Animal decisions trade-off the mortality risks of starvation and predation, and anti-predator behaviors generally incur a cost of reduced energy intake. Torpor and shallow rest-phase heterothermy are widespread physiological responses to starvation risk among small mammals and birds. Here, we present a field-based experimental test of the hypothesis that energy savings from torpor use can also reduce predation risk by moderating the energy cost of anti-predator behavioral responses in a small bird during winter. We manipulated perceived predation risk in wild populations of the superb fairy-wren (Malurus cyaneus) by playback of conspecific alarm calls during the daytime active-phase and tested for effects on body temperature measured continuously by telemetry during the nocturnal rest-phase. We found that alarm call playback was associated with subsequent rest-phase torpor bouts that were significantly deeper (minimum skin temperature: 28.7 ± 1.7 °C vs. 30.0 ± 1.5 °C) and longer (duration in torpor: 6.0 ± 2.7 h vs. 3.8 ± 2.3 h) compared to control periods. By demonstrating the connection between resting energy expenditure and energy costs of behavioral decisions during activity, our study has implications for understanding both the ecological functions of torpor and survival consequences of behavioral responses by small birds to environmental challenges.

Plant community biodiversity can be maintained, at least partially, by shifts in species interactions between facilitation and competition for resources as environmental conditions change. These interactions also drive ecosystem functioning, including productivity, and can promote over-yielding- an ecosystem service prioritized in agro-ecosystems, such as pastures, that occurs when multiple species together are more productive than the component species alone. Importantly, species interactions that can result in over-yielding may shift in response to rising C-O2 concentrations and changes in resource availability, and the consequences these shifts have on production is uncertain especially in the context of tropical mixed-species grasslands. We examined the relative performance of two species pairs of tropical pasture grasses and legumes growing in monoculture and mixtures in a glasshouse experiment manipulating CO2. We investigated how over-yielding can arise from nitrogen (N) niche partitioning and biotic facilitation using stable isotopes to differentiate soil N from biological N fixation (BNF) within N acquisition into above-ground biomass for these two-species mixtures. We found that N niche partitioning in species-level use of soil N versus BNF drove species interactions in mixtures. Importantly partitioning and overyielding were generally reduced under elevated CO2. However, this finding was mixture-dependent based on biomass of dominant species in mixtures and the strength of selection effects for the dominant species. This study demonstrates that rising atmospheric CO2 may alter niche partitioning between co-occurring species, with negative implications for the over-yielding benefits predicted for legume-grass mixtures in working landscapes with tropical species. Furthermore, these changes in inter-species interactions may have consequences for grassland composition that are not yet considered in larger-scale projections for impacts of climate change and species distributions.

The accumulation of silicon (Si) is widely reported to have anti-herbivore defensive properties in grasses. There is emerging, but fragmentary, evidence that Si could play a similar role in legumes. Here, we sought to understand the effects of Si supplementation on anti-herbivore defensive properties in lucerne ( Medicago sativa ), especially in relation to other potential defences (i.e. phenolics) and the phytohormone that regulates anti-herbivore defences, jasmonic acid or jasmonate (JA), which is also linked to Si accumulation. We determined how growth, root nodulation and chemistry (carbon, nitrogen and phenolic concentrations) of four genotypes of lucerne responded to Si supplementation, with and without the application of JA, and we used feeding assays to determine the subsequent effects on the feeding success of adult Sitona discoideus weevils. Si supplementation increased plant mass and root nodulation of M. sativa by 61% and 227%, respectively, and reduced relative consumption (RC) and frass production by S. discoideus by 38% and 30%, respectively. Si supplementation had no effect on foliar nitrogen concentrations, most likely due to the dilution effects of increased plant growth and foliar carbon. Phenolic concentrations were negatively correlated with leaf RC; RC also decreased by 34% when JA was applied to plants. When Si was combined with JA application, phenolics were significantly enhanced, demonstrating the potential to stimulate multiple anti-herbivore properties in M. sativa . Synthesis . The novel findings suggest that Si accumulation may play a more important role in legume resistance to herbivorous animals than previously thought. The ubiquity of soil Si and its emerging functional role in plant biology, including plant–animal interactions, suggest that these patterns could be common amongst legumes.

