CockroachesARTHROPODA, INSECTAInsects have 3 body regions:Head, thorax, abdomenSix legs (as adults)Most have wings (although wings lost for some ectoparasites such as lice, fleas)Metamorphosis (incomplete: egg, nymph, adult; or complete: egg, larva, pupa, adult)Class InsectaOrder Blattodea* (=Blattaria)Incomplete metamorphosisEggs in oothecaPronotum large, shield-likeHead directed downwardMandibulate mouthpartsAntennae very longLong hairy legs-fast runnersForewings thickenedPaired cerci on abdomen*Problems associated with roaches:- Can be involved in mechanical transmission of pathogens- How? Roaches feed indiscriminately on garbage, sewage, and then move to food anddishes. They transport lots of bacteria on their sticky feet and body hairs.- However, no evidence of biological transmission of any pathogen (i.e. bacteria do notgrow or change)*Mechanical vs. Biological Transmission- Mechanical: the transfer of a pathogen or parasite, usually via external body parts of thevector, without the pathogenic organism undergoing any biological development.- Biological: the transfer of a pathogen or parasite via a vector after the pathogenundergoes important biological change (development, propagation) inside the vector.Biological or mechanical?An insect walks across a bacteria laden surface and get a pathogenic bacterium on its feet. Youaccidently swallow the insect, and get sick after the bacterium multiples in your gut. Biologicalor mechanical?An insect swallows a worm egg and it develops into a mature worm in its gut. You swat theinsect on your arm, and the worm escapes, penetrates your skin, and makes you sick. Biologicalor mechanical?An insect swallows a pathogenic worm, the worm passes harmlessly through the gut and isdeposited on your skin while you sleep. The worm penetrates your skin and you get sick.Biological or mechanical?Remember: Mechanical means no change in the pathogen in the vector*Cockroach allergies- Roaches are a source of allergens (body oils, feces), and can be strong triggers of asthma,especially in children- 47% or more of inner-city children with asthma were found to be hypersensitized tocockroaches- Asthmatic children sensitive to cockroach allergens and then exposed to cockroachallergen had 2X more unscheduled medical visits and 3X more hospital visits than otherasthmatics- In several studies in inner cities, 50-98% of homes (including children’s bedrooms) foundwith high levels of cockroach allergen- Schools and day-care facilities also found with high levels of allergen- Problem: eating in bedroom or other areas where children spend a lot of time can lead tohigh roach populationsProblems with roaches- People hate roaches; this reduces enjoyment of homes, can even produce fear andphobias- Roaches can destroy property (roaches eat paper products, people have to dispose of foodcontaminated by roaches, etc)- Veterinary problems with roaches: can be intermediate hosts of some intestinalnematodesRoach life cycle (incomplete metamorphosis)German cockroach is the most problematic roach,including in Athens*Details of Biology:Ootheca with 30-40 eggsFemale carries ootheca, drops it in hidden area and the eggs hatchFemale produces ootheca every 20-25 days, 4-8 lifetime total6-7 nymphal stages in about 60 days (depends on temperature)All stages aggregate in dark enclosed spaces, prefer wood orpaper surfacesAggregation pheromone in fecesNeed humid warm environment (optimally 30-33o C)Few individuals forage at any one time, bring food back to colonyHigh reproductive rates means problems can develop rapidly (note y-axis is millions)Oriental cockroachDetails of Biology:Ootheca with 16 eggsFemale can produce up to 8 oothecae in her lifetimeOotheca deposited in areas with foodEggs hatch in about 2 monthsDevelopment to adults requires about a yearPreferred habitats that are humid, coolerOften associated with drains and sewers, where there are lots of bacteria for mechanicaltransmissionBut not highly mobile, so infestations are localizedAmerican cockroachDetails of Biology:Largest roach species infesting houses in North AmericaOotheca with 12-16 eggs; female produces 6-14 oothecaeover lifetime, deposited in cracks or crevices, hatch in 1-2 months13 nymphal molts over 13-14 monthsAdults usually live about a year, but can exceed 2 yearsPrefer warm and humid areas, e.g. around pipes, waterheaters, drains, sewers, crawl spaces, attics, voidsin walls and between floors, etcCan travel several hundred meters through pipes, so move readily from place to