Author Archives: ngr1

When I was at home in Dallas over this Thanksgiving breaking, I noticed that the weather was unusually warm, or at least not as cold as other Thanksgiving weekends I have experienced in the past. I also saw an unusually large amount of insects for this time of the year, and I imagine that it is partly because of the unusually warm temperatures.

Having done a bit of research into the matter, it is not surprising, then, that insect abundance and distribution are partly regulated by abiotic factors, chiefly temperature and humidity (http://www.hindawi.com/journals/psyche/2012/167420/). Both of these factors were noticeably well above average for this time of year in Dallas.

A study by E. Muller and E. Obermaier observed the effect of daily exposure to a variety of temperatures on the beetle species Galeruca tanaceti, with results indicating that average temperatures close to or below the developmental threshold retard development and in many cases increase mortality (http://www.hindawi.com/journals/psyche/2012/167420/). I saw an unusual abundance of insects for the time of year, but the insects did not look very healthy at all. I hypothesize that this warm front ‘tricked’ the insects into thinking that spring was already here, and the lack of consistent, sustained warm temperatures along with predictable undernourishment caused the larvae to result in unhealthy adults.

Another study led by E. Penarrubia-Maria explored how long into winter the Mediterranean fruit fly, Ceratitis capitata, would persist. Results indicated that this species of insect was unable to withstand temperatures once they dropped below freezing (http://www.hindawi.com/journals/psyche/2012/497087/). I find it fascinating that the presence of insects in the later months of fall can be used to determine how cold of a fall a habitat endured, even if one has not even been in the habitat. Based off of my observations, I can predict with confidence that Dallas has had a warmer fall than usual with temperatures failing to fall below freezing. I checked a history of Dallas weather, and I was almost right. The temperatures had fallen below freezing only once (http://www.accuweather.com/en/us/dallas-tx/75201/november-weather/351194?monyr=11/1/2013). Ceratitis capitata, the model insect used in the study by Penarrubia-Maria, thus may exhibit slightly higher threshold temperatures than the insects in Dallas, Texas, but the general relationship of insects with cold temperatures seems to hold true.

My most notable encounter with an insect over break occurred when I observed a noticeably malnourished wasp crawling on a window in my house. I took this as an opportunity to add to my insect collection for the lab portion of this class, but unfortunately, I did not have a kill jar at my disposal. So I was forced to make a makeshift kill jar:

Makeshift Kill Jar

This particular wasp, I believe, is a polistine paper wasp. Because food resources are particularly scarce for wasps once late November and December roll around, it was not surprising that this wasp was visibly low in energy, as it exhibited little ‘fight’ once caught.

Paper Wasp

It is safe to say that mosquito bites have been a nuisance for humans ever since the early days of our species, both in terms of the itchy and sometimes painful reactions we get and in terms of the vector transmitted diseases caused from such bites, ranging from malaria to yellow fever. But recent insect collecting trips to the Spring Creek Greenway Nature Center and Brazos Bend State Park for the lab portion of this course exposed me to a higher density of mosquitoes (and thus mosquito bites) than I am accustomed to living in the big city.

Our first collecting trip took place at the Spring Creek Greenway Nature Center, and for the three hours we were there, I did not notice a single Diptera species bite me. This was odd, not only because I did not apply any insect repellent, but also because many of my peers were complaining about how much they were getting bit. I began doing some research about this discrepancy, and found out that there are an abundance of factors that influence the reason why mosquitoes bite some people more than others.

According to an article published on the Smithsonian magazine’s website (http://blogs.smithsonianmag.com/science/2013/07/why-do-mosquitoes-bite-some-people-more-than-others/), factors that are thought to play a role in mosquitoes’ preference on whom to bite include blood type, the amount of carbon dioxide exhaled, metabolism, skin bacteria, blood alcohol content, pregnancy, clothing color, and other genetic factors.

For whatever the reason, however, our next trip to Brazos Bend State Park did not have the same result for me. I did not put on repellent, a decision that perhaps was a bit arrogant because I returned home bite-free the previous week. But boy, was I mistaken. Not only was I being bitten, but my shirt did not even serve as a barrier for the particular mosquito. It felt as if I was being eaten alive!

