A Few Common at ACR A Few Common Spiders at ACR Mygalomoprh (“primitive”) Spiders Orb Weavers

egg case

back abdomen Yellow & Black Garden Silver-banded Garden Spider () False () Turret Spider (Atypoides sp.) Trapdoor Spider (Aliatypus sp.) - both of these spiders hang head down in web Calisoga longitarsus egg case •Turret of stiff silk •Look for trapdoors in mossy - both of these spiders have webs with a stabilimentum Look for burrows in •Added to each year banks in road cuts and along the middle of trails; almost •Up to 8” long trails perfect circles; after •Can go 6 months without food! first rains evidence of •Can molt to get smaller! “spring cleaning.” Cribellate Spiders (produce fine hackle silk that “snaps”)

Pumpkin Spider ( trifolium) - build retreat to the side Debris Spider (Cyclosa conica) of web -line of debris down center of web False Widow -spider is concealed in debris sp. Steatoda grossa Labyrinth (Condo) These 4 spiders can be found around and on Spider buildings, in electrical and fire hose cabinets (Metepiera sp.) Triangle Spider ( sp.) -orb web with messy •Spider part of web portion (see above left) Missing Triangle •When she senses prey, she -Í retreat is in messy Spider → releases tension thread and portion (Zygiella sp.) triangle collapses -constructs lens-shaped -always a few on staff (look for these spiders in the egg sacs in retreat room railing redwoods under the heronry) Black Widow House Spider area Latrodectus hesperus Achaearanea tepoidariorum

Hunting Spiders ↓Sheet Web Weavers→

Cellar Spider↑ -inside buildings and cabinets -touch web and watch it vibrate! ↑ ↑ Crab Spider (w/ prey) ( radiata) ( pyramiitela) -usually found on prepared by Gwen Heistand (w/ egg sac) Camouflaged sit and -spider hangs out on vegetation in cool, moist places for ACR Education Runs to catch prey wait predator Jumps at prey from above underside of “bowl” i Spider External Anatomy 28

Q: Do all spiders make the same kind of silk?

A: No … and each individual spider is capable of making more than one kind of silk.

1. Aciniform glands: silk for wrapping prey, called swathing silk. Most spiders have this.

2. Cylindrical (tubuliform) glands: silk for wrapping eggs. So males usually don't have them, and some families (Salticidae and Dysderidaei) don't have them at all.

3. Ampullate glands: non-sticky silk for draglines or to form the frames of their webs (non-sticky foundations). All spiders have this, to produce the safety lines they leave behind them as they move about

4. Piriform glands: silk made into attachment disks at the bottom of web suspension lines. All families have them .

5. Aggregate glands work like a glue gun, producing sticky droplets, which regularly dot the silk to trap prey. Only three families have them (Araneidae, and )

6. Lobed glands: wrapping silk (only in Theridiidae which have reduced aciniform glands).

7. Cribellar glands: fluffy woolly silk that is very fine and combed into a single strand. (very stretchy and good for catching flying because bounces back to the web like on a horizontal bungee jump). The woolly silk also snares hairy insect legs. Only cribellate spiders have these gldlands an d com b(bs (see page 9). 1 5 7 0 5 5

………….. ……………… 1 )

spiders) asciata f tri ………………………… ) . pe p p p) ………………………...…….. 9 ………………………………. 1 Argio ) ( sp.)………………………………… ………………………………….. 21 ider OF CONTENTS rossa ……………………………………. 22

Araneomorph spiders) g p p( Frontinella s ……………………………………... 11 ( …………………………………...…. 20 ……………………………………… 12 vs

ider ider …………..…………………...………… 2

p g Atypoides ( Steatoda S

( y yp ( TABLE ……………………………………………….. i Spiders

False Tarantula (Calisoga longitarsus) Tarantula False …………………… 2

(Mygalomorph Badmuna sp. (From )…………………………….. 9

Pumpkin Spider (Araneus trifolium)………………………….Pumpkin Spider (Argiope Garden Spider & Black Yellow aurantia)……………. 13 S Garden banded Silver 14 Trapdoor Spider (AliatypusTrapdoor Spider sp.)………..………………………Turret Spiders ( 3 (Uloborus spider Triangle sp.)………………………………… 6 Bowl & Doil (Neriene Filmy Dome Spider sp.)…………………………….. 8 (LatrodectusWidow Black Widow or Western hesperus)………… Widow False 10 (AchaearaneaHouse Spider tepidariorum)…………………….. 10 (Cyclosa Spider Debris sp.)………………………………….. (Metepeira Condo or Spider Labyrinth sp.)……………………. 16 sp.)………………………… (Tetragnatha Long-Jawed Spider 17 (Zygiella Spider Triangle Missing sp.)………………………… 18 19 …………………...………………………………………... 28 ……………………………………………………………….. 27 Spiders

