Term
| About how many spider species do we know of? |
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Definition
| 45,000 known spider species. there may be 130-170k species of spiders on earth. |
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Term
| where can spiders be found on earth? |
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Definition
| they are found everywhere on earth, except for the antarctic or the ocean. there are millions of spiders in the tropics, and you can even find them on mt. everest |
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Term
| what does the term "ballooning" mean? |
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Definition
ballooning spiders can disperse a very long distance.
Darwin saw spiderlings on the sails of the HMS Beagle at sea; they were ballooning, which allows them to disperse to new areas via wind currents. |
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Term
| name the primary traits that define a spider |
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Definition
jointed exoskeleton
8 legs
8 eyes usually (and usually 2 rows of 4 eyes)
2 primary body segments: cephalothorax (head and thorax fused) and abdomen
no segmentation on abdomen
pedipalps
abdominal silk glands = spinnerets
silk production - all spiders produce silk, though not all use webbing for prey-capture
fangs and cheliceral poison glands (poison glands associated with fangs) |
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Term
| how are spider eyes different from insect eyes? |
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Definition
| eyes are NOT compound eyes |
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Term
| how does the body segmentation differ between spiders and insects? |
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Definition
2, not 3 primary body segments: the cephalothorax (head + thorax fusion) and abdomen.
no segmentation on abdomen |
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Term
| how do spiders produce silk? |
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Definition
| spiders can produce 8 different kinds of silk by mixing from different abdominal silk glands. |
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Term
| describe the different ways spiders produce silk. |
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Definition
| some silk may be sticky for prey capture, some is not sticky but used for shelter, web support, lining burrows, etc |
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Term
| do all spiders use webs for capturing prey? |
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Definition
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Term
| for what other uses might spiders use their silk? |
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Definition
silk can be used for shelter, web support, lining burrows, etc.
webs also expand the sensory range of a spider: they can feel the vibrations of anything that comes in contact with it. |
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Term
| what is extra-oral digestion? |
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Definition
| spiders inject enzymes into prey that will break down tissue, liquefying it and making it drinkable through their fangs. spiders drink their prey. |
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Term
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Definition
| nope! their mouthparts cannot chew. venoms are used to paralyze or slow down their prey. then the liquifying happens. |
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Term
| are most spiders predators? |
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Definition
yup! nearly 100% of spiders are predators, mostly eating insects. though some recently discovered species can eat pollen adn some can eat plant-produced beltian bodies, and another will eat from extrafloral nectaries on certain plants.
large spiders can capture small birds and bats.
almost all are generalist predators |
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Term
| describe how a spider grows and develops |
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Definition
| they develop from egg, molting 10-11 times until becoming an adult. huge increase in size with each molt. some females can live 25 yrs. |
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Term
| do spiders have holometabolous development? |
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Definition
| nope! they have incomplete metamorphosis |
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Term
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Definition
males have modified pedipalms. they use them like a hypodermic syringe to inject sperm into females. males place sperm on a "sperm web", suck up sperm into pedipalps, and use the palps like lock-and-key to inject sperm into female genitalia.
fun fact: much of male's anatomy and behavior is designed to keep the female from eating him during courtship and copulation. sexual cannibalism is a huge prob for male spiders. |
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Term
| what role do pedipalps play? |
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Definition
| pedipalps function as a penis. |
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Term
| most important venemous spider |
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Definition
| black widows bcs of combo of commonness and venom. (even tho technically not THE most venemous, its a power combo) |
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