Chemical basis of pupal cannibalism in a caterpillar (Utetheisa ornatrix)

The mothUtetheisa ornatrix derives protection against predation from systemic pyrrolizidine alkaloids (PAs) that it sequesters as a larva from its foodplants (Leguminosae,Crotalaria spp.). We here show, in laboratory tests, thatUtetheisa deficient in body PA can make up for the chemical shortfall by cannibalizing pupae. We present evidence indicating that cannibalism in larvae is elicited not by hunger, but possibly by PA deficiency itself, and that in making cannibalistic choices larvae prefer PA-containing over PA-free pupae. PAs themselves, either in crystalline form or as additives to food items, proved phagostimulatory to larvae. In natureUtetheisa tend to pupate away from their foodplant, essentially out of reach of larval attack. The threat of cannibalism may have contributed to the evolution of this pupation behavior.Paper No. 102 of the series Defense Mechanisms of Arthropods; No. 101 is Eisner et al., Chemoecology (in press).     

Oenocyte and prothoracic gland activity inManduca sexta under varying photoperiod and light conditions

Summary Manduca sexta larvae were subjected to diapause-inducing and diapause-preventing photoperiods, using two types of fluorescents (Indorsun and Blacklight-blue). The oenocytes, prothoracic glands (PTG) and ecdysone levels were examined in 3-day-old 5th instar larvae, 2-day-old and 10-day-old pupae. Our results indicate that oenocytes and PTG cells tend to be more active under long photoperiods while oenocytes only are active under short photoperiods in pupae in diapause. UV light has a definite effect on oenocytes while PTG cells seem to be unaffected. Ecdysone and ecdysterone levels vary with PTG and oenocyte activity at the pupal stage. The significance of these findings is discussed.This work was supported by a research associateship to L.M. by the People's Republic of China and a grant from NSERC to B.J.R.P.     

MAPK pathway activation in pilocytic astrocytoma

Pilocytic astrocytoma (PA) is the most common tumor of the pediatric central nervous system (CNS). A body of research over recent years has demonstrated a key role for mitogen-activated protein kinase (MAPK) pathway signaling in the development and behavior of PAs. Several mechanisms lead to activation of this pathway in PA, mostly in a mutually exclusive manner, with constitutive BRAF kinase activation subsequent to gene fusion being the most frequent. The high specificity of this fusion to PA when compared with other CNS tumors has diagnostic utility. In addition, the frequency of alteration of this key pathway provides an opportunity for molecularly targeted therapy in this tumor. Here, we review the current knowledge on mechanisms of MAPK activation in PA and some of the downstream consequences of this activation, which are now starting to be elucidated both in vitro and in vivo, as well as clinical considerations and possible future directions.     

Enzymatic characterization of nine endoparasite species of small ermine moths (Yponomeutidae)

Summary Eight hymenopterous and 1 dipterous species, all endoparasitic in eggs, larvae, or pupae of small ermine moths (Yponomeuta) were investigated for their allozyme variation at 3–29 loci. The mean heterozygosity level of the hymenopterous species is one-third of that of the dipterous species. Zymogram patterns of the parasite larvae do not interfere with those of the host.     

Establishment of a colony of the mosquitoCuliseta longiareolata under laboratory conditions

Summary A colony ofCuliseta longiareolata was set up in the laboratory starting with more than 700 larvae and pupae collected from an old well. Procedures for successful establishment of a colony and laboratory maintenance of this mosquito are described.     

Acid phosphatases inDrosophila auraria

A study was carried out dealing with the acid phosphatases in larvae, pupae and adults ofDrosophila auraria. The most interesting finding is that the acid phosphatases are observed in 3 different phenotypes appearing as groups of 3 bands of different mobilities in the homozygotes and giving a 5 band phenotype in the heterozygote. A hypothesis is discussed in an attempt to explain the phenotypes observed and their variation during the development of the species.     

Protein content of various developmental stages of three strains of the pink bollworm,Pectinophora gossypiella

Summary Comparison of the total body protein of male and female larvae, pupae, and adults of a diapause and 2 nondiapause strains of the pink bollwormPectinophora gossypiella indicated that the protein content of larvae of the diapause strains was significantly higher than of the non-diapause strain.I thank Drs D.R. Nelson and R.A. Bell of the U.S.D.A. Metabolism and Radiation Research Laboratory, Fargo, for facilities and guidance.     

Influence of oxygen concentration on development ofDrosophila melanogaster

Summary 1st, 2nd, and early 3rd instarDrosophila larvae are extremely sensitive to 100% O₂ or 75% O₂/25% N₂ (at atmospheric pressure) whereas eggs, late 3rd instar larvae, and pupae are relatively insensitive under our exposure conditions. Eclosing flies exposed to an O₂ enriched environment consistently possessed 2 eye abnormalities: dark eye color and altered eye shape.Supported by NSF-URP grant SP1782684 and a Summer Faculty Fellowship to Harry Nickla.     

