Mastotermes

Mastotermes is considered to be the most phylogenetically basal (‘primitive’) of all termites (Kambhampati & Eggleton, 1999), and is placed in a family of its own (the Mastotermitidae, with a single extant species Mastotermes darwinensis), along with several fossil genera and species (see Grasse, 1985). DeSalle et al. (1992) claimed to have sequenced DNA from Mastotermes electrodominicus from 25-30 million year old amber, and thus place the extinct taxon phylogenetically in context with extant genera, but the validity of this is disputed (Austin et al., 1997).

Biologically, the genus shows an unusual mixture of characteristics which are either unique (multiflagellate sperm, Bacetti & Dallai, 1977) apparently primitive (a completely developed ovipositor in adult females, Roonwal, 1984; Klass, 1998: eggs laid in a cluster, Hill, 1942: presence of intracellular bacteriocytes, Grasse & Noirot, 1959; Bandi et al., 1997) or apparently derived (presence of a true worker caste, Noirot & Noirot-Timothee, 1987: the use by soldiers of quinone chemical defences, Prestwich, 1983, 1984).

In natural ecosystems Mastotermes forms relatively infrequent small colonies in logs, the stems of woody shrubs and in the hypogeal and epigeal nests of other termites (Hill, 1942). They seem to be much more abundant in occupied areas, where they can form very large colonies in buried timber or under buildings (Hill, 1942; Gay & Calaby, 1970).

Mastotermes normally feeds on wood and living trees. Hill (1942) describes the characteristic “ring-barking” of living trees (especially Eucalyptus) attacked by Mastotermes. Termites enter the tree below ground level and tunnel upwards within apparently sound wood for a distance of 3-20 feet, then outward to the cambium, where the tree (or branch) is girdled by up 20+ deep grooves. When the bark breaks, sap (or gum) is exuded, and at this point the termites fill the holes in the with carton material, or cover the whole band of affected wood with cement. During this process several feet of branch or trunk may be covered carton. However, infected trees often show no external signs of infestation until they are fatally weakened. Subterranean runways are used to travel to their feeding sites (i.e. wood or living trees), and these are usually 7 - 15 cm below soil, but may go as deep as 5 m. Runways are known to extend as far as 70 metres from the nest (Hill, 1942).

Colonies can reproduce by normal production of alates or by budding of sub-colonies from the main colony. In the second case nymphs develop within the sub-colony without nuptial flights and are brachypterous reproductives. Within colonies, queens are not physogastric (Hadlington, 1987), and lay eggs together in enclosed clusters of 20, which appear to be cemented on to the inside of the nest. The eggs are grouped together in an oothecae-like mass, but this structure may not be homologous with similar structures laid by cockroaches (Thorne & Carpenter, 1992). Alates are released in early November and have been recorded throughout the summer monsoon season (Gay & Calaby, 1970).

[Tandem running and pairing or co-operative breeding as in Hodos??]