Pedipalps…………………………………………………………...Eyes………………………………………………………………. 23 24 : Dipluridae: Antrodiaetidae Sheet Web Weavers Linyphiidae: : Funnel Web Spiders : Theridiidae: Comb-footed Spiders Cellar Spiders : Araneidae: Orb Weavers (Hunting Spiders) Lycosidae Wolf Spiders : Salticidae: Jumping Spiders :Crab Spiders …………………………………………………………….…….. 26 of

Spider External Anatomy Makes / a Spider Spider? What Types of Spiders (Mygalomorph Mygalomorph Spiders Araneomorph Spiders Identification Characteristics / Matin Spider Molting Spinnerets Types of Silk l ns i a t con ilk strongest m t e goa th 5 times stronger than stee a, il Silk comes out from tiny nozzles According to the folks that have that have According to the folks , vo d ng to farm tigers. Think about it. So, ng to farm Think about it. So, tigers. figured out how to insert figured out how the silk s an t . Spider silk is

Spinnerets Scanning em of Aciniform Gland spools (see of diagram above): is th gland center this for wrapping makes silk prey that spinnerets. n goa i ers silk? id causes it to solidify. It is one ofcauses it to solidify. the rom sp f ension T 3 times tougher than Kevlar. ng genes i uc d i f id i t d il th t ilk t i and about tryi like tried to raise spiders for silk, it’s the US Army and a Canadian firm have Q: How do spiders make do spiders make Q: How as a liquid. pro A: They have structures TheyA: called have substances known lightweight spider silk. 27 coming out silk of Colorized scanning em spigots 1 26 What Makes a Spider a Spider? How Do Spiders Grow?

•Abdominal silk glands and spinnerets Spiders have an external skeleton which they need to •Males with palpal sperm transfer •Cheliceral v enom glands shed in order to grow. Those spider bodies you see in your hose that are hanging out in webs and not moving All (spiders, ticks, mites, opiliones, scorpions, whip are often the shed exoskeletons of the actual spider. scorpions, pseudoscorpions, sun spiders) have:

•4 pairs of walking legs •Two body segments (cephalothorax & abdomen) 2 Major Groups of Spiders Mygalomorph False (and real ones) along with our turret spiders and trapdoor spiders are all ppjgpgart of a major grouping called mygalomorph spiders. These spiders are considered to be more primitive. Their fangs only move up and down instead of side-to-side (they operate parallel to the midline of their body, not perpendicular to it). So … mygalomorphs moves up and down need to rear up and come down on their prey, trapping them against a surface. Mygalomorphs have 2 pairs of book lungs (and only book lungs ) which distinguish them from all but one group of the “true spiders”. Mygalomorphs also have long, segmented, spinnerets, which trail out behind their body visibly. Their eyesight is not great and courtship often relies on the male stroking and caressing the female. Mygalomorphs are long-lived (females 8-20 years, males 3-7 years!). Araneomorph (“True” Spiders) 90% of spider are araneomorphs. Fangs these spp(iders (orb weavers, sheetweb moves weavers , wolf spiders, crab side-to- spiders, jumping spiders, etc.) are side able to move side to side. Their jaws work independently from any surface and they are able to impale their prey between them. This allows araneomorphs to ca tc h prey on the flimsy surface of their webs. Along with one pair of book lungs, most araneomorphs also have tubular tracheae.. 25 2 Spider Reproduction False Tarantula (Calisoga longitarsus) • Courtship involves lots of signaling (vibrational visual, chemical) and different courtship positions (see below) Q: What do these spiders look like? • Male sacrifice is less common than believed. • and epigynum act as lock and key (see page 23) A: They’re large and “tarantula-like” though • Male spigots for sperm web are not part of spinnerets not as large as the tarantulas we are familiar • Use varying amounts of silk to protect eggs with. In the fall, I often get calls from people • Egg numbers vary between 1 and 1000 (cave spiders produce 1 big that find large spiders in their bathrooms or egg) around their house. The males of this species • Developmental stages go on walk-about in the fall searching for • Prelarva (immotile –usually in egg) females and it is usually this spider that • Larva (limited motility and leg segmentation) people are asking about. Q: Where can we find Calisoga • Nymph – motile, (can feed), functional spinnerets burrows? • Generally, araneomorphs don’t molt past maturity; female mygalomorphs molt throughout life (shed spermatheca so need to Look in the middle of trails and trail get reinseminated) and males don’t molt once they’re mature. margins,,p especiall y on the Griffin trail • MtMaternal care (fema les o f some groups guard egg cases and across the Sheerin Bridge and the first spiderlings) part of trail to Volunteer Canyon. I’ve also seen them on the trail past the spider patch on the way under the heronry. In the fall, after the first rains, they’re easier to spot. Look for little piles of dirt and a white glob next to an almost perfectly round hole about the size of a nickel. The white glob is the remains of last year’s egg sac. If you tease it open and have a hand lens you can see the Q: Where do these spiders get their shed exoskeletons of the tiny sometimes common name of spiderlings who undergo their first molt mygalomorph mating positions “aggressive false tarantula”? while still in the sac! orb weaver mating positions • Male approaches female • Often, male will create a from front, female raises A: They have a threat display of rearing Q: If these are “false” tarantulas … do courtship line to the web prosoma, male inserts up on hind four legs, raising and we have “true” tarantulas at BLP? • Males are often a lot palps spreading the front four, and baring the smaller than females fangs. The display turns your stomach A: True tarantulas ((ypFamily Theriphosidae ) upside down . are common in hot, dry areas of the East Joel Ledford Bay, like Mt. Diablo, and Henry Coe State Park. Reports of tarantulas on Mt. Tamalpais refer to Calisoga. There are no records of “true” tarantulas from Marin County. American tarantulas defend themse lves aga ins t vert eb rat e pred a tors b y sheet web mating position scratching off fine abdominal hairs which crab spider mating positions are hollow and venom filled and irritate the • Male will often bind female nasal linings of like coyotes, foxes, with some silk and skunks. 3 24 Trapdoor Spider (Aliatypus sp.) Spider Eyes (Family Antrodiaetidae) Q: What are some of the ways we can distinguish between families of spiders?

