Spiders 101

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Spiders 101

• Kelly V. Tindall
• Extension Entomologist
• Twin Falls County

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Most Spiders

• Are good and beneficial HOWEVER there is
  irrational fear about them
• Have fangs too small to bite
• Bite only when threatened
• Suspected most bites are from sac spiders
• Most are not toxic to humans
• Bites usually produce slight swelling,
  inflammation, and/or itching

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Classification System

• Kingdom (Animalia)
• Phylum (Arthropoda)
• Class (Aráchnida)
• Order (Aràneae)
• Family (Agelenidae)
• Genus (Tegenaria )
• Species (agrestis)
• Common Name Hobo spider

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Classification System

• Kingdom (Animalia)
• Phylum (Arthropoda)
• Class (Aráchnida)
• Order (Aràneae)
• Family (Agelenidae)
• Genus (Tegenaria )
• Species (agrestis)
• Common Name Hobo spider

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Classification System
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Classification System

• Kingdom (Animalia)
• Phylum (Arthropoda)
• Class (Aráchnida)
• Order (Aràneae)
• Family (Agelenidae)
• Genus (Tegenaria )
• Species (agrestis)
• Common Name Hobo spider

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Arthropoda Characteristics

• Exoskeleton
• Chitin
• Segmented appendages
• Segmented body
• Bilateral symetry
• Dorsal tubular heart
• Ventral paired nerve chord

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Classes of Arthropods

• Arachnida spiders, mites, ticks
• Diplopoda millipedes
• Chilopoda centipedes
• Insecta insects

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Classification System

• Kingdom (Animalia)
• Phylum (Arthropoda)
• Class (Aráchnida)
• Order (Aràneae)
• Family (Agelenidae)
• Genus (Tegenaria )
• Species (agrestis)
• Common Name Hobo spider

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Arachnida Characteristics

• Body divided into two parts
• Four pairs of legs
• No antennae
• No wings

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Classes of Aráchnida

• Scorpiones scorpions
• Uropygi whipscorpions
• Araneae spiders
• Opiliones harvestmen
• Acari mites and ticks
• Pseudoscorpiones pseudoscorpions
• Solifugae windscorpions

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Classification System

• Kingdom (Animalia)
• Phylum (Arthropoda)
• Class (Aráchnida)
• Order (Aràneae)
• Family (Agelenidae)
• Genus (Tegenaria )
• Species (agrestis)
• Common Name Hobo spider

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Spiders - Araneae

• Wingless and lack antennae
• 2 parts, chepalothorax (head) and abdomen
• Six or eight eyes
• Variable in size and shape
• All food intake is liquid
• All are beneficial, few are hazardous

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Spider Facts

• 42 types (Families) of spiders
• Hundreds of species in Idaho
• All are beneficial
• Almost all have venom
• Hazardous spiders include black widow and hobo
  spiders
• Reactions vary with individual

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Prey Capturing Tactics

• Web builders
• Webs can help ID the type of spider
• Designs vary, many elaborate
• Active hunters
• May construct web but used for resting
• Passive hunters
• Lay in wait then pounce

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Prey Capturing Tactics

• Web builders
• Cobweb spiders
• Orb weaver spiders
• Cellar spiders
• Funnel web spiders
• Active hunters
• Wolf spiders
• Jumping spiders
• Nursery web spiders
• Passive hunters
• Crab spiders
• Trantualas

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Web Builders

• Use webs to catch prey
• Webs vary in design and size
• Can be used to help ID spider
• Includes
• Combfooted spiders
• Orb weaver spiders
• Cellar spiders
• Funnel web spiders

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Combfooted Spiders

• Irregular, sticky webs on structures pest
• Sheltered sites, indoors or outdoors
• Inconspicuous, BUT web is not
• Abandon non-productive webs and make new webs
• Example Black widow

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Combfooted Spiders

• Legs Named for row of bristles (comb) located
  on 4th leg
• Lack thick hairs on legs
• Three tarsal claws
• Eyes 8 eyes
• Body Spherical abdomen
• No teeth on chelicerae
• Often confused with orb weavers

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Black Widow

• Females with red hourglass
• Usually non-aggressive
• Will retreat when disturbed unless defending egg
  sac
• Bite usually when trapped
• Webs in secluded, cluttered areas
• 150-400 eggs/sac 4-9 sacs/year
• Female 3 years in the lab

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Orb Weaver Spiders

• Circular, flat, elaborate web
• Species specific web design
• Webs usually occur outdoors
• Poor vision - locate prey by vibration and
  tension
• Wrap victim in silk
• Oddly shaped abdomens (pointed spurs, conical
  tubercles)
• Though scary, not dangerous
• May bite if handled

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Orb Weaver Spiders

• Body Spherical abdomen
• Often brightly colored
• Thick spines on abdomen
• 1/10 1 inch
• Eyes 8 eyes with 4 in center cluster w/ side
  pairs separated
• Legs Long legs with spines
• Most characteristic web

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Orb Weavers

• Wheel Weavers
• Nocturnal

Golden Garden Spider
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Cellar Spiders

