PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Competitive Behavior”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed1993

Gaining time.

Explore the source record for details and available documents.

Competitive Behavior↗
PubMed1995

Reproductive constraints on aggressive competition in female baboons.

Competitive interaction between females of same social group is characteristic of most primate species. In Old World monkeys, females of high social rank maintain priority of access to scarce resources and harass low-ranking companions. But different field studies have found differing correlations between female dominance and reproductive success: several populations show an advantage of rank whereas others do not. Although such variation may reflect divergent levels of predation, food availability or social stress in different environments, female competitive ability may also be balanced by significant reproductive costs and thus be subject to strong stabilizing selection. We report here that high-ranking female baboons (Papio cynocephalus anubis) at Gombe National Park, Tanzania, enjoy shorter interbirth intervals, improved infant survival, and accelerated maturation of their daughters. These advantages, however, are countered by a significantly higher probability of miscarriage, and a proportion of high-ranking females suffer from reduced fertility.

Abortion, Veterinary↗
PubMed1995

Mutual policing and repression of competition in the evolution of cooperative groups.

Evolutionary theory has not explained how competition among lower level units is suppressed in the formation of higher-level evolutionary units. For example, the key problem of early evolution is small, individual replicators formed cooperative groups of sufficient complexity to allow accurate copying of the genetic material. The puzzle is why parasites did not subvert the formation of cells by obtaining benefits from the group without contributing to shared traits that enhance reproduction. These parasites would outcompete other replicators within the cell, disrupting reproductive fairness among subunits and destroying the functional coherence of the group. A similar problem arose at a later evolutionary stage with the orderly mendelian segregation of subunits (chromosomes) within cells, and reproductive fairness continued to be a problem in the evolution of insect and human societies. Here I present a simple model to show how reproductive fairness evolves among subunits to create functional coherence and higher-level units. Self-restraint, which evolves according to the kin-selection coefficient of relatedness, is not sufficient: mutual policing and enforcement of reproductive fairness are also required for the evolution of increasing social complexity.

Biological Evolution↗
PubMed1995

Tonegawa defended.

Explore the source record for details and available documents.

Competitive Behavior↗
PubMed1997

Trade-off between parasitoid resistance and larval competitive ability in Drosophila melanogaster.

The extent to which an organism is selected to invest in defences against pathogens and parasites depends on the advantages that ensue should infection occur, but also on the costs of maintaining defences in the absence of infection. The presence of heritable variation in resistance suggests that costs exist, but we know very little about the nature or magnitude of these costs in natural populations of animals. A powerful technique for identifying trade-offs between fitness components is the study of correlated responses to artificial selection. We have selected Drosophila melanogaster for improved resistance against an endoparasitoid, Asobara tabida. Endoparasitoids are insects whose larvae develop internally within the body of other insects, eventually killing them, although their hosts can sometimes survive attack by mounting a cellular immune response. We found that reduced larval competitive ability in unparasitized D. melanogaster is a correlated response to artificial selection for improved resistance against A. tabida. The strength of selection for competitive ability and parasitoid resistance is likely to vary temporally and spatially, which may explain the observed heritable variation in resistance.

Animals↗