Associative learning for host-induced fruit volatiles in Psyttalia concolor (Hymenoptera: Braconidae), a koinobiont parasitoid of tephritid flies.

Parasitic wasps are fascinating organisms that rely on a wide range of communication channels to locate their hosts. Associative learning for foraging kairomones has been demonstrated for various parasitic wasps, but little is known for parasitoids of Tephritidae flies. Psyttalia concolor (Hymenoptera: Braconidae) is a koinobiont parasitoid able to attack at least 14 tephritid pests. Females are innately attracted by some host-induced plant volatiles (HIPVs), whereas others of the same bouquet are unattractive. We hypothesize that females may detect unattractive HIPVs in association with key resources, such as food and hosts, learning to respond favourably to these cues in consecutive experiences. We evaluated associative learning for HIPVs in P. concolor females, testing if they are able to associate a food reward with the presence of different dosages of three HIPVs, thus developing a preference for an odour innately unattractive. Results demonstrated that P. concolor responded favourably to the learned cue in consecutive experiences. For all tested HIPVs (nonanoic acid, decanoic acid and geranyl acetone), regardless of dosage, trained females preferred the reward-associated odour, whereas naïve did not. Both HIPV-trained and naïve females did not show consistent differences in latencies when choosing HIPVs over blank. HIPV-trained and naïve wasps did not spend more time on HIPVs over blank. Odour learning is of adaptive importance for this generalist parasitoid, since it enhances host location efficiency by reducing the time wasted on the decision of where to search for hosts. From an applied perspective, these HIPVs could be used to train mass-reared P. concolor in pre-release, to potentially improve its efficacy in the field.

Increasing the complexity of young adolescents' beliefs about poverty and inequality: results of an 8th grade social studies curriculum intervention.

Poverty and economic hardship remain a reality for many of America's children. Although the causes of poverty are varied, Americans strongly endorse individual responsibility as a primary cause. Because beliefs about poverty originate in childhood and adolescence, intervention efforts targeting young people may be particularly effective in shifting attitudes about the poor and policies designed to help the disadvantaged. To test this proposition, the current study evaluated the efficacy of a 1-week 8th grade social studies curriculum focusing on poverty and inequality. Study participants were upper middle-class youth enrolled in multiple sections of a Social Studies course taught by a single teacher. Participants had little direct contact with marginalized groups such as poor and homeless individuals in their communities. Students (N=66) completed a survey assessing their attitudes and beliefs about poverty and poor people prior to, and 1 week and 6 months post-instruction. Results indicated that the curriculum was partially effective in increasing the complexity of students' beliefs about poverty. Students were more likely to emphasize fatalistic causes and less likely to list individualistic causes for poverty following instruction than before, but rarely emphasized structural causes for poverty and rated individual effort as the most influential factor in determining one's success. Implications of the study findings for curriculum efforts targeting young adolescents' reasoning about economic inequality and inequity and directions for future studies are discussed.