• Found in dark, damp places
• cellars, basements, crawlspaces, outbuildings
• Loose, irregular-shaped web in dark corners
• Add to their web large webs
• Male female live together
• Large populations in a structure

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Cellar Spiders

• Commonly misidentified as daddy long legs
• Long bodies and legs
• Hang upside down in irregular-shaped webs
• Found in dark places
• Either 6 or 8 eyes

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Funnel Web Spiders

• Large, flat, horizontal, NONsticky webs with a
  funnel
• Hides in narrow end of funnel attacks when
  feels vibration
• Carries prey back to the funnel
• Silk once used to cover wounds to stop bleeding
• Infest structures, but webs typically on lower
  levels

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Funnel Web Spiders

• Body large brown (gt1/2 inch)
• 2 rear spinnerets extend past abdomen
• Eyes 8 similar sized eyes
• 2 curved rows
• Sometimes confused with
• wolf or nursery web spiders

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Funnel Web Spiders

• Grass spider carapace - yellowish to dark brown
  with 2 dark stripes abdomen yellowish gray to
  dark brown legs distinct rings
• House spider covered with light plumose hairs
  abdomen various markings carapace 2 dark
  stripes

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Hobo Spider

• Brown spider ¼-? inch
• Dozens of similar looking spiders
• Sure ID - dissect reproductive structure
• Each species has a distinctive "lock and key"
  design

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Hobo Spider

• Brown spider ¼-? inch
• Dozens of similar looking spiders
• Sure ID - dissect reproductive structure
• Each species has a distinctive "lock and key"
  design

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Hobo Spider

• AKA aggressive house spider but not too
  aggressive
• Introduced from Europe
• Found in PNW British Columbia, MT, WY, CO, ID,
  OR, WA and northern UT
• May cause necrotic wounds
• Can have dense populations in certain habitats
• Web often found in a crack between bricks or
  under wood, stones, or vegetation

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Hobo Spider

• Easier to say it is NOT a hobo
• 1st is it associated with a funnel web?
• Yes maybe No not a hobo
• 2nd how many eyes does it have and the
  arrangement?
• 8 eyes in 2 rows of 4 maybe 6 eyes or 8 in
  different arrangement not a hobo
• Maybe answers arent always hobos, still finer
  details must be examined

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Hobo Spider
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Hobo Spider Bites

• Suggested progressive necrotic wound
• Lab studies with rabbits venom not to be
  poisonous
• Different animals react differently to venoms
• More research is needed to determine its
  importance
• Headache that persists for 2-7 days
• Does not go away with pain relievers
• Other organisms that may be responsible for hobo
  bites
• Arthropods mites, fleas, bed bugs, soft ticks,
  hard ticks, conenose bugs, and kissing bugs
• Medical conditions and diseases bacterial
  infections a non-Hodgkin's lymphoma diabetic
  ulcer herpes

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Giant House Spider

• Mistaken for Hobo Spider
• Non-venomous
• Beneficial

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Active hunters

• Actively search for prey
• Webs (if any) used as resting areas
• Encountered when venture for prey
• Includes
• Wolf spiders
• Jumping spiders
• Nursery web spiders

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Wolf Spiders

• Fast runners that chase their prey
• Sometimes confused with tarantulas
• Hunt day and night
• Usually occur outdoors, but may wander indoors
  in search of prey
• Tend to stay at or near floor level
• Web retreats in sheltered sites
• Females carry large, egg sac attached to
  spinnerets
• Spiderlings climb onto moms back and stay there
  several days before dispersing
• Look scary but not aggressive
• May bite if handled

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Wolf Spiders

• Legs long and sometimes spiny
• 4th pair of legs is longest
• 3 tarsal claws
• Body black and white or earthtones, hairy
• Hairy and large (¼-1½ in)
• Eyes appearance of three rows of 4-2-2
• Carapace pear shaped
• Head sits higher than body

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Jumping Spiders

• Named for jumping ability
• Jump many times their length
• Make quick, sudden jumps to capture prey or
  avoid threat
• Able to walk backward
• Best vision of all spiders
• Active during day, prefer sun
• Normally live outdoors
• May become established indoors
• Hunting activities often center about windows
  and entry doors

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Jumping Spiders

• Body 1/8 3/4 inches long, very hairy, stocky
• Brightly colored or iridescent scales
• Cephalothorax large in relation to abdomen
• Legs short-legged, hairy
• Front legs thickest and longest
• Tarsi have 2 serrated claws
• Eyes 8 eyes in 3 rows
• Middle eyes of front row LARGE
• Appearance of 2 eyes sometimes

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Sac Spiders

• Club spiders/yellow house spiders common in
  Idaho
• Thought to be the most common biter of humans
• Mostly when fall from ceiling onto beds and get
  traped
• Symptoms like that of a bee sting
• Commonly found resting in silken tube in ceiling
  corners, under eaves, rocks, wood, etc.
• Nocturnal

