I need easy explaination of the methods B and C of this article and explain abou

Question

I need easy explaination of the methods B and C of this article and explain about the figures.

2. Material and methods

(b) Partner-switching experiment

In this experiment, we quantified food sharing before, during and after a treatment period. During this treatment, inhibited food sharing between members of seven targeted dyads, then tested for near or neibhbour partner switching, i.e. that a targeted past donor contributed significantly less than before to feeding the fasted subject (figure 1). The targeted dyads were 14 female subjects paired according to food sharing (electronic supplementary material, table S3). We paired as many females as possible with their most frequent donor, which resulted in two pairs of non-kin, four mother–adult daughter pairs and one other kin pair (electronic supplementary material, table S3). We focused on testing females because they perform about 80% of food donations and targeted frequent donors to maximize our ability to detect a decrease in donation rate.

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Figure 1.

Illustration of how the partner-switching experiment was conducted for a representative individual. Circles are female bats. Arrows show food given. Fasted bats are labelled blue. Each of 14 subjects (S) started the experiment with a baseline history of sharing with several prior donors (red) ranked by donation rate (number). For each subject, we targeted a unique donor of highest possible rank (*). In treatment trials, we prevented donations from this targeted donor. In pre- and post-treatment trials, we prevented donations from a control bat. We measured food donations in each trial. (Online version in colour.)

We tested each subject six times for a total of 84 fasting trials{6 multipulied by 14}. We conducted two trials each trial day; one round of testing all 14 subjects lasted one week. For each trial, we fasted the subject and measured any donations from bats in the group. A subject{food} could potentially be fed by 13 females and 11–15 males, but one female (the other subject that day) was fasted on the same night and was therefore either missing or unfed. We grouped these ‘missing’ and ‘unfed’ conditions together because we did not detect any difference in how bats responded to these two ways of preventing donations. During the first two-week pre-treatment period, we prevented donations from a control bat that had not previously fed the subject much. During the next three-week treatment period, we prevented donations from the targeted donor. In the final post-treatment week, we again prevented donations from a control bat. We predicted that the treatment would:

(i) Reduce the amount of food received by subjects,

(ii) Reveal that bats that fed more non-kin in previous years would have more donors and receive more food when their primary donors could not feed them

(iii) Reduce food sharing with targeted donors relative to other donors.

(c) Statistical analyses

Before conducting any parametric test for deviations from normality using a goodness of fit test and assumed unequal variances for all t-tests. Whenever parametric assumptions were violated, we used permutation tests (lmPerm package in R). To help interpret null results, We accounted for repeated measures by testing before versus after contrasts by bat.

To examine the effect of prior non-kin donations on sharing success in the experiment, we first used permuted simple linear regressions to test whether the number of male or female non-kin recipients in prior years predicted: (i) number of donors in prior years.

(ii) number of donors during the experiment.

(iii) total food received across all treatment trials.

To select the best multivariate model for predicting total food received during treatment, Entered six predictors into backwards and forwards stepwise regression and evaluated model fit using minimum Akaike and Bayesian information criterion (AIC and BIC). The number of times the bat was fasted (which is proportional to the number of times they could have donated), and the numbers of previously fed male kin, male non-kin, female kin and female non-kin and Spearman's correlation to confirm that females with more donors per trial received more food. If targeted donor contributions were replaceable then repeated this analysis for the number of donors per trial. to determine if the bats showed a response to a past donor's inability to reciprocate, we first compared the targeted donor's contribution to food received in the pre-treatment and post-treatment periods. We tested both absolute values of donation sizes and arcsine-transformed proportions of subjects' total food received.

Finally, if the targeted donor's contribution to a subject's total food received became more variable after the treatment period.

Explanation / Answer

Social benefits of non-kin food sharing by female vampire bats

Partner switching method was done in order to identify if the habit of helping bats that are not related , I.e. Non kin would increase ones chances of expanding networks. When there is a discrimination of kin done by these organisms, there is an indirect benefit on the fitness. There is an important point being emphasised in this experiment, which is of kin selection. The organism under study is vampire bats who are obligate blood feeders and have very less energy to expend. It had been observed, that roost mates give back blood to kin ans non kin individuals as a result of failed blood or food acquisition. This suggests that this blood donation is a result of maternal care for the adult kin. For inclusive fitness, it is being suggested that the donation of blood should occur within close kins and the non kin donation behaviour is still under question.

It is being said that the non kin donation behaviour seems as a result of network maintenance. This might also be as a result of generating or creating possible donors. Some hypothesis also suggest that this non cooperative behaviour maybe as a result of either partner choice or partner control and that non kin sharing would increase groupmate survival and should also have more donors at the time of need.

B) in the partner switching method

The bats were kept at fasting and also the partner with whom they previously shared the food, non kin, was removed from a dyad and checked if

- the donors could be changed

- if donations could be taken from control bats ( unknown ) from whom past donations and exchanges did not happen.

- if the bats are not able to reciprocate and there is an inability for the same by not being able to feed the past donor on a repetitive basis, then the past donor would gradually stop feeding that bat.

In this method, the food sharing was quantified before, at the time and after fasting of the bat. Food sharing was not allowed between the pre established dyads, new partners were placed by partner switching . The dyads included female bats, fourteen in number, and separated from their past donors. Females were used as they perform 80% of donations . Every individual was tested with six cycles of fasting with one cycle lasting for 7 days.

In the first two weeks, donation was allowed from past donor bat and not from the control bat. In the subsequent three weeks donation was allowed from the control donor and not past donor bat and in the sixth week donation was again allowed from the past donor. And the quantification of food was done , which is expected to be lower.

The same thing is represented in the figure, fig 1, where S is the subject, 13,12,11,10,9 and 14 are bats having no past history which are control. The interactions of these bats were not allowed during the pre treatment phase, specifically 13. In the treatment phase, donation from donor 1 was stopped, which is the highest ranked last donor, followed by again prevention of control bat, i.e. 13.

Next C) statistical analysis with a paired t test was done to check if the food received by the bat during the treatment period was affected or not. This analysis was repeated for each of the six trials in order to determine the changes in the levels of donations . To test the response of the bat to reduced reciprocation of the past donor , absolute values of donation sizes were determined.

O brien's test was performed on arcsine transformed percentages to test the food contribution of the targeted donor.

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