A: One way is the eyes. Look at the eyes – the size and placement. Who below makes their living by actively running around and looking for prey? Who might depend more on sensing web vibrations?

Q: What is proper trapdoor spider etiquette?

A: Use a very small twig to lift the door. Anything heavy has a higher chance of damaging the door. I recommend letting the children watch as YOU lift th e d oor. H ave th em l ook for o ther t rapd oors on th e b ank . Wh en they think they’ve found one, have them point it out and YOU lift it. In areas that are used often, we usually try to designate one or two trapdoors that are used and save the rest of them from disturbance. Q: If trapdoor spiders live in burrows, how do they find each other when they want to mate?

A: The female trapdoor spider may spend her entire life in the same burrow, enlarging it as she grows. When the male is of reproductive age, he leaves his burrow in search of a gal. He is guided by a (a special chemical attractant) that the female releases and by the distinguishing pattern of silk around her burrow. Once he has mated, he is not long for the world .

Q: How do trapdoor spiders make their burrows (1)?

A: Trapdoor spiders have spines (rastella) on the sides of their chelicerae (the mouthparts where you find their fangs). The spider uses these spines like a digging rake to loosen and move earth. She also uses her fangs and the muscles at the base of her fangs. . Once there is enough loose dirt in the burrow for removal, the spider will spin some silk around it and haul it out of the nest (another amazing use of spider silk!).

Most spiders have 8 eyes. Can you tell from the drawings above whose faces are in the pictures? 23 4 Pedipalps Trapdoor Spider (Aliatypus sp.) (Family Antrodiaetidae) Q: How can you tell a male spider from a female spider? The trapdoor itself is a silk A: The male spider has swollen pedipalps (sometimes called palps) wafer that the spider covers that make him look like he is wearing little boxing gloves. Pedipalps with dirt and other bits and are one of the structures used in spider identification. They can be pieces from the surrounding relatively simple of very complex. environs. Once the burrow is finished, the spider will use Q: What are male ppppedipalps used for? saliva to line the nest with mud in order to strengthen it. A: Pedipalps are used to transfer sperm to the female. The Last, but not least, she lines it analogous female structure is called an epigynum. The palps and with silk. the epigynum work together like a lock and key.

Males palps which transfer sperm, are not connected to area whiddhere sperm is produced. MlMales nee dtd to sp in sperm webs, ldload note the “cork” wedge the the webs with sperm, and then charge their palps before they can spider has constructed in this transfer sperm to a female. cut-away. Our trapdoor spiders don’t create cork wedges, they make wafer-like trapdoors but the process is the same.

Q: Where does the female make her egg sac and what happens to the kids?

