1232 S. Mali, R.M. Borges / Biochemical Systematics <strong>and</strong> Ecology 31 (2003) 1221–1246Table 5Comparison of Bhimashankar with other tropical forestsParameter Bhimashankar, India Kakachi, India Kibale, Ug<strong>and</strong>a Douala-Edea, Sepilok, Borneo Kuala Lompat,Cameroon MalaysiaAltitude (m) 910 1325 1400 Lowl<strong>and</strong> 200 Lowl<strong>and</strong> 200 Lowl<strong>and</strong> 200Rainfall (mm) 3000 3080 1485 NA 3000 2000Forest type Semi-evergreen Evergreen Evergreen Evergreen Evergreen EvergreenADF (fibre) a 35.19 (19.0–47.37) 39.4 (24.0–55.1) 35.4 (10.3–67.8) 47.0 (20.8–77.2) 58.3 (40.7–71.7) 46.1 (21.5–73.2)Condensed tannin in mature 6.86 (0–23.40) 6.9 (0–22.0) 5.8 (0–39.6) 5.4 (0–17.0) 8.8 (0–37.0) 4.8 (0–30.5)leaves aN 15 14 23 38 17 33ADF, acid detergent fibre; N, number of species; NA, rainfall value unavailable for Douala-Edea from above-mentioned sources. Numbers in parenthesesindicate range of values.aValues for ADF <strong>and</strong> condensed tannin are mean percents on dry weight basis (values other than for Bhimashankar are obtained from Gartlan et al.,1980; Oates et al., 1980; Waterman et al., 1988).
S. Mali, R.M. Borges / Biochemical Systematics <strong>and</strong> Ecology 31 (2003) 1221–12461233indicated by Milton (1979) <strong>and</strong> Waterman (1984), we also found that the secondarychemistry of flowers is more comparable to foliage that any other plant part.4.1.2. Cyanogenic <strong>glycosides</strong>, <strong>alkaloids</strong>, <strong>and</strong> <strong>saponins</strong>Cyanogenic <strong>glycosides</strong> were present in only 2.3% of species screened. This virtualabsence of cyanogenesis was also recorded in a lowl<strong>and</strong> rain forest in Costa Ricawherein only 25 out of 488 species (5.1%) of woody plants screened were <strong>cyanogenic</strong>(Thomsen <strong>and</strong> Brimer, 1997). Cyanogenesis appears to be limited only to certainfamilies such as Leguminosae, Rosaceae, Euphorbiaceae <strong>and</strong> Passifloraceae (Conn,1979), <strong>and</strong> <strong>cyanogenic</strong> <strong>glycosides</strong> appear to be very much less ubiquitous as defencechemicals than <strong>alkaloids</strong>, <strong>saponins</strong> <strong>and</strong> phenolics. Alkaloids were absent from semiripe<strong>and</strong> ripe fruit, which could reflect the fact that defences that are deterrent topotential seed dispersers need to be minimised (McKey, 1974). Saponins were foundin all plant parts examined. The lowest occurrence of <strong>saponins</strong> was found in treetwigs. Much more work needs to be done on the distribution of <strong>saponins</strong> in planttissues, especially given their possible interactions with both condensed <strong>and</strong>hydrolysable tannins in influencing the potency of these secondary compounds.4.2. The condensed tannin–hydrolysable tannin interactionOnly in ripe fruit pulp did we find a higher number of species that containedcondensed tannins rather than hydrolysable tannins. The role of hydrolysable tanninsin defence against herbivores has barely been investigated. The seminal <strong>and</strong> detailedstudies of food selection in primates, especially colobines (e.g. Gartlan et al., 1980;McKey et al., 1981; Waterman et al., 1988; Kool, 1992) have neither quantifiedhydrolysable tannins nor investigated their role in food selection. However, the barkeatingtropical squirrel Sundasciurus lowii was found to select barks with low levelsof hydrolysable tannins (Whitten <strong>and</strong> Whitten, 1987). Since condensed tannins areprobably not effective deterrents against insect <strong>and</strong> mammalian herbivores(Waterman <strong>and</strong> Kool, 1994; Reed, 1995; Ayres et al., 1997) <strong>and</strong> probably functionlargely as anti-microbial or anti-fungal agents (Waterman, 1983), it is possible thathydrolysable tannins have a more potent action against herbivores than condensedtannins (Swain, 1977; Zucker, 1983; Reed, 1995). Zimmer (1997) found that ingestedgallotannins increased the surface tension of gut fluid, indicating reduced concentrationsof free surfactants, while Barbehenn et al. (1996) found that the gut peritrophicmembrane in polyphagous grasshoppers was easily permeated by severalgallotannins. It is, therefore, interesting that we found that significantly fewer specieshad ripe fruit containing hydrolysable tannins rather than condensed tannins as thesemight deter dispersal agents. However, there are conflicting claims for beneficial <strong>and</strong>toxic effects caused by hydrolysable tannins such as ellagitannins in various animalspecies including rodents <strong>and</strong> ruminants (Clifford <strong>and</strong> Scalbert, 2000). Similarlyalmost no information is available on the occurrence of gallotannins <strong>and</strong> ellagitanninsrelative to each other. Our study has shown that gallotannins <strong>and</strong> ellagitannins arenot significantly segregated in any plant part. Furthermore, of the 31 species thatwere examined for gallotannins <strong>and</strong> ellagitannins, only 10 species contained both
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