ECOLOGICAL STUDIES ON TILE SYMBIOSIS OF TER ITOMYCES ...

(stark 1973)-,, This. show3 what a highly concentrated source of nitrogen
the myc9tatez are and may explain how the 14acrotermitinae overcome what
has been considered the twat difficult problem In the metabolism of
wood-eating Insects IL,, e,, how the deficient nitrogen In obtained. Wood
in a poor source of nitrogen,, nitrogen values usually ranging from 0*03
(Ruyooks 1979) to o. 44% (Datra and Batra 1979)- The nitrogen content
of the termites Is similar but slightly higher than that of the mycot'Otes
(Rohzvmm 1978)o Nitrogen In esitential for the termites growth and
development* This may be one of the reasons for the differences In the
presence of Temitomyces In the out of workers of ýbcrotermes bellicosus
(Table 5o2*l5),. The YMMO termites had a far higher proportion of
Termit2nces% probably suggesting they are feeding an mycotAtes, a rich
source of nitrogen* In comParison the older workers probably eat the
combs accounting for the lower isolation of Tormitpmyces" There is a
similar came with XYlebOrus, where developing larvae require a protein
rich diet while adult workers mainly require carbohydrates as an activity
fuel (Norris 1972)o
Non-fungus-grovers may obtain imtra nitrogen trom nltrogen-fWng
bacteria present in the gut (Denemann 197: 19 13reznak at al., 197,3, French
et al* 1976), * An additional source of nitrogen could be from cwmiballx=
(PO-Khatwa 1977)o Dreznak (197.5) considerc4 that these nitrogen-fixing
bacteria or their metabolic Vro4ucts might serve directly an a nitrogen
sourceq and might, also provide vitamins and other growth factors*
Rohrmann and Ropan. an (1930) found no n1trocen fixation In the fungus
grower htcrotermes ukuzil,
Nitrogýn in excreted by temItes minly In tho f0M Of Uric acid or
urates* No insects are known to have tho full c=plcmcnt of enzymes
359*