Most problematic Wasps !• 26 species! !Hornet!Vespa cabro !• Colonies are build either suspended in the air, or underground and in structures !• !Mature colony size ranges from 500 to 15,000 cells !• !Introduced in US in 1850!!• !Closely related to Yellow jackets and similar in biology Yellow Jackets: 1Most problematic Wasps Cont’d !• !Typical mature colonies contain 30-70 adults!!• 200 species worldwide !!• !Great affinity for building in and around buildings, encounters with humans is common!Paper Wasps: !• !In paper wasps other queens sometimes join the colony and compete for reproductive dominance !• !Colony is a single open faced cone 2Honey Bee !• !Introduced from Europe to produce honey and for pollination in agriculture!!• !Most colonies are artificial !• !Also produces colonies and can mobilize workers for defense of colony!!• !Bee stinger is barbed and will stay in the victim • Also produces pheromone that marks the victim for other workers!31990: Southern Texas 1993: Arizona 1995: California 2005: Florida Africanized Honey Bee (Killer Bees) !• Introduced from Africa to Brazil in 1956 by Genetics professor Warwick Kerr to cross with European bee to produce a type more adapted to tropical climate!!• !Escaped in 1957 4Killer Bees: Medical Importance !• !Approx. 1000 deaths since introduction !• !14 deaths in US since introduction !• A!famous!case in Costa Rica (1986): 8000 stings 5Why are Africanized honey bees so dangerous? Africanized Honey Bee pursues for 300 yards Africanized honey bee pursues in larger numbers Africanized bees are much easier disturbed than european honey bees European Honey Bee pursues for about 30 yards Venom is about the same strength as European Honey Bees 6Ants !• !All ants bite, only some sting!!• !Two main groups of medically relevant ants: 1) Imported fire ants: 2 species - Red imported fire ant; Black imported fire ant 2) Harvester ants 26 species in US !• !Sting is very painful very aggressive!7Fire Ants !• !Hypersensitivity is a problem (in about 5% of cases medical treatment is necessary) !• !At the slightest disturbance large numbers of workers are mobilized • Sting: Burning sensation at first and wheal 24 hrs pustule develops !!• Extremely aggressive !• !No evidence that venom can kill human (unless allergic) 8Current and predicted distribution Fire Ants !• !Introduced in the early half of 20th century!!• !Black fire ant from Uruguay!!• !Red fire ant from Brazil!!• !Red form has spread aggressively!9Scorpions: !• 2000 species worldwide !• !Contain neurotoxic venom -> interferes with transmisson of neural impulses!!• !The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths!!• !Deathstalker, most potent venom(North Africa, Middle East) • Nervous and agrresive Readily available in the pet trade !!• !Only handful are deadly Most at risk are children, elderly, Infirm !10Centruroides exilicauda Arizona Bark Scorpion !• !Anti-venom is experimental, non- FDA approved and available only in Arizona!!• !America’s only dangerous scorpion; Mostly to infants and children; No deaths reported since 1968 in US !!(excluding!anaphylac8c!shock)"!• !90 species of scorpions in the US !• !Treatment of sting: Stay calm; Do not move stung body part; Seek medical treatment !• !Distribution: USA (Arizona, California, Nevada, New Mexico and Utah) and northwestern Mexico 11Texas scorpions !• The sting of this species causes local pain and swelling • Deaths attributed to this species have not been substantiated !• !C. vittatus is an active forager, and will climb trees and move into attics. When it gets warm, it will move down into living quarters!!• !Texas has 18 species and only one species, Centruroides vittatus (Striped Bark Scorpion), is spread throughout the eastern part of the state!12Poisonous Arthropods: MilliPedes!!• Vegetarians, feed on dead plant and leave matter !• !Some can produce irritating secretions • Symptoms to exposure: pain; itching; local erythema; edema; blisters; eczema; and occasionally cracked skin !• Some non-US species poduce Hydrogen cyanide 13Buck moth Io moth Puss caterpillar Saddle back caterpillar “very severe pain, radiating up a limb and causing burning, swelling, nausea, headache, abdominal distress, rashes, blisters, and sometimes chest pain, numbness, or difficulty breathing” Poisonous Arthropods: Caterpillars!!• 150 species medically relevant !• !Fatalities are rare !• Several species posses urticating (stinging ) hairs or spines that release poison when touched !• !Generally: local reaction; swelling; pain; numbness • Systemic reaction: nausea headache; vomiting; paralysis; acute renal failure!!• !Watch out for this one! 14Striped blister beetle !• !When ingested may lead to abdominal pain, kidney damage, and sometimes death!!• !In case of hay (alfalfa), infestation may kill horses (50 beetles)!!• Spanish fly: Blister beetle from southern Europe: used as aphrodisiac Poisonous Arthropods: Blister Beetles, Family Meloidae!15Public!Health!Entomology!Lecture!4!!!The!evolu8on!and!dynamics!of!vectorBborne!disease!16A very brief (and simplistic) Introduction to evolutionary theory Survival of the fittest? Natural selection: Evolution is not really about survival -> reproduction is the key concept Heritable traits that increase relative reproductive success will become fixed in a population Herbert Spencer One of the main forces of evolution: Charles Darwin 17Fitness: The proportion of the individual’s genes in the next generation """If population size is stable, 1 copy of a gene on average contributes one copy to the next generation. If all individuals contribute equally, all have fitness = 1 (no change in frequency, unless by chance; “genetic drift”) If some individuals have a gene A that increases reproductive success with 5%, fitness => 1.05 Then other gene B has lower fitness < 1 Gene A will replace B, and will go to fixation 18Fitness:"The proportion of the individuals genes in the next