae, one of many orders within the class arachnida, meaning it has a body consisting of two segments, a cephalothorax and an abdomen, as well as eight legs. All spiders are predators that feed off insects, and some larger species have been known to catch small reptiles, birds, and amphibians (Levi and Levi, 2002). Until recently, insects and arachnids have not been considered for inclusion on threatened and endangered species lists. It was not until 1994 that most invertebrates were recognized as being as vulnerable as other fauna. Because of this, there are very few species of spiders listed as threatened or endangered and many are simply classified as "undetermined".

Endangered species While many organizations agree completely on which spiders are endangered or threatened, a few commonly listed species are listed below.

Spruce-fir moss spider (Microhexura montivaga) The spruce-fir moss spider is listed as endangered under the U.S. Endangered Species Act of 1973. This spider resembles a tiny tarantula with adults measuring in at only 14.3 to 3.8 millimeters. It inhabits high-elevation forests in western North Carolina and eastern Tennessee. The species is extremely vulnerable to desiccation, causing it to shelter in damp shady areas such as shaded moss. The spider builds a tube shaped web between the moss and a rock or fir tree, hence the name.

Kauaʻi cave wolf spider (Adelocosa anops) The Kauaʻi cave wolf spider is found only on the island of Kauai in the U.S. state of Hawaii. As of 2006, this species can be found in a single cave and only 16 to 28 individuals have been encountered. Compared to other spider species, the Kauaʻi cave wolf spider has a low reproductive rate and due to habitat constraints, has little access to food sources. This spider is one of the largest documented cave-dwelling organisms measuring up to 8 centimeters. Because it spends its life in the darkness of a cave, this spider has no need for sight and is therefore completely eyeless.

Katipō (Latrodectus katipo) The katipō spider is related to the Australian redback and other widow spiders. This spider can be found in New Zealand in burrows or trees. The name means "night-stinger" in native Māori language. This species is listed as endangered due to habitat loss, as well as non-native spider introduction. It is estimated that only a few thousand of these spiders remain in the wild.

Vulnerable species A vulnerable species is one listed by the International Union for Conservation of Nature as likely to become endangered unless the circumstances threatening its survival and reproduction improve.

Dolloff cave spider (Meta dolloff) While not listed as endangered, this spider is considered to be vulnerable to extinction. Much larger than Microhexura montivaga, this spider ranges in size from 10 to 15 millimeters. This species makes large orb shaped webs at the entrance of caves and as of 2001 has only been found in caves located in Santa Cruz, California.

Great raft spider (Dolomedes plantarius) The great raft spider is a declining species and is listed as vulnerable. It occurs throughout Europe but a lack of records make assessment of the species difficult. In the UK there are only three known populations, one stable, one threatened and one not assessed. This spider is a semi-aquatic species and its dependence on water may have led to the population's decline. The information on the great raft spider is very recent and due to a lack of historical records, the level of decline cannot be accurately measured.

See also Endangered arthropods List of U.S. federally endangered arthropods List of extinct arachnids

Notes

References Krajick, K. 2001. "Cave Biologists Unearth Buried Treasure". Science. Vol. 293. pp. 2378–2381. Levi, Herbert W. and Lorna R. Levi. 2002. Spiders and Their Kin. St. Martin's Press. New York, U.S. Smith, Helen. 2000. "The status and conservation of the fen raft spider (Dolomedes plantarius) at Redgrave and Lopham Fen National Nature Reserve, England". Biological Conservation. Vol. 95. Issue 2. pp. 153–164. Ubick, Darrell. 2001. Cavernicolous Invertebrates of Cave Gulch, Santa Cruz County, California. Department of Entomology, California Academy of Sciences. San Francisco. U.S. Fish and Wildlife Service. 2006. Recovery Plan for the Kauai Cave Arthropods: the Kauai Cave Wolf Spider (Adelocosa anops) and the Kauai Cave Amphipod (Spelaeorchestia koloana). U.S. Fish and Wildlife Service. Portland, Oregon. 64 pp. U.S. Fish and Wildlife Service. 1995. Endangered and Threatened Wildlife and Plants; Spruce-Fir Moss Spider Determined To Be Endangered. Federal Register. Vol.60. No. 24. pp. 6968–6974

Worked examples

Example 1 — a first encounter with List of endangered spiders

Start with the simplest possible case. Write down what List of endangered spiders claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to List of endangered spiders before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about List of endangered spiders ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of List of endangered spiders

In research: List of endangered spiders appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses List of endangered spiders in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: List of endangered spiders is common in secondary-school and first-year university syllabi. It links to neighbouring topics Endangered animals, Lists of spider species, so understanding it makes those chapters shorter.
In everyday life: Look for List of endangered spiders outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study List of endangered spiders in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what List of endangered spiders means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain List of endangered spiders out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is List of endangered spiders in simple terms?

Why does List of endangered spiders matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study List of endangered spiders?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on List of endangered spiders.