The role of olfactory cues in the sequential radiation of a gall-boring beetle, Mordellistena convicta

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.

The Role of Olfactory Cues in the Sequential Radiation of a Gall-boring Beetle, Mordellistena convicta

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.

Does the Presence of a Learning Disability Elicit a Stigmatization?

Aims: To determine whether or not a Learning Disability(LD) label leads to stigmatization. Study Design: This research used a 2(sex of participant) x 2(LD label)x 2 (Sex of stimulus person) factorial design. Place and Duration of Study: Bucknell University, between October 2010 and April 2011. Methodology: Sample: We included 200 participants (137 women and 63 men, ranging in age from 18 – 75 years, M = 26.41. Participants rated the stimulus individual on 27 personality traits, 8 Life success measures, and the Big-5 personality dimensions. Also, participants completed a Social Desirability measure. Results: A MANOVA revealed a main effect for the Learning Disability description, F(6, 185) = 6.41 p< .0001, eta2 = .17,for the Big-5 personality dimensions, Emotional Stability, F(1, 185) = 13.39, p < .001, eta2 = .066, and Openness to Experiences F(1,185) = 7.12, p< .008, eta2 = .036.Stimulus individuals described as having a learning disability were perceived as being less emotionally stable and more open to experiences than those described as not having a learning disability. Another MANOVA revealed a main effect for having a disability or not, F(8, 183) = 4.29, p< .0001, eta2 = .158, for the Life Success items, Attractiveness, F(1, 198) = 16.63, p< .0001, eta2 = .080, and Future Success,F(1, 198) = 4.57, p< .034, eta2 = .023. Stimulus individuals described as having a learning disability were perceived as being less attractive and with less potential for success than those described as not having a learning disability. Conclusion: The results of this research provide evidence that a bias exists toward those who have learning disabilities. The mere presence of an LD label had the ability to cause a differential perception of those with LDs and those without LDs.

The role of olfactory cues in the sequential radiation of a gall-boring beetle

Species diversity itself may cause additional species diversity. According to recent findings, some species modify their environment in such a way that they facilitate the creation of new niches for other species to evolve to fill. Given the vast speciesdiversity of insects, the occurrence of such sequential radiation of species is likely common among herbivorous insects and the species that depend on them, many of them being insects as well. 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 host-specific populations, facilitating speciation. Previous research by our laboratory has established that there are two distinct populations of thegall fly, Eurosta solidaginis (Tephritidae), which attack different species of goldenrods, Solidago altissima (Asteraceae) and S. gigantea. The gall fly’s host-associated differentiation is facilitating the divergence and potential speciation of twosubpopulations of the gall-boring beetle Mordellistena convicta (Mordellidae) by providing new resources (galls on stems of the galdenrods) for the gall-boring beetles. These beetles exist as two host-plant associated populations of inquilines that inhabit the galls induced by the gall fly. While our previous research has provided genetic and behavioral evidence for host-race formation, little is known about the role of their host plants in assortative mating and oviposition-site selection of the gall-boring beetles’ hostassociated populations. 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. The present study investigated the role of host-plant volatiles in host fidelity (mating on the host plant) and oviposition preference of M. convicta by measuring its behavioral responses to the host-plant volatile emissions using Y-tube olfactometers. In total, we tested behavioral responses of 615 beetles. Our resultsshow that M. convicta adults are attracted to their natal host galls (67% of S. altissima-emerging beetles and 70% of S. gigantea-emerging beetles) and avoid the alternate host galls (75% of S. altissima-emerging beetles and 66% of S. gigantea-emerging beetles),while showing no preference for, or avoidance of, ungalled plants from either species. This suggests that the gall beetles can orient to the volatile chemicals emitted by the galls and can potentially use them to identify suitable sites for mating and/or oviposition. Thus, host-associated mating and oviposition may play a role in the sequential speciation of the gall-boring beetle.