It has always
fascinated me how some insects creep around on the ground or fly around at
night time. The flying insects are particularly fascinating as
some appear dim witted at night. Much like myself they have a
tendency to crash into objects an example of this are huhu beetles. Then there
are other insects that can navigate through complicated habitats unimpeded. An
example of these agile critters is the mosquito which has the tendency to buzz
around your ear, seemingly to provoke you. They always miss the swipe of your
hand. Then you find out that you have planted it on your face. Ouch I can
still feel the sting of my hand.
Vision and visual
navigation in nocturnal insects is the article I chose. I chose this article to
develop my understanding of the complex way in which insect can navigate at
night. This article takes an in depth look at how some insects are able to
navigate and see at night time.
Insects can be
active during the night because they can navigate during and through the night.
Due to the extremely high number of different species of insects it can be
expected they don't
mechanism for navigation in the dark. Through recent research it
is believe that nocturnal insect can preform the same level of
activity as diurnal insect. Some species of dung beetles use celestial cues
such as the moon. The nocturnal dung beetle (Scarabaeus zambesianus) have apposition
eyes which are sensitive enough for basic celestial navigation of the
milky way and dim moon light. They use the and milky way/ moon to orientate
themselves in a straight line and keep their ball of dung safe were they can
manipulate the dung. This method prevents competition from other dung beetles. This method seems somewhat primitive because they seem to orientate themselves
in a straight line if the night sky is cloudy and the moon and Milky Way is not
visible. The beetles however are just being efficient The
insects that require more accurate vision have slightly different compound
eyes. Some insects, such as forest insects use terrestrial cues (land marks)
which are silhouetted in the moon and star light under forest canopies.
This is the same form of navigation we might use in new or old geographical
locations during the day. We might use large buildings, mountains, etc. These
insects use different contrast of light silhouettes. These are determined by
different forest densities and different trees. The insects that require
more accurate vision have different compound eyes again but
the structure is different. They have compound eyes called refracting
superposition compound eyes.
Deilephila elpenor or commonly known as the hawk moth
is a nocturnal nectar feeding moth. The hawk moth has refracting superposition
compound eyes. these eyes have the ability to capture low levels of light and
essentially amplify it to produce an image. Since this moth feeds on nectar it
should be able to associate different shades and colours. This moth has
refracting superposition compound eyes. This eye operates under similar principles as superposition of waves, which have a similar or the same frequency. This allows the hawk moth
to differentiate which flowers will reward it with nectar and sugar,
with those shades that won't. This hawk moth essentially has colour vision at
night time. However the resolution is not as good in the hawk moth as in
diurnal insects.
Despite what
people say about how simple insects are. They are wrong!
Thanks for reading
my blog. Hope you have gained more knowledge about nocturnal navigation.
If you would like
to know about the differences between apposition eyes and superposition eyes
view the following videos.
If you want to read the journal the following link will give you
access.
This is a really interesting topic to consider. Is it that the insects are able to navigate using constellation positions (eg like Captain Cook did) or are they restricted to just using the light? And any idea why the huhu beetle is so good at crashing in to things?
ReplyDeleteBecause I've somehow managed to become half an expert on mosquitoes, most mosquitoes are attracted to and orientate themselves towards dark objects and react negatively to light, and the reason nocturnal mosquitoes are so good at navigation is because instead of light, they are highly sensitive to thermal gradients and have chemoreceptors on their antennae that respond to changes in chemical concentrations such as carbon dioxide and lactic acid.
Also just a heads up that when I tried to follow the link, the server website said 'the
requested article is not currently available on this site'.
Good from you DCW!
DeleteThats some pretty cool theories behind navigation at night! I wonder how these insects do this on a cloudy night? A large proportion of nights will be very dim lit, so like in mosquitos as DCW eluded to i wonder if prehaps other insects use these sort of cues for navigation! Maybe they can associate certain chemicals with certain landmarks or prey items of interest?
DeleteI wonder if it has been observed that insects are less active on cloudy nights because they can't navigate as well. But no light make them less easily predated upon. I think I'll stick to bugs I can see not bugs that can only see me!
Deletesorry about the link to my paper not working. I found it on the Lincoln hub. I am not sure why it is no longer there. I have a hard copy if you would like to read it. As far as i am aware DCW I don't think they use the relative positioning of the stars to find their way around.The Milky-Way galaxy stars produce a line of light that they use to silhouette their dung ball. If their is a linear silhouette on their ball they are going straight. Also I don't think they can navigate on a cloudy night due to the reduction of light. There is also some debate about the dung beetles ability to use polarized moon light to navigate in a straight line. My paper focused on the insects eyes rather than chemical navigation (antenae). There is a lack of research with reference to the endophyte and tree interactions such as secondary metabolite production let alone the possible chemical association that forms a commensalistic relationship between insects and trees. As for the huhu beetle crashing into objects. I am not particularly sure why they do. But i think they have apposition eyes. These eyes are not as sensitive at night time. As the light decreases so does the resolution and visual picture they see. It will decrease its ability to see windows etc. I also think most of the beetles have these eyes hence why huhu beetle are not the only clumsy species in that order.
ReplyDeleteOk, yep, cheers. And thanks for opening my eyes to insect vision. :D
DeleteAlso insect eye is primarily designed to pick up movement rather than objects. The human eye is probably more likely to pick up a plane of clear glass in the dark than a insect with apposition eyes. yet a relatively clear object is even extremely difficult for us to see in the dark.
ReplyDelete