Artist, engineers and miss judged.

The movies always portray these creatures as evil. It is not surprising I continuously see people destroying their beautiful piece of artwork and incredible feat of engineering. Spiders! 
Spiders have always fascinated me. The way they movie. Their cunning traps to get their prey. But the thing that fascinates me the most is what comes out of their rare end. No I am not talking about feces, i am talking about the silk they excrete. This fascinates me because spiders have developed a material that far surpasses anything humans have ever made for tensile strength. Yes spider silk is stronger than any kind of man made rope or steel for the same diameter. Diversity of Molecular transformations Involved in the Formation of Spider silk is the paper I decided to do my third blog on.

I always thought spiders produce one type of silk and it was made in a single gland in the abdomen. After reading this article, these little invertebrates which creep or scare people, tend to make me more fascinated. Orb web spiders have  glands such as serigene glands. The glands are located in the abdomen. Spiders can secrete up to seven different types of silk. Each type of silk has its own gland. The glands between spider species can differ greatly. They can be a different size and shape. The shape can be spherical, tubular or pear shaped. They can be singular or multiple and can differ in length. The silk is made from aqueous proteins that become solid. The organs themselves consists of three parts. A tail, sac and a duct. These three compartments work together to make the proteins. store the proteins in a aqueous solution and the conversion from solution into a fiber. The proteins are collectively known as spidroins. This process is usually under tension. The strength of the silk fiber is determined by the secondary structures forming by particular repeats in proteins. An example of the structure is a beta sheet. These proteins fold to form their secondary and tertiary structures the same as amino acids fold to make functional proteins. Rather than single amino acids folding (dependent on their side chains) to form a protein, the proteins have motifs and submotifs. The motifs are short repeating units which fold to form secondary and tertiary structures. The different proteins also respond differently to temperature. It is very difficult to research the glands and silk due to their size. Although with advancements on technology probes could be used. The probes detect the vibrational bands due to amino acid side chains. The paper went into detail about the protein conformations of the different silks. If you are interested in finding more the link below will hopefully work and you can read the paper.This technology is similar way as infrared spectroscopy does. This paper went into a lot more biochemical detail than i did. But hopefully after reading this blog you have a better understanding and appreciation for the achievements by the orb web spiders.            




http://www.sciencedirect.com.ezproxy.lincoln.ac.nz/science/article/pii/S0022283610011824

confused hyperparasitoid

I have always found insect adaptations interesting. I also find the complexity of their heiarchy levels rather interesting. How a plant is parasitised/ preyed on, then that parasite is eaten by another parasite. Then that parasite will be undoubtedly be eaten by something completely different, so on and so forth. It is quite disgusting and interesting how the larvae are injected into the host and bursts out when it is ready for the next stage in its life cycle.




The way in which insects can adapt to their environment really is quite amazing. A research article I was reading indicates and explains how a hyperparasitoid has adapted from diurnal to diurnal and nocturnal parasitism on another parasitoid.

Hyperparasitoid is a parasitoid that has a host that is a parasite or parasitoid. This is particularly interesting, their mechanisms in which they use to help the survival of their species.

A paper written by V.Wolfgang and K. Petra investigated the Dendrocerus carpenteri's ability or inability to 'hunt' at night. This a hyperparasitoid which has very specific ovipositing conditions. The paper studied these wasps interactions with the night and eggs counts of females. This showed that the female D. carpenrteri has developed the ability to find its host on plants and oviposit at night. The various tests indicated that in unfavorable conditions diurnal activity decreased and nocturnal activity such as flying around at night time to plants with its hosts on, or ovipositing increased. D. carpenrteri  will simply find shelter from the sun if the temperature is too high or low. This wasp also has the same response for humidity as temperature. Once the conditions have optimized for this insect it becomes active again. If the temperature during the day does not optimize and the female has a high egg count, she will become more active during the night in order to lay her eggs or fly around to find new hosts. Although if female D. carpenrteri have  low numbers of eggs, activity during the night will not increase as much as they will have already laid  some of their eggs.

Since this insect has such a short life span it has given it the ability to survive as a species through fluctuating climates. Also the species can reproduce in harsher conditions allowing the species popto survive for the same amount of time as in favorable conditions. The portion of eggs laid in the host will not fluctuate as much between the favorable to unfavorable conditions. This adaption have increased the over fecundity of the population. It makes me wonder just how far these adaptions will actually go. Will organisms become to advanced they can't evolve anymore? Or, what will the future hold for insects? These thoughts can be scary to a certain extent but also very exciting at all the possibilities the future holds for us all.



If you want to read this particular article load the website below.

http://onlinelibrary.wiley.com.ezproxy.lincoln.ac.nz/doi/10.1111/j.1365-2311.1995.tb00459.x/pdf

star gazing

 I have often gone for a night time stroll to enjoy the beauty of nature, the smell of fresh air and all of the minute sounds of the wildlife. The next thing I know I have walked into an object like a fence or a tree stump. More often than not I have end up flat on my back. Looking up into night sky, the specks of stars and the moon staring down at me. It makes me ponder several things such as the Fermi paradox theory, materialistic/ vitalistic view points and celestial navigation. The whole reason I am doing this blog is for an entomology assignment so I may as well integrate one of my philosophical daydreams with my entomology assignment.

  

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 all have the same

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.

http://www.annualreviews.org.ezproxy.lincoln.ac.nz/doi/abs/10.1146/annurev-ento-120709-4852