Evolutionary Relationships of Courtship Songs in the Parasitic Wasp Genus, Cotesia (Hymenoptera: Braconidae)

Acoustic signals play an important role in premating isolation based on sexual selection within many taxa. Many male parasitic wasps produce characteristic courtship songs used by females in mate selection. In Cotesia (Hymenoptera: Braconidae: Microgastrinae), courtship songs are generated by wing fanning with repetitive pulses in stereotypical patterns. Our objectives were to sample the diversity of courtship songs within Cotesia and to identify underlying patterns of differentiation. We compared songs among 12 of ca. 80 Cotesia species in North America, including ten species that have not been recorded previously. For Cotesia congregata, we compared songs of wasps originating from six different host-foodplant sources, two of which are considered incipient species. Songs of emergent males from wild caterpillar hosts in five different families were recorded, and pattern, frequency, and duration of song elements analyzed. Principal component analysis converted the seven elements characterized into four uncorrelated components used in a hierarchical cluster analysis and grouped species by similarity of song structure. Species songs varied significantly in duration of repeating pulse and buzz elements and/or in fundamental frequency. Cluster analysis resolved similar species groups in agreement with the most recent molecular phylogeny for Cotesia spp., indicating the potential for using courtship songs as a predictor of genetic relatedness. Courtship song analysis may aid in identifying closely related cryptic species that overlap spatially, and provide insight into the evolution of this highly diverse and agriculturally important taxon

Short-range correlations in (e,e′'p) and (e,e′'pp) reactions on complex nuclei

The influence of short-range correlations (SRC) on the triple-coincidence (e,e$'$pp) reactions is studied. The non-relativistic model uses a mean-field potential to account for the distortions that the escaping particles undergo. Apart from the SRC, that are implemented through a Jastrow ansatz with a realistic correlation function, we incorporate the contribution from pion exchange and intermediate $\Delta _{33}$ currents. The (e,e$'$pp) cross sections are predicted to exhibit a sizeable sensitivity to the SRC. The contribution from the two-nucleon breakup channel to the semi-exclusive $^{12}$C(e,e$'$p) cross section is calculated in the kinematics of a recent NIKHEF-K experiment. In the semi-exclusive channel, a selective sensitivity in terms of the missing energy and momentum to the SRC is found.Comment: 9 pages, Revtex, 3 figures included as an uuencoded and compressed Postscript fil

Policy Coherence and Coordination for Trade Facilitation: Integrated Border Management, Single-Windows and other Options for Developing Countries

There is now increasing recognition of the critical importance of trade facilitation to further international commerce, accelerate growth, and enhance welfare if not alleviate poverty among trading nations. But there is also increasing appreciation that it is not just attention to the barriers and bottlenecks behind-the-border that are involved in trade facilitation (TF), it also calls for coherence between policies and regulations at the border and inside the border. The unavoidable participation of many government agencies and private stakeholders in border transactions calls for coordination among them towards a harmonized approach to trade facilitation. This paper discusses the need and relevance of policy coherence and coordination to facilitate trade and to what extent some trade facilitation measures (concepts) such as integrated border management and single-windows may be applicable in developing countries to improve both policy coherence and coordination.Trade Faclitation, Border trade, Policy coherence, Economic Integration