Lecture 2.1 - Cockroaches and Mechanical Vectors Flashcards
How many species of cockroaches are there?
8,000
How many species of cockroaches are pests?
30
What is the class of a cockroach?
insecta
What is the order of a cockroach?
blattodea
What is a highly specialized eusocial cockroach?
termites
Periplaneta americana
American cockroach
Where is the American cockroach native, and what is it previously known as?
native to tropical areas such as south and west Africa
“ship cockroach” … likely arrived to America via trans-Atlantic slave trade
What do American cockroaches feed on (Periplaneta Americana)?
omnivorous - also cannibalistic scavengers
eat dead members of same species
Where do P. Americana live?
dark, damp habitats, warm/ high humidity
Where do we often find P. Americana in human homes?
basements, bathrooms, kitchens
Where do we often find P. Americana outside home environments?
sewers
What are three ways a cockroach might transmit a pathogen?
1) can move pathogens on the external surfaces of their body to new locations
2) spread pathogens via their feces
3) can contaminate food by feeding on it
In what broad way does a cockroach transmit their pathogens?
MECHANICALLY
mechanical vectors
Mechanical vs. Biological transmission
Mechanical: pathogen does not undergo any developmental change or increase in number in the vector
Biological: pathogen either increases in number or undergoes a developmental change in the vector
Is this a mechanical transmission or biological:
A cockroach crawls out of a sewer pipe, into your drain, and across your toothbrush. Bacteria from the sewage is on your toothbrush from when it crawled on it.
mechanical
Is this a mechanical transmission or biological:
A cockroach ingests a few cells of an enteric pathogen which multiply in its gut. Later, it defecates in your coffee cup, inoculating it with a large number bacteria.
bacterial
Is this a mechanical transmission or biological:
A cockroach eats the eggs of a parasitic worm. The eggs pass through the cockroach and are deposited through the feces onto a cookie you left on the counter overnight.
mechanical
Is this a mechanical transmission or biological:
A cockroach eats the eggs of a parasitic worm. The eggs hatch in the cockroach and develop into a worm. You accidentally eat the cockroach as it was in a bag of fruit you used for a smoothy.
biological
What other insects might be mechanical vectors?
house flies (Musca domestica)
What makes house flies meaningful mechanical vectors?
synanthropy: the ability to live in close association with humans
When did house flies (Musca) diverge from Drosophila?
between 48 and 86 MYA
Where do M. domestic (house flies) breed? Feed?
Prefer wet food (nectar, syrups, mucus) but will eat solid food, it regurgitates saliva and sucks up the digested substance
They LOVE meat, cheeses, wounds
What are the top three preferred breeding sites of house flies (M. domestica)?
horse manure is preferred
trash is also a favorite
human feces is a close second
What do breeding sites of house flies (M. domestica) present?
present opportunities for acquisition of pathogens (bacteria, viruses, and protozoans)
Sacrophagidae
flesh flies
adults and larvae feed on carrion, dung, and decaying organic matter
Calliphoridae
blow flies
adults and larvae feed on carrion and dung
Stomaxys
stable flies
adults feed on blood (cattle), larvae develop in organic matter
Prevalence of antimicrobial resistance phenotypes and genes in stable fly.
Why is this a concern?
horizontal transfers (sharing genetic information with something NOT closely related to) spreading leading to potential antibiotic resistance via the movement of these genes
What aspects of modern farming might be contributing to this antibiotic resistance?
we use MANY antibiotics in animals, if they are constantly exposed to these antibiotics they get antibiotic resistance therefore leading to antibiotic resistant bacteria
Periplaneta fuliginosa
somkeybrown cockroach
Where is Periplaneta fuliginosa (smokeybrown cockroach) likely native, and what habitat is preferred?
native to east Asia (possibly Japan)
attics, leaf litter, tree holes, sheds (unlikely to be found in kitchens, rarely in sewers)
Where might you as a human find a smokeybrown?
outside your door in a pile of leaves
Should you be concerned about the smokeybrown cockroach transmitting pathogens?
no, not really they aren’t associated with sewers or food
Blatta orientalis
oriental cockroach
Where is blatta orientalis (oriental cockroach) likely originated and what habitat is preferred?
