Weekly Series
Nature Weekly
Short Notes on Nature Singapore

29 January 2017 | Booklice & Barklice | Order: Psocoptera |

photo photo Booklice does not always stay in books but barklice always appear on the bark of trees. In fact, booklice are common resident in our homes. They feed on the starch of book bindings and wallpaper glue. Both booklice and barklice are under the Order Psocoptera.

I found out its existence in my home in July 2013 on some walls. After the walls were repainted, they disappeared but had made a comeback last year. They were so tiny with a size slightly larger than a full-stop "." In this page, which made them easily missed. Fortunately, they are benign to human being, unlike the notorious head lice (Family: Pediculidae). Booklice are also known as psocids --- they were not true lice. True lice usually referred to the parasitic head lice.

Due to their micro size of less than 1 millimetre, it was difficult to have a view their body features even after magnifying the pictures taken. Nevertheless, the limited view showed that they resembled tiny termites but with a pair of longer antennae. Some of them seemed to have wings. However, they were not capable of flying. Instead, they jump around. I had observed this characteristic when I gathered some of them in a container.

photo photo In the wild, there was another type of lice known as barklice. Again, barklice are not parasitic lice that invade human and animals. Tiny barklice are hard to detect on bark of tree. As some of them spin thick web, the web become a clue of their existence. One particular type of barklice that I often seen on tree trunk in the nearby parks were much larger, about the size of mung bean (Vigna radiate). Hence, they were giant compared to the booklice described above. Another common name of barklice is Tree Cattle; reason being that they looked like herds of cattle, moving around in group to graze on fungi, algae, dead plant tissues and other debris on the bark. Similar to the booklice, they are considered harmless. In addition, they may be beneficial to the trees. The nymphs are wingless while the adults have wings.

The reason that the booklice remain a common home resident is likely due to their inconspicuous size. If they were to be the size of the barklice, they would have been eradicated from the homes. Few would tolerate any bean-size creatures crawling on their walls even if they were supposed to be harmless.

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