Abstract For successful colonization of host roots, ectomycorrhizal (EM) fungi must overcome host defense systems, and defensive phenotypes have previously been shown to affect the community composition of EM fungi associated with hosts. Secondary metabolites, such as terpenes, form a core part of these defense systems, but it is not yet understood whether variation in these constitutive defenses can result in variation in the colonization of hosts by specific fungal species. We planted seedlings from twelve maternal families of Scots pine (Pinus sylvestris) of known terpene genotype reciprocally in the field in each of six sites. After 3 months, we characterized the mycorrhizal fungal community of each seedling using a combination of morphological categorization and molecular barcoding, and assessed the terpene chemodiversity for a subset of the seedlings. We examined whether parental genotype or terpene chemodiversity affected the diversity or composition of a seedling's mycorrhizal community. While we found that terpene chemodiversity was highly heritable, we found no evidence that parental defensive genotype or a seedling's terpene chemodiversity affected associations with EM fungi. Instead, we found that the location of seedlings, both within and among sites, was the only determinant of the diversity and makeup of EM communities. These results show that while EM community composition varies within Scotland at both large and small scales, variation in constitutive defensive compounds does not determine the EM communities of closely cohabiting pine seedlings. Patchy distributions of EM fungi at small scales may render any genetic variation in associations with different species unrealizable in field conditions. The case for selection on traits mediating associations with specific fungal species may thus be overstated, at least in seedlings.

Since the publication of the "The Ecology of Browsing and Grazing" (Gordon and Prins, The ecology of browsing and grazing. Springer, 2008), a number of researchers have taken the approach outlined in the book to assess the impacts of differences in food and nutrient supply on the ecology of other vertebrate taxa. In line with the slightly altered emphasis of the current book (The Ecology of Browsing and Grazing II), we also asked the authors of the Sections in this Chapter to provide insights into the impacts that these different vertebrate taxa have on the ecosystems in which they exist. As you will see, the depth of research on the ecology and impacts of the different herbivorous vertebrate taxa varies considerably and demonstrates the importance of further research endeavours, on herbivore/plant interactions, across the board.

Austral EcologyVolume 35, Issue 2 p. 238-239 The Ecology of Browsing and Grazing BEN MOORE, BEN MOORE The Macaulay Land Use Research Institute, Craigiebuckler Aberdeen, UKEmail: [email protected]Search for more papers by this author BEN MOORE, BEN MOORE The Macaulay Land Use Research Institute, Craigiebuckler Aberdeen, UKEmail: [email protected]Search for more papers by this author First published: 29 March 2010 https://doi.org/10.1111/j.1442-9993.2009.02103.xCitations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume35, Issue2April 2010Pages 238-239 RelatedInformation

Many fitness benefits of polyandry have been proposed. We addressed four hypotheses that are relevant to the agile antechinus, Antechinus agilis, a highly promiscuous marsupial: polyandry (1) involves females 'trading up' to obtain good genes for offspring; (2) promotes sperm competition/sperm choice to obtain good genes; (3) enables females to avoid genetically incompatible gene combinations (specifically inbreeding); or (4) enables females to avoid infertility. We tested the predictions of these hypotheses using female choice trials, manipulative mating experiments and microsatellite analysis of paternity. Because timing of mating affects fertility and prenatal abnormality rates in this species, we also tested whether it affects offspring growth rates. We found support for a genetic benefit of polyandry: offspring of polyandrous females grew faster than offspring of monandrous females, and this effect was more pronounced for females that mated close to ovulation. However, although larger males sire more offspring in the wild in this species, females did not initially choose large mates and did not 'trade up' based on male size. We found no evidence of genetic incompatibility effects. Monandrous females were not less likely to conceive than polyandrous females, although females in the wild are more likely to encounter infertile and subfertile males than in this study. Females that mated closer to ovulation had slower-growing litters. We conclude that female antechinuses benefit through increased offspring growth rates by mating with multiple males, and by mating several days before ovulation. (c) 2005 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Austral EcologyVolume 31, Issue 8 p. 1027-1028 Why Does the World Stay Green? Nutrition and Survival of Plant-Eaters BEN MOORE, BEN MOORE School of Marine and Tropical Biology, James CookUniversityTownsville, Queensland, AustraliaEmail: [email protected]Search for more papers by this author BEN MOORE, BEN MOORE School of Marine and Tropical Biology, James CookUniversityTownsville, Queensland, AustraliaEmail: [email protected]Search for more papers by this author First published: 21 December 2006 https://doi.org/10.1111/j.1442-9993.2006.01688.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. REFERENCE Begon M., Harper J. L. & Townsend C. R. (1996) Ecology: Individuals, Populations and Communities, 3rd edn. Blackwell Science, Oxford. 10.1002/9781444313765 Google Scholar Volume31, Issue8December 2006Pages 1027-1028 ReferencesRelatedInformation