Although I did not capture and properly identify the species that was biting me through my shirt, I began to research what mosquito could have been overwhelming me at Brazos Bend when I returned to Rice – I could simply not stop itching, eventually draping my exterior into a slough of scabs. According to a World Health Organization pamphlet on mosquito biology and control measures (http://www.who.int/water_sanitation_health/resources/vector007to28.pdf), I learned that horseflies (Tabanidae) have the rare ability to bite through clothing. But I knew that I wasn’t being bitten by Tabanidae simply because the bites were not like the characteristically painful horsefly bites.

Aedes sollicitans pictured above

http://farm1.static.flickr.com/50/152742527_e7335f5819.jpg

So I continued to read about the subject and realized that Fort Bend and Harris Counties have succumbed to an invasion of salt marsh mosquitoes, or Aedes sollicitans, over the past few weeks. After the recent drought of 2011-2012, a few years’ worth of salt marsh mosquito larva were lying dormant. The ground must flood for these larvae to grow, so windy conditions that led to an elevation in tide level in early September allowed for ideal conditions for a mosquito population explosion (http://www.houstonchronicle.com/news/health/article/These-mosquitoes-eat-round-the-clock-4800349.php). This is the critter that I believe is to blame for incessantly biting me, even through my shirt. The salt marsh mosquito is known to be such a prevalent mammal bloodfeeder that this species was used to study the first mosquito repellents’ effectiveness (http://www.cabdirect.org/abstracts/19411000124.html;jsessionid=BA9AD7A67B4FD49A7200B474444C42AF#). This study was published in 1940, so we know that salt marsh mosquitoes have been annoying us to the point of forcing us to create a repellent specifically against them.

Oh yea, and it certainly did not help that I was wearing a red shirt, the perfect color to attract any species of bloodthirsty mosquito.

One of the first times I had the privilege of truly experiencing the vast diversity of the insect world occurred several years back when my family visited Victoria in British Columbia, Canada on a vacation during Christmas break. Of course, you may be thinking, how many insects could one possibly encounter in Canada, especially during the winter? Well, the answer to this occurred by chance when we happened walk by the Victoria Bug Zoo and my younger brother became intrigued by the idea of being able to both see and handle exotic insects. At the time, I did not know that I would be taking a course on insect biology, but this “zoo” visit marked the first time I was truly able to appreciate the vast diversity of the insect world.

Ironically enough, this zoo did not only include “bugs,” but was also the home to other orders of insects. So despite being coined a “bug” zoo, the more scientifically correct description of the collection would in fact be an “insect” zoo. (One is left to wonder who is responsible for the misnaming of the zoo, or what the entomologists working there think of this foolish mistake.) Notable residents of the zoo range from giant stag beetles to phasmatodea, scorpions to centipedes, just too name off a few.

When we entered the zoo, I was immediately taken aback by the size and color of many of these mysterious insects hailing from all over the globe. In all, the zoo housed over 50 different species of insects, many of which I had never even seen or heard of before my eye-opening visit. Thinking back on the experience, this zoo visit was a lot like our class’s behind-the-scenes visit to the HMNS Butterfly Center in the sense that it was awe-inspiring and raised the visitors’ awareness of the insect diversity. I was a lot younger at the time of the bug zoo visit than I am now, so perhaps this is the reason why I found the collection of insects to be so impressive and memorable – maybe being physically smaller in size made the insects seem bigger than they truly were!

Of all the insects that I encountered there, the most memorable one was definitely the giant African millipede, or Archispirostreptus gigas. There are multiple reasons why the giant millipede from the zoo still sticks in my memory. For starters, this species is huge – adults can grow to be nearly a foot long. They also live a long life that ranges from about 7 to 10 years. Another fascinating fact is that after each molt, they add more segments and thus more legs, although they never quite reach the milestone 1,000 legs, maxing out at around 400. (http://exoticpets.about.com/cs/centipedes/a/millipedes.htm)

But the most memorable aspect of this creature lies in the fact that they are very docile and can even be handled by kids. Case in point, see the picture below provided courtesy of my mom:

Above is a picture of my younger brother with a millipede mustache. Although I did muster up the courage to handle the millipede with my hands, I was not as courageous as my brother. He was the only one in the zoo that day who volunteered to have the millipede crawl on his face.

So if you ever find yourself in Victoria, have time to spare, and want to acquire a millipede mustache, the Victoria Bug Insect Zoo is just the place for you. For more info on the zoo, visit:  www.bugzoo.com