We examined how individuals may change their voices when speaking to attractive versus unattractive individuals, and if it were possible for others to perceive these vocal changes. In addition, we examined if any concurrent physiological effects occurred when speaking with individuals who varied in physical attractiveness. We found that both sexes used a lower-pitched voice and showed a higher level of physiological arousal when speaking to the more attractive, opposite-sex target. Furthermore, independent raters evaluated the voice samples directed toward the attractive target (versus the unattractive target) as sounding more pleasant when the two voice samples from the same person presented had a reasonably perceptually noticeable difference in pitch. These findings may have implications for the role voice plays in mate selection and attraction.

This study examined the ability to make age estimates based upon hearing voice samples of speakers whose ages vary across the lifespan while considering the raters' own age and sex. It was hypothesized that voices are a strong index of reproductive viability and therefore, members of both sexes would be most accurate in assessing age of those around puberty and females approaching menopause. Voice samples were obtained from 101 individuals of both sexes, ranging in age from 2 to 67 years and an additional 97 independent raters of different ages were asked to estimate the exact age of the speakers from voice recordings. Results showed that accuracy of voice assessment tended to decrease as the speakers' ages increased, with assessments of children and adolescents being the most accurate. Overall, raters tended to underestimate the age of speakers as the speaker age increased regardless of the raters' own age. Whereas accuracy in ratings decreased when male speakers reached age 46-55, accuracy remained high for female speakers in their menopausal years, suggesting that both sexes are sensitive to vocal changes during this developmental period. These findings illustrate that the human voice may be used as a salient cue for assessing reproductive viability.

1. Herbivorous insects often have close associations with specific host plants, and their preferences for mating and ovipositing on a specific host-plant species can reproductively isolate populations, facilitating ecological speciation. Volatile emissions from host plants can play a major role in assisting herbivores to locate their natal host plants and thus facilitate assortative mating and host-specific oviposition.2. The present study investigated the role of host-plant volatiles in host fidelity and oviposition preference of the gall-boring, inquiline beetle, Mordellistena convicta LeConte (Coleoptera: Mordellidae), using Y-tube olfactometers. Previous studies suggest that the gall-boring beetle is undergoing sequential host-associated divergence by utilising the resources that are created by the diverging populations of the gall fly, Eurosta solidaginis Fitch (Diptera: Tephritidae), which induces galls on the stems of goldenrods including Solidago altissima L. (Asteraceae) and Solidago gigantea Ait.3. Our results show that M. convicta adults are attracted to galls on their natal host plant, avoid the alternate host galls, and do not respond to volatile emissions from their host-plant stems.4. These findings suggest that the gall-boring beetles can orient to the volatile chemicals from host galls, and that beetles can use them to identify suitable sites for mating and/or oviposition. Host-associated mating and oviposition likely play a role in the sequential radiation of the gall-boring beetle.