The hummingbird tongue is a fluid trap, not a capillary tube | PNAS
1993) Effect of sexual dimorphism in bill length on foraging behavior: An experimental analysis of hummingbirds. Oecologia 94: ... 2001) Hummingbird foraging behavior in different patch types: Simulation of alternative strategies. Ecol Modell 137:201-209. ... 2010) Bill shape and sexual shape dimorphism between two species of temperate hummingbirds: Black-Chinned hummingbird ( ... 1983) Mechanical determinants of nectar feeding strategy in hummingbirds: Energetics, tongue morphology, and licking behavior. ...
Disintermediating your friends: How online dating in the United States displaces other ways of meeting | PNAS
How Sexual Racism and Other Discriminatory Behaviors are Rationalized in Online Dating Apps ... Associations Between Methods of Meeting Sexual Partners and Sexual Practices Among Heterosexuals: Cross-sectional Study in ... Feeling Like a Fetish: Racialized Feelings, Fetishization, and the Contours of Sexual Racism on Gay Dating Apps ... Examining Variations in Participation and Outcomes of Consensual and Nonconsensual Extradyadic Behavior among Ashley Madison ...
Prescriptive scientific narratives for communicating usable science | PNAS
Behaviors ranged from extremely low on the continuum, such as talking and kissing, up to highly risky sexual behaviors. For ... The first and arguably most central finding of the descriptive research was that adolescents perceived sexual behaviors to be ... The absolutist view of risk fundamentally undermined important messages for reducing the risk of sexual behavior for a ... Students demonstrating the "Risk-O-Meter" to reinforce the concept of relative risk for sexual behaviors and mitigation ...
Social supports and serotonin transporter gene moderate depression in maltreated children | PNAS
Sixty-three percent of the sample had a history of physical abuse; 19% had a history of sexual abuse; 81% had a history of ... the investigators were able to prevent the deterioration in maternal care behaviors and subsequently prevent most of the long- ... Severity of five maltreatment subtypes (i.e., physical abuse, sexual abuse, neglect, emotional abuse, and exposure to domestic ...
Weak warning signals can persist in the absence of gene flow | PNAS
Such behaviors most often involved beak wiping and head shaking. Each trial ran for 5 min, followed by 5-min rest, after which ... Sexual dimorphism and intra-populational colour pattern variation in the aposematic frog Dendrobates tinctorius. Evol. Ecol. 27 ... We measured the number of times the bird wiped its beak, which is a known aversive behavior (89), and the percentage of the oat ... Polymorphism of melanic ladybirds maintained by frequency-dependent sexual selection. Biol. J. Linn. Soc. Lond. 23, 101-111 ( ...
Comparing crime rates between undocumented immigrants, legal immigrants, and native-born US citizens in Texas | PNAS
The exceptions to this pattern are homicide, where the rates are roughly equal, and sexual assault, where arrest rates for ... and third-generation immigrants look more like their native peers in their criminal behaviors (6). Another common finding in ... 2 shows the rates for homicide, assault, robbery, sexual assault, burglary, theft, and arson. Without exception, undocumented ... and sexual assault. The gaps for robbery, burglary, theft, and arson are considerably larger, whereby native-born citizens are ...