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

Wasp Stinger

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

Probable Eventual Distribution of Africanized Bees

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.

Medical Use of Hymenoptera

• Ant head sutures– Uses soldier ant heads– Used for at least 3,000

years

• Bee venom therapy– 1980 FDA licensed its use

for desensitation– Now >500 human and

veterinary applications– American Apitherapy

Society