Friday, June 29, 2018
Companion Planting Banting Organic Vegetable Garden June 2018
Banting Organic Vegetable Garden June 2018 - Check out what we have planted!
Thursday, June 21, 2018
The Canadian National Collection of Insects and its Relevance to the Biological Subjects Covered in SBI4U
The Canadian National Collection of Insects and its Relevance to the Biological
Subjects Covered in SBI4U June 21, 2018
Subjects Covered in SBI4U June 21, 2018
M. Beaudin
Introduction
In February 2017, I started a co-op position at Agriculture and Agri-Food Canada in the department of entomology. I had always been fascinated by insects and was excited to get the chance to further learn about insects and increase my understanding and passion for the subject. I was working with Hymenoptera (the insect order containing bees, wasps, sawflies, and ants), and more specifically, Microgastrinae, a subfamily of parasitoid wasps that parasitise Lepidoptera (butterflies and moths).
I thoroughly enjoyed the work that I was doing at the experimental farm. I was databasing specimens, georeferencing records, and curating the Microgastrinae collection. I was so invested in what I was doing that I started working from home, developing a program to facilitate the annotation of specimen photos. Many projects were tackled during that summer. Through the several projects that I had partaken in, I saw a lot of relevance to the subjects that I learned about in my biology course. This essay will discuss how the work I’ve done in the CNC relates to each unit of the SBI4U course.
Unit 1: Biochemistry
The field of biochemistry is constantly being used throughout the CNC. The collection houses millions of insect specimens. When specimens are being added to the collection, they first need to go through a conservation process called critical point drying (CPD). CPD uses biochemistry technologies to ensure that specimens are kept in optimal conditions. I had previously written an description of the process of CPD, restated here.
“The CPD method keeps the natural shape of insects and optimizes their conservation. CPD uses the critical point of a substances to quickly replace the liquid inside a specimen with gas, removing its internal fluids and causing it to be keep its’ structural integrity. Using the critical point of water to dehydrate the specimen would not be feasible, since its’ critical point lies at 374 °C and 229 bar (1 bar = 100 000 Pa), where any biological sample would be destroyed. To overcome this problem, water is replaced with liquid carbon dioxide (CO2), whose critical point lies at 31 °C and 74 bar. This is more appropriate for biological applications and relatively easy to maintain. Since CO2 is not miscible with water, the water naturally contained within an insect must be replaced fluids like ethanol or acetone - which are miscible in both water and liquid CO2 - before being put in the CPD machine. This is why the specimens are dehydrated with ethanol beforehand. In the CPD machine, the alcohol-filled specimens are replaced with liquid CO2. The temperature of the machine increase until it reaches 35°C. The CO2 then turns into its gaseous form and is slowly released from the specimens.” -M. Beaudin
The unit of biochemistry is also heavily related to what I do in the CNC because it covered the carbon chemistry of life. Insects are all composed of carbon-based molecules just like humans are. They are also made up of animal cells, containing the organelles discussed in the unit. I can look at hundreds of wasp specimens under a microscope every day, but it wasn’t until after reading this unit that I understood the specimens on a cellular level.
Unit 2: Metabolic Processes
The CNC also relates to metabolic processes in a more indirect way. Firstly, it should be noted that the main goal of my work at the CNC is to find relationships between parasitoid wasps and agricultural pests. Agricultural pests are insects that have the potential to decrease or completely devastate the yield of farmed crops. This field is important because it informs us of methods we could be using to increase our food production - and as we all know, food is very important. But it wasn’t until I read this unit that I learned why food is important. I learned about how food is used as the energy source of all metabolic processes with our body. I also learned about the complex processes involved in photosynthesis. I learned about how light energy energized electrons to produce ATP in the light-dependent reactions of photosynthesis. I learned about how chlorophyll is used as a pigment that captures light energy at specific wavelengths. Now, when I go the to experimental farm and look at the crops that are being grown, I will know how the plants are gaining energy their from the sun, and how we are gaining energy from them when we consume them.
Unit 3: Molecular Genetics
As I put more and more effort into my work at the CNC, I was able to be trained in laboratories at the research centre. I was trained in the DNA extractions of bees. I performed gel electrophoresis, Polymerase chain reaction, and DNA sequencing using a MiSeq system. The training will be put to two weeks from now when I will be running sequences on the genera of Microgastrinae and learning about their phylogenetic relationships. This was all very heavily related to the unit of molecular genetics. It was to the point where I was reading about gel electrophoresis and PCR running and would excitedly think: “Hey, I’ve done that!”. It was interesting to learn more about DNA and RNA, their structure and how they are transcribed. I used to feel like I was following the protocols at work and not truly understanding what I was doing. If the protocol said to place 8μl of reverse primer into the PCR plates, then I would simply but 8μl of reverse primer into the PCR plates, but I didn’t know what reverse primers were - now I do! This unit has given me so much knowledge on how DNA carries hereditary information in living organisms and how DNA replication is checked and edited by enzymes. This information is something that I will carry with me as I continue to perform DNA extractions, PCRs and DNA sequencing!
Unit 4: Homeostasis
The unit of homeostasis can be related in a clever way to what I do at the CNC. It can be related because throughout my day there, from taking photos of specimens with a digital microscope to identifying the genera of Microgastrinae specimens, my body needs to maintain homeostasis. This unit has taught me about the feedback mechanisms that maintain homeostasis within my body as well the anatomy and physiology of the human body. Another key concept that this unit covered is stress. There are several times at work when I start to feel stressed. Whether it be because of a deadline or a mistake that I made in the lab, I have gotten stressed a fair amount while at work. This unit was taught me how my body is reacting to stress and how it can be managed. I will take what I have learned from this unit and put it to use the next time that I feel myself getting stressed at work or elsewhere.
Unit 5: Population Dynamics
Perhaps the most heavily related unit, population dynamics covers so much of what I do at the CNC. I study the population dynamics of Microgastrinae. I analyze the relationships between the microgastrine population, their host population, the host plant population, and compare with the human interferences of urbanization and technological development. I study the interactions between the parasitoid wasps and their host species. The interaction would fall in the “parasitism” category of population interactions, as Microgastrinae gain nutrients from a host larva and kill the larva in the process. I also get to study the defense mechanisms used by the caterpillars in an attempt to avoid parasitism. The caterpillars display both behavioural defences as well as physiological defences. The behavioural defence that the caterpillars demonstrate are a series of convolution-like movements that impede the wasp from landing on the larva and inserting her eggs. Another behavioural defence that some caterpillars demonstrate is to spend most of their time on the underside of a leaf. It is thought that this reduces the chances of the caterpillar getting spotted by the parasitoid. There are a few different physiological defences that caterpillars have adopted. (See figure below). Some of the caterpillars have dorsal spines, needles, or hairs that help prevent parasitoids from landing on them. Certan caterpillars also demonstrate warning colouration, which is the use of a certain colour pattern to warn predators that the caterpillar is toxic. Warning colouration does not come into play in the parasitoid-host relationship because parasitoids are highly host specific and are adapted to the hosts body, whether certain aspects of it are toxic or not.
Warning Colouration in Danaus plexippus Spines on Hyalophora cecropia
I have also contributed to two papers at the CNC which are related to population dynamics. One regarded a species of potential importance in the biological control of a pest of amaranth (an ornamental and agricultural plant cultivated throughout the world), and the other regarded species of Microgastrinae in the Canadian Arctic Archipelago and Greenland. It was an amazing experience to help collect data and edit these papers, and I've learned valuable information about entomology, population dynamics, and relationships betweens different species.
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