A: The eggs are laid in the burrow, in a cocoon attached to the silk lining. Hatchlings look like miniature versions of their mother and stay with her for several weeks. When you find a trapdoor, look around. You will often see other trapdoors in a range of sizes. The fruit doesn’t fall far from the tree..

↑simple pedipalps

← complex pedipalps 5 22 Turret Spider (Atypoides sp.) Crab Spiders (Family Antrodiaetidae) (Family Thomisidae)

Q: What’s the deal with the turrets?

A: Turrets are stiffened silk connected to a long silk-lined burrow in which the spider lives. Douglas fir needles, dirt, leaves, and twigs are incorporated into the turret and act as trip-lines. At dusk, the spider sits at the edge awaiting victims. Q: Why are they called crab spiders?

A: Look at them! They have long front legs and are able to move Q: When you find a large-ish turret, sideways, frontward, and backwards, like a crab. With the small back yyyou very often see a bunch of smaller legs the spider holds itself steady. The front legs, which are held ones around it. What’s this about? outwards, are more powerful, and grab unsuspecting flower visitors with amazing speed, while administering a poisonous bite. Prey is mostly eaten on the flower and is sucked dry through tiny holes, leaving A. As with the trapdoor spiders, very often the offspring don’t stray too far from home. behind an almost complete exoskeleton. Some pretty cool population studies have Q: Why do we often find these spiders in or around flowers? been done with turret spiders. A: They’re sit-and-wait predators. They camouflage themselves to blend in with their background. When a pollinator or other visitor comes to the flower … wham! … It’s spider food. Some female crab Q: What do these spiders look like? spiders are even able to change color. New information shows us that bees PREFER flowers with crab spiders in them. It’s thought that A: They are mygalomorph (?!) spiders that look a little like this is a result of crab spiders reflecting UV light in a range tarantulas. They have thick bodies and small eyes. desirable to the bees!! (There are even some crab spiders (not at BLP) that disguise themselves as perfect imitations of bird poop (smell and look) with a white blobby web underneath them. Bird dung Ífemale in spiders prey on the that feed on bird poop) burrow

male out at night searching for female Î

Q: How often do these spiders need to eat?

A: As often as they can … AND they can wait six months without eating. (I always find them on the poppies in They may even shed their skin to get smaller if need be! Garden Club Canyon. Look at that camouflage!) 6 21 Jumping Spiders Triangle Spiders (Family Salticidae) (Family Uloboridae)

The triangle spider is a member of the only family of spiders known to lack venom glands (Uloboridae).

QQyyjp: Do they actually jump?

A: YES! They raise their front legs in preparation and thrust with their hind Q: Where’s the rest of the web?? legs. Just before jumping, a spider will fasten a safety net to the substrate. Then it pulls its legs close to the body – et voila. If wolf spiders are the A: Triangle spiders are not in the orb weaver family (Araneidae). (They’re cheetahs of the spider world then jumping spiders are the leopards. in the Uloboridae family.) Though they spin webs that look like someone cut a With eyes so large they can resolve an image up to a foot away; pie out of an orb web – it’s different from “orb weaver” webs in several major jumping spiders stalk prey, then jump 10-20 times their body length to ways: capture it! (They trail lines of silk when they jump( • The spider is actually part of her web! • The web contains no sticky silk. Triangle spiders are cribellate Q: With such big eyes, does their courtship ritual involve visual spiders; meaning they produce a special kind of silk that is very wooly and cues? has electrostatic features to help it cling to prey. A: Yes . In fact they have some fairly elaborate courtship maneuvers. The cute spider above (Phiddipus johnsoni) will use both visual and Q: What do you MEAN the chemotactile methods to court a female. If a male comes across a nest spider is part of her web? where the female is hidden, he’ll rub his front legs over the surface of the nest while his body oscillates up and down. If he sees her, he will approach A: The spider attaches a thread her in a zigzagging dance, raising his legs, twitching his abdomen, and to some solid object and a vibratinggpp(p his palps. (The spider to the ri gpght performin g a courtshi p dance is tension thread to the apex of not P. johnsoni.) the web. She is a living part of her web! She holds on at the Q: Do male jumping spiders ever face-off? point of attachment taking up slack and creating tension. A: Yes. However, threatening behavior is almost as ritualized as mating When a prey item of the behavior (fighting rarely occurs). In more primitive jumping spiders, courtship appropriate size stumbles into and d e fense movements are the same. O ne thi ng tha t I use d to do w ith a little hbthtiithher web, the tension in the jumping spider that lived on my porch for several months was to bring a small attachment line is released by mirror outside and hold it up. I could elicit defensive behavior by showing the the spider causing the web to spider his own reflection! collapse on her victim. 7 Bowl & Doily Spiders (Frontinella sp.) Wolf Spiders 20 (Family Liniphiidae – Sheet web weavers) (Family Lycosidae) Q: Do these spiders make webs?

