I See Through You

For decades, scientists have been baffled by insects' respiratory system.  For decades, scientists knew that insects did not have any lungs, which raised questions such as "how can they breathe without lungs?"  Due to advances in technology, they have been able to see insects' respiratory system in action.

Before scientists could see how insects breathe, they had to figure out how to see through the insects exoskeleton.  To do this, they used a synchrotron.  A synchrotron is a type of cyclic particle accelerator in which a magnetic and electrical field are synced with the beam of particles.  The synchrotron produces the world's most intense X-rays, which is perfect for seeing through the insects' exoskeleton.  Synchrotrons are mostly used in chemistry and for medical imaging.

By using the synchrotron, scientists were able to observe the insects' respiratory system.  They concluded that insects use a system of breathing tubes, called tracheae, to transport oxygen to and from different parts of their body, similar to the way our blood transports oxygen though our arteries.  The tracheae connect  breathing holes on the insects' exoskeleton.  In addition to the tracheae and the breathing holes, insects also have small air sacs that help pump air throughout the body. 

This advance has opened many windows in entomology, the study of insects.  This kind of technology will allow scientists to see how insects' circulatory system works.  Unfortunately, this kind of technology won't be used on "advanced" animals.

Image of insect in  synchrotron.

http://ipm.osu.edu/trans/013_242.htm
http://en.wikipedia.org/wiki/Synchrotron

The Black Widow

Black widow spiders are a wide variety of spiders, consisting of 31 species.  These species range all over the world from Asia, to South America, to Africa, to the United States, except for colder regions.  Although these species are known for their infamous red hourglass, not all species have it.  Instead, they may have other red markings or lack markings altogether.  Females are usually black and red, males are gray to brown.  Female black widows are 38 mm in length and 6.4 mm in diameter.  Males are only a quarter of this size. 

Black widows are called black widows because after a female mates, the male is usually eaten by the female.  Although this occurs regularly, male are sometimes fast enough to escape.  Often times, they will mate with another female.

A misconception that people have with black widows are that they are very aggressive and bite whenever they get the chance.  In fact, they are solitary spiders that will not bite unless bothered.  Another misconception is that their bite is deadly.  Their bites is almost never deadly.  A black widow bite causes muscle aches, nausea, and difficulty breathing.  These ailments rarely cause injury- let alone death. 

The only things that should fear black widows are other bugs.  When another bug crawls, or flies, into their web, the black widow spins them into the web, and injects an enzyme into their body.  This enzyme causes thier insides to liquify. 

We tend to prejudge things by what they look like, for example, with the black widow spider.  I think that we can only judge things once we get to know them.  Something that could seem bad or harmful, may acually turn out differently.




http://animals.nationalgeographic.com/animals/bugs/black-widow-spider/

Atrazine's Adverse Affects

A couple of months ago, a student from  University of California, named  Ngoc Mai Nguyen, was working in the university laboratory with a group of frogs.  After observing the frogs, he realized that some of the frogs were exhibiting unusual behavior.  Some of the frogs were acting like females, which was peculiar because all of the frogs were male.

Nguyen told her boss, biologist Tyrone Hayes, of their unusual behavior.  Hayes advised her to observe the frogs on a daily basis.  Nguyen was perplexed because she knew that all of the frogs were male.  Hayes was not as confused because he put a substance called atrazine in the water that the frogs were in.

30 percent of the male frogs changed gender, due to the atrazine.  In fact, some of the transgender frogs sent out chemical signals to attract other males.

The laboratory is not the only place where this has happened.  Atrazine is used as a weed killer, so it can pollute water near the crops it is used on.  The concentration of atrazine in nearby water is 2.5 parts per billion, the same amount used in Hayes' experiments.  This proves that  frogs can be changing their gender in their natural habitats.

The  Enviromental Protection Agency, or the EPA, is responsible for defining the concentration of certain chemicals in U.S. waterways.  The EPA concluded that 3 parts of atrazine per billion is safe.  The water that the frogs were tested in was 2.5 parts atrazine per billion parts.  This means that even through the atrazine levels are safe to humans, the level is two high for frogs.

Its is not only the frogs' behavior that is altered by atrazine.  Two frogs that behaved like females were dissected.  To Hayes' surprise, they had female reproductive organs.  Two other transgender frogs, that were introduced to male frogs, successfully mated. 

Other scientist conducted similar experiments and came up with the same results, proving that Hayes' studies were accurate.

Knowing atrazine's affects on frogs is crucial because it can threaten a species reproduction.  If there is an increase, or decrease, in an animal's reproduction, it can throw off the ecosystem's balance.  With studies like these, we can be sure that our ecosystems will not be tampered with.

Dissection of female (transgender) frog.

http://www.sciencenewsforkids.org/articles/20100324/Note2.asp