Structure of Peyer's Patches and Their Associated Nodules in Relation to Food Habits of New World Bats

Abstract

Histology of gut-associated lymphoid tissue, Peyer's patches, was examined in 24 species of New World bats with diverse, but generally obligate food habits. Insect feeders of the genus Molossus , fruit bats, and nectar feeders have well-developed germinal centers within nodules, indicating a relatively high level of activity within this portion of the immune system. Other tropical and all temperate insect feeders have nodules with poorly-developed histological characteristics including indistinctive germinal centers. Carnivorous and piscivorous bats have small to moderately-developed germinal centers. Nodules within specimens are nearly uniform in histological characteristics. Variation within species was rare where sample sizes were large enough to test it. Nodules within the patch which uniformly occurs at the ileocolonic junction often have particularly large germinal centers, are tightly compact, and generally are well developed histologically. Nodules are found in abundance at the gastro-duodenal junction only in species of Molossus . They have large size and distinctive germinal centers. It is suggested that the lymphoid tissue of the gut responds to intestinal contents, and that plant material or its associated microbial flora is of particular importance.