View from a fish eye lens (a) before and (b) after tree removal. from Subtle changes in the landmark panorama disrupt visual navigation in a nocturnal bull ant

Figure S1. View from a fish eye lens (a) before and (b) after tree removal. (a) Three trees (T2, T3, T4) marked with an ‘X’ were removed. A hypothetical path (in green) from the nest (yellow circle) to the main foraging tree T1 is shown

Distance travelled using the path integrator by <i>M. bagoti</i> ants.

<p>Homing trajectories of ants caught at feeder placed 6 m, 12 m, 20 m and 35 m from the nest. End point of the trajectories indicates the start of search. Fictive nest position (N*) and release point (R) is indicated. Inset: means±se of distance travelled before the start of search for each of the four distances from the nest to feeder. Dashed line indicates predicted path integration if animals had travelled the entire HV. Modified from Narendra 2007a <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0050451#pone.0050451-Narendra3" target="_blank">[29]</a>.</p

Optimal search distributions for a familiar route.

<p>A. Probability density heat map for a familiar route (straight line segment) between and , with Gaussian uncertainty whose standard deviations . B. The marginal optimal search density for a total search effort, , of 1, 2 or 4 arbitrary units. Note that the integral under each search density function equals the total search effort <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0050451#pone.0050451-Koopman2" target="_blank">[32]</a>. C and D as per A and B, respectively, with (twice the width of the uncertainty distribution as A).</p

Positional uncertainty at the start of homing.

<p>A. Positional uncertainty due to errors accumulated during outbound foraging beyond the familiar route. B. Positional uncertainty due to sudden displacement from the end of the familiar route.</p

Homing success and navigational efficiency of the nocturnal bull ant, <i>Myrmecia pyriformis</i>.

<p>Top row: Homing paths of ants released at the base of their foraging tree (R, blue circle) to the nest (N, black circle) in three one-hour slots: (a) Dark: 60–120 minutes before sunrise, (b) Dim: 30 minutes on either side of sunrise, (c) Bright: 60–120 minutes after sunrise. Red: ants that successfully returned to the nest; grey: ants that did not return to the nest within 50 minutes of tracking. Bottom row: (d) Sinuosity of all paths: the larger the E_max value the straighter are the paths; (e) homing duration of successful ants (difference between the times of release and nest entry); (f) travel speed of all ants including pauses. Sector graphs show the proportion of ants that reached the nest within the recording duration of 50 minutes. Significance codes: *<i>p</i><0.05; **<i>p</i><0.01; ***<i>p</i><0.001.</p

The study species, <i>Myrmecia pyriformis</i> and its daily activity rhythm.

<p>(a) The nocturnal bull ant, <i>Myrmecia pyriformis</i>. Graduations are in mm. (b) Activity rhythm of <i>M. pyriformis</i> on one summer day. Bars indicate the proportion of outbound (red) and inbound (blue) workers in 10-minute bins. Modified from Narendra <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058801#pone.0058801-Narendra3" target="_blank">[34]</a>.</p

Effect of ambient light intensity on walking speed and pause duration and frequency in the nocturnal ant, <i>Myrmecia pyriformis</i>.

<p>(a) Example trajectories of 9 ants and pauses they made (blue dots) on their foraging route at (i) 0–30 minutes after sunset, (ii) 30–60 minutes after sunset and (iii) 60–90 minutes after sunset. Time taken to travel from the nest to tree is shown as means±SD. (b) Pause duration and (c) walking speed of animals plotted against light levels. Two nests were studied and are indicated as red and black. Regression lines for each dataset are shown.</p

Visually mediated homing in bright and dark conditions.

<p>Responses to displacement (a) before sunset, and (b) after sunset. Blue: outbound paths of 15 individual ants from nest (N) to tree (T). Ants were captured at the tree (T), fed and transferred in the dark to R (12 m in a direction perpendicular to the normal foraging direction). Red: ants that successfully returned to the nest; grey: ants that did not return to the nest. Circular plots indicate initial bearing of ants at 0.5 m from release. Black arrow: true nest direction; blue arrow: fictive nest direction based on a path integrator (blue arrow) is shown. Sector graphs show the proportion of ants that reached the nest within the recording duration of 50 minutes.</p

FreasC_DataSet_ESM from Polarized light use in the nocturnal bull ant, <i>Myrmecia midas</i>

Supplementary Data Set from Polarized light use in the nocturnal bull ant, Myrmecia midas. Data set comprises all refined data for all four experimental conditions. Exit orientation data was compiled by taking the compass direction difference between the forager's heading before the filter was placed overhead and the compass direction of the forager leaving the filter. Reorientation data was compiled by taking the compass direction difference between each forager's exit orientation and their heading 50cm after exiting the filter

The intertidal ant <i>Polyrhachis sokolova</i> and its typical activity.

<p>(a) A worker of <i>P. sokolova</i>. (b) Daily activity schedule of ants from three nests determined by counts of outgoing and returning foragers in 5-minute bins over a 24-hr period on a single day in the month of April. This illustrates that ants are active during both day and night.</p