Feeding behavior of bollworm and tobacco budworm (Lepidoptera: Noctuidae) larvae in mixed stands of nontransgenic and transgenic cotton expressing an insecticidal protein.

Feeding behavior of third-instar bollworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.), was observed in pure and mixed stands of nontransgenic and transgenic cotton (BTK), Gossypium hirsutum L., expressing an insecticidal protein CryIA(c) from a bacterium, Bacillus thuringiensis Berliner subsp. kurstaki. Five plant stands composed of BTK and non-BTK plants were evaluated; two pure stands and three mixed stands. Percentage ratios of BTK to non-BTK plants in the stands were 100:0, 75:25, 50:50, 25:75 and 0:100, respectively. In all stands with BTK plants, fewer bollworm and tobacco budworm larvae were found on BTK plants than non-BTK plants 24 h after infestation with third instars. At 48 h, significantly fewer tobacco budworm larvae, but not fewer bollworm larvae, were found on BTK plants. However, the number of larvae of either insect did not increase on non-BTK plants compared with the initial infestation density of three larvae per plant. The number of obacco budworm injured flower buds, and capsules was lower in all plant stands containing BTK plants compared with the pure stand of non-BTK at 48 h after infestation. Higher numbers of larvae on non-BTK plants were possibly the result of larval intoxication, reduced feeding, and increased plant abandonment and death on BTK plants rather than a classical feeding preference. Unexpectedly, the number of flower buds and capsules injured by bollworm and tobacco budworm when averaged per plant for all plants in a stand, differed little among the 75:25, 50:50 and 25:75 plant mixtures. These data suggest that larvae of both species frequently moved among plants, feeding indiscriminately on BTK and non-BTK plants.

Postpneumonectomy lung growth following thyroparathyroidectomy.

Hormonal regulation of compensatory lung growth is not well understood, but it may be similar to that during compensatory growth of other organs. Liver regeneration is blocked by hypocalcemia in thyroparathyroidectomized (TPX) animals. Although calcium status is an important regulator of growth in many biological systems, the effect of TPX on compensatory lung growth is unknown. In male Sprague-Dawley rats, TPX lowered blood ionized calcium by 42% (p < .01) within two days; it remained depressed for at least one additional week. Thyroid-intact and TPX animals were therefore subjected either to sham thoracotomy or to left pneumonectomy on post-TPX day 2. Growth of the right lung was assessed on day 9 when, in pneumonectomized animals, lung mass had increased 23% (p < .01). TPX had no effect on right lung mass in sham animals. Similarly, TPX had no effect on the postpneumonectomy increase in right lung mass, which reached 118% (p < .01) of that in TPX controls. Analysis of right lung DNA, RNA, and protein concentrations on day 9 revealed that tissue macromolecule content increased postoperatively in both PNX and TPX/PNX rats in proportion to lung growth. These results demonstrate that postpneumonectomy compensatory growth of the lung is not blocked in the thyroparathyroprivic hypocalcemic rat.

Collection of pheromone from atmosphere surrounding boll weevils,Anthonomus grandis.

An effluvial method was developed to collect the pheromone, grandlure from actively calling male boll weevils,Anthonomus grandis Boheman. The adsorbant, Porapak Q (ethylvinylbenzene-divinylbenzene), was utilized to trap and concentrate the pheromone. Captured pheromone was desorbed from columns packed with Porapak Q by elution withn-pentane and quantified by capillary column gas-liquid chromatography. In recovery studies with known amounts of synthetic grandlure, we found that the amount of each pheromone component collected was a function of collection duration, elution volume, and initial concentration. This effluvial method was capable of recovering as much as 94.9% of a known quantity (80 µg) of grandlure. The chromatograms were free of extraneous peaks. In studies of insect-produced pheromone, the effluvial method was used to collect pheromone from the air space surrounding male boll weevils as they fed on flower buds from CAMD-E cotton. The quantity and quality of boll-weevil-produced pheromone was determined for days 6, 8, 10, 11, 12, 13, and 14 of boll weevil adulthood. The maximum quantity of natural pheromone was produced on day 13 (4.2 µg/weevil) with a pheromone component ratio of 2.41∶2.29∶0.95∶1 for components I, II, III, and IV, respectively. The effluvial method described in this report is an efficient method to collect and quantify boll weevil pheromone from the atmosphere surrounding actively calling insects. Other applications of this method are suggested.

Fertility and teratogenic studies of diethylene glycol monobutyl ether in rats and rabbits.

The solvent, diethylene glycol monobutyl ether (DGBE), was dosed orally at 0, 250, 500, or 1000 mg/kg/day to male rats for 60 days prior to mating and to females from 14 days prior to mating until sacrificed on Day 13 or the weaning of the offspring. Untreated males were bred to treated females and vice versa. One-half of each group of females was sacrificed on Day 13 of gestation and the uterine contents were examined. The remaining females delivered their young and the offspring were followed to weaning. The solvent had no adverse effect on fertility in either sex and no adverse effects on embryos, fetuses, or neonates, except that the mean pup weights were reduced slightly during the later stages of lactation among the offspring of the females dosed with 100 mg/kg/day. Pregnant rabbits treated topically with the solvent applied to the dorsal skin at 0, 100, 300, or 1000 mg/kg on Days 7-18 of gestation exhibited a dose-dependent mild skin irritation but no other signs of toxicity. No adverse effects were seen on intrauterine survival or on the incidence of fetal malformations.