TERMITE MOUNDS
A M IC R O C O SM
One o f the m ost co n sp icu o us features of the Orange Free State landscape are the d om e shaped m ounds of the S nouted harvester te rm ite (M ie rsh o o p te rm ie t), T rine rvite rm e s trinervoides. These vary considerably in size and m ay a tta in dim e n sio n s of up to 9 m in circu m fe re nce and 1 m hrgh, and extend to a depth of 3 0 0 m m below g ro un d level.
W ith in the se m o u n d s , " l it t l e w o r ld s ” o r m icrocosm s exist. W ell kn o w n in th is regard is Eugene M a ra is ' d escriptio n of the in h a b ita n ts of s im ila r m ounds fro m his acclaim ed "D ie siel van die m ie r". Incide n ta lly, M a ra is and others, co llo q u ia lly refer to term ite s as ants, but th is is m isleading as term ite s are not in a n y w a y related to ants but are, in fact, closely related to cockroaches.
The m icrocosm I w is h to describe is not akin to M a ra is ', but refers to one o c c u rrin g in m o u nd s devoid of all term ites. T erm ite m ounds become d is u s e d (d e a d ) th r o u g h se ve re d r o u g h t co n d itio n s and because of the in va sion by ants w h ic h are alleged to be the te rm ite 's m ain enem y. It is w ith in these dead m ounds th a t new m icroco sm s are created.
Research w h ic h is c u rre n tly being undertaken by the D epartm ent of M a m m a lo g y at the N a tio n a l M u se um established th a t the Lesser d w a rf shrew , S u n c u s varilla, w h ic h is one of the sm allest m a m m a ls in the w o rld and having a mass of c. 3 ,5 g, is the only m am m al kn o w n to make exclusive use of dead term ite m ounds in w h ic h to nest, raise its young, and take cover. T his means th a t nearly its e n tire life is spent w ith in them . There are o f course several o ther m a m m a l species such as the B lack-footed cat, Genet, A a rd w o lf and others w h ic h also use dead m ounds but then o nly p a rtia lly or in te rm itte n tly .
W ith in these m in ia tu re w o rld s the Lesser d w a rf s h re w b uilds its te n n is ball-shaped and -sized grass nest, gives b irth and raises its young. M ovem ent th ro u g h the maze of honey-com bed cells and co nn e cting passages, b u ilt by the fo rm e r occupants, testify of the m in u te size and
C .D . Lynch
a g ility of th is shrew . W ith H o u d in ia n m ovem ents it easily traverses the round 10 mm w id e tu n n e ls and 7 x 20 m m oblong passages.
However, dead te rm ite m ounds are also the abodes of a variety of o ther fauna w h ic h e ith e r c o -in h a b it or live separately w ith in them . In h a b ita n ts of these m ounds include at least 30 species of invertebrates, such as scorpions, beetles, fis h m o th s , w o o d lic e , s p id e rs and centipedes. Six species of toads and frogs, one gecko species, three kinds o f lizards and 22 species of snakes. The m ost fre q u e n tly fo u n d snakes w ere the Centipede-eater and Egg-eater w h ile o ccup a nts such as the e xce p tio n a lly rare V ariable Q u ill-s n o u te d snake have also been collected (see M u se um News No. 30).
"W h y choose an old te rm ite m ound to live in?” one m ig h t ask. There are probably d iffe re n t reasons fo r each species. For the Lesser d w a rf shrew , m ounds act as a su b s titu te fo r a lterna tive cover such as rocks and bushes, they provide
A section th ro u g h a dead term ite m o u n d in d ic a tin g the p o s itio n o f a s h re w nest a n d the maze o f honey com bed cells and connecting passages th ro u g h w h ic h the sh re w moves
A female Lesser d w a rf sh re w a n d three young, d w a rfe d by a h u m a n finger.
P rio r to excavating a term ite m o u n d fo r research purposes, various dim ensions are recorded.
very suitable pro te ctio n aga in st veld fires, and p ro b a b ly m o s t im p o r ta n t, is th e id e a l m icro clim a te they provide.
W ith in these little w o rld s the s h re w has a home for all seasons. T his is made possible in th a t m any of these m ounds have more th a n one nest situated at va ryin g h orizontal and vertical distances. It is therefore postulated that nests w h ic h are b u ilt in the m iddle of the m ound have a relatively c o n sta n t c lim a tic e n v iro n m e n t and are occupied th ro u g h o u t the year w h ile those situated on the n o rth e rn and w estern sides o f the term ite m ound are ideally suited fo r a w in te r resident and those on the so uth ern and eastern sides fo r a sum m er dw eller. S im ila rly the height of the nest w ith in the m ound also appears to have relevance. For exam ple d u rin g prolonged w e t periods a nest situated at gro un d level or below ground level m ig h t become too dam p and be vacated for one h igher in the m ound w h ile d u rin g d ro ug h ts or dry seasons the s h re w m ig h t seek a more hum id clim ate and occupy a nest below g ro un d level.
H ow th is sym b io tic re la tio n s h ip (partnership) between the Snouted harvester term ite and Lesser d w a rf shrew arose is speculative but th a t these conspicuous dom ed features of the Orange Free State landscape be considered a ne w and th a t they deserve re co g n itio n is undisputable. In th is regard, perhaps Eugene M a ra is 's title should a p p ro p ria tely be am ended to "D ie siel van die dooie te rm ie th o o p ". IjjO
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