\u3ci\u3eMicroctonus Pachylobii\u3c/i\u3e (Hymenoptera: Braconidae): New Host Record From \u3ci\u3eHylobius Radicis\u3c/i\u3e (Coleoptera: Curculionidae), and Additional Notes on Its Biology

The endoparasite Microctonus pachylobii was discovered parasitizing a new weevil host, Hylobius radicis. Thirteen of the 154 H. radicis adults collected were parasitized (8.5%). The median numbers of parasites per weevil were 26 (x =22.5) during the period April through June, and 4 (x =9.4) during August and September. The median male:female sex ratio was 0.91 (x =0.65). Males emerged approximately 1 day earlier than females. Median parasite mortality while in the cocoon was 10.2% per parasitized weevil (x = 11.8%). Microctonus pachylobii was not found parasitizing two previously recorded weevil hosts from field samples, Hylobius rhizophagus and H. pales, and a laboratory study suggests that the parasite may have difficulty parasitizing the latter species

The newly developed CRF1-receptor antagonists, NGD 98-2 and NGD 9002, suppress acute stress-induced stimulation of colonic motor function and visceral hypersensitivity in rats.

Corticotropin releasing factor receptor 1 (CRF1) is the key receptor that mediates stress-related body responses. However to date there are no CRF1 antagonists that have shown clinical efficacy in stress-related diseases. We investigated the inhibitory effects of a new generation, topology 2 selective CRF1 antagonists, NGD 98-2 and NGD 9002 on exogenous and endogenous CRF-induced stimulation of colonic function and visceral hypersensitivity to colorectal distension (CRD) in conscious rats. CRF1 antagonists or vehicle were administered orogastrically (og) or subcutaneously (sc) before either intracerebroventricular (icv) or intraperitoneal (ip) injection of CRF (10 µg/kg), exposure to water avoidance stress (WAS, 60 min) or repeated CRD (60 mmHg twice, 10 min on/off at a 30 min interval). Fecal pellet output (FPO), diarrhea and visceromotor responses were monitored. In vehicle (og)-pretreated rats, icv CRF stimulated FPO and induced diarrhea in >50% of rats. NGD 98-2 or NGD 9002 (3, 10 and 30 mg/kg, og) reduced the CRF-induced FPO response with an inhibitory IC50 of 15.7 and 4.3 mg/kg respectively. At the highest dose, og NGD 98-2 or NGD 9002 blocked icv CRF-induced FPO by 67-87% and decreased WAS-induced-FPO by 23-53%. When administered sc, NGD 98-2 or NGD 9002 (30 mg/kg) inhibited icv and ip CRF-induced-FPO. The antagonists also prevented the development of nociceptive hyper-responsivity to repeated CRD. These data demonstrate that topology 2 CRF1 antagonists, NGD 98-2 and NGD 9002, administered orally, prevented icv CRF-induced colonic secretomotor stimulation, reduced acute WAS-induced defecation and blocked the induction of visceral sensitization to repeated CRD

Plant architectural barriers to feeding site selection by the meadow spittlebug, Philaenus spumarius (L.)