A: No. They are hunting spiders. One often sees them running in the grass, especially in moist areas and near ponds and streams. They run just as well on the surface film of water! This is the cheetah of the spider world, running down prey by speed, rather than stealth. Since they chase down prey, they need good eyes Just imagine if your mother were a wolf spider … she would almost have eyes on the Q: How does this web work?? back of her head – at least on the AThA: The snare cons itists o f a cuplike s truct ure (bow l) a bove a s hee twe b side an d top !! (doily). The spider sits on the underside of the cup. Small flying and crawling insects get caught in the many trap lines constructed above and Q: How do they find each other when it’s time to make babies? around the bowl and tumble in at which point the spider bites them from below and pulls them through the web. The Bowl and Doily. Does the A: A female will trail a pheromone-laden dragline behind her to lead male “doily” or “saucer” play a role? Yes, It is composed of fresh spider silk just wolf spiders in the right direction. When a male “smells” her like the bowl or cup. They spider, resting below the surface of the bowl, is with his palps , he follows the dragline to the female. As he approaches, he protected from attacks from below by the doily. Frontinella then wraps its will begin a courtship song and dance - waving his palps, raising and prey in silk and saves it for when it wants to eat lowering his front legs, and vibrating his abdomen. In some species the males also vibrate their legs. These vibrations elicit a response in kind from Q: Are there any “web parasites” in the spider world, like there are a receptive female who responds with leg vibrations of her own. “nest parasites” in the bird world? You might see a spider scurrying around A: Funny you should ask! Yes. Argyrodes trigonum is a kleptoparasite looking like it has three body parts … you of bowl & doily spiders that feeds on their food – and, as been recently might actually be watching a wolf spider shown, occasionally them. In summer months, A. trigonum may inhabit up carrying her egg sac. She wraps the egg sac to 20% of bowl and doily webs, where it has caused death or departure of with bluish-green threads and attaches it to her its host. Possibly as a result of this, Bowl and doily females will actually spinnerets. She carries the sac around until allow males to use their webs to capture prey. It is thought that the the spiderlings hatch. If one tries to take the function of this ppy()ermissiveness may be to deflect (onto the males) the risk of egg case away, she will vehemently defend it. being captured. (Bowl and doily spiders also go through what is termed If it is taken, she will search for it for hours and pseudocopulation. The male will get close enough to determine whether or even accept substitutes (paper balls, not the female is a virgin. If she is – he stays, if not – he’s out of there.) snailshells…). Mom assists during “hatching” Q: How do these spiders move from by opening the rim of the cocoon. The newly area to another (disperse)? emerged spiderlings climb on mom’s back and hold fast to her abdominal hairs for 7 or 8 A; In the autumn many of these spiders days. They live from their yolk supply and become aeronauts, migrating by what is mom doesn’t eat during brood care. There commonly called ballooning. They let out may be as many as 100 tiny spiderlings silk until there is enough to be caught by resting on top of each other on top of mom! the breeze to carry them off!! 8 19 Long-jawed Spiders (Tetragnatha sp. usually) Filmy Dome Spider (Neriene radiata) (Family: Teragnathidae) (Family Linyphiidae)

