Mindy's focal taxon

From BiodivBorneo09

Jump to: navigation, search

Mindy

Contents

Focal Taxon: Termites

Soldier, alate (beside it) and worker castes

Termites are insects belonging to the order Isoptera and are sister to Blattodea (also known as your not-so-welcome neighbourhood cockroach). As is the norm in the taxonomical world, revisions are always on-going and there is some debate now on whether the isoptera order belongs as a subset of the Blattodea or if they are their own order.

Termites are eusocial insects that live in colonies, and often create their own mounds using digested wood or sand particles cemented together with saliva. The following are some of the mound types that have been seen throughout this course.

Types of Mounds

While mounds are generally recognisable from far, it takes a practised eye to know what you are looking at. Sand mounds tend to be covered by vegetation and leaf litter depending on where they are, and ground mounds are virtually not visible at all. Dead logs that lie on the ground can harbour a range of hosts, and only some of them contain termite nests, others may host ants, scorpions, mealworms and other critters.

Sand Mound
Description : Usually made of sand particles cemented together with saliva, these mounds can be incredibly thick (~5cm thickness and more) and hard to access. No particular location that it is found in, and sometimes inconspicuous despite its size due to plants/fungi/moss growing on it, as well as how well it fits with the ground.
Tower
Description : Most of the time found at the base of living/dead trees, and sometimes found at the edge of large dead logs that the colony is feeding on. Several towers are joined at the base and 'bud' out not unlike how yeast reproduce. Seems to be made of wood fibres, mud and saliva, and even so it is difficult to break through.
Ground Mound
Description : I have only seen one of these so far, due to the fact that they are located on the ground, and can be found buried under even 20cm of leaf litter. Material seems to be similar to tower mound material, but less dense and much easier to break through.
Dead Wood Nest
Description : Majority of these termites have been found in dead wood (logs), which upon opening can be recognised by various interwoven tunnels lined with digested wood particles within the log. Sometimes scorpions, crickets and ants have been found living inside these tunnels and galleries both when the termites are still occupants of the log and when they have already vacated the log.
Arboreal Nest
Description : Largely located on branches, these 'mounds' are not unlike that of bees nests, and the ones I have seen have ranged from 30cm to nearly 100cm across. Generally relatively easily broken into.

Termite Identification

How, and why?

Differentiating a group of animals based on morphology is a instinctual habit of people - if it looks like each other, they must be either in the same group or somehow related to each other. This method works to some extent, however one should be aware of variation within a species for different members of the species (termed 'intraspecific variation'), and this is particularly important for termites, since there are different castes (and even sub-castes), and within each caste there may be distinct morphological differences that may at first seem to separate them into different species.

Immature alate (wings not fully grown) beside two soldier termites.
Queen termite.

Focussing on the soldier termites to 'pigeon-hole' a taxon is commonly practised in termite taxonomy, due to:

  • 1. their abundance at all times of the year and distinct differences between species
  • 2. alates (the reproductives) are only available during breeding seasons and difficult to attain
  • 3. the worker caste is very conservative across most species, and so would not be a reliable caste to use.

To see the different groups, just click on the names below (alternatively you can click to see all).

All termites collected in this study were done in the day time, and no inter-species interactions were observed to be taking place. Termites were always found in colonies/groupings of >100 individuals and collected from the mentioned nests (arboreal, ground, sand, etc), so constituting their habitat.

Termite Anatomy

Some simple anatomy up for grabs. Trivia: the body exoskeleton of most termites are thin and as a result, they dry up or dessicate easily. To counter this, they use their saliva and their surrounding materials to construct mounds and tunnels that allow them to move around the forest and above ground without drying up.

Termite tree

Training the eye in examining the morphology in a practice of taxonomy is just one of the aims of having a focal taxon in this course - the other practice was in creating a phylogenetic tree depicting evolutionary relationships between specimens collected/observed. Of 26 taxa collected from various locations, I created a character matrix of 16 characters (see left) and subsequently constructed a phylogenetic tree (see right)

With intraspecific morphological variation, limitations of the human eye and various other ailments, taxonomy by morphology may not always be accurate, and this is where molecular genetics and DNA assessments supplement, but do not always surpass. As can be seen, certain taxa that are supposed to be sister to each other turn out to form a clade or turn out in a separate clade in the tree I created, and this could be due to various limitations: I could have collected an instar polymorphic individual of a caste or even missed a particular character that is only visible with greater power microscopes.

To download the file for viewing in Mesquite, click File:Termites.nex

Finally, this is the presence absence table of termites collected in the different locations:

Acknowledgements

  • My super reference book:
    • Tho Y.P. (1992) Termites of peninsular malaysia. Press: Forest Research Institute Malaysia.
  • Programmes (yayy freeware!):
    • Mesquite
    • Notepad++
    • PhotoScape
  • People:
    • Cam for teaching me the wiki!
    • Bekti and Ross for being ever accommodating with equipment :D
    • Rod and Dave for fuelling my interest in insects!
    • Nuwan for superb photo at top!
    • Shana for swapping insect collections :D
    • Pitfall team from Maliau Basin: Agri, Molly, Serena :)
Retrieved from "http://phylodiversity.net/bb09/index.php?title=Mindy%27s_focal_taxon"
Personal tools