Mixed life cycles in the transitional zone between voltinisms in the fall webworm,Hyphantria cunea

The fall webworm,Hyphantria cunea Drury, was introduced from North America into Japan at half a century ago. At present, the populations north of 36° N are bivoltine and those south of 36° N are trivoltine. In the present study, the life cycle in the transitional zone between voltinisms was clarified in Tsukuba (36.1° N). When fourth instar larvae of the second generation were collected in the field and maintained in the laboratory, the incidence of pupal diapause increased when the sampling date was delayed from 16 August to 5 September. The fact that some developed without diapause inidcates the occurrence of a trivoltine life cycle in this locality, where a bivoltine life cycle is predominant. The critical photoperiod for diapause induction at 20 and 25°C was 14 h 13 min and 14 h 10 min, respectively. The photoperiodic response may explain the rapid increase in diapause incidence in late summer. In laboratory-reared diapause pupae, the time and period of chilling (5°C) greatly influenced the time required for adult emergence at the final incubation temperature of 25°C. However, diapause pupae chilled for a sufficiently long period developed to adulthood rapidly, irrespective of the conditions before chilling. Therefore, the difference in timing of entering diapause between pupae of the second and third generations would not result in their temporal reproductive isolation in the following spring. It is concluded that the mixed voltinism in Tsukuba is not a result of a mixture of genetically distinct bivoltine and trivoltine populations, but a result of the phenotypic plasticity in a genetically rather homogeneous population.     

Developmental patterns of supercooling capacity in a subantarctic wingless fly

Anatalanta aptera is a wingless fly which lives in subantarctic islands, particularly in sea bird colonies. Developmental patterns of supercooling capacity were studied in an experimental population reared at 5°C and fed ad libitum. Mean supercooling points of the eggs, second and third instar larvae, pupae, teneral and mature adults were –28.0°C, –10.8°C, –8.8°C, 17.6°C, –16.6°C and –8.2°C respectively. Low mean supercooling points were found for inactive stages (eggs, pupae) and, unexpectedly among Diptera, teneral adults. Mature adults had a combination of low supercooling ability, high lipid content and physogastry. The results are compared with those obtained in winged species from other families of Diptera.     

Variations des taux d'ecdystéroïdes au cours du développement deBombyx mori; rapport entre ces variations et les phases de croissance et de morphogenèse

Summary During the development ofBombyx mori (monovoltin race) ecdysteroid levels were determined in oocytes, eggs, and haemolymph of larvae, and in the haemolymph of pupae. In haemolymph, the only RIA reactive materials are ecdysone and ecdysterone. In oocytes and eggs, other ecdysteroids are also detected. During larval instars, the ecdysteroid levels are low whereas they are very high during morphogenetic periods. During embryonic diapause, the ecdysone titer decreases during the cessation of morphogenesis.     

Dihydropyrrolizine secretions associated with coremata ofUtetheisa moths (family Arctiidae)

Zusammenfassung Die Duftorgane der männlichen BärenspinnerUtetheisa pulchelloides undU. lotrix (Fam. Arctiidae) scheiden Dihydropyrrolizine aus, die im Typ den Pheromonen von Schmetterlingen der Subfamilie Danainae (Fam. Papilionidae) gleichen. Wahrscheinlich handelt es sich um Derivate von Pyrrolizidin-Alkaloiden, die in den Wirtsplanzen der Raupen in hoher Konzentration vorkommen.     

Influence de l'humidité sur les cocons du Ver à soie(Bombyx mori)

Summary Experiments were carried out to test the effects of relative humidity on prepupae and pupae of the Silkworm,Bombyx mori L., at 25⁰ C. It was found that:(1) duration of prepupal + pupal stages is the same at all relative humidities between 7 and 100%;(2) mortality seems unaffected in all these humidity conditions;(3) moths obtained in percentages between 55 and 100% R. H. have the same average wet weight; moths obtained under dryer conditions have a lower average weight (expressed in percentage of initial weights of prepupae);(4) pupae extracted from their cocoons develop as quickly and as well as pupae in their cocoons.     

Laich-Räubern und -Kannibalismus bei sympatrischen Anuren-Kaulquappen

Summary Spawn eating (predation and cannibalism) by tadpoles of sympatric Anurans. Tadpoles of 5 Anuran species were tested with spawn of 4 sympatric species or 3 sympatric and their own species respectively. All spawn offered was eaten. Spawn cannibalism as well as spawn predation amongst species which occur in ecological sympatry (e.g.Bufo calamita, Hyla arborea andBombina variegata may act as a density regulation mechanism.

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Mit Unterstützung des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung.     

