glands shortly after emergence. In Ixodidae the dermal 

 glands undergo a complex cycle of growth aM degeneration, 

 but their products appear to add nothing of functional 

 significance to the substance of the cuticle." 



IK 



Lees' important contributions indicate why 0. moubata is 

 capable of surviving in the dry niches in which domestic popu- 

 lations occiir. However, we still lack data on the actual rel- 

 ative humidity of these niches in natiure. We know only that the 

 tampan can withstemd these conditions in laboratory investiga- 

 tions. And it should be stressed that we still know nothing 

 about preferences and critical levels of temperature and humidity 

 among burrow-haunting populations. The Bahr El Ghazal collections, 

 from warthog burrows in the ""Nile sponge area'", especially ex- 

 cites curiosity in this respect. 



Laboratory studies on the optimum temperature and hvimidity 

 conditions under which 0, moubata survives have resulted in wide- 

 ly differing data and conclusions. The reports in question are 

 those of Cunliffe (1921 J and Brett (1939) together with those of 

 Robinson (19^2C ) and others already reviewed in the section on 

 the life cycle of 0, moubata . 



Cunliffe found that a satiorated atmosphere has no inhibitory 

 influence on molting but is decidedly unfavorable for vitality 

 (only one specimen passed the third nymphal stage under these 

 conditions J. Even under ""medium conditions of humidity", mor- 

 tality is high, but under '"dry conditions'", 66^ of the nymphs 

 complete metsimorphosis and the rate of developiosnt is increaised. 

 High temperature increases the number of eggs laid but decreases 

 fertility, longevity, and time required for metanxirphosis. 



Brett, on the other hand, found that (at 25°C.) higher rel- 

 ative humidity (up to 80^ J was more favorable for survivsil of 

 eggs, larvae, and first instar nymphs (the only stages and iru 

 stars tested) though a proportion of all eggs were able to dev- 

 elop at any '"low humidity normally met with in nature'". He also 

 found that the first nymphal instar is much more resistant to 

 desiccation than larval and egg stages. The apparent inconsist- 

 ency between Brett's findings and the known feict that domesticated 

 populations of 0. moubata are chiefly inhabitants of drier areas 



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