Q: We often see nearly horizontal webs with open hubs near Not as common at BLP, but very prominent at Bouverie is the filmy water at ACR – what spider makes them? diddome spider, whhtbiitd(hose sheetweb is an inverted cup (concave d)ithdown) with the spider underneath at the apex of the dome. The filmy dome spider is A: These spiders have a few common names – long-jawed, a riparian beast, and the further from the creek you go the fewer you see, streamside, stretch, and marsh spider are a few of them. They’re and the smaller each individual is. Webs are usually found on herbs or called long jawed due to their large chelicera, streamside and marsh low bushes in cool moist places as in the borders of woodland paths or because they are riparian and wetland spiders and stretch because the shrubs fringing a shady stream. (It helps to have a piece of dark they have an elongated body form. They the sit with six legs extended board or cloth to show these webs off.) parallel to their bodies, often on a grass blade or reed, holding on with their short third pair of legs, and blending into the vegetation. Webs Q: We often see the webs of these spiders along are often horizontal or close to it, rather than the typical near-vertical the sides of the Canyon Trail at Bouverie. What do orientation and is missing the central hub. the spiders look like? Q: Are there any adaptations Tetragnatha has for living near A: The female is about 3/8 inch and slightly larger than water? the male . Abdomen is yellowish-white and marked with dark bands and stripes. Neriene hangs beneath the A: They are able to run over water using a diagonal rhythm with their 1st apex of the dome. When insect gets entangled in the and 2nd pair of legs and dragging legs 3 and 4 passively behind them. web and falls on the dome, the insect is seized and Interestingly, Tetragnatha can run faster on water than it can walk on pulled through. land! XXX RATED: Tetragnathid Sex: Q: We alwayyps hear about female spiders eating their mates. Does The male has special spurs on his chelicerae. this happen with filmy dome spiders? When courting, the male and female approach each other with jaws agape. Their front legs A: No, unlike some spider species, in which the male is so tiny that the come in contact with each other and male pushes female does not even notice him, or others where the size of the genders female’s legs apart and employs the special is almost equal but the female has a penchant for eating the male rather spurs on his jaws to lock into opposing spurs in than treating him as a mate, these spiders are experts at domestic hjher jaws … keep ing hjher jaws ou tft of comm iiission harmony. HthitiktthiHowever, there is a trick to this … MlMales guar did immat ure and facilitating non-fatal sperm transfer. The females. When the female molts to maturity … the male mates trouble often comes when he leaps backwards to immediately while she’s still soft. Males will fight over immature females safety. This leap is not always successful. that are being guarded. 18 9 Funnel Web Spiders Missing Triangle Spider (Family Agelenidae) (Zygiella sp.) Q: What are makes those webs that look like funnels that we often see in the vegetation around Monday-Tuesday Ponds and in the grasses in Garden Club Canyon? Q: What is the “missing” part of the web all about? A: Funnel web weavers (not to be confused with toxic funnel ) are A: Zygiella constructs her retreat at sometimes called ggprass spiders. Their webs are the ppgeak of the “missing” part of her flat, often slightly concave, sheets narrowing to web. It’s easy to find the spider if a funnel-tube retreat at one end. The retreat is you look closely because she has a open at both ends and the spider can usually signal line attached from her be found sitting in it waiting in ambush with its retreat to the center through the front legs stretched out to feel vibrations “missing” portion of her web. from its web. The actual feeding process altkllways takes place ithtin the retrea t. These spiders are very ftfast – tthitry catching one and you’ll see what I mean. The flat, horizontal layers of dry silk don’t so much capture prey, as confuse them, allowing the agile funnel web spider to rush out and pounce. These webs have been used as canvases to paint on, and as band-aids to stop bleeding. ______Badumna sp. (Family Desidae) Q: Where can you find the missing triangle spider at BLP? These spiders are all over the buildings at BLP. A: Look on the railings in front of the staff room and around buildings. Look for their lacy webs. Zygiella is an introduced spider (from ) and does will around human habitation. Q: When you touch these webs they’re sticky in a different way than orb weavers? What causes this? The drawing to the left is what happens when you give a A: Badumna (introduced from Australia) is a missing triangle spider caffeine cribellate spider. It has a specialized spinneret … makes you think … called – what else – a . The cribellum can have up to 40,000 sppgigots ppgroducing silk thread about 0.00001 mm thick which is combed with special hairs on the hind legs (like carding wool) to produce fluffy, wooly silk (hacklebands) with electrostatic properties. Ícribellum

sem shthot o f crib iblltellate silk Î

Q: What other spiders that we see are cribellate spiders?

A: triangle spiders, black widows, false widows and more … 17 Labyrinth or Condo Spiders Comb-footed Spiders 10 (Metepeira sp.) (Family Theriidae) Black Widow, False Widow, House Spider

western (black) widow house or domestic spider (Latrodectus hesperus) (Achaearanea tepidariorum) Q: Why are they called comb-footed spiders?