Physical activity and the endocannabinoid system: an overview

Recognized as a “disease modifier”, physical activity (PA) is increasingly viewed as a more holistic, cost-saving method for prevention, treatment and management of human disease conditions. The traditional view that PA engages the monoaminergic and endorphinergic systems has been challenged by the discovery of the endocannabinoid system (ECS), composed of endogenous lipids, their target receptors, and metabolic enzymes. Indeed, direct and indirect evidence suggests that the ECS might mediate some of the PA-triggered effects throughout the body. Moreover, it is now emerging that PA itself is able to modulate ECS in different ways. Against this background, in the present review we shall discuss evidence of the cross-talk between PA and the ECS, ranging from brain to peripheral districts and highlighting how ECS must be tightly regulated during PA, in order to maintain its beneficial effects on cognition, mood, and nociception, while avoiding impaired energy metabolism, oxidative stress, and inflammatory processes.     

Triglyceride metabolism inEphestia cautella pupae exposed to carbon dioxide

Summary The triglyceride content ofEphestia cautella pupae exposed to increased carbon dioxide atmospheres at low relative humidity was not markedly affected. There was a significant increase in weight loss of pupae exposed to low relative humidity. Results indicate that forE. cautella, metabolic water formation by fat utilization can hardly regulate water exigencies for the pupae and cannot fully compensate for water losses in high carbon dioxide atmospheres.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No. 123-E 1979 series.     

Cholinergic, monoaminergic and glutamatergic changes following perinatal asphyxia in the rat

Perinatal asphyxia (PA) is considered to lead to a variety of brain disorders including spasticity, epilepsy, mental retardation, and minimal brain disorder syndromes and may form the basis for psychiatric and neurodegenerative diseases later in life. We examined markers for neuronal transmission involved in the pathomechanisms of PA and candidates as mediators for long-term sequelae. We tested tyrosine hydroxylase (TH) and the vesicular monoamine transporter (VMAT) representing the monoaminergic system, the vesicular acetylcholine transporter (VAChT), and the excitatory amino acid carrier 1 (EAAC1), a neuronal subtype of the glutamate transporter, using immunohistochemistry on brain sections of rats subjected to graded PA. Three months following the asphyxiant insult immunoreactive (IR)-TH was decreased in striatum, hippocampus, thalamus, frontal cortex, and cerebellum; IR-VMAT was increased, and IR-VAChT was decreased in striatum. IR-EAAC1 glutamate transporter was increased in frontal cortex. The cholinergic, monoaminergic, and glutamatergic changes, still observed 3 months after the asphyxiant insult, may reflect their involvement in the pathomechanisms of PA and indicate mechanisms leading to long-term complications of PA. The variable consequences on the individual markers in several brain regions may be explained by specific susceptibility of cholinergic, monoaminergic, and glutamatergic neurons to the asphyxiant insult. Received 16 March 1999; received after revision 20 May 1999; accepted 8 July 1999     

Long-term sequelae of perinatal asphyxia in the aging rat

Information on the consequences of perinatal asphyxia (PA) on brain morphology and function in the aging rat is missing although several groups have hypothesized that PA may be responsible for neurological and psychiatric deficits in the adult. We therefore decided to study the effects of PA on the central nervous system (CNS) in terms of morphology, immunohistochemistry, neurology and behavior in the aging animal. Hippocampus and cerebellum were evaluated morphologically by histological, immunohistochemical and magnetic resonance imaging and cerebellum also by stereological tests. Neurological function was tested by an observational test battery and rota rod test. Cognitive functions were examined by multiple-T-maze and the Morris water maze (MWM). Increased serotonin transporter (SERT) immunoreactivity in the CA2 region of the hippocampus and a significant difference in the escape latency, when the platform of the MWM was moved to a new location, were observed in asphyxiated rats. We showed that deteriorated cognitive functions accompanied by aberrant expression of hippocampal SERT and impaired relearning are long-term sequelae of perinatal asphyxia, a finding that may form the basis for understanding CNS pathology in the aging subject, animal or human.     

Juvenilizing effect of ecdysone mimic RH 5849 inGalleria mellonella larvae

The response of the final instar larvae ofG. mellonella to topical application of the non-steroidal ecdysone mimic, RH 5849, was age-related as well as dose-dependent. In young final instar larvae, moderate doses of RH 5849 induced perfect supernumerary larval moults, but doses equal to and higher than 8.5 μg per larva caused premature formation of larval cuticle and were lethal. Application of RH 5849 significantly increased allatotropic activity of the brain, and also activated synthesis of juvenile hormone (JH) by the corpora cardiaca/corpora allata complex. Simultaneous application of RH 5849 and FMev, a potent inhibitor of JH synthesis, to young final instar larvae lowered the incidence of perfect supernumerary larval moults. We conclude that the effect of RH 5849 on the developmental programme inG. mellonella is mediated by the corpora allata.     

Über eine seltene,durch Sauerstoffmangel bedingte Entwicklungsstörung der Honigbiene (Apis mellifica L.)

Summary Abnormal pupae of the honeybee are described. The heads and the fore legs of these pupae show a distinct arrest of development and are therefore non-pigmented, whereas the rest of the body is normally developed and pigmented. The disturbance is due to an obstruction of the prothoracic tracheae, which prevents the head and prothorax region from being provided with oxygen.