Malaria & Mosquitoes

Many insects are vectors of disease. Perhaps the most infamous of the insects associated with disease are flies in the family Culicidae or more commonly known as mosquitoes.  Mosquitoes vector a wide assortment of disease causing protozoans, viruses, and bacteria.  Malaria is perhaps the most deadly vectored disease from mosquitoes.  The chart below from the CDC (2012) provides a quick overview of how the Plasmodium completes its life cycle in humans and mosquitoes in the genus Anopheles.

Mosquitoes are crucial for the pathogens transmittance to new host as the mosquito releases new "spores" to hosts when they take a blood meal.  The CDC website also provides a more detailed overview of the infection stages and can be found in the works cited page.  Malaria is a serious problem in my countries and deserves more public attention in the United States.

Works Cited:  

Malaria: Biology. (2012, November 9). Retrieved October 27, 2014, from http://www.cdc.gov/malaria/about/biology/

Insects and Water Quality

Insects are ubiquitous.  They inhabit nearly every habitat on the planet including freshwater lakes and streams.  Having clean freshwater is not only important for human consumption but for the general health of aquatic ecosystems.  Many insect species can be indicators of clean water as their larvae develop over extended time periods in freshwater.  Of these species, insects in the orders Plecoptera, Ephemeroptera, and Trichoptera are often associated with clean, fast moving waters.  By contrast, many Dipteran species such as midges and mosquitoes can thrive in sub-optimal conditions with little oxygen or significant organic nutrient waste.

For more information regarding insects used in water quality testing visit: EPA: Macroinvertebrates.  

Insects as food

While it may seem repulsive to some, the consumption of insects or entomophagy is a common practice in many countries around the world.  Insects when compared to other sources of meat require less natural resources and have pound for pound more protein than other more common meat sources (Holland, 2014).  Live Science author, Marc Lallanilla (2013), highlights 7 insects that we will more than likely be eating in the near future.  Of these insects listed here, meal worms are probably the most widespread and type of insects a budding entomophagist would consume.  I personally have no objections to consuming insects for food and have tried a number of different dried samples of meal worms, wax worms, and crickets. The wax worms were particularly tasty and reminded me of a cheese curl.  I provided a table showing the protein, fat, and other nutrients in various organisms from Slate.com.  You can check out the article here.

So would you eat insects?  I know I would if I could readily purchase them at the store like a steak or hamburger patty.  Let the food revolution begin!

Works Cited:

Holland, J. (2013, May 14). U.N. Urges Eating Insects; 8 Popular Bugs to Try. Retrieved October 21, 2014.

Lallanilla, M. (2013, October 1). 7 Insects You'll Be Eating in the Future. Retrieved October 21, 2014.

Martin, D. (2014, April 28). Stop Adding Protein Powder to Your Post-Workout Shake. Add Bugs Instead. Retrieved October 21, 2014.

Insect Respiration

Insects respire through opening in the sides of the abdomen or thorax known as spiracles.  Spiracles regulate the flow of oxygen and carbon dioxide gases within the insect tissues.  Unlike humans which use blood to transport gases both to and from the tissues, insects do not use their blood (hemolymph) for this purpose.  Instead oxygen gas passes directly into the tissues through a series of hollow tubes called tracheoles.

Microscopy of Insect Spiracle (Kelly, Fellers, & Davidson, 2003)

Insects that are aquatic have a number of other modifications for accessing oxygen from water.  In some cases external gills, such as those seen on a mayfly larva, are used to gather oxygen from running water.  Air bubbles, thoracic pumping, and breathing tubes are also employed by insects that live aquatic or semi-aquatic lives.  For more information about insect respiration visit this link: Insect Respiration

Works Cited:

 Kelly, C.D.,  Fellers, T.J.,  & Davidson, M.W. (2003)Molecular Expressions: Science, Optics & You - Olympus MIC-D: Oblique Gallery - Insect Spiracles. (n.d.). Retrieved October 13, 2014.

Insect Development: Complete Metamorphosis

Insects exhibit a diverse array of developmental strategies.  The development most commonly associated with insects is the life cycle of a butterflies in which an egg hatches into a caterpillar, the caterpillar creates a cocoon or chrysalis, and then the adult butterfly emerges.  This type of development exhibited by butterflies is termed holometabolous development.  Many insects exhibit holometabolous development such as beetles (Coleoptera), flies (Diptera), Dobsonflies (Megaloptera), and a number of other insect orders.  Insects that have complete or holometabolous development look vastly different when comparing larval forms and adults.  Also all holometabolous insects have a pupation period where physiological changes occur in the last instar that lead to adult characters.

Confused Flour Beetle Life Cycle (Baldwin & Fasulo, 2014)

Control of when to pupate or molt is largely controlled by the hormones ecdysone and juvenile hormone.  As the name implies, juvenile hormone promotes larval characteristics and inhibits molting or pupation.  By contrast ecdysone promotes molting, pupation, and the development of adult characteristics (Meyer, 2006).  For a more thorough introduction to molting and the hormones associated with it visit this link. 

Works Cited: 

Baldwin, R. & Fasulo, T.R. (2014) "Featured Creature: Confused Flour Beetle".  http://entnemdept.ufl.edu/creatures/urban/beetles/red_flour_beetle.htm

Meyer, J.R. (2005).  "The Endocrine System: Hormonal Control of Molting & Metamorphosis" North Carolina State.  http://www.cals.ncsu.edu/course/ent425/tutorial/endocrine2.html