The transition from solitary life to sociality is considered one of the major transitions in evolution. In primates, this transition is currently not well understood. Traditional verbal models appear insufficient to unravel the complex interplay of environmental and demographic factors involved in the evolution of primate sociality, and recent phylogenetic reconstructions have produced conflicting results.
View Article and Find Full Text PDFWithin social groups of primates, males commonly compete over reproduction, but they may also rely on cooperation with other males. Theory suggests that it may be adaptive for male primates to tolerate some reproduction by other males if reproductive tolerance fosters cooperation, particularly that dominant males yield so-called reproductive concessions to subordinates to entice their cooperation. We review four recent studies that claimed to have found evidence for reproductive concessions or similar forms of reproductive tolerance.
View Article and Find Full Text PDFIn many animal species individuals compete for the sole possession of a breeding territory, whereas in other species communal territories are shared among same-sex conspecifics. Under what conditions does natural selection favor the evolution of individual territoriality, and under what conditions does it favor the evolution of sociality? We develop a self-consistent game-theoretic model that allows for feedbacks between evolutionary and population dynamics. In this model, nonresident floaters can chose between three strategies: they can wait for a territory vacancy to arise, they can try to forcefully take over an already-occupied territory, or they can share a territory with an established resident.
View Article and Find Full Text PDFRecent decades have seen rapid development of new analytical methods to investigate patterns of interspecific variation. Yet these cutting-edge statistical analyses often rely on data of questionable origin, varying accuracy, and weak comparability, which seem to have reduced the reproducibility of studies. It is time to improve the transparency of comparative data while also making these improved data more widely available.
View Article and Find Full Text PDFModels of social conflict in animal societies generally assume that within-group conflict reduces the value of a communal resource. For many animals, however, the primary cost of conflict is increased mortality. We develop a simple inclusive fitness model of social conflict that takes this cost into account.
View Article and Find Full Text PDFRecent theory in social evolution has been mainly concerned with competition and cooperation within social groups of animals and their impact on the stability of those groups. Much less attention has been paid to conflicts arising as a result of solitary floaters (outsiders) attempting to join groups of established residents (insiders). We model such conflicts over group-membership using a demographically explicit approach in which the rates of births and deaths in a population determine the availability of group-vacancies and the number of floaters competing over these vacancies.
View Article and Find Full Text PDFThe evolution of group living has attracted considerable attention from behavioral ecologists working on a wide range of study species. However, theoretical research in this field has been largely focused on cooperative breeders. We extend this line of work to species that lack alloparental care (hereafter termed "noncooperative species") but that may benefit from grouping by jointly defending a common territory.
View Article and Find Full Text PDFThe evolution of group-living has fascinated but also puzzled researchers from the inception of behavioural ecology. We use a simple optimality approach to examine some of the costs and benefits of group-living in redfronted lemurs (Eulemur fulvus rufus). We show that dominant males profit from accepting subordinates within their groups, as the latter significantly decrease the likelihood that the group is taken over by intruders.
View Article and Find Full Text PDFOptimal group size and composition are determined by both the costs and benefits of group living for the group's members. Verreaux's sifakas (Propithecus verreauxi), a diurnal lemur, form multimale multifemale groups with the tendency toward even adult sex ratios despite a small average number of females per group. The unexpected presence of multiple adult males may be explained by tolerance of other group members if subordinate males provide benefits to the group that outweigh the costs associated with their presence.
View Article and Find Full Text PDFCompared to the overall multiplicity of more than 20 plant Hsfs, detailed analyses are mainly restricted to tomato and Arabidopsis and to three important representatives of the family (Hsfs A1, A2 and B1). The three Hsfs represent examples of striking functional diversification specialized for the three phases of the heat stress (hs) response (triggering, maintenance and recovery). This is best illustrated for the tomato Hsf system: (i) HsfA1a is the master regulator responsible for hs-induced gene expression including synthesis of HsfA2 and HsfB1.
View Article and Find Full Text PDFHsfA2 is a heat stress (hs)-induced Hsf in peruvian tomato (Lycopersicon peruvianum) and the cultivated form Lycopersicon esculentum. Due to the high activator potential and the continued accumulation during repeated cycles of heat stress and recovery, HsfA2 becomes a dominant Hsf in thermotolerant cells. The formation of heterooligomeric complexes with HsfA1 leads to nuclear retention and enhanced transcriptional activity of HsfA2.
View Article and Find Full Text PDFHeat stress transcription factors (Hsfs) are the major regulators of the plant heat stress (hs) response. Sequencing of the Arabidopsis genome revealed the existence of 21 open-reading frames (ORFs) encoding putative Hsfs assigned to classes A-C. Here we present results of a functional genomics approach to the Arabidopsis Hsf family focused on the analysis of their C-terminal domains (CTDs) harboring conserved modules for their function as transcription factors and their intracellular localization.
View Article and Find Full Text PDFWe describe a new class of plant small heat stress proteins (sHsps) with dominant nuclear localization (Hsp17-CIII). The corresponding proteins in tomato, Arabidopsis, and rice are encoded by unique genes containing a short intron in the beta4-encoding region of the alpha-crystallin domain (ACD). The strong nuclear localization results from a cluster of basic amino acid residues in the loop between beta5 and beta6 of the ACD.
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