Cockroaches Most have wings although wings lost for some ectoparasites such as lice fleas Metamorphosis incomplete egg nymph adult or complete egg larva pupa adult ARTHROPODA INSECTA Insects have 3 body regions Head thorax abdomen Six legs as adults Class Insecta Order Blattodea Blattaria Incomplete metamorphosis Eggs in ootheca Pronotum large shield like Head directed downward Mandibulate mouthparts Antennae very long Long hairy legs fast runners Forewings thickened Paired 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 and dishes 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 not grow or change Mechanical vs Biological Transmission Mechanical the transfer of a pathogen or parasite usually via external body parts of the vector without the pathogenic organism undergoing any biological development Biological the transfer of a pathogen or parasite via a vector after the pathogen undergoes 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 You accidently swallow the insect and get sick after the bacterium multiples in your gut Biological An insect swallows a worm egg and it develops into a mature worm in its gut You swat the insect on your arm and the worm escapes penetrates your skin and makes you sick Biological or mechanical or mechanical An insect swallows a pathogenic worm the worm passes harmlessly through the gut and is deposited 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 Roaches are a source of allergens body oils feces and can be strong triggers of asthma 47 or more of inner city children with asthma were found to be hypersensitized to Asthmatic children sensitive to cockroach allergens and then exposed to cockroach allergen had 2X more unscheduled medical visits and 3X more hospital visits than other In several studies in inner cities 50 98 of homes including children s bedrooms found with 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 to Cockroach allergies especially in children cockroaches asthmatics high roach populations Problems with roaches phobias nematodes People hate roaches this reduces enjoyment of homes can even produce fear and Roaches can destroy property roaches eat paper products people have to dispose of food contaminated by roaches etc Veterinary problems with roaches can be intermediate hosts of some intestinal Roach life cycle incomplete metamorphosis German cockroach is the most problematic roach including in Athens Details of Biology Ootheca with 30 40 eggs Female carries ootheca drops it in hidden area and the eggs hatch Female produces ootheca every 20 25 days 4 8 lifetime total 6 7 nymphal stages in about 60 days depends on temperature All stages aggregate in dark enclosed spaces prefer wood or paper surfaces Aggregation pheromone in feces Need humid warm environment optimally 30 33o C Few individuals forage at any one time bring food back to colony High reproductive rates means problems can develop rapidly note y axis is millions Oriental cockroach Details of Biology Ootheca with 16 eggs Female can produce up to 8 oothecae in her lifetime Ootheca deposited in areas with food Eggs hatch in about 2 months Development to adults requires about a year Preferred habitats that are humid cooler Often associated with drains and sewers where there are lots of bacteria for mechanical transmission But not highly mobile so infestations are localized American cockroach Details of Biology Largest roach species infesting houses in North America Ootheca with 12 16 eggs female produces 6 14 oothecae over lifetime deposited in cracks or crevices hatch in 1 2 months 13 nymphal molts over 13 14 months Adults usually live about a year but can exceed 2 years Prefer warm and humid areas e g around pipes water heaters drains sewers crawl spaces attics voids in walls and between floors etc Can travel several hundred meters through pipes so move readily from place to place