Sitona lineatus flight patterns in the pea growing region of northern Idaho and eastern Washington were monitored with omnidirectional sticky traps from 1974 to 1976. Trapping sites ranged in altitude from 256–1006 m. Flight occurred from April to September in all years of study, but spring migration occurred at approximately the same time at all trapping sites within each year of the study. Late‐summer migration by new generation adults did not occur at nearly the same time for each study site over the 3 years of the study, but appeared to follow the maturity of peas. RÉSUMÉ MIGRATION SAISONNIERE ET VOL DU CHARANÇON DES FEUILLES DU POIS, SITONA LINEATUS, DANS L'IDAHO DU NORD ET WASHINGTON ORIENTAL Les caractéristiques du vol de Sitona lineatus dans la zone de culture du Pois du Nord de Idaho et de l'Est de Washington ont été examinées aves des pièges omnidirectionnels de 1974 à 1976. Les lieux de piégeages se situaient entre 256 et 1006 m. Les migrations printanières dans toutes les localités se sont produites à peu près à la même époque chaque année, indépendamment de la date de semis des pois, de leur phénologie, de la densité de population de Sitona lineatus ou du temps. Les migrations estivales tardives des adultes de la nouvelle génération n'ont pas eu lieu toujours à la même époque chaque année dans toutes les localités mais suivant la maturité des pois. Les pièges s'étageaient entre 61 et 183 cm. Aux périodes de vols les plus importantes, plus d'adultes étaient capturés aux niveaux les plus élevés alors qu'aux autres périodes, les captures étaient à peu près les mêmes à tous les niveaux. Ces résultats conduisent à la conclusion qu'il y a une véritable migration chez Sitona lineatus.

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Field experiments were conducted to determine growth and yield responses of Pisum sativum L. to defoliation by adult Sitona lineatus (L.). Seedlings grown under conventional (moldboard plowed) and conservation (chisel plowed) tillage treatments were infested for a 1‐week period with 0, 1 and 8 weevils per plant at two times: at 75% field emergence and 1 week later. After the early infestation, defoliation for the control, low and high weevil densities was about 0, 15 and 50%, respectively, while defoliation after the late infestation was about 0, 10 and 35%. An undercompensatory growth response was observed in one experiment after seedlings were subjected to moderate levels of early defoliation. Exact compensation was observed in two experiments after early infestations of low and high Sitona densities. Sitona defoliation reduced the number of pods per plant and pod length in two experiments. However, seed biomass was never significantly reduced. Averaged over all experiments, reduction in seed biomass due to high Sitona densities was 10 and 5% for early and late infestations, respectively. Tillage treatments did not affect Pisum compensatory growth response, although yield components were sometimes greater in conservation tillage than in conventional tillage, possibly due to slightly greater soil moisture in the conservation tillage plots.

Granulosa cells from follicles of different sizes from Booroola x Merino ewes which were homozygous (FF), heterozygous (F+) or non-carriers(++) of a fecundity gene were obtained 0-48 h after cloprostenol injection on Day 10 of the oestrous cycle. The highest mean amounts of cAMP produced by the cells did not differ between the genotypes. However, in the ++ ewes it was attained by cells from follicles greater than or equal to 5 mm in diameter, whereas in F+ and FF ewes it was attained by cells from follicles 3-4.5 mm in diameter. Cells from 1-2.5-mm diameter follicles of FF ewes were more sensitive to FSH and LH than were corresponding cells from F+ or ++ ewes. Granulosa cells from greater than or equal to 5 mm diameter follicles of ++ ewes 12-24 h after injection of cloprostenol had a lower mean response to FSH and LH than did cells obtained 0-6 or 36-48 h after cloprostenol. No such effect of time was evident for cells from any size of follicles obtained from F+ or FF ewes. In 1-2.5-mm diameter follicles, the mean aromatase activity of granulosa cells from ++ and F+ ewes was similar, but significantly lower than that of cells from FF ewes. In 3-4.5 mm diameter follicles, the mean aromatase activity of cells from F+ and FF ewes was similar, and significantly higher than that of cells from ++ ewes. For all 3 genotypes, there was a significant positive relationship between FSH or LH stimulation of granulosa cell cAMP production and cellular aromatase activity.

