Potential for use of nicotinic acid as a selective agent for isolation of high nicotine-producing lines of Nicotiana rustica hairy root cultures

The addition of exogenous nicotinic acid, nicotinamide or nicotine was studied with reference to their effects on growth and alkaloid production by hairy root cultures of Nicotiana rustica. Nicotinic acid and nicotinamide were toxic (50% phytostatic dose being 2.4 and 9 mM respectively) while nicotine was not toxic below 10 mM. Nicotinic acid (up to 5 mM) was found to be phytostatic rather than phytotoxic. Roots exposed to increasing nicotinic acid or nicotinamide levels had altered alkaloid accumulation patterns relative to the controls. The principal effects were to increase the intracellular and extracellular levels of anatabine and nicotine, with a markedly greater proportion of anatabine being produced. The use of nicotinic acid as a selection agent for the recovery of higher alkaloid-producing lines is identified and discussed.     

Studies on ecology and behavior of Japanese black swallowtail butterflies. 6. Nectar feeding ofPapilio helenus nicconicolens Butler andP. protenor demetrius Cramer as main pollinators of glory bower,Clerodendron trichotomum,Thunb

The butterfliesPapilio helenus andP. protenor were shown to feed mainly on the nectar of the glory bower,Clerodendron trichotomum, which was the most abundant nectar plant in summer in the study area. Both the species were found to have a proboscis longer than 24 mm corresponding to the length of the corolla tube ofC. trichotomum. Visits to the flowers by these butterflies were observed more frequently than visits by sphingid moths which had previously been believed to be the major pollinators ofC. trichotomum. The male butterflies visited trees ofC. trichotomum frequently, while visits by the females were less frequent. However, once females had visited the tree ofC. trichotomum, they remained there longer than the males. Since the flower ofC. trichotomum has long protruding sexual organs, its pollen grains were found to adhere efficiently to the bodies of butterflies, mainly the thorax, during nectar feeding. Most of the butterflies became loaded withC. trichotomum pollen, and the mean number of pollen grains per butterfly was 1,776 forP. helenus and 2,817 forP. protenor. The flowers opened at any time of day but more frequently in the morning. The nectar was secreted throughout the day. In the maturation of the protandrous flower ofC. trichotomum, the duration of the pistillate phase was about twice as long as the staminate phase. The long flowering period and the short duration of the staminate phase resulted in asynchrony of the flowering stages even within a single cyme on a tree. Such asynchrony and the abundance of attractive flowers on a tree facilitates efficient pollination by the butterflies.     

Metabolic effects of glucose, medium chain triglyceride and long chain triglyceride feeding before prolonged exercise in rats

The purpose of this study was to test the hypothesis that oral ingestion of lipids could increase endurance by slowing the rate of glycogen depletion. Trained rats were killed after a 2 h run on a rodent treadmill, following an intragastric infusion of water, glucose, medium chain triglycerides (MCT) or long chain triglycerides (LCT). Glucose and triglycerides were administered in equicaloric concentrations (50 kJ). The results show that oral ingestion of lipids (MCT or LCT) did not reduce glycogen depletion in liver, heart or skeletal muscle after exercise whereas the fat diet increased muscle and heart glycogen stores in resting conditions. In contrast, glucose feeding induced a significant sparing effect on endogenous carbohydrate utilization and reduced physical exercise lipolysis. These data indicated, firstly, that enhanced lipid availability induced by a single lipid meal before exercise was not able to modify the glycogen depletion occurring after exercise and, secondly, that the glucose/fatty acid cycle was not effective in these conditions. The comparison between lipids indicated that the effect on glycogen use of MCT did not differ from that of LCT, and did not seem to be of any particular importance during physical exercise.     

Predation by wasps on lepidopteran larvae in an Ozark forest canopy

ABSTRACT.