A: They have a comb of serrated Q: Where in all of this silk can one find the spider? bristles (setae) on the tarsus of the fourth leg (too small to see without a A: Look in the messy portion of the web. There will be a tangle of leaves scope). The combs are used to throw and junk. This is where the spider builds her retreat. The spider sits hidden in sticky silk over prey. Theridiids may her retreat with a line to the orb hub to sense prey. The retreat is usually wrap their prey in silk before applying made of a leaf rolled conically, open end down. It is usually possible to false widow (Steatoda sp.) a poisonous bite (wrap attack. The view her with a mirror. wrap attack allows theridiids to delay direct contact with prey until it is safely Q: What do the egg sacs of condo spiders look like? immobilized. A: Condo spiders enclose their eggs in lenticular (shape of a double convex Q: The webs of these spiders looks like a messy tangle. Is there a lens) sacs. The first egg sac is formed near the entrance of the retreat and particular name for it? the others are placed successively in a line below it and fastened to a strong cord of silk. There are usually 5-6 sacs with about 30 eggs in each. The cord A: These webs are officially cobwebs! They are a remarkable tangle, with a supporting the egg sac is stretched between two branches and is strengthened number of taught vertical lines attached to the ground or surrounding substrate. with additional draglines. Egg sacs can survive winter storms and will be held Prey is snared when they bump the loosely attached taught-lines and are securely in place after all traces of the web have disappeared. (Although some whipped up into the tangle! (There is a great tale of an arachnologist watching a accounts say that the young spider hatchlings use the messy web portion as a house spider subdue a mouse: at 2pm silk was thrown around tail; by 4 pm nursery.) the mouse could barely touch the floor; by 9 pm the mouse was 1 ½ inches above the ground; by the next morning, the mouse was dead.) These are Q: Often we see many of these spiders in close proximity in the same cribellate spiders like Badumna and the triangle spider (see page 9). bush. What is this about? Q: What type of toxin does the black widow have? A: We don’t really know! There’s some debate that condo spiders might be semi-colonial. Large Ceanothus bushes may sport as many as twenty labyrinth A: The toxin is a neurotoxin. It causes ppgain throughout the bod y,,y, nausea, webhbhibs, each branch opening suppor ting one or more spid(Ifditthiders. (If you drive to the dizziness, sweating, muscle spasms. The anti- are good. These are preserve through the Olema Valley on a misty morning, you can see many, not aggressive spiders. Most injuries to humans are due to defensive bites many webs. I stopped counting at 100 one morning –only because I was going delivered when a spider gets unintentionally squeezed or pinched. Some bites to be late for an appointment.) This is a good question to ask the kids. See if may result when a spider mistakes a finger thrust into its web for its normal prey, they can come up with a hypothesis. Talk to them about the scientific process! but ordinarily intrusion by any large creature will cause these spiders to flee. 11 Cellar Spider (Family Araneidae) 16 (Family Pholcidae) Debris Spider (Cyclosa sp.) (in houses, around buildings, in pond cabinet, fire hose cabinets, etc.) Q: People often get confused between the debris spider and the condo (or labyrinth) spider. What’s the difference?

A: The debris spider has a single orb web with a string of debris down the center (this is also a stabilimentum like the zigzag in the garden spider webs). The debris spider hangs out in the middle of this string of debris. The condo spider’s web has a messy part and a female with egg sac perftbfect orb part as well as a vibrating in web retreat in the messy part. Q: How can these spiders be distinguished from the common house spiders or cobweb spinners? Q: What does the debris spider use to make its “string of debris” or stabilimentum? A: They can be distinguished from house spiders by two behaviors: (1) they carry their whitish egg cases in their jaws (see above), and (2) they d osucho such A: The debris consists of plant material, as well as prey items (old and rapid pushups when disturbed that they appear to vibrate in circles in their new) and shed skins. When the spider is ready to lay eggs they are web. (They will also shake their webs to hasten entanglement of prey.) I highly added to the line of debris. recommend you do this with the kids … there are always a few in the corners of the display hall. Q: What does the debris spider actually look like? Males live in the same webs as females and look like them except for their swollen palps (see page 23). A: There are actually 4 species of debris spider (Cyclosa) in the bay area. BLP’s Q: These spiders are called most common one is Cyclosa conica, sometimes called daddy long legs. named for the cone-like projection on the Aren’t there other things called end of its abdomen. I teased one to the daddyygg longlegs too? toppgp of her web to get a photo.

A: Yup. Daddy longlegs “officially” refers to a group of spider-like critters called Opiliones. Opiliones also have eight legs BUT they have only one distinguishable body part. We see them i n the so il, un der logs, in the an d around the fire hose cabinets and other places. 15 12 Silver-banded Garden Spider Orb Weavers (Family Araneidae & others) (Argiope trifasciata) Orb webs are made up of three elements: 1. radial threads (converging to a central spot – the hub) 2. frame threads (provide web perimeter and insertion sites for radial threads 3. catching spiral (studded with glue droplets)

The frame and the radii provide a stable construction that is also good for transmitting vibrations used in prey capture and mating. The sticky spiral is also veryyp elastic. When preygy struggggles the energyyyp is absorbed by the spiral and less damage is made to the web.

The number of radii vary from species to species ( has 25-30; our long-jawed spider only about 18).

