Blog for 2010-06-05

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Kripeecawlidae (Insect Day 1)

Chen Dexiang

Crematogaster ants 'milking' scale insects on a Macaranga

We started off the day with an Entomology lecture by Dr. Dave Lohman. The concise introduction on different orders of insects was a preview on the great diversity of insects we were going to see today. In my opinion, the highlight of the lecture would be the part on carnivorous caterpillars and slave making ants.

Euphoria butterfly displaying its bright yellow hair pincers under stress.

After the lecture, we proceeded to the field to catch ourselves some insects. We were introduced to three different insect collecting techniques. Firstly, we used the sweep net to catch a variety of insects by going through the vegetation and flipping the net over itself. Next, we also used the pooter. Inhaling air at one end creates a vacuum which sucks the insect into a collecting container while the netting on the inhaling tube makes sure the insect remains in the container. Finally, we observed the insects collected in the malaise traps which were set up beforehand by Rod and Dave. These nets work like huge permanent sweep nets with a collecting container filled with alcohol attached to the top end of the netting. Insects that are trapped in the nets would fly upwards and eventually get trapped in the collecting container. We came across many insects but I was most intriguied by the beautiful hair pincers on the Euphoria butterfly as well as the mutualistic relationship between the Crematogaster Ants, the scale insects and Macaranga.

Rod and Dave explaining how a Malaise trap works.
Rod inspecting the pitfall traps after they have been set up.

We had lunch before setting out once again to the field to set up some pitfall traps to answer the question: In there a difference in insect dversity in a gap compared to the natural insect diversity in a mixed dipterocarp forest. A random area in the forest was first selected and a coin thrown eight times to decide on the point to sample. At the point of sampling, five pitfall traps were set up. The coin is thrown twice again to select a direction the 'walker' would take and the spot to sample in the forest would be 80 paces away from the selected spot in the gap. After setting up the first set of pitfall traps together at the crane gap, we spilt off into two groups, with one group following Rod and another following Dave to set up two more sets for comparison. In addition, we also collected leaf litter samples which we placed in Burlese Funnels overnight.

Dinner was at 6.30pm as usual after which Dr Chuck Davis gave us details on his research on the use of phylogeny in identifying the effects of climate change on tracking tree species and horizontal gene transfer. It was a great way to end our day as we went back thinking about the various ways phylogeny could be applied.