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In 24-h cultures, steroid production by cells from non-atretic follicles increased with increasing follicular diameter. Cells from atretic follicles, of all sizes, produced low amounts of oestradiol-17 beta, but very high amounts of progesterone, relative to cells from non-atretic follicles. Increasing the culture period to 72 h caused little change in daily progesterone and oestradiol-17 beta production by granulosa cells from atretic follicles. In contrast, in cells from non-atretic follicles, daily progesterone production increased and daily oestradiol-17 beta production decreased to the levels observed with cells from atretic follicles. Dibutyryl cyclic AMP (1.0 mM) significantly stimulated progesterone production by cells from atretic, but not from non-atretic, follicles. Testosterone (1 microgram/ml) had no effect on progesterone production by cells from atretic follicles, while oestradiol-17 beta, oestrone, testosterone, androstenedione and 5 alpha-dihydro-testosterone (0-1000 ng/ml) each significantly suppressed progesterone production by cells from non-atretic follicles in a dose-dependent manner. Morphometric analysis revealed few subcellular differences between cells from non-atretic and atretic follicles. Mean cell volume was significantly higher for cells from atretic compared to non-atretic follicles, but the mean volumes of the major subcellular components were not influenced by follicle health. The mean surface area of the plasma and nuclear membrane, and granular endoplasmic reticulum was also significantly higher in cells from atretic compared to non-atretic follicles.

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The presence and possible assimilation of Rhizobium leguminosarum in the gut of the pea leaf weevil (***Sitona lineatus (L.)) larvae was investigated with a fluorescent antibody technique and electron microscopy. The fluorescent antibody technique proved that many R. leguminosarum bacteroids were present in the gut of 14‐day old larvae which had been feeding within pea (Pisum sativum L.) root nodules. Examination of larval midgut thin sections with transmission electron microscopy also revealed many R. leguminosarum bacteroids as a constituent of the gut contents. Intact bacteroids were more prevalent in the anterior and middle portions of the midgut while bacteroids with disrupted cell walls were observed more often in the posterior portions of the midgut. Of the hindgut sections examined, none showed the presence of intact bacteroids. These results provide strong evidence that R. leguminosarum bacteroids are digested, absorbed and possibly assimilated by pea leaf weevil larvae. RÉSUMÉ PRESENCE ET ASSIMILATION POSSIBLE DE RHIZOBIUM LEGUMINOSA RUM DANS LE TUBE DIGESTIF DES LARVES DE SITONA LINEATUS Des anticorps fluorescents et la microscopie électronique ont été utilisés pour déceler la présence et une possible assimilation de Rhizobium ***leguminosarum dans le tube digestif des larves de Sitona lineatus L. La technique des anticorps fluorescents prouve que de nombreux bactéroïdes de R. leguminosarum sont dans le t.d. de larves agées de 14 jours qui se sont alimentées sur des nodules racinaires de Pisum sativum L. L'examen de coupes fines de l'intestin moyen en microscopie électronique a révelé de nombreux bactéroïdes R. leguminosarum comme constituants du contenu du t.d. Des bactéroïdes intacts sont plus fréquents dans les portions antérieures et moyennes du t.d. moyen, tandis que des bactéroïdes avec des parois cellulaires brisées sont observés plus souvent dans les parties postérieures du t.d. moyen. Aucune section du t.d. postérieur examinée ne contenait de bactéroïde intact. Ces résultats fournissent des arguments solides sur la digestion, l'absorplion, et peul être l'assimilation, des bactéroïdes R. leguminosarum par les larves de S. lineatus L.