Im doing my biology A2 coursework (AQA specA) on "how do blowfly maggots respond to different wavelengths of light"
We've been given this information from our teachers...
But for our background information we've got to expand on it, Ive searched google and wikipedia but i can't seem to find much that helps.A taxis – is a directional response of a whole organism to a stimulus.
Phototaxis – a phototropism occurs when a whole organism moves in response to the light stimulus.
Blowfly larvae can be negatively phototactic (helping maintain position within a carcass) or positively phototactic (at time of pupation).
The larvae may have rod-like photoreceptors, some of which appear to be pigmented, which could suggest a crude ability to detect different wavelengths of light. These photoreceptors are situated on either side of the head so that as the larvae moves its head from side to side it can detect the direction and possibly the intensity of the light. This could explain why the larvae change direction. If the intensity were the same on either side presumably the larvae would travel in a straight line. Insects can perceive UV light so it is likely that the larvae can also.
Has anyone done this coursework before or does anyone know anything about it?
Or where I might be able to find some more useful information? a good website? or book even - do you think if i went to a big library (say birmingham..) that they'd have a book with something about this is.. ive tried our school library - but there really isnt much about it in the biology books we have there...
Also - anyone got any ideas for how I could do the experiment... i think Im going to do something along the lines of shining a light with differnet filters onto a piece of paper with a circle drawn on it, put the maggot on the circle and see which way it goes....
Any help is muuuuch appreciated!! thank you all!!
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Maggots - how do they react to light? Coursework! help please! watch
- Thread Starter
- 29-01-2006 13:41
- 02-02-2006 17:14
heya. I've just started a similar sort of experiment, titled:
'Why do fishermen put maggots in their mouths to make them wriggle?'
Sounds weird, but we're basically investigating whether factors such as pH, temperature and light intensity make maggots move more, or less.
The method we've been told to use, is to either:
1) Cut a slit right the way along an art straw, then blue tack it to a table, keep the maggots at the selected temp/pH/ light intensity, and time how long it takes for them to go along the little track - maggot racing as we affectionately call it now.
2) expose the maggot to the required pH/temp/ light intensity, then stick it on the middle of a big blank piece of paper, time 30 seconds, and follow it with a pencil, to show where it moves - then measure this line, and whether its in a straight line etc.
Then this can then all be linked to taxis etc.
Hope thats of some help!
- 06-02-2006 00:39
Question S2... Might help, I just did it as a past paper homework.
- 19-04-2009 17:42
This coursework can be quite tricky but is easy enough if you can get it started. The best places to go to are Wiki as it provided an excellent source of information for my plan. I would recommend things to include such as the theorized phototaxis of a maggot, the taxonomic groups (only up to the genus is really necessary) of the maggot, the life cycle of a maggot (larval and pupating stages). With the experiment, I would recommend the procedure you have stated. It provides decent results but I would include a light meter to measure the lux (light intensity), a dark room to prevent any other sources of light interfering, a water tank to absorb the thermal energy emitted by the lamp (you're measuring the phototaxis, not thermotaxis), place the lamp to one side and not above the maggot, draw a circle split into 4 (two 120 degree sections and two 60 degree sections (If it moves towards the light it is photo positive, away= photo negative, either direction= neutral)). I wouldn't suggest timing it because it may take too long. Take about 20 maggots and see which direction they head to. If you do a Chi- squared test afterwards, then you can still end up with a conclusion even if your results seem random. Hope this helped.