Foraging Behavior

With some exceptions, three feeding syndromes characterize the cockroaches that can be observed from ground level in tropical rainforest. First, nymphs of most species become active at nightfall, and begin to forage in the leaf litter on the forest floor. They can be seen skeletonizing wet, dead leaves, leaving harder veins and similar tissue. Leaf chips or dead leaf mush dominate the gut contents, but nematodes, fungi, insect larvae, and oligochaetes are also found. This feeding strategy was confirmed in the laboratory, where cockroach nymphs were observed ingesting the entire "sandwich": the leaf and everything on it (WJB, pers. obs.). Second, adults emerge from tree holes, leaf litter, and other harborages, and begin a vertical migration up into the canopy; the heights reached are species specific and probably relate to nutritional preferences (Schal and Bell, 1986). When the adults have reached the "correct" height, they move onto leaves and begin feeding on materials that have fallen or grow on the leaves. Third, a subset of species, mostly blattellids, shelter in curled dead leaves at a height of 1.5 to 2 m; palm fronds are commonly chosen as harborage. At night the cockroaches flit about leaves in the canopy, scraping algae and other microvegetation from the phyl-loplane. These species do not feed at a preferred height. Other foraging strategies include feeding on bark and epiphylls of rotting logs (Capucina) and feeding in rotting wood (nymphs of Megaloblatta). Some species have never been observed feeding, such as the green cockroach Panchlora nivea, but their guts contain a sweet-smelling substance that may be nectar from the upper canopy (WJB, pers. obs.)

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