Likely south-west Asia (Crimea-Greece)
both natural and man-made environments, high humidity, sewers, buildings, leaf litter, bat caves
Where is blatta orientalis (oriental cockroach) least likely found?
rarely found above the 1st floor of a building
What are blatta orientalis (oriental cockroach) the most tolerant of?
of urban cockroaches, they are the most cold tolerant and can survive freezing for hours
What is probably the first cockroach to adapt to human civilization, and how was this assumption made?
blatta orientalis (oriental cockroach)
found in Egyptian mummy wrappings
pest documented in Aristotle
Blattella asahinai
Asian cockroach
What is the habitat of Blattella asahinai (asian cockroach)?
leaf litter, mulch
Where is the Blattella asahinai (asian cockroach) rarely found?
indoors
Whaat does the Blattella asahinai (asian cockroach) like to do?
likes to fly, attracted to lights
Blattella germanica
German cockroach
What is the habitat of the German cockroach (blattella germanica)?
MAJOR INDOOR PEST
almost NEVER found outside structures, and NEVER in natural environments
Where can the German cockroach (blattella germanica) NOT survive?
cold temperatures or low humidity
How does the German cockroach (blattella germanica) feed?
omnivorous - but also necophagic (eats dead members of the same species)
What do German cockroaches (blattella germanica) form?
forms large colonies of closely-related individuals, display significant group foraging behavior
When was the German cockroach described?
in Europe in the late 1700s
Why are the called German cockroaches?
first described/identified in Germany
Where did the German cockroach come from? Spontaneous generation?
NO - they’re from Asia
their most closely related cockroach was the Asian cockroach
What are the three major dispersals of the German cockroach?
1) from SE Asia about 1.2 thousand years ago, coinciding with major trade routes between Middle East and SE Asia
2) into Europe and Africa about 270 years ago corresponds with increase in European and Islamic colonial expansion
3) into Americas, Oceania, about 120 years ago first recorded in US in 1842 in NYC arrival corresponds with increase in advances in shipping technology and controlled environments
German cockroaches aren’t a sewer roach, are rarely found outside. so why do we care? Are they likely a major mechanical vector?
they could be…but really are not major at all
So, why do we care about German cockroaches?
exposure to them leads to if you have an allergy against them and are exposed to them you are likely to develop asthma
What do German cockroaches produce that is so harmful to allergies and causing asthma?
they produce proteins that are highly antigenic to humans
Bla g1 and Bla g2 originate in the cockroach gut and are excreted in feces, and can become a component of dust
What happens to kids exposed to high levels of Bla g1/g2?
they have 3.4x more annual hospitalizations due to asthma
Where is asthma more prevalent?
in urban areas with high rates of poverty
What are five ways you can induce cockroach control?
1) integrated pest management (IPM) - takes into account the biology of these pests to control them and has many different control measures
2) monitor them to discover location of 3 things all species need - food, water, harborage.. a place to hide
3) eliminate access to food - wash dishes, secure food waste
4) remove harborage as much as possible
5) limit movement - caulk around drains and seal around pipes
What are insecticide based methods, and are they likely to be effective?
barrier spraying - prevents cockroaches from entering homes/structures via doors, windows
insecticidal fogging around home
NOT THAT EFFECTIVE
the cockroaches are likely to be hiding, they kill bugs but don’t control them, when cockroaches are hiding the foggers can’t get them and only gets few visible ones
So what is one of the most effective ways to control cockroaches?
a sweet trap that contains an attractant food (glucose) and a slow-acting insecticide (fipronil, 6-14 hours) or hydomethylnon (2-4 days)
the slow acting insecticide is more beneficial as it allows the cockroaches to bring food back that has the insecticide AND when the infected cockroach dies other cockroaches eat him and spread the insecticide more
If we have treatments, why do we still have cockroach problems?
resistance
it is increasing, but most populations are still susceptible to these pesticides
Other than resistance, why do we still have cockroach problems?
these glucose baits are failing to control cockroaches, the cockroaches learn sugar is associated with death
How do cockroaches learn glucose is associated with death?
they have gustatory receptors bind tastings, which activate neurons (GRNs) which connect to the brain
GRN2 is the deterrent, typically activated by high salt
in glucose, averse population, they perceive glucose as bitter now (this neuron perceives glucose in a totally different way)
With continued widespread use of insecticide baits, what would we expect to happen to the populations of glucose averse cockroaches? Of cockroaches that are not glucose averse?
the glucose averse cockroaches contain a cost
they don’t sense maltose, fructose, sucrose, etc. as being bitter
cockroaches have salivary amylase inhibitors which
Why do wild type cockroaches have higher fitness than GA cockroaches, even when there is no glucose in the diet?
salivary amylase inhibitors increase acceptance of complex carbohydrate diets in GA cockroaches
What is cockroach mating like?
the male offers a nuptial gift which is food
during courtship, males expose specialized herbal glands and offer females an oligosaccharide-rich (lots of sugar) secretion that includes maltose and malt trios, phospholipids, cholesterol and various amino acids
