Social learning is central to innovation, in primates and beyond

AbstractMuch of the importance of innovation stems from its capacity to spread via social learning, affecting multiple individuals, thus generating evolutionary and ecological consequences. We advocate a broader taxonomic focus in the field of behavioral innovation, as well as the use of comparative field research, and discuss the unique conservation implications of animal innovations and traditions.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/S0140525X0700247

Whistle Convergence among Allied Male Bottlenose Dolphins (Delphinidae, Tursiops sp.)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75053/1/j.1439-0310.1999.00441.x.pd

Agent-based modeling of multilevel selection : the evolution of feeding restraint as a case study

Evolutionary biologists are increasingly interested in the dynamics of multilevel selection, or selection acting simultaneously at more than one level in a hierarchy of reproducing entities (e.g., gene, chromosome, organelle, cell, organism, social group, multi-species community). Systems of linear equations are the usual tool for studying evolution, but are limited in their ability to capture important dynamics of multilevel selection. Here we use an agent-based model to study the evolution of cooperation in spatially structured populations. This work addresses the long-standing controversy over the role of group selection , or natural selection between versus within groups of interacting individuals. In an ecologically plausible setting, cooperative individuals with lower rates of food consumption. The results show that changing the spatial distribution of food, and thus the distribution of the individuals seeking it, can determine whether or not cooperation evolves. In this model cooperation evolved under a fairly wide range of parameter values, even without the kinship effects and discrete mixing phase that are sometimes thought to be necessary. We suggest that integrating equation-based analysis tools into agent-based models is a powerful way to study selection in systems with complex dynamics

Foraging ecology of the South Australian glossy black-cockatoo ( Calyptorhynchus lathami halmaturinus )

The endangered South Australian glossy black-cockatoo ( Calyptorhynchus lathami halmaturinus Mathews 1912) feeds almost exclusively on the seeds of the drooping sheoak ( Allocasuarina verticillata ), and shows marked preferences for individual trees. This field study investigated foraging ecology and tree selection through observations of foraging birds and measurements of trees and seed cones. The cockatoos spent the vast majority of their foraging time (94%) handling seed cones, and handling behaviour was highly stereotyped. Handling time per cone was correlated primarily with cone size, while seed intake rate was correlated primarily with seed mass per cone. The cockatoos fed mostly in trees with signs of previous feeding. They tended initially to sample trees with large seeds, and to stay for long feeding bouts in trees with high ratios of seed-to-cone mass. As a result of these biases, feeding was concentrated in trees with high seed mass per cone. Preferred trees were also larger, with higher ratios of seed-to-cone mass and larger seeds containing more lipid and protein. By feeding from selected trees the cockatoos increased both their seed intake rate and the nutritional quality of the seeds ingested, thereby increasing their energy intake rate by an estimated 28%. They did not discriminate against trees that had re-grown from basal shoots after fires. Insect larvae were present in some seed cones but the cockatoos did not appear to actively seek them. Males foraged 19% more efficiently than females, resulting in greater daily food intake. The characteristics of individual A. verticillata trees that determined the cockatoos' feeding rates were also correlated with their distribution on a regional scale. This suggests that the distribution of this endangered cockatoo depends not only on the presence of food trees, but also on their regionally varying feeding profitability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72786/1/j.1442-9993.2000.tb00003.x.pd

Animal Cell Differentiation Patterns Suppress Somatic Evolution

Cell differentiation in multicellular organisms has the obvious function during development of creating new cell types. However, in long-lived organisms with extensive cell turnover, cell differentiation often continues after new cell types are no longer needed or produced. Here, we address the question of why this is true. It is believed that multicellular organisms could not have arisen or been evolutionarily stable without possessing mechanisms to suppress somatic selection among cells within organisms, which would otherwise disrupt organismal integrity. Here, we propose that one such mechanism is a specific pattern of ongoing cell differentiation commonly found in metazoans with cell turnover, which we call “serial differentiation.” This pattern involves a sequence of differentiation stages, starting with self-renewing somatic stem cells and proceeding through several (non–self-renewing) transient amplifying cell stages before ending with terminally differentiated cells. To test the hypothesis that serial differentiation can suppress somatic evolution, we used an agent-based computer simulation of cell population dynamics and evolution within tissues. The results indicate that, relative to other, simpler patterns, tissues organized into serial differentiation experience lower rates of detrimental cell-level evolution. Self-renewing cell populations are susceptible to somatic evolution, while those that are not self-renewing are not. We find that a mutation disrupting differentiation can create a new self-renewing cell population that is vulnerable to somatic evolution. These results are relevant not only to understanding the evolutionary origins of multicellularity, but also the causes of pathologies such as cancer and senescence in extant metazoans, including humans

