W9: Invertebrate Physiology (Reproduction, Forensics & SIT) [Dr. Blair] Flashcards
Kinds of insect reproduction/Insect reproductive strategies? (3) HOP
- Haplodiploidy.
- Oviparous.
- Parthenogenesis.
Haplodiploidy attributes? (3)
- Sexual reproduction.
- No fertilisation (haploid) (ie, eggs develop without fertilisation).
- Seen in eusocial insects (bees & ants).
Oviparous attributes? (3)
- Sexual reproduction.
- Fertilisation of eggs occurs & produces diploid (2n) offspring.
- Seen in most insects (flies, mosquitoes).
Parthenogenesis attributes? (3)
- Asexual reproduction.
- No fertilisation (ie, eggs develop without fertilisation).
- Seen in aphids, wasps & stick insects.
Egs of oviparous insects? (2)
- Bees.
- Ants.
Egs of parthenogenetic insects? (3)
- Wasps.
- Aphids.
- Stick insects.
Eg of haplodiploidy insects?
Flies.
Diptera attributes? (3)
- Order of flies.
- Two wings.
- Part of the important species in medical & applied entomology.
Family under Diptera to focus on?
Calliphoridae.
Calliphoridae is AKA?
Blow flies.
Blow flies attributes? (2)
- Over 1100 species.
- Important in forensics as they often found on dead, often bloated, bodies upon which these flies/larvae are found.
Fly life cycle layout in order? (6)
- Eggs.
- 1st larval stage.
- 2nd larval stage.
- 3rd larval stage.
- Pupa.
- Adult.
- Repeat process.
Why are maggots eyes positioned where they are positioned?
Blow flies courtship process: Finding Ms. Right? (5)
- Males will find a female (7 day old females).
- Courtship process is initiated by the male.
- Done by mating with the female and spreading her wings.
- Female’s eggs are fertilised provided she is accepting of the male.
- Females mate once, while males mate multiple times.
Myiasis?
= the invasion of vertebrate tissues/organs (dead or living) by Dipteran larvae.
Flies that cause myiasis in South Africa? (2)
- Tumbu flies.
- Screw-worm flies.
Tumbu flies?
= under Calliphoridae family.
Screw-worm flies attributes? (4)
- Under the Calliphoridae family.
- Have a rapid life cycle (3 weeks).
- Partake in obligate myiasis.
- Cause significant damage by laying eggs in vertebrate tissues, affecting livestock and sometimes humans.
Economic impact of myiasis?
Infestation leads to secondary infections & significant economic losses, especially in livestock farming.
What happens when they get into vertebrate tissue: Larvae in livestock? (4)
- More than just painful wounds.
- Secondary infection (death).
- Economic losses (livestock farming).
- Attracts more flies (feedback: outbreak).
Screw-worm flies myiasis affects who? (2)
- Larvae in livestock.
- Larvae in humans.
Screw-worm flies distribution attributes? (5)
- Severe losses to the livestock brought pressure to control/eradicate these flies (1900s-1930s).
- Pesticides & pheromone traps were unsuccessful in controlling this beast.
- Approached entomologists, Bushland & Knipling, who initiated research in 1930.
- Bushland suggested using chemicals on cattle (perhaps to make them unpalatable to the flies?).
- Knipling suggested breaking the insect life-cycle (sterile insect technique).
Sterile Insect Technique (S.I.T)?
= genetic control programme that releases very high numbers of artificially sterilised males into the population, resulting in sterile matings & consequently a reduction in population size.
S.I.T is AKA?
Sterile Male Release.
S.I.T process (lay it out for me in order)? (7)
- Mass rearing of insects.
- Sterilise males with radiation, but ensure no noticeable change (eg, sickly, etc).
- Release millions of sterile males to significantly alter the sex ration (males : females).
- Sterile males mate with wild females.
- Eggs fail to develop, leading to decreased progeny & decreased population.
- Repeat the process.
Did the S.I.T work?
YES, IT WORKED!
Explain how the S.I.T worked? (4)
- Started in Curacao in Venezuela & screw-fly populations were eliminated (7 weeks).
- Controlled in the USA (1960s-1970s).
- Eliminated in Mexico (1980s).
- Eliminated in Libya (1991).
What is key to the S.I.T working?
The female needs to mate once because if females mate multiple times it makes the …..
Forensic entomology: Role of blow flies? (3)
- Able to sense freshly dead organic matter.
- Are first to arrive (<10 mins).
- Lay egg batches.
Particular types of blow flies in Forensic entomology? (2)
- Green bottles.
- Blue bottles.
Green bottles scientific name?
Lucilia cuprina.
Blue bottles scientific name?
Calliphora vomitoria.
Green bottles attributes? (3)
- Smaller.
- Maggots.
- Compete with blue bottles for food (carrion, excreta & nectar).
Blue bottles attributes? (3)
- Larger.
- Maggots.
- Compete with green bottles for food (carrion, excreta & nectar).
Forensic entomology: In the field? (4)
Forensic entomologists:
- Collect as much data as possible such as,
- Flies, maggots & pupae.
- Ambient weather conditions (temperature affects the rate of development of flies).
- Position of the body (outdoors, shade, buried).
Forensic entomology: In the lab? (3)
Forensic entomologists:
- Determine the developmental stage & species collected from the field.
- Calculate the development rate of the stages.
- Data are compared against weather conditions to estimate the time of oviposition (Post Mortem Interval).
Explain the graph of Temperature & fly development? (9)
- Graph illustrates the importance of temperature for fly development from an egg to adult.
- x-axis = Temperature.
- y-axis = Developmental time (days).
- Flies fail to develop at 10-13 degrees celsius.
- As temperature increases, the developmental time decreases exponentially from egg to adult.
- At 20C, eggs take about 25 days to develop into an adult & that decreases as it develops into an adult with increasing temperature.
- At 25C, it took about 15 days to develop from egg to adult.
- At 30C, it took about 12 days to develop from egg to adult.
- At 35C, it took 10 days to develop from egg to adult.
PMI stands for?
Post Mortem Interval.
Forensic entomology: PMI? (2)
- PMI graph.
- Forensic entomologists work backwards when determining the PMI.
Explain the PMI graph?
Forensic entomology: Added benefits from flies? (4)
- Locality, through the potential movement of the victim or locality of their death (eg, dumping).
- Trauma, through the presence & abundance of maggots within a corpse being used as a trauma guide.
- Toxins, through flies/maggots being examined for the presence of drugs/toxins (entomotoxicology).
- DNA identification, through the fact that maggots feeding on a corpse may retain testable DNA.
Types of entomology covered? (2)
- Forensic entomology.
- Medical entomology.
Medical entomology: Benefits from flies?
Sterilised blow flies, particularly green bottles, are used in Maggot therapy.
Maggot therapy?
= where sterilised blow flies, especially green bottles, are used in medicine to help clean wounds by removing dead tissue, promoting healing & reducing infection.
Maggot therapy benefits? (3)
- Aid in removal of damaged tissue.
- Regeneration of new cells.
- Decreasing infection by microbes.
Super summary? (3)
- Reproduction (majority of insects are oviparous, asexual reproduction is possible in some).
- Life cycle (understanding the reproductive cycle, larva to adult).
- Useful applications (sterile insect technique, forensic entomology, medical uses via maggot therapy).