Wild animals invariably obtain their nutrient requirements, regulate their ingestion of toxins and even self-medicate. This review suggests that, while size and morphology dictate gross diet, the ability to select a diet is learnt. Animals learn to distinguish nutritious foods from less beneficial or toxic items through the positive and negative consequences of ingestion. In this process, early life experiences appear to be critically important. Zoo animals can rarely be provided with their wild diets and caretakers substitute nutrients from other sources. Thus, a suitable range of ingredients should be provided to give the animals a stimulating and nutritious diet that ensures excellent health.

The koala is the quintessential specialist herbivore, feeding almost exclusively on Eucalyptus foliage. Consequently, the limitations imposed on the koala's diet by plant defences indicate the extent to which evolutionary adaptations allow mammalian herbivores to circumvent such defences. We tested whether a recently discovered group of plant secondary metabolites, the formylated phloroglucinol compounds (FPCs), deters koalas from feeding on some eucalypt foliage. We found that captive koalas ate less foliage in a single night from trees with high FPC concentrations. Individual trees also differ in the types of FPC they possess, but for a given eucalypt species, most FPCs were similarly effective deterrents. Two closely related and sympatric eucalypt species could be clearly separated by the amounts that koalas ate from each; however, this difference could not be explained by total FPC concentrations alone. We suggest, that in this case, the presence of a distinct type of FPC deters koala herbivory on the less palatable species, and may have facilitated the evolutionary divergence of these species. We conclude that plant defences probably play an important role in determining the distribution and abundance of koalas.

Plant secondary metabolites can constrain the diet of vertebrates and these effects can flow through to community dynamics. Recent studies have moved beyond attempting to correlate diet choice with secondary metabolite profiles and instead focus on mechanisms that animals use to detect toxins and to regulate their intake and absorption. These include molecularly determined taste specificity, serotonin-mediated learning and the control of toxin absorption by permeability-glycoproteins. Focus on the detoxification pathways employed by specialist and generalist herbivores has facilitated explicit tests of the long-standing hypothesis that detoxification rates limit feeding. Understanding the molecular basis of differences amongst species in their tolerance of plant secondary metabolites opens many opportunities for understanding the evolutionary history of interactions between vertebrates and their food plants.

The distribution of marsupial folivores in Australian eucalypt forests is extremely patchy and, although distribution patterns are known to be partly determined by nutritional factors, the role of plant secondary metabolites (PSMs) has been little studied. We investigated variation in the foliar concentrations of five constituents: total phenolics (TP); the foliar component bound by polyethylene glycol (PEGBC); the formylphloroglucinol compound, sideroxylonal (a strong deterrent of mammalian herbivory); the terpene, cineole; and nitrogen (N). These constituents were analyzed using near infrared spectroscopy in 501 individual tallowwood ( Eucalyptus microcorys ) trees at 42 sites across a broad geographic range in eastern Australia. We tested three hypotheses: (1) trees with lower foliar N produce higher PSM concentrations; (2) PSM concentrations are greater at colder sites; and (3) PSM concentrations are higher at sites with low resource availability. Hypothesis 1 was true for all PSMs considered and was the result of variation that occurred within sites. This is consistent with the carbon/nutrient balance hypothesis and with the hypothesis that PSMs protect leaves from photodamage. Hypothesis 2 was upheld for all constituents. This was consistent with both the growth–differentiation balance hypothesis, and with the hypothesis that PSMs represent an evolutionary adaptation to greater risks of photodamage and frost damage in cold environments. Hypothesis 3 was rejected, with one PSM, sideroxylonal, being affected by resource availability in a manner opposite to that predicted. The optimal defense hypothesis offers an explanation for this result (as sideroxylonal concentrations increased along with the apparent nutritional quality of the foliage, possibly to provide defense against higher rates of herbivory). We found that trees associated with koala fecal pellets had lower concentrations of sideroxylonal and cineole. We discuss this finding and further implications for the herbivores of Eucalyptus of the patterns of plant defense that we detected.