• 1 Predation by birds, crawling arthropods (ants, harvestmen, spiders), and social wasps (Vespula) spp. on introduced stocks of Heliothis virescens (Fabricius) larvae was investigated in a oak-hickory forest canopy in northwestern Arkansas (U.S.A.).
• 2 Wasps, Vespula maculifrons (Buysson) and V.squamosa (Drury), removed over 90% of the larvae. Repeated visits to a feeding site by the same marked wasps accounted for removal of either a single larva or all larvae. Larvae pinned (punctured) to artificial leaves were selected over 70% of the time by wasps when compared to attachments that did not puncture larvae; however, unpunctured larvae were taken.
• 3 Crawling arthropods accounted for low levels of predation, and birds did not appear to prey on larvae. Apparently wasps removed larvae rapidly and efficiently, thereby depleting the feeding sites before other predators discovered the larvae.
• 4 Although attaching larvae to artifical hickory leaves provided an easy method for placing larvae into the forest canopy, a lower percentage of larvae were removed from these leaves compared to natural hickory leaves. Moving feeding sites did not influence the number of larvae taken.

     

Plant water deficits and insect responses: the preference of Corythucha arcuata (Heteroptera: Tingidae) for the foliage of white oak, Quercus alba

ABSTRACT.

• 1 The preference of Corythucha arcuata (Say) (Heteroptera: Tingidae) for the foliage of Quercus alba L. (Fagaceae) grown under water deficit was examined. Potted Q.alba saplings were grown under controlled levels of water deficit in a glasshouse. Adult C.arcuata were exposed to excised Q.alba foliage under controlled conditions in a growth chamber, and feeding preference assessed by recording the percentage of individuals feeding on leaves from each level of water deficit.
• 2 Two experiments were performed. In the first, all foliage was supplemented with water (via the petiole) to alleviate physical changes in the leaves that accompany plant water deficits. In the second experiment, leaves were not supplemented with water.
• 3 C.arcuata had no preference when presented water supplemented leaves, but preferred leaves that were fully hydrated when presented leaves that were not supplemented with water.
• 4 These results suggest that plant water deficits are important in determining the feeding preference of C.arcuata because they lead to avoidance of drought grown foliage. This avoidance may be caused by an increase in the metabolic cost to the herbivore of maintaining water balance when ingesting drought grown foliage or to an increase in foliage toughness.

     

Archives of insect biochemistry and physiology guide for authors

Several carbohydrases and glycosidases from the alimentary cancal and/or salivary glands of feeding larvae of mayetiola destructor have been identified. Pectinase activity was identified in the midgut and may be present in the salivary glands. No endocellulase activity was found in larvae; however, hemicellulase activity was detected in extract of larvae. Amylase activity was present in midguts from feeding larvae and at a low level in extract of salivary glands. Amylases detected in the midgut showed mobilities during polyacrylamide gel electrophoresis similar to the two major amylases in tissues of the insect's host plant. The possibility exists that Hessian fly larvae utilize amylases obtained from their host plant in the digestion of starch. The major glycosidases detected in the midgut lumen of larve were: α-D-glucosidase and α-D-and β-D-galactosidase. The role of these enzymes in the feeding process of Hessian fly larvae is discussed as well as their potential role in feeding damage to wheat.     

The diet of the olive colobus monkey,Procolobus verus,in Sierra Leone

Observations of the feeding behavior of wild olive colobus monkeys (Procolobus verus)were made in southern Sierra Leone, West Africa. Most data came from systematically sampling one habituated social group, which inhabited old secondary rain forest on Tiwai Island. Olive colobus at Tiwai were highly selective feeders, obtaining most of their food from a small number of uncommon middle-canopy trees, from the forest understory, and from climbers. Mature leaf blades were largely ignored; young foliage (particularly of climbers) was a year-round dietary staple, while seeds, flowers, and mature leaf petioles were seasonally important. It is argued that this diet results largely from selection for two different attributes of food: high digestibility and physical location. Preferred foods had low fiber and tannin contents, while preferred feeding sites were in thick low growth and climber tangles. P. verusis the smallest extant primate species using a foregut fermentation system. Observations of its diet accord with inferences drawn from dental anatomy, digestive physiology, and considerations of body size.     

