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Gut content analysis (GCA) is the most widely accepted method for generalising about a species' food habits. GCA is valuable if the purpose of the study is to determine the frequency or strength of interactions between species, or to establish new food links. However, determining all food links through GCA is impossible for large speciose webs. Furthermore, GCA may not reveal the true nature of linkage dynamics due to environmental and physiological stochasticity. It is therefore parsimonious to assume that linkages between species recorded in the literature will be found in all food webs, if the same prey and predator species occur in those systems. To reveal new linkages, fresh GCA is desirable, but impracticable for large speciose webs containing many rare and endangered species, in which case it may be replaced by several non-dissective methods. High-resolution data for tropical webs could be generated through observations made by trained indigenous peoples.

Two sets of time-specific food webs were constructed using all known details of trophic biology of the 87 component species found in two tropical freshwater pond systems. Analysis of the webs showed that several food web statistics were scale-dependent. To examine the robustness of this finding, 11 500 computerized analog webs were built upon the specified rules of non-random trophic links (L) between the organisms found in the ponds. The structural properties of the analog webs, like the recently published species-rich webs, disagreed with several generalizations made by food web theorists over the last two decades. The magnitude of L and the frequency of long food chains increased with S. Proportions of top, intermediate and basal species showed strong nonlinear variation with S. The mean number of links between different trophic levels seemed to be scale-dependent, though apparently scale-invariant for the pond webs. However, the relative proportions of link fractions appeared to be scale-invariant, with the intermediate-basal links most numerous. The mean predator-prey ratio appeared to be the most scale-invariant of 'all the web properties, but the scale invariance of the ratio may not be directly derived from species fractions. The study represents the largest tropical aquatic food web database, and indicates that (a) as many details of inter-specific interactions as possible within a web are necessary for unraveling the actual complexity of real ecosystems, and (b) computerized analogs of real webs, incorporating all necessary details of interactions, may be fruitfully used to ensure robustness of conclusions about the web features