Antagonistic Yeasts for Biocontrol of the Banana Postharvest Anthracnose Pathogen Colletotrichum musae

The biocontrol potentials of Candida tropicalis YZ1, C. tropicalis YZ27 and Saccharomyces cerevisiae YZ7 against the postharvest anthracnose pathogen Colletotrichum musae were investigated. Treatments with all the three biocontrol agents (1 × 10⁸ CFU/ml) significantly reduced the natural anthracnose disease severity of harvested banana fruits stored at ambient condition. Germination and survival of C. musae spores were markedly inhibited by all the three yeast strains in in vitro tests. The niche overlap index (NOI) was used to determine the interaction between the antagonists and C. musae, and the results (high NOI values) suggest competitive exclusion of C. musae by the yeast strains. C. tropicalis YZ27 inoculated on banana wounds exhibited rapid colonization and maintenance of its population on the inoculated site. The biocontrol efficacy was also observed as a function of concentration of the antagonist applied. The fruits treated with C. tropicalis YZ27, 36 h before pathogen inoculation, showed the best results with 96.0% disease inhibition followed by those treated 24 h before with 84.0% inhibition. The above results point to competition for nutrients and space as the main mechanism of antagonistic action of C. tropicalis YZ27 against C. musae.     

Chew,shake, and tear: Prey processing in Australian sea lions (Neophoca cinerea)

Pinnipeds generally target relatively small prey that can be swallowed whole, yet often include larger prey in their diet. To eat large prey, they must first process it into pieces small enough to swallow. In this study we explored the range of prey‐processing behaviors used by Australian sea lions (Neophoca cinerea) when presented with large prey during captive feeding trials. The most common methods were chewing using the teeth, shaking prey at the surface, and tearing prey held between the teeth and forelimbs. Although pinnipeds do not masticate their food, we found that sea lions used chewing to create weak points in large prey to aid further processing and to prepare secured pieces of prey for swallowing. Shake feeding matches the processing behaviors observed in fur seals, but use of forelimbs for “hold and tear” feeding has not been previously reported for other otariids. When performing this processing method, prey was torn by being stretched between the teeth and forelimbs, where it was secured by being squeezed between the palms of their flippers. These results show that Australian sea lions use a broad repertoire of behaviors for prey processing, which matches the wide range of prey species in their diet.