Evidence for a substantial host‐use bottleneck following the invasion of an exotic,polyphagous weevil

1. The successful establishment of novel plant–insect interactions may depend on the availability of suitable hosts, which itself is influenced by the inherent flexibility of the herbivore for the native plants in its new range. The polyphagous beech leaf mining weevil, Orchestes fagi L., is a recent invader to eastern Canada, and while beech is a primary host, it remains unclear the extent to which it might also utilise co‐occurring secondary hosts, as has been observed in its native European range. 2. A combination of field and laboratory feeding trials were used to quantify weevil secondary host use. Based on its expansive native host range in Europe, it was predicted that American beech (Fagus grandifolia Ehrh.), as well as several additional plant species, would be susceptible to weevil damage. 3. Contrary to this prediction, weevil feeding was almost entirely exclusive to beech in both the field and laboratory feeding trials. This result is further supported by field observations that revealed an absence of weevils and eggs on species other than beech. In general, the lack of pre‐diapause feeding on any alternate host species represented an extreme departure from feeding habits observed within the native range. 4. Overall, this host‐use bottleneck suggests that the adoption of a novel primary host by O. fagi, in this case American beech, may remove the normal requirement for secondary hosts and suggests a significant departure from native feeding habits with possible consequences for related life‐history parameters such as overwintering survival and fecundity.     

Vocal Individuality of Great Gray Owls in the Sierra Nevada

ABSTRACT The cryptic plumage and nocturnal nature of the great gray owl (Strix nebulosa) make it difficult to study in its densely forested habitat. We investigated whether the vocalizations of individual great gray owls could be distinguished and used as a tool for population survey and monitoring. We recorded 312 territorial calls produced by 14 male and 11 female great gray owls between March and July 2006 and 2007 in the Sierra Nevada range of California, USA. We recorded 19 owls on multiple occasions within a season and 8 owls between seasons. We extracted 17 frequency and 15 temporal variables from the sonograms of each call. Discriminant analysis selected 9 variables and classified 92.8% of calls to the correct individual within a season; 71.4% of calls were classified to the correct individual between seasons. Our results indicate that territorial calls could be used to monitor individual great gray owls for both short- and long-term studies. Vocal individuality could be useful as a noninvasive method to improve census estimates and yield information on site fidelity, turnover rates, seasonal movements, and behavioral traits of great gray owls.     

Measuring Proliferation In Routine Fine Needle Aspirates. Immunocytochemical Detection of Bromodeoxyuridine Incorporation and Ki-67 Expression In Breast Aspirates

Two simple quantitative means of measuring tumour proliferation which can be applied to cytological material are described. One method involves immunocytochemical staining of cytological smears prepared from breast aspirates with the monoclonal antibody Ki-67. The other method involves incubation of aspirated material with 5-Bromo-2-deoxyuridine (BrdU). Direct measurement of the S phase of the cell cycle is feasible in breast fine needle aspirates by Bromodeoxyuridine incorporation and subsequent immunocytochemical detection. The proliferation indices obtained correlate with those derived from Ki-67 staining. This technique is suitable for routine use in the assessment of tumour proliferation.