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Sac Spiders

• Legs long legs
• Body slightly flattened abdomen
• Conical shaped spinnerets are characteristic
• Eyes 8 similar sized eyes
• 2 rows (letter D)
• Carapace pear shaped

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Nursery Web Spiders

• Live near lakes and streams
• Occasionally found indoors
• Walk on water can be submerged under water
• Hunt day and night
• Feed on aquatic insects small fish
• Male bring pre-nuptial gift
• Females carry around an egg sac
• Prior to hatch, eggs are fastened to leaves
  enclosed w/in a nursery web
• Female guards the nursery web

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Nursery Web Spiders

• Similar to wolf spiders
• Legs 3 tarsal claws
• Body usually earthtones with light stripes
• Eyes 8 similar sized eyes
• 2 curved rows
• Carapace pear shaped
• Head not elevated like Wolfs

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Passive Hunters

• Lay in wait for their prey rather than searching
• When prey approaches, they jump or pounce
• Includes
• Crab spiders
• Brown spiders
• Tarantulas

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Crab Spiders

• Can walk forward, backward, or sideways
• Many have horns or ornaments on the
  cephalothorax or abdomen
• Some mimic bird droppings

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Crab Spiders

• Legs legs out to side at right angles
• Body abdomen flattened
• Females triangular
• Color blends environment
• Ground hunters gray, brown, or black,
• Plant hunters bright red, yellow, orange,
  white, and/or green
• Eyes 8 similar sized eyes
• 2 rows

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Brown Spiders

• Legs long legs with 2 tarsal claws
• Body brown
• Long thin abdomen
• ? inches
• Eyes 6 similar sized eyes in 3 pairs
• Carapace often violin-shape on top

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Brown Recluse

• Poisonous
• Not established in ID
• Records are from transport
• Violin on cephalothorax points towards rear
• Likes homes

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Tarantula

• Jaws move up and down
• Fang with distinct groove
• Usually brown to black
• Legs 5 inches two claws and claw tuft
• Anal tubercule behind spinnerets
• Many short kinked, barbed hairs (allergenic)

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Tarantula

• Females long lived 20 years
• Males 5-7 yrs 6 mos dies soon after mating
• 800-850 eggs per sac
• Mate in 2006 egg sac in 2007
• Bites only when harassed
• Painful bite but NOT poisonous

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Preventing Bites

• Shake clothing before dressing
• Inspect bedding towels before use
• Wear gloves when handling firewood, lumber, and
  rocks
• Remove bedskirts move bed away from wall
• Dont use under bed for storage
• Use care when handling boxes (spider habitat)

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Control

• Achieved by integrated pest management (IPM)
• Approach that involves multiple tactics
• Preventive measures
• Exclusion
• Sanitation
• Chemicals applied to targeted sites.
• Inspection of building locate the pest and its
  harborages (at night if nocturnal)

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Control

• 1st correctly identify the spider
• Determines management tactics based on biology
  and habits
• Example web builder - target its web (where
  most of its time is spent)
• Active hunters move about more likely to
  contact insecticide-treated surfaces at ground
  level
• Tactics vary in efficacy depending on the
  species of spider

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Control Exclusion

• Tight-fitting screens on windows, doors vents
• Weather stripping around doors
• Seal cracks and crevices that allow entry
• Attract less insects (prey) to your house
• Use yellow or sodium vapor light bulbs outdoors
• Turn lights off (reduces web building)
• Have lights away from the house
• Use sensible storage
• Seal boxes used for storage (prevents entry)
• Plastic bags (sealed) to store loose items

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Control Sanitation

• Reduce areas of harborage
• Remove trash boxes, wood piles, rock piles,
  etc.
• Eliminate clutter in less frequented rooms
• Store items off the floor away from walls
• Eliminate household insect pests (prey)
• Do not stack wood against the house
• Remove heavy vegetation leaf litter near
  foundation
• Wash webs off house with high-pressure hose

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Control Non-Chemical

• Indoors
• Capture and release it outdoors
• Vacuum to remove spiders, webs, egg sacs
• Dispose of vacuum bag in container outdoors
• Squash individuals when discovered
• Sticky traps or glueboards to entangle spiders
• Outdoors
• Regularly destroy webs around the house
• Often move when webs are disrupted

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Control Insecticides

• Many labeled pesticides for spiders
• Some labeled for homeowner use, others only for
  licensed, certified pesticide applicators
• Non-residual aerosol spray
• Kills visible spiders but not egg sacs (vacuum)
• Nonrepellent insecticidal dust
• Provides residual
• Good for web builders dust sticks on webbing
• Can be applied to voids and inaccessible areas

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Control Insecticides Cont

• Wettable powders / microencapsulated products
• For active hunters
• Residual insecticide, slow release formulations
• Applied to corners, behind and under furniture,
  etc.
• Prevent establishment of new spiders
• Flushing agents (pyrethrins) wont control but
  will send them on the move,
• Residual liquid sprays
• Not effective for web-sitting species
• Applied to outside perimeter of the home
• under eaves, patios, decks behind shutters
• Use along cracks and crevices of decorative
  molding, undisturbed corners, and other suspected
  habitats