Presentation_1_Male intrasexual aggression and partial dominance of females over males in vervet monkeys.pdf

Females dominate a subset of the males in a minority of mammalian species despite male-biased sexual dimorphism. How this may arise is suggested by a computational model, DomWorld. The model represents male-biased sexual dimorphism through the males’ greater initial dominance and higher intensity of aggression, meaning that fights initiated by males have a greater impact than those by females. The model shows that female dominance over males increases with a greater proportion of males in the group. This happens because when males are involved in a larger fraction of fights this results in greater hierarchical differentiation (i.e., steepness). This causes rank overlap between the sexes (i.e., partial female dominance). We test the validity of these processes in vervet monkeys (Cercopithecus pygerythrus), a primate species with partial female dominance. We confirm that the proportion of males in the group is significantly positively correlated with the degree of dominance by females over males and with the steepness of the hierarchy among males exclusively, but not with the steepness of the hierarchy among all adults of the group. The steepness in male hierarchies correlated positively with female dominance over males in these groups. We show that steeper hierarchies among vervet males resulted from male-to-male fights being a larger proportion of the fights among all adults of the group. We conclude that the higher frequency of male intrasexual aggression favors female dominance in vervet monkeys. We also show that females received coalitionary support when they were in conflict with a male, mainly from other females, and that this favors female dominance in this species, but this does not explain why partial female dominance increased with the proportion of males in the group. We advocate further investigation of the influence of male intrasexual aggression on the degree of female dominance over males in other species with partial female dominance.</p

Data from: Direct fitness benefits explain mate preference, but not choice, for similarity in heterozygosity levels, Ecology Letters

Data from: <b><i>Direct fitness benefits explain mate preference, but not choice, for similarity in heterozygosity levels - </i></b><i>Lies Zandberg, Gerrit Gort, Kees van Oers, Camilla A. Hinde</i><p><i></i></p><div><i>Ecology Letters</i></div

The time series for the variance/mean ratio of the distribution of parasitoids across the 16 patches.

<p>(a) the five replicates for <i>A. tabida</i>, (b) the five replicates for <i>A. citri</i> and (c) the resulting mean transformed Ricker functions from the non-linear mixed model analysis for the two parasitoid species.</p

The number of replicates (<i>R</i>) with distributions of parasitoids across patches that are more regular than Poisson is determined at 5 minute intervals for all replicate time series (5 for <i>A. tabida</i> and 5 for <i>A. citri</i>) and plotted against time.

<p>The number of replicates (<i>R</i>) with distributions of parasitoids across patches that are more regular than Poisson is determined at 5 minute intervals for all replicate time series (5 for <i>A. tabida</i> and 5 for <i>A. citri</i>) and plotted against time.</p

The experimental set-up: the arena consists of a four by four grid of 16 patches.

<p>The grey circles represent patches of yeast, containing <i>Drosophila</i>-larvae. These are surrounded by an area of agar. Both are level with a circular plastic arena (diameter 23 cm). At each of the “+” marks, 10 parasitoids were introduced into the arena.</p

Isoclines of relative fitness by patch defence and superparasitism for an environment with patches with 32 hosts.

<p>Ti, the time spent in fighting and chasing an intruder,  = 200 s. On the x-axis the parasitoid density is plotted, and on the y-axis the average travel time between patches in s is plotted. Superparasitism and patch sharing are the better strategy for clines with negative values. Patch defence and fighting is the better strategy for clines with positive values.</p

Relation between fighting behaviour and a change in the number of parasitoids on a patch.

<p>Relation between fighting behaviour and a change in the number of parasitoids on a patch.</p

Posterior probabilities for both pollen unit and carpel fusion characters.

<p>Posterior probabilities for each rate prior E(T) given a standard deviation S(T) for both pollen unit and carpel fusion characters. x-axis: rate of transformation. y-axis: sampling frequency ( = posterior probability) of each discrete rate category.</p

Average number of transformations estimated for each combination of the mean rate value (E(T)) and the level of confidence (SD(T)) estimated after 1000 simulations on the 201 last trees sample from the MCMC run.

<p>The maximum parsimony numbers of transformations were taken from a single most parsimonious tree arbitrarily chosen out of the seven found. The bold values represent a centred posterior distribution around the mean rate as visualized with the posterior distribution graphs.</p

Posterior probabilities for all inferred character histories for the carpel fusion character.

<p>Negative logarithm (base 10) of the posterior probabilities for all character histories that have occurred during the simulation for the carpel fusion character and the combinations E(T) = 1, 5 and 10 and SD(T) = 1 and 5. The x-axis represents the total number of transformations from 1 to 0 (i.e. number of gains) and the y-axis from 0 to 1 (i.e. number of losses). It is important to note that as we used the negative logarithm thus the lowest values (dark red) represent the highest PP_cs. The colours for the PP_c are not the same across the graphs, as they represent the values for each independent analysis.</p