Electronic Supporting Material from Food quality and conspicuousness shape improvements in olfactory discrimination by mice

How animals locate nutritious but camouflaged prey items with increasing accuracy is not well understood. Olfactory foraging is common in vertebrates and the nutritional desirability of food should influence the salience of odour cues. We used signal detection analysis to test the effect of nutritional value relative to the conspicuousness of food patches on rates of foraging improvement of wild house mice <i>Mus musculus</i> searching for buried food (preferred peanuts or non-preferred barley). Olfactory cues were arranged to make food patches conspicuous or difficult to distinguish using a novel form of olfactory camouflage. Regardless of food type or abundance, mice searching for conspicuous food patches performed significantly better than mice searching for camouflaged patches. However, food type influenced how mice responded to different levels of conspicuousness. Mice searching for peanuts improved by similar rates regardless of whether food was easy or hard to find, but mice searching for barley showed significant differences; improving rapidly when food was conspicuous but declining in accuracy when food was camouflaged. Our results demonstrate a fundamental tenet of olfactory foraging that nutritional desirability influences rates of improvement in odour discrimination, enabling nutritious but camouflaged prey to be located with increasing efficiency

Yard size, paving and watering frequency were not related to the type of pet owned.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031804#s3" target="_blank">Results</a> of the χ2 tests of independence for control variables vs. type of pet owned. Values are the exact probability (significance evaluated at α = 0.05) that each contingency table would occur if that particular combination of variables were independent.</p

Bandicoot activity was not affected by size, number of pets, or whether pets or food were outside overnight.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031804#s3" target="_blank">Results</a> of the χ2 tests of independence for each variable vs. each of three measures of bandicoot activity in yards. Values are the exact probability (significance evaluated at α = 0.05) that each contingency table would occur if that particular combination of variables were independent.</p

Typical frequency (A) and quantity (B) of diggings appearing in yards with each pet type.

<p>Dog owners were more likely to report rarely or never seeing fresh diggings (A), and seeing no new diggings (B). Data are proportions of survey respondents choosing each answer. Numbers above the bars are adjusted standardized residuals from the contingency analysis of each question for dogs versus no pets and cats versus no pets. Residuals greater than two indicate a lack of fit of the null model in that cell (denoted by asterisks). Negative residuals indicate a smaller proportion choosing that answer, and positive residuals indicate a greater proportion choosing that answer than expected if factors were independent.</p

CThrelfall_DATA_Nest_Predation_2010

Raw data collected in the field from a nest predation experiment. The metadata tab describes more detail about when and how the data was collected

Map of sampled landscapes in Sydney, NSW, Australia.

<p>Landscapes include Urban (Ur, n = 6); Suburban Shale (SSh, n = 6); Suburban Sandstone (SSa, n = 5); Suburban Transition (STr, n = 6); and, Vegetated (Ve, n = 6) categories. Within each landscape, four elements were sampled: backyard, bushland remnant, riparian corridor and open space.</p

Nocturnal insect biomass (g) for each landscape element across landscape categories.

<p>(A) total biomass; (B) moth biomass; (C) beetle biomass; and (D) other biomass. The data are log (x+0.01 transformed) Least Squares means (± standard error), after adjusting for average nightly temperature. Results of planned contrasts (which combine categories) are included in the text.</p

Arboreality of bush rats and black rats.

<p>A comparison of the arboreal activity of black and bush rats, shown as the average percentage length of spool left in trees (where arboreality is defined by spool left > 1.5 m above the ground) by both species. Error bars represent standard error, and different letters indicate that means differ with <i>p</i> < 0.05.</p

Regression tree for foraging activity.

<p>Each split corresponds to a rule which is displayed with the variable causing the split (ConditionFigure 4.</p

Total bat passes containing a feeding buzz.

<p>Recorded in each of the landscape categories and landscape elements (Note: analysis was done separately on the categories and elements due to the number of zeros recorded).</p