This paper discusses the intraspecific variation and the patchiness of Eucalyptus forest for folivorous marsupials in Australia. The chemical basis of feeding inhibition and regulation of formylated phloroglucinol compounds (FPCs) intake of marsupials is described. The physiological effects of foliar terpenes and FPCs into behaviour of marsupials are also presented.

Glucuronuria is normal in marsupial folivores such as the koala (Phascolarctos cinereus), which excretes 2–3 g glucuronic acid daily. Although this has long been attributed to the metabolites of Eucalyptus terpenes, we have found that these are mostly excreted in the unconjugated form. We now report on the aglycones that account for most of the glucuronic acid in koala urine. Urine (24 hr) was collected from six male koalas (8.8 ± 0.4 kg, mean ± SE) that were maintained on E. cephalocarpa foliage. Urine samples were analyzed by liquid and gas chromatography (LC and GC) coupled with mass spectrometry (MS). Glucuronides were readily identified by LC-MS/MS, which generated characteristic product ions at m/z 113 and 175. From the corresponding parent glucuronide ions, the masses of the aglycones were calculated. Confirmation of identity was by GC-MS after hydrolysis with β -glucuronidase and comparison with standard compounds. Quantitation was by GC. The major non-terpene aglycones were 4-methylcatechol, resorcinol, salicyl alcohol, and two unidentified C7H8O2 phenols. Smaller amounts of benzoic acid, benzyl alcohol, orcinol, p-cresol, phenol, and phloroglucinol were detected. We have previously reported that terpene metabolites account for about 10% urinary glucuronides in the same koalas fed E. cephalocarpa. The present study found that an additional 60% urinary glucuronic acid is conjugated with non-terpene, mainly phenolic, aglycones. It seems likely that these phenolic compounds are present in leaves as glycosides and are chiefly responsible for the glucuronuria in koalas.

The in vivo metabolic fate of 1,8-cineole was investigated in six male koalas. Koalas were fed ad lib a diet of Eucalyptus cephalocarpa leaf with a 1,8-cineole concentration of 2.53+/-0.70% dry mass of leaf, corresponding to a 1,8-cineole intake of 2.4+/-1.1 mmol/kg (3.1+/-1.3 g). Urine and faeces were collected for 24 h and metabolites identified by GC-MS and LC-MS. Metabolites were quantified before and after hydrolysis with beta-glucuronidase to give free and total levels, respectively. Fractional recovery of ingested 1,8-cineole was 1.3+/-0.4 and 1.4+/-0.4 (mean+/-S.D.) for free and total measurements, respectively. Seven metabolites were identified and quantified: 9- and 7-hydroxycineole, 9- and 7-cineolic acid, 7-hydroxy-9-cineolic acid, 9-hydroxy-7-cineolic acid and 7,9-dicineolic acid. The hydroxycineolic acids dominated the metabolite profile (85%). 7,9-Dicineolic acid, a novel metabolite of 1,8-cineole, accounted for almost 10% of the recovered dose making it the second most abundant metabolite after 7-hydroxy-9-cineolic acid (77%). Together, the less oxidised metabolites, the hydroxycineoles and cineolic acid, accounted for only 5% of the cineole consumed. Significant conjugation only occurred with four minor, less oxidised, alcohol and carboxylic acid metabolites. We have shown that the koala detoxifies and eliminates 1,8-cineole primarily by extensive oxidation without utilising conjugation pathways.