We found that familiarization with a single high quality nest site prior to emigration increased emigration speed in single choice emigrations (experiment 1) and led to biased nest choice and increased group cohesion in binary choice emigrations (experiment 2).
We also found that familiarization with a high quality and a low quality nest sites prior to emigration led to increased group cohesion and improved both speed and accuracy of emigrations (experiment 3), in apparent contradiction with the classical implications of a speed-accuracy trade-off.
For example, if after the first production-emigration experiment the phage population contains 25% of the HA-Stf phage, then 25% of HA-Stf and 75% of LA-wt phages would be withdrawn from the original phage stocks to simulate the proportion before the next production-emigration process starts.
To test this hypothesis, we conducted reconstruction experiments using fresh HA-Stf phages from the original phage stock, rather than the phages that have diffused into the liquid medium after the production-emigration experiment, to reconstitute the proportion of the HA-Stf phage before conducting the next transfer.
Clearly, our results demonstrated that the reason why the LA-wt phage, though with its overwhelming advantage, was unable to reach fixation during the production-emigration experiment is because all the HA-Stf-derived phages that were able to diffuse out of the plaques are phenotypically and genotypically side-tail-fiber-less LA phages.
The overwhelming advantage of the low-adsorption phages in the biofilm environment is demonstrated by the competitive production-emigration transfer experiments.
In experiment 2 and 3, we took pictures of both new nest sites immediately after the end of emigration and (in experiment 3 only) 24 hours after the onset of emigration.
Observation over 22 hours showed 312 divisions, 15 deaths and 17 emigrations in the control experiments and 316 divisions, 21 deaths and 7 emigrations in the Johrei experiments.
"Skilled emigration and skill creation: A quasi-experiment" by Satish Chand and Michael A.Clemens.
We have also experimented with setting the emigration intentions dummy equal to one if the respondent reported 1) "very high" and, respectively, 2) "very high" or "rather high" likelihood of emigration; the estimated coefficients had the expected sign but were, at best, marginally significant.
Even though we have not conducted the serial transfer experiments with the complete settlement-production-emigration cycle, the summary in Table 1 makes it apparent that low adsorption rate is advantageous when the phage fitness is dependent on its ability to be transmitted to the next locale.
