Tropical trees may show positive density dependence in fruit set and maturation due to pollen limitation in low-density populations. However, pollen from closely related individuals in the local neighbourhood might reduce fruit set or increase fruit abortion in self-incompatible tree species. We investigated the role of neighbourhood density and genetic relatedness on individual fruit set and a...

In a series of three experiments, we examined the hypothesis that female Japanese quail, Coturnix japonica, are motivated to form aggregations to reduce the probability of harassment by conspecific males. When in the presence of a conspecific male, female quail both sought others of their sex and remained near them. However, if no males were present, females were indifferent to or tended to avo...

1) Evolutionary advantages of intersubjectivity and self-consciousness: * Anxiety limitation process (1), (2), (3): Intersubjectivity and identification with suffering/endangered conspecifics => anxiety increase. Anxiety limitation by development of Empathy, Imitation, Language, Group life, Intersubjectivity. Positive feedback. Evolutionary advantage. * Action programs improvements: Intersubjec...

Abstract Environmental noise has a significant negative impact on acoustic communication in most situations, as it influences the production, transmission, and reception of signals. However, how animals respond to conspecific sounds when there is interference from environmental noise, whether males females display convergent behavioral responses face masking remain poorly understood. In this st...

In an effort to distinguish among adaptive models and to improve our understanding of behavioral mechanisms of sex ratio manipulation, this study examines sex ratio response to other wasps in the solitary parasitoid wasp Spalangia cameroni. Relative to when alone, females produced a greater proportion of sons in the presence of conspecifics, regardless of whether the conspecifics were female or...

Few data are available on the effectiveness of reproductive isolating mechanisms in externally fertilizing taxa. I investigated patterns of conspecific and heterospecific fertilization among three coexisting sea urchin species, Strongylocentrotus droebachiensis, S.franciscanus, and S. purpuratus. In the laboratory, both among and within species, eggs from individual females whose eggs are more ...

A cannibal has to weigh the benefits of the consumption and removal of competing conspecifics against the potential loss of fitness through filial cannibalism. We examined the role of the presence of conspecific females in informing adaptive cannibalism decisions. Females of the hemipteran bug Geocoris pallens express low egg cannibalism when alone but become much more cannibalistic in the pres...

The function of the central nervous system neurotransmitter serotonin (5-HT) contributes to individual differences in impulsive behavior in humans and nonhuman primates. We investigated the relationship between 5-HT function and behavioral responses to a novel social scenario in marmosets. In the first study, marmosets (n=10) were treated orally with fluoxetine HCl (FLX) or vehicle for two tria...