Comparative carbon-specific ingestion rates of phytoplankton by Acartia tonsa,Centropages velificatus and Eucalanus pileatus grazing on natural phytoplankton assemblages in the plume of the Mississippi River (northern Gulf of Mexico continental shelf)

During four cruises in continental shelf waters of the northern Gulf of Mexico in the winters of 1981–83, we performed quantitative studies on the grazing of the copepods Acartia tonsa, Centropages velificatus, and Eucalanus pileatus, on phytoplankton using natural particulate assemblages as food. Stations were in, or adjacent to the plume of the Mississippi River, thereby providing wide spectra of phytoplankton and suspended riverine particulate concentrations. Phytoplankton cell volume was converted to carbon, and this, coupled with carbon content measurements of these three copepod species, allowed comparisons of daily ingestion effort even though the copepods were of different sizes. Data were expressed in the same units (% of copepod body carbon ingested copepod ^–1 d^–1) for each species. Over similar ranges of phytoplankton carbon concentrations (0.21–92.06 gCl^–1), Acartia tonsa had higher carbon-specific ingestion rates (x = 22.31%, range = 0.08–152.37%) than C. velificatus (x = 2.8%, range = 0.00–31.09 %) or E. pileatus (x = 1.27%, range = 0.10–2.80%). Carbon-specific ingestion rates increased with increasing phytoplankton carbon concentration for A. tonsa (R² = 0.81) and there was no evidence of saturated feeding on the carbon concentrations offered. A similar, but weaker trend was evident for E. pileatus (R² = 0.71), but not C. velificatus (R² = 0.49). Over a wide range of suspended particulate concentrations (10.6–95.2 mg l^–1), there was no systematic effect of particulates on carbon-specific ingestion rate for any of the three copepod species. However, A. tonsa appeared more adept at grazing in highly turbid water than C. velificatus or E. pileatus.     

Food and feeding behavior of the hoplonemertean Oerstedia dorsalis

The monostiliferous nemertean Oerstedia dorsalis was collected from eelgrass (Zostera marina) beds located along the coast of New Jersey, and feeding responses to amphipods and isopods were observed in the laboratory. Tests with 46 worms showed that they fed suctorially on Ampelisca vadorum, Ampithoe longimana, Corophium acherusicum and C. tuberculata. Corophiids were preferred. Upon contact with an amphipod, the proboscis is everted and strikes the prey on the ventral side, immobilizing it in a few minutes. The worm probes the sternal region with its head and everts its proboscis one or more times during the process. The exoskeleton is eventually penetrated by the head, and the stomach is everted into the hemocoel as a flattened funnel-like structure. Peristaltic undulations of the body signify the suctorial action that removes the living contents from the exoskeleton. The actual feeding process (from head penetration to removal of the head) takes about 7 min. O. dorsalis is only the third species within the Prosorhochmidae for which the feeding behavior has been documented. The other two are terrestrial species, and are also suctorial.     

Performance of the tsetse, Glossina morsitans morsitans reared under various feeding regimens in Zambia

Groups of Glossina morsitans morsitans Westwood fed at emergence and thereafter daily, every second or third day respectively, up to the end of their first pregnancy cycle, survived well (73–79%) and produced virtually the same number of puparia/ (0.83–0.85) in the same puparial weight class (23–24 mg). However, adult survival (29%), number of puparia/ (0.30) and puparial weight (19 mg) were much lower in the group consistently fed every 4th day after the initial meal at emergence. It is proposed that tsetse colonies could be fed on Mondays, Wednesdays and Fridays without jeopardising adult survival, puparial production/ and the size (weight) of puparia produced.

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Performances en Zambie de la mouche Tsé-Tsé (Glossina morsitans morsitans) élevée en utilisant différents régimes alimentaires

Résumé Afin d'estimer si une alimentation quotidienne de G. morsitans morsitans présente un avantage sur une alimentation moins fréquente, nous avons enrigestré la survie des adultes, la production et le poids des pupes chez des individus nourris à l'émergence et, ensuite, tous les jours ou tous les 2, 3 ou 4 jours. Les femelles alimentées quotidiennement, ou tous les 2 ou 3 jours, ont produit le même nombre de pupes (0,83–0,85), avec des poids de même ordre (23–24 mg), et avec une aussi bonne survie (73 à 79%). Alimentées tous les 4 jours, elles ont produit 0,30 pupe/femelle, pesant 19 mg/pupe et avec une plus faible survie (29%). Ces résultats montrent qu'il est inutile de nourrir les mouches chaque jour au lieu de tous les 2 ou 3 jours. Cependant une alimentation à des intervalles supérieurs à 3 jours, a eu des conséquences clairement défavorables. Ainsi, peuvent être considérablement réduits et le travail et le coût des élevages, sans porter préjudice à la production, en alimentant les mouches 3 fois par semaine, par ex. les lundis, mercredis et vendredis.