The effect of nutrition education on nutrition-related health outcomes of Aboriginal and Torres Strait Islander people: a systematic review.

OBJECTIVE: To determine the effectiveness of nutrition education on improving nutrition-related health outcomes in Aboriginal and Torres Strait Islander people. METHODS: Databases Medline, Cinahl, Scopus, ProQuest and ATSI Health were searched in September 2013 to identify nutrition education intervention studies in Indigenous Australian populations. Peer-reviewed and grey literature with nutrition-related biochemical or anthropometrical health outcomes were included in a qualitative comparative analysis. RESULTS: Of 1,162 studies identified from the search, six met inclusion criteria. Three studies were from a remote setting and three from an urban setting. Four of the six education interventions were shown to improve body mass index (BMI) and/or nutritional biochemical indicators. Components of the nutrition education interventions showing greatest effect included cooking skills workshops, group education sessions and store interventions. Community involvement in the program design was most strongly associated with a positive effect on BMI. CONCLUSION: Nutrition education had some effect in reducing biochemical and anthropometric risk factors for chronic disease in Indigenous Australians. IMPLICATIONS: Nutrition education can be considered as part of a range of strategies to improve nutrition-related health for Aboriginal and Torres Strait Islander people. Further evidence is needed to strengthen this recommendation.

Hearing is not necessarily believing in nocturnal anurans.

The recent discovery of the use of visual cues for mate choice by nocturnal acoustic species raises the important, and to date unaddressed, question of how these signals affect the outcome of mate choice predicted by female preference for male calls. In order to address this question, we presented female Hyla arborea tree frogs with a series of choices between combinations of acoustic and visual cues of varying quality in nocturnal conditions. While females exhibited the expected preference for a combination of attractive values for visual and acoustic signals over combinations of unattractive values for both signals, when presented with conflicting acoustic and visual cues, they equally adopted one of two strategies, preferring either attractive calls or intense vocal sac coloration. This constitutes novel evidence that the outcome of mate choice, as predicted on the basis of male calling quality, can be drastically different when additional communication modalities--in this case vision--are taken into account. These results also highlight the possible existence of individual variation in female rules for cue prioritization. The implications of these results for the study of mate choice in nocturnal acoustic species are discussed.

Multiple signals and male spacing affect female preference at cocktail parties in treefrogs.

Effective acoustic communication in the face of intense conspecific background noise constitutes a constant sensory challenge in chorusing and colonial species. An evolutionary approach suggests that behavioural and environmental constraints in these species should have shaped signal design and signalling behaviour to enable communication in noisy conditions. This could be attained both through the use of multicomponent signals and through short-term adjustments in the spatial separation of calling males. We investigated these two hypotheses in a chorusing anuran, the hylid Hyla arborea, through a series of phonotaxis experiments conducted within a six-speaker arena in a high background noise situation, by presenting females with male calls containing either single or multiple attractive call components, and by modifying distances between speakers. We found that female ability to discriminate attractive calls increased when several attractive call components were available, providing novel evidence that the use of multicomponent signals enhances communication in complex acoustic conditions. Signal discrimination in females also improved with speaker separation, demonstrating that within natural choruses, spatial unmasking conditioned by male density and spatial separation probably improves female discrimination of competing males. Implications of these results for the accuracy of mate choice within choruses are discussed.

The role of nocturnal vision in mate choice: females prefer conspicuous males in the European tree frog (Hyla arborea).

Nocturnal frog species rely extensively on vocalization for reproduction. But recent studies provide evidence for an important, though long overlooked, role of visual communication. In many species, calling males exhibit a conspicuous pulsing vocal sac, a signal bearing visually important dynamic components. Here, we investigate female preference for male vocal sac coloration-a question hitherto unexplored-and male colour pattern in the European tree frog (Hyla arborea). Under nocturnal conditions, we conducted two-choice experiments involving video playbacks of calling males with identical calls and showing various naturally encountered colour signals, differing in their chromatic and brightness components. We adjusted video colours to match the frogs' visual perception, a crucial aspect not considered in previous experiments. Females prefer males with a colourful sac and a pronounced flank stripe. Both signals probably enhance male conspicuousness and facilitate detection and localization by females. This study provides the first experimental evidence of a preference for specific vocal sac spectral properties in a nocturnal anuran species. Vocal sac coloration is based on carotenoids and may convey information about male quality worthwhile for females to assess. The informative content of the flank stripe remains to be demonstrated.