While current theories describing the insect-plant interaction have emphasized the biochemical aspects of the relationship, morphological components can also play a significant role in determining which plants or tissues are susceptible to insect attack. Xylem sap on which spittlebugs feed may lack many of the plant compounds responsible for host selection and preference, and for this species architectural barriers may be more significant in restricting host plant utilization. This investigation examined the role of plant anatomical structures as barriers to the selection of feeding sites by the meadow spittlebug, Philaenus spumarius (L.). The distribution pattern of f_. spumarius on Anaphalis margaritaceae (D.C.) suggested that trichomes on the stem may restrict the first through third instar nymphs to feeding on the leaves, while tissue hardness may prevent nymphs from feeding on the lower stem. Fifth instar nymphs feeding on Medicago sativa (L.) may also be confronting a tissue hardness barrier on the lower stem. Caging experiments on hirsute vs. shaven stems confirmed that trichomes were a barrier to the first three instar nymphs at the apex of the plant. Depth of xylem elements and tissue hardness were not significant barriers to feeding. The mechanism of resistance appeared to be that trichome height exceeds the length of the nymphs' beak, and thereby interferes with the initiation of stylet penetration. Fewer nymphs were able to feed when caged at increasing distance below the terminal bud (DBTB). For A. margaritaceae, tissue hardness and the trichome layer were the barriers to feeding; for M. sativa, tissue hardness and decreased availability of xylem vessels reduced feeding. Stem segments within the cages were sectioned to determine which tissues were impeding stylet penetration. In A. margaritaceae the progressive lignification of the bundle cap and interfascicular region with increasing DBTB were the main tissues preventing stylets from reaching the xylem. In M. sativa on the other hand, the bundle cap and the interfascicular parenchyma were penetrable at maturity, but the increasing number of lignified fibers in the xylem prevented the stylets from reaching a xylem element. The predictive capability of a needle penetrometer was assessed by correlating feeding ability of fifth instar nymphs with tissue hardness measurements on the two hosts. Penetrometer measurements on the lower stem lacked sensitivity to tissues impeding stylet penetration, and were a poor indication of feeding potential in this region. Preference tests in the absence of trichome and tissue hardness barriers showed that the nymphs fed on normally restricted areas of the plant. Gradients in two parameters-of the spittlebugs' food niche, xylem sap tension and the concentration of amino acids in the sap, indicated that the preferred stem was more favorable in terms of xylem sap tension. While tissue hardness restricted nymphs from a portion of their preferred range of feeding sites, the uniform distribution of nymphs suggested that they either did not respond to variation in these parameters, or responded to a combination of parameters with opposite gradients

Weak Charge-Changing Flow in Expanding r-Process Environments

We assess the prospects for attaining steady nuclear flow equilibrium in expanding r-process environments where beta decay and/or neutrino capture determine the nuclear charge-changing rates. For very rapid expansions, we find that weak steady flow equilibrium normally cannot be attained. However, even when neutron capture processes freeze out in such nonequilibrium conditions, abundance ratios of nuclear species in the r-process peaks might still mimic those attained in weak steady flow. This result suggests that the r-process yield in a regime of rapid expansion can be calculated reliably only when all neutron capture, photodisintegration, and weak interaction processes are fully coupled in a dynamical calculation. We discuss the implications of these results for models of the r-process sited in rapidly expanding neutrino-heated ejecta.Comment: 21 pages, AAS LaTex, 2 postscript figure

Fertilization of Epichloë typhina stromata by mycophagous slugs

Epichloë typhina, a fungal endophyte of cool season grasses, is heterothallic and an obligate out-crosser. In areas of endemism, its spermatia are moved between stromata of the two opposite mating types through egg-laying activities of Botanophila flies. In western Oregon, where the fungus was inadvertently introduced into seed-production fields of Dactylis glomerata (= orchardgrass, cocksfoot), flies do not appear to be the sole vectors for E. typhina fertilization. Here we examined the role of the common agricultural slug pest Deroceras reticulatum and mycophagous slug species Prophysaon andersoni and Arion subfuscus in E. typhina spermatia transfer. Frass from P. andersoni, A. subfuscus and D. reticulatum fed stromata of one mating type was transferred to stromata of the opposite mating type, resulting in 100%, 93% and 25% stromata fertilization respectively. An experiment designed to mimic field conditions examined stromata fertilization on E. typhina-infected plants of opposite mating type in the presence of slugs. Treatments with P. andersoni and D. reticulatum had greater stromata fertilization compared to the no-slug control, but the slug treatments were not different. This appears to be the first report of mollusks vectoring viable spermatia leading to the cross fertilization of stromata of different mating types.This is the publisher’s final pdf. The article is copyrighted by the the Mycological Society of America and published by Allen Press Inc. It can be found at: http://www.mycologia.org/.Keywords: Mollusks, Choke disease, Clavicipitaceae, Dactylis glomerata, Fungal endophyte, Gastropod

Synthesis of the elements in stars: forty years of progress

Forty years ago Burbidge, Burbidge, Fowler, and Hoyle combined what we would now call fragmentary evidence from nuclear physics, stellar evolution and the abundances of elements and isotopes in the solar system as well as a few stars into a synthesis of remarkable ingenuity. Their review provided a foundation for forty years of research in all of the aspects of low energy nuclear experiments and theory, stellar modeling over a wide range of mass and composition, and abundance studies of many hundreds of stars, many of which have shown distinct evidence of the processes suggested by B2FH. In this review we summarize progress in each of these fields with emphasis on the most recent developments