Construction of orb web: 1. Star t w ith a hihorizont tlthdal thread by le tting silk out until it is carr ie d by a dra ft and catches on something. Bite through this, grasp the cut thread and Q: These spiders often hang with their “belly” side visible (as opposed move to the middle, reeling off a new thread. to their “back”). What is the circular looking structure in the middle 2. Descend vertically until the thread can be fastened to a surface, creating a part of their abdomen? Y-like structure. 3. Create radial threads (a complicated process) and add frame lines, A: Her spinnerets! These are the structures that produce silk. Many orb deciding at hub which sector the next radius will be placed. weavers produce up to 7 kinds of spider silk. Spinnerets are actually made 4. While placing radii, connect them with a few narrow circles in center of up of hundreds to thousands of tiny silk-producing spigots. web, eventually creating and auxiliary spiral tying the radii together. 5. Starting at periphery of web, use the auxiliary spiral as a guide, lay down Q: Why do these spiders (and other orb weavers) seem to suddenly sticky threads of catching spiral, attaching them to radii and removing appear in autumn? Where have they been the rest of the year? the auxiliary spiral.

A: They’ve actually been around since the spring – only smaller and lower down in the vegetation. In fall, they (especially the females) grow larger, reproductively active, prepare to make their egg cases, and die. This is one strategy for getting through the hard times. Make a waterproof egg case. Stick the next generation in it (pass your genes on) and exit the scene.

Q: How can you tell a silver- banded egg sac from a yellow & black garden spider egg sac?

A: Silver-banded garden spiders make egg sacs with flat tops, whereas yygellow & black garden spiders make egg sacs that are pear ↑silver banded shaped. yellow & black→ 13 Pumpkin Spider Yellow & Black Garden Spider 14 (Araneus trifolium) (Argiope aurantica)

Q: Where would you find the male spider?

A: The male is much smaller than the female and can often be found hanging out around the edge of the female’s web. There’s something pretty dramatic going on in the sex life of our beloved Argiope aurantica. During spider sex male spiders insert sperm into the females using their pedipalps sequentially, one after the other. When the male A. aurantica uses his second palp, he “suffers irreversible seizure,” his heart stopping altogether within 15 minutes. “The dead male’s inflated palp remains wedged inside the female, acting like a copulatory plug , preventing her from mating again, and giving his sperm crucial minutes to fertilize her eggs. Other males try hard to pull the dead male Q: L ook at tth the or b we b o fthif this sp ider. I s it ith hangi ng st rai ght up & out and fail.” Pretty wild! The female will eventually eat her mate; however she is not responsible for his down with respect to the ground – or is it oriented at an angle? An (Some folks thrink the pattern on death. angle. (This is true of many orb webs) …. Why might this be? the back looks like Marge Simpson) A. What if the spider had to drop suddenly to avoid a predator, or to Q: What is that zig-zaggy thing down the middle of the web? capture an insect? She doesn’t want to get stuck in her own web –so she orients the web at an angle to ground. The angle also comes in A: It’s called a stabilimentum. It was given this name because it handy when she cleans her web. (Look at other orb webs as well…) was thought to provide stability. It doesn’t. It may act as camouflage. (It is always built by spiders that sit in the middle of their Q: Why is it important to look for the web of this spider and not the webs.) It may also reflect uv light and warn birds not to into the spider herself? web. The uv light may actually attract insect prey. (We don’t really know – which is cool!) A: She is often in a retreat off to the side of her web. You can always find the retreat by looking for a strand of silk the leaves the center of the web and goes Q: Sometimes near where we see these spiders, we off to what often looks like a clump of leaves. She hangs out in her retreat see a dark brown, pear-shaped structure suspended with one of her legs on this signal line. from silk in the vegetation – what is it?

Tip: Use a mirror to show the kids the spider. A: Her egg sac – her magnum opus. She dies not too long after its construction. (She may actually produce Q: As autumn progresses, why does it seem from 1 to 3 sacs , most often 1 .) Each sac contains 300- that we see more and more webs that looked like 1400 eggs! The female constructs her egg sac hanging they’re not being maintained? downwards in her web. First she builds a scaffold, followed by a rectangular roof on A: The spider is putting more and more of her which she spins a thick tuft of fluffy silk. energy into egg production. When the cost of Into this silk bed she spins a firmer sheet of web reppgair is no longer worth the ener ggyyy taken away silk and layyggps her eggs upwards against it. from reproduction, the web is shut down. If you are The she spins a fluffy covering and over this REALLY LUCKY you will see a spider with a a padded finer covering of silk that hardens deflated abdomen preparing her egg sac (usually and turns a brownish color. (To summarize: in lower vegetation). 6 different sheets, tufts or covers, making three envelopes!).