4 W. A. SANDS 



INTRODUCTION 



This work was begun as a revision of the African species of the genus Anopiotermes. 

 These soldierless termites have long been known throughout the tropical parts of 

 the continent as common inhabitants of the soil and the mounds of other groups 

 of termites. Ecological observations by Kemp (1955), Harris (1963) and Sands 

 (1965a) have shown that they are among the most important constituents of the 

 soil fauna, being second only in abundance to Microtermes (Macrotermitinae). 

 They are not distinguished by any striking external feature other than the absence 

 of a soldier caste, and have often been confused with other Termitidae, sometimes 

 widely unrelated. In the course of the study it soon became clear that more than 

 one genus was involved. With few exceptions they feed on soil and superficially 

 look very like various Termitinae and Nasutitermitinae with the same habit. One 

 slight difference from the majority of these is visible only in the live insects, that is 

 the curious transversely striped appearance of the abdomen as the worker moves 

 about. It arises from the folding of the thin translucent cuticle over the powerful 

 transverse and longitudinal muscles that produce the phenomenon referred to in 

 subsequent sections as abdominal dehiscence. This is not universal in the soldierless 

 termites, but in Africa there are few exceptions. When molested by predators such 

 as ants, or when grasped by forceps and placed in alcohol, the abdominal muscles 

 contract convulsively and the abdomen ruptures across a line of weakness behind the 

 first tergite. The intestines erupt through the gap and themselves tend to burst, 

 scattering their slimy contents. This reaction is elicited even when the termite is 

 only held to the substrate by the extreme tip of an appendage such as the tarsus; 

 no contact with or pressure on the abdomen is required to set off the mechanism. 

 Fragility of the body wall and intestines as a defensive mechanism against Doryline 

 ants in Cubitermes was noted by Williams (1959). There is no doubt that the 

 contents of the worker hind gut of many soil-feeding termites are offensive to ants. 

 Speculitermes in India have been observed by the present author to whip the tip of 

 the elongated mobile abdomen forwards to deposit a blob of rectal contents on the 

 head of a predator. The same response was elicited to the collector's forceps. No 

 such behaviour has yet been recorded from Africa but the alternative suicidal 

 defence of abdominal dehiscence has developed to a high degree. In some genera 

 the sclerotized spiny armature of the enteric valve appears to form a linking structure 

 between the two sections of the hind gut. This probably prevents the rupture at the 

 valve from taking place too easily, as it is apt to do in less specialized forms. In 

 Ateuchotermes the link snaps across the narrower part of its sclerotized stem when 

 pulled hard enough. In some Anenteotermes the dual link has a click-over action, 

 again giving way suddenly to excess tension. These parallel though distinct 

 mechanisms may result in a build-up of hydrostatic pressure and a correspondingly 

 more devastating defensive explosion when the release occurs. A similar suicidal 

 type of defence has been observed in Neotropical species of Anopiotermes 

 (A. Mathews, personal communication). The rarity of the soldier caste in Speculi- 

 termes and its absence in other genera attests the effectiveness of these methods of 

 deterring predators. 



Their very lack of a soldier caste has led to this group of termites being regarded 



