Sunday, April 14, 2013

Memoirs of a Light-Trapper: expeditions and experiments in light-trapping pt. 1


Hey ya'll

Chasing after butterflies and other flying insects with a net can be great fun during the day, but catching nocturnal insects is a totally different ball game altogether. It is, after all, not very practical for one to go traipsing about in the forests in pitch darkness while waving a net blindly around in hopes of accidentally catching something that flies by! As such many entomologists and lepidopterists have developed, over the years, a variety of techniques and methods that are quite reliable at attracting insects for the purposes of study or collection. The most efficient of all these, is probably light trapping. Light trapping is basically a method of attracting insects that involves the use of a light source (usually a mercury vapor bulb, or some other source that emits UV light). The light is often dispersed through the use of a white cloth (that can greatly increase the light's surface area) and functions as a veritable beacon that attracts moths, beetles, and any large number of flying insects to its surface. Think of a bug zapper, but on a larger scale. And minus the deadly electricity. Insects attached to the white cloth may then be studied in closer detail, photographed, or collected depending on its purpose.


Recently, I've had the opportunity of conducting one such expedition which took place in the form of a mini experiment. Two light traps were set with different bulbs, one emitting a specturm of UVA (orange/warm light), the other of UVB (white light). Through the course of the night we discovered that different insects were attracted to different spectrum of light. While the UVA bulb seemed to attract more insects on the initial stage, many of them eventually shifted their focus over to the UVB bulb where they proceeded to swarm and seethe in a writhing mass of antennae, legs, and wings. The diversity of insects which arrived was also, to say the least, quite astounding and we had (in addition to moths of just about every shape, size, and color) some very attractive looking beetles and cicadas. Below are some of the amazing insects that were attracted to our light traps that night.

These are some of the moths that were attracted to our light traps. Among all the insects that eventually came to the traps and stayed, I'd have to say that the moths were the most numerous. Most of them were small and brilliantly patterned, although we would eventually come across several sphingiids and saturniids as well. Geometriids were the most common and most of these came in various shades of yellow or green, many similarly patterned with geometrical map-like markings on both wings. 



We eventually nicknamed this moth "Hellboy" until a more concise definition
can be offered.




Aside from moths, the traps also attracted more than their fair share of cicadas! The large insects are clumsy fliers and, after slamming unceremoniously into the light bulbs and walls repeatedly, they would often crash onto the ground where they remained, seemingly in a state of stupor. They were so stunned by this I could even pick them up and place them side by side on my outstretched palm with little or no effect. 


Cicadas came in all shapes and sizes that night! We counted no less than 6 different species that were attracted to the traps. 


There were also an astounding diversity of beetles at our traps. Of all the insects, these were perhaps the worst! Beetles are clumsy fliers at best and when in a state of fright, have sharp claws that they can use to devastating effect. I had many bad experiences with beetles that fell down my color and proceeded to dig their claws into any portion of my skin they happened to come into contact with that the time! I shall take note to wear tighter fitting clothes when I try this again in the future! Most of the beetles weren't particularly remarkable, but we did find several of the long horn (Cerambycidae) and rhinoceros (Dynastidae) variety. Some of these, I ended up keeping, for virtue of their unique appearances! Second note to self: long horn beetles have fearsome jaws and can deliver quite a bite!!! 

The largest cerambycidae that was attracted to our traps that night. It measured several inches from head to tip of abdomen and eventually managed to bite hard enough to crack the flimsy plastic lid of the container.
Of all the other insects that were attracted, most were aletes, the winged generation of various ants and termite species whose identification simply goes beyond my capabilities. There was also a stick insect that somehow found its way there, and a rather opportunistic praying mantis. There really are a lot more pictures to go through, and I will upload them in the second part of this blog post when our photographer, Miss Joanne Tong, has sorted them out from her camera. Until then, Happy Monday.





Cheers, 

Cyren.

1 comment:

Kanak Hagjer said...

Hello Cyren, your posts and pictures are on a different level. Although I love winged creatures, I really don't know much about them except that I need to capture them on film!!

Thanks for your comment on my blog today. I'll be glad if you stop by and check out the rice wine on my food blog.:)