Complex Interactions among Sheep, Insects, Grass, and Fungi in a Simple New Zealand Grazing System.

Epichloë fungi (Ascomycota) live within aboveground tissues of grasses and can have important implications for natural and managed ecosystems through production of alkaloids. Nonetheless, vertebrate herbivores may possess traits, like oral secretions, that mitigate effects of alkaloids. We tested if sheep saliva mitigates effects of Epichloë alkaloids on a beetle pest of perennial ryegrass (Lolium perenne L.) in a New Zealand pasture setting. Plants with one of several fungal isolates were clipped with scissors, grazed by sheep, or clipped with sheep saliva applied to cut ends of stems. We then assessed feeding damage by Argentine stem weevils on blade segments collected from experimental plants. We found that clipping plants induced synthesis of an alkaloid that reduces feeding by beetles and that sheep saliva mitigates this effect. Unexpectedly, the alkaloid (perloline) that explains variation in beetle feeding is one produced not by the endophyte, but rather by the plant. Yet, these effects depended upon fungal isolate. Such indirect, complex interactions may be much more common in both managed and natural grassland systems than typically thought and could have implications for managing grazing systems.

The Use of Stereology Method to Estimate the Volume of Feto-Maternal Exchange Area of the Bovine Placentome during Gestation.

The functional surface areas of the feto-maternal unit of the bovine placentomes were quantified from Day 100 to 260 of gestation by using stereology. This study was achieved using intact placentomes obtained from an abattoir. There was no change in volume and surface densities of binucleate cells, fetal trophoblast, fetal and maternal tissues, and maternal epithelium with gestation age, although the total volume of these components increased with gestation age from Day 126 to 260. The total surface area of the feto-maternal interface increased in a similar pattern as the placentomal components without a change in the fetal to maternal tissue ratio when estimated with stereology. This is one of the recent studies in cattle to quantify and describe the functional surface area of intact placentomes at different stages of gestation and it emphasised the differences between the yak and cattle placentomal development. Anat Rec, 299:1571-1577, 2016. © 2016 Wiley Periodicals, Inc.