The Role of Multilevel Selection in the Evolution of Sexual Conflict in the Water Strider Aquarius remigis

In evolution, exploitative strategies often create a paradox in which the most successful individual strategy “within” the group is also the most detrimental strategy “for” the group, potentially resulting in extinction. With regard to sexual conflict, the overexploitation of females by harmful males can yield similar consequences. Despite these evolutionary implications, little research has addressed why sexual conflict does not ultimately drive populations to extinction. One possibility is that groups experiencing less sexual conflict are more productive than groups with greater conflict. However, most studies of sexual conflict are conducted in a single isolated group, disregarding the potential for selection among groups. We observed Aquarius remigis water striders in a naturalistic multigroup pool in which individuals could freely disperse among groups. The free movement of individuals generated variation in aggression and sex-ratio among groups, thereby increasing the importance of between-group selection compared to within-group selection. Females dispersed away from local aggression, creating more favorable mating environments for less-aggressive males. Furthermore, the use of contextual analysis revealed that individual male aggression positively predicted fitness whereas aggression at the group level negatively predicted fitness, empirically demonstrating the conflict between levels of selection acting on mating aggressio

General Gregariousness and Specific Social Preferences among Wild Chimpanzees

Wild chimpanzees form temporary parties that vary in size and composition. Previous studies have revealed considerable intraspecific variation in party compositions. We examined patterns of association among age, sex, and reproductive classes of chimpanzees at Ngogo in the Kibale National Park, Uganda. We employed a class-based association index and a randomization procedure to control for confounding factors and to test for differences between classes. Results indicate that males associated with other males significantly more than expected if all classes behaved equivalently, while females generally associated with individuals of the same sex less than expected. To interpret these patterns we used two additional indices that separate associations into two components: general gregariousness and preference for particular classes of associates. Males and estrous females were more gregarious than other classes, while anestrous females were less so. After controlling for general gregariousness, adult males as a class showed no specific preference for associating with each other. Anestrous females preferred each other as party members, and estrous females avoided each other. These results are consistent with previous findings that adult males are more gregarious than females. They diverge from the standard picture of chimpanzee society, however, by suggesting a mutual affinity among anestrous females, but not among adult males as a class.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44563/1/10764_2004_Article_409685.pd

Population Structure Influences Sexual Conflict in Wild Populations of Water Striders.

In sexual conflict, aggressive males frequently diminish the long-term reproductive success of females in efforts to gain a short-term advantage over rival males. This short-term advantage can selectively favour high-exploitation males. However, just as the over-exploitation of resources can lead to local extinction, the over-exploitation of females in the form of harassment by aggressive males can yield similar consequences resulting in reduced female fecundity, increased female mortality and overall decline in mating activity. This outcome may often be prevented by selection acting at multiple levels of biological organization. Directional selection favouring aggressive exploitation within groups can be balanced by directional selection amongst groups opposing exploitation. Such between-group selection has recently been demonstrated in laboratory studies of water striders, where the conditional dispersal of individuals increased variation amongst groups and influenced the balance of selection toward reduced male aggression. This multilevel selection (MLS) framework also provides predictive value when investigating natural populations differing in their relative strength of selection within versus among groups. For water striders, the consequences of local exploitation cause fitness differences between groups, favouring less aggressive males. Inconsistently flowing ephemeral streams consist of isolated pools that prevent aggressive male water striders from escaping the consequences of local exploitation. We, therefore, predicted that inconsistently flowing ephemeral streams would favour the evolution of less aggressive males than would perennial streams, which allow aggressive males to move more freely and to escape the group-level costs of their aggression. Comparing two neighbouring streams during the mating season, we found that males dispersed naturally between pools at much higher rates in the perennial stream than in the ephemeral stream. As predicted, we found that males from the perennial stream were significantly more aggressive than those from the ephemeral stream. We also found that dispersers were significantly more aggressive than non-dispersers within each stream. These field results illustrate the relevance of the MLS framework in our understanding of the evolution of sexual conflict