Termites

Introduction to Subterranean Termites
Subterranean Termites account for more damage to Australian Homes each year than all Natural Disasters combined – Flood, Fire etc. One in three homes will be attacked during the first ten years of their life and you cannot insure against subterranean termite attack. Subterranean Termites are estimated to cost Australia a staggering $1 billion in damage and treatment each year.

Colony Structure    
Each subterranean termite colony may comprise more than a million insects divided into specialised groups called castes. Each caste is physically different and performs a particular function.

Primary reproductives – King & Queen

  • Primary reproductives are the king and queen that established the nest after leaving existing colonies. 
  • In an established nest the queen may be enlarged and practically immobile. 
  • In some species, the queen can lay 2000 to 3000 eggs per day. 
  • The king and queen may live for 15 years and are replaced when too old to meet the needs of the colony. 
  • From the eggs nymphs hatch
  • Nymphs may form soldiers, reproductives, or workers

Workers

  • Workers are the sterile males and females that feed the colony, rear young and repair and enlarge the nest. 
  • They are the only caste that can chew and digest the cellulose in wood and are the most numerous caste of the colony.

Soldiers

  • Soldiers are sterile males and females. Their main function is to protect the colony. They also scout and locate new sources of food. 
  • Soldiers have a thin, white or light brown cuticle over most of the body and a thicker, dark brown cuticle covering the head.
  • Soldiers are physically distinctive and are the primary group used for species identification. 
  • Soldiers cannot feed themselves and are dependent on the workers for their nutrition. 
  • Some soldiers exude an acid fluid as a means of defense. This fluid can corrode metal and will penetrate mortar and low grade concrete.

Alates – winged reproductives

  • Winged reproductives or alates are the future kings and queens of new nests.
  • They have a well developed cuticle, compound eyes, and two pairs of usually dark brown elongated membranous wings of equal length. 
  • Alates disperse in large numbers from mature colonies. They are weak fliers and quickly land and drop their wings. The females release pheromones to attract a male with which to establish a nest. 
  • Alates are only produced in well-established, mature nests. It takes several years of development before a nest can do significant damage.

During their dispersal flight, alates commonly land on the roofs of buildings and move inside. This is not a matter for concern since they must first establish a nest in the ground.

What can the presence of cast member tell us about an infestation?

  • Presence of winged alates would indicate the colony is relatively mature 
  • Alates seen emanating very close to a structure suggest a nest is nearby
  • Presence of nymphs or eggs suggests the queen is close by
  • Presence of soldiers are necessary for species identification
  • Presence of unusually high proportions of soldier to workers may indicate the colony is under stress of some kind

Nesting Habits
The nesting habits of subterranean termites can be described in two basic groups:
Multi-site nesters (e.g. Heterotermes, Schedorhinotermes, Mastotermes)

  • May utilise number of timber sources
  • Can move quickly between food sources
  • Each food source can become a potential nest – potential for multiple nests in one site

Central-site nesters (e.g. Coptotermes, Nasutitermes)

  • Generally one queen and one nest
  • Workers gather food and return to central nest
  • Can infest multiple timbers but don’t reproduce within them

 Why is termite ID useful

Different species behave in different ways that may affect your approach to management. For example:

  •  Some are more prone to leaving upon minor disturbances (e.g. Schedorhinotermes) compared to others. Have implications for activities such as dusting and baiting.
  • Some are more destructive in shorter periods of time (e.g. Mastotermes). Damage may be widespread and/or quick eradication is needed
  • Some have different nesting behaviors. A multi-site nester means you could have more than one nest in a  structure or on a site 



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