Chemical ecology

Question 1

Identification of volatile source

Answer 1

• what is the source?
• what behaviour does it cause?
• prove that semiochemical are involved
• How do you exploit this?

Question 2

Olfactometers

Answer 2

Contain airflow
good for rapid screening of odours
groups of insects used
insects should never be used more than once
needs to be designed for each arthropod type

Question 3

The Y tube

Answer 3

mosquito ha to decide to go left or right at the junction
doesn’t work well for anopheles or tsetse
wind tunnel better for anopheles

Question 4

Wind tunnel

Answer 4

can video flight path of mosquito

important fro trap development

Question 5

Still air olfactometer

Answer 5

for walking insects eg. bed bugs

infrared camera - measures how long the stay in each area

Question 6

Servosphere

Answer 6

treadmill for walking insects

airflow over insects

Question 7

Collection of volatiles

Answer 7

can use solvent extraction

or Air entrainment - put poop in a bag and collect into a charcoal filter

Question 8

Host volatiles - microbacteria

Answer 8

bacteria convert sweat into carbolic acid and also produce Co2
Human odour is genetically dtermined by MHC genes

Question 9

Does infection alter attractiveness to vectors

Answer 9

yes - disease can cause changes in individuals odour profile

Question 10

Analysis of volatiles

Answer 10

can use Electroantennography
or single sensillum recordings
or gas chromatography

Question 11

Electroantennography

Answer 11

attach microelectrodes to antennae
records response of all olfactory receptor neurones on antennae
tells you if insect can detect individual chemicals

Question 12

single sensillum recordings

Answer 12

Microelectrodes inserted into sensillum and recording made from ORNs
one electrode in sensillum and reference electrode in lymph or eye of insect

Question 13

gas chromatography

Answer 13

liquid sample injected into gas chamber and vapourised
chemicals separated in relation to weight
accurate quantification of chemicals
in human odour 400-500 volatile chemicals