Predation by non-bioluminescent firefly larvae on a tepui-summit endemic toad.

Tepuis are Precambrian sandstone tabletop mountains in South America that can reach up to ∼3,000 m in elevation. Their highest summits are both physiographically and ecologically isolated from the surrounding upland savannah and lush tropical rainforest, and they face particularly hostile, challenging environmental conditions [1,2] (Figure 1A). Taxa thriving on high tepui summits must adapt to resource-limited and highly competitive ecosystems. The toad genus Oreophrynella is exclusively found on tepui slopes and summits [3] and is particularly well-adapted to the tepui top environment. We here report on an unanticipated and possibly large-scale predation on this endemic toad by non-bioluminescent firefly larvae.

Comparative studies on intestine ultrastructure of third-stage larvae and adults of Cystidicoloides ephemeridarum (Nematoda, Cystidicolidae).

The intestinal epithelium of third-stage larvae and adults of Cystidicoloides ephemeridarum from haemocoel of mayflies and stomach of brown trout was studied by electron microscopy and cytochemistry. In section, the intestine of both stages is composed of a single layer of about ten undifferentiated intestinal cells in a ring. A labyrinth of deep invaginations is present in the basal region of each cell. The apical surface is modified into well developed, regularly arranged microvilli. These, together with numerous organelles engaged in metabolism and a well defined gut lumen filled with unidentifiable material suggest that the intestine may function in digestion and absorption during both stages. The adults seem to feed upon the semifluid content of the stomach of brown trout. Fortuitous oral infection with undetermined bacteria in vitro led to degenerative changes in the intestinal tissue and probably caused death of the infected specimens. Up to 75% of the cell volume in the L(3) is occupied by glycogen deposits. In the adults, a minor portion of glycogen, together with lipid droplets, has been observed. The adults are considered to rely more on aerobic metabolism, whereas anaerobic metabolism (glycolysis) may prevail in L(3).

Ultrastructure of the body wall of infective larvae of Cystidicoloides ephemeridarum (Nematoda, Cystidicolidae) from mayflies.

Scanning and transmission electron microscopic examinations of tissue-dwelling third-stage larvae of the nematode Cystidicoloides ephemeridarum from the intermediate host (Ephemera danica) were carried out with respect to the morphological changes in the body wall associated with the transfer from the intermediate to the definitive host. The ultrastructure of the cephalic end and zonation of the somatic cuticle of infective larvae basically correspond with those of adults. The somatic cuticle is composed of a fuzzy epicuticle, an outer and inner cortical zone, a median zone and a basal zone consisting of three subzones. Globular bodies are absent from the median zone of the infective larvae. The lateral hypodermal cords of the infective larvae are cellular, consisting of a median cell enclosed by two sublateral cells. The excretory canal is present within each of the lateral cord in both the infective and adult stages. Walls of the excretory canals contain Golgi-derived vesicles which communicate with the lumen of the canal. Large deposits of glycogen, suggesting anaerobic respiration, are present in the hypodermal cords and noncontractile parts of the muscle cells of the third-stage larvae within the intermediate host.