W12 L1 anthropogenic selection: sensory system

Question 1

Animal sensory system

Answer 1

-Animal have a different sensory system comparing to us
-We have different experience of the world

Question 2

What is PM pollution

Answer 2

-solid or liquid particles suspended in the air, either from a natural sources or anthropogenic (fossil fuel, road traffic, mining , cooking)

Question 3

Pattern of PM pollution

Answer 3

Not only in populated areas
* Over 40% of world’s landmass has PM higher than WHO recommendation (10μg/m3 per year)
* Including ecological hotspots, such as rain forests in Amazon, West Africa, Southeast Asia.
* Some remote and pristine areas are affected by PM: over 42% of world’s natural reserves

Question 4

PM contaminates insects around the world

Answer 4

Large number of PM discovered on flies collected in urban areas in Beijing
Some PM were discovered on insects collected during bushfire season in Australia
Other records of PM found on insect surfaces in India, Singapore, and Europe

Question 5

PM pollution affects insect chemical communication experiment

Answer 5

• After exposure in contaminated urban atmosphere for only 12 h in Beijing, PM accumulates on houseflies
• Highest density of PM on the surface of antennae than other body parts,
• Contaminated antennae have much denser PM than controls

Question 6

The diversity of insect antennae

Answer 6

Main olfactory organ of insects, perceiving crucial olfactory cues to locate mates, food, oviposition sites, and conspecific social signals
Insects live in a world dominated by chemical signals – antennae to an insect is like eyes to human.

Question 7

Structure of insect antennae

Answer 7

Insect antennae are full of porous sensilla, each specialised to one type (or a group) of chemical odours
-Different types: mechanical, chemical, thermal, and hydro sensors
-Some of these sensilla surfaces are full of microscopic pores 1-2μm, allowing odour molecules to enter
-Also allows pollutants to enter and impact the function of antennae

Question 8

PM pollution affects insect chemical communication

Answer 8

Y-maze olfactometer behavioural assays:
Two treatments: contaminated and clean air control
Examined the response of houseflies to series of diluted food odours and sex pheromones
The ability of houseflies to respond to odours was compromised by exposure to air pollution

Question 9

evolutionary consequences of insect decline

Answer 9

Insects are at the base of the foodweb, pollinate 65% of all plant species, higher proportion of crops
Widespread indirect effects
Specific selection pressures on inspect species depends on stressors

Question 10

Importance of light

Answer 10

-light has been a constancy experienced by life on earth
-pattern in life vary with the lunar cycle
-light is an important in circadian rhythm

Question 11

Effect of light artificial light in animal: spider example

Answer 11

-Spider make web underneath light as insect are attracted to it (much more prey compare to those that have web in no light)
-However, the spider raised under light mature faster but have a smaller size at maturation
-smaller body size lead to less fecundity (produce less egg)
-the change in body size could be due to artificial light exposure