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Ants, Wasps, & Bees
Announcements
• Speaking Today: Amanda Meadows
• Speaking Next Tuesday: Elizabeth Andrews
• QUIZ NEXT TUESDAY OVER CHAPTERS 25, 26, 21, 24
New Spider Threat in N America
• Tegenaria agrestis, Hobo Spider
• Introduced from Europe to Seattle in 1930’s
• Moved into homes• Bite is similar to brown
recluse• Now responsible for more
necrotic envenomations in US than any other sp.
Spiders & MRSA
• MRSA = methicillin-resistant Staphylococcus aureus
• Community-Acquired has been associated with spiders
• Association is two-fold– Transmission of MRSA via spider bites– Misdiagnosis of MRSA as spider bites
• Misdiagnosis has been largely corrected by including MRSA screen as part of the spider bite diagnostic protocol. Example– Educational effort continues in the medical community
Other effects: Urticating Hairs
• Barbed hairs on the abdomen of many New World tarantulas
• Used as a defense, territorial marker.
• Commonly encountered by pet owners when they clean tarantula cages
• Nonvenomous but some people have allergies.
Order Hymenoptera: Ants, Bees, & Wasps
• Relatively recent evolutionary origin• Generally the most beneficial group of insects to
man– Useful products (e.g. honey)– Biological control
• Members have the most advanced communication, learning, and vision
• Most of the social insects in this group– Including specializations for social defense– Most attacks on humans are colony defense actions
Medical significance of this group is in its sting
• Stingers are modified ovipositors so only females sting• Most stinging females are not reproductive• Stinger itself can be a problem but mostly it’s the venom• Hymenopteran families of most medical significance are:
– Ants• Formicidae – Social
– Solitary Wasps• Mutilidae – Velvet ants; Cow Killers
– Social Wasps• Vespidae – Yellow Jackets; Hornets; Paper Wasps
– Social Bees• Apidae – Honey bees; Bumble Bees
Hymenopteran Stinger
Source
Hymenopteran venoms
• Depending on the size/species one sting is generally 0.01 – 0.15 mg venom– Typical Human LD50 is ~100 mg
• Most are chemically similar to snake venom and can be deactivated with ethanol– Neurotoxins and agents to assist them– In vertebrates, neurotoxins cause temporary pain, the
other agents cause real damage
• Often contain non-toxic components– Pheromones (trail marking, alarm, marking)
Example: Apitoxin (Honeybee)
Name % Function
Melitten 52 Anti-inflammatory agent; induces of cortisol production; cell-lytic.
Apamin 15 - 20 Cortisol production; neurotoxin
Phospholipase A2 (A1 in wasps)
10 - 12 Cell-lytic; decreases blood pressure; anticoagulant; prostoglandin stimulant
Hyaluronidase 1 - 3 Dilates capillaries speeding inflammatory spread
Protease Inhibitors 2 Prevents Inactivation of other constituents
Dopamine & noradrenalin
1 - 2 Increases pulse rate
Histamine 0.5 - 2 Allergic response
Reactions to Hymenopteran Stings
• Immediate localized reaction or swelling (non-allergic responses)– Mild: erythema, swelling, and transient pain at the sting site that
subsides within a few hours– More Severe: may involve an entire extremity. Swelling of the
airway, tongue etc can occur. • Systemic toxic response from multiple stings
– Mild: Hives– More Severe: vomiting, dizziness, confusion, rash, general
weakness, shortness of breath and wheezing, and chest pain • Systemic allergic reactions - rare
– May occur from an initial sting or may be acquired– anaphylactic shock, difficulty in breathing, and death within 30
minutes
Example Symptoms
Bee sting hives on arm from a sting on leg
Adult Onset Allergy
Paper wasp sting near eye
Ants
• ~10,000 spp world wide only a few are medically important
• Ant “venom” varies dramatically across species, most are non-toxic to vertebrates.
• Medically important species– Fire ants– Bull-dog ant
Fire Ants
• Solenopsis spp.• S. invicta, Red Imported Fire
Ant (RIFA) the most important
• Introduced into US in the 1930’s, now in most of SE US.– Have had many ecological
ramifications. Ex. here• Sting 15 – 25 million/year in
US• Cause $750 million damage
in Agriculture/year
Bulldog Ants
• Ants in the genus, Myrmecia. M. pilosula is the “Jack Jumper”.
• Australia & Tasmania (Jack Jumpers).
• In Tasmania, they cause more deaths than spiders, wasps, snakes & sharks combined.
• Generate anaphylactic shock in high incidence. Life-threatening reactions in 1-2% of cases.
• Antivenom stocks maintained throughout their range.
Jack Jumper
Solitary Wasps
• Velvet ants, several spp.
• Nest parasites of ground-nesting bees & wasps
• Very painful sting
Social Wasps• Yellowjackets, hornets & paper wasps
• Yellowjackets are the important group.– Large, annual nests– Aggressively defended
by workers– Often in situations with
human contact.
• Baldfaced hornets are actually yellow jackets which act like hornets.
Above: Western Yellow Jacket
Above: European hornetBald faced hornet (right) & nest (above)
Hornets vs Wasps
Character Hornets Wasps
Genus Vespa Dolichovespula, Vespula
Nest Habitat Above ground, tree hollows
Below ground, wall voids
Spp in N. America
1 ~12 important
Bees
• Insects in the unranked taxon, Anthophila, several families
• 20,000 spp most of which are harmless
• A group that switched from predation to feeding on nectar & pollen
• Co-evolved with flowers.
• Few are agressive
Africanized Bees
• Hybrids of the European honey bee and the African honey bee (different subspecies)
• Originally imported to Brazil to increase honey production
• Defends hive more aggressively
• Kill 1 – 2 people/year in US
Animated map of spread
First Aid
• Topical steroid cream (hydrocortisone),
• Cream containing aloe vera.
• Fire ant creams: – regular toothpaste. – Solution of half bleach and half water applied
immediately to the area can reduce the pain, itching and, perhaps, pustule formation.
• Oral medicines: antihistamines.