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).     

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

The moth Utetheisa 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, that Utetheisa 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 nature Utetheisa 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.     

Cycles of juvenile hormone esterase activity during the juvenile hormone-driven cycles of oxygen consumption in pupal diapause of flesh flies

During diapause O2 consumption in fly pupae is a cyclic event (4-day periodicity at 25 degrees C) driven by cycles of juvenile hormone activity. Levels of juvenile hormone esterase activity change systematically during the cycle, with highest activity observed at the nadir of the O2 consumption cycle.     

Cycles of juvenile hormone esterase activity during the juvenile hormone-driven cycles of oxygen consumption in pupal diapause of flesh flies

Summary During diapause O₂ consumption in fly pupae is a cyclic event (4-day periodicity at 25°C) driven by cycles of juvenile hormone activity. Levels of juvenile hormone esterase activity change systematically during the cycle, with highest activity observed at the nadir of the O₂ consumption cycle.Supported in part by grant 88-37153-3473 from the USDA Competitive Grants Office and grant 23-088 from the USDA Forest Service. Thanks to Dr Ming Tu Chang for her helpful advice.     

The effect of diet on the hemolymph amino acid constituents of the larvae and pupae ofSarcophaga ruficornis (Fabricius): (Diptera)

Zusammenfassung Es werden zwei Zuchtgruppen vonSarcophaga ruficornis-Larven hinsichtlich ihres Aminosäuregchaltes des Blutes untersucht. Den auf Fleisch gezüchteten Tieren fehlt Lysin, Glutamin und Taurin, während diese Aminosäuren bei den auf Hundebisquit aufgezogen Larven vorhanden sind, ihnen dagegen Threonin fehlt. Der Aminosäuregehalt im Blut der Puppen beider Zuchtgruppen ist gleich.     

Morphological basis of follicle cells - oocyte interaction in normal pupae and isolated pupal abdomina ofGalleria mellonella L.

Résumé Le plasmalemme des oocytes se caractérise par une grande activité pinocytosique au cours de la vitellogenèse. Celle-ci semble être contrôlée par des facteurs hormonaux, car l'ablation des glandes endocrines bloque complètement cette activité.

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This work was supported in part by Grant No. FG-Po-221 from the U.S. Agricultural Department.     

Oxygen permeability of the chorion in relation to diapause termination in Bombyx eggs

Oxygen permeability of the chorion of the silkworm, Bombyx mori, was measured in relation to embryonic diapause. It did not change appreciably when the eggs were freed from diapause by being kept under long chilling. This finding suggests that the increase in oxygen permeability of the chorion is not a pre-requisite for the termination of the diapause and resynthesis of glycogen from 2 polyols.     

Two mechanisms in the biological clock ofPieris brassicae L.: an oscillator for diapause induction; an hour-glass for diapause termination

Summary Resonance experiments for photoperiodic termination of pupal diapause demonstrated thatPieris brassicae uses a night-measuring hour-glass mechanism. In previous work the same resonance technique for diapause induction revealed that photoperiodic time-measurement is a function of the circadian system. For the first time in a living organism it has been shown that the biological clock operates by means of an oscillator for photoperiodic onset of a phenomenon and according to an hour-glass system for photoperiodic termination.     

Photoperiod manipulation to control diapause in the pink bollworm,Pectinophora gossypiella

Zusammenfassung Im 12-h Kurztag gehaltenePectinophora gossypiella gehen zu 78% in Diapause. Zusätzlich applizierte, einstÜndige Perioden mit 15 Lichtpulsen von je 1 min Dauer reduzieren die Diapauserate. Die besten Resultate ergeben 2 Pulsperioden, je 1,5 h vor und nach der Hellphase appliziert.     

Production of antibodies to amanitins as the basis for their radioimmunoassay

Summary The production of antibodies against amanitins is described. By means of these antibodies, a radioimmunoassay was developed which allows detection of as little as 0.5 ng of amanitins in 1 ml of serum. By this method, the clearance of α-amanitin from the blood of poisoned mice was measured. Acknowledgments. We thank ProfessorT. Wieland and Dr.H. Faulstich (Heidelberg) for their generous gift of β-amanitin and [³H]O-methyl-demethyl-γ-amanitin. This work was supported by grants from C.N.R., Rome.     

Ontogenetic fate of the neurosecretory cells in the larval brain ofSarcophaga ruficornis (fabricius, 1794) (diptera: Cyclorrhapha)

Résumé Il y a quatre groupes, 1, 2, 3 et 4, de cellules neurosécrétrices dans chaque demi-sphère du cerveau larvaire duSarcophaga ruficornis. Pendant la métamorphose, les groupes 1 et 2 deviennent antérieurs dorsaux et forment des cellules neurosécrétrices médiales de la mouche adulte; le groupe 3 devient ventral mais s'évanouit après l'éclosion de la mouche; le groupe 4 s'évanouit aussi, mais plus tôt.     

Production of antibodies to amanitins as the basis for their radioimmunoassay.

The production of antibodies against amanitins is described. By means of these antibodies, a radioimmunoassay was developed which allows detection of as little as 0.5 ng of amanitins in 1 ml of serum. By this method, the clearance of alpha-amanitin from the blood of poisoned mice was measured.     

Hormonal control of the reproductive diapause in the grasshopper,Oedipoda miniata

Résumé La greffe de 2 paires de corpora allata provenant de criquets migrateurs mâles adultes (Locusta migratoria migratorioides), provoque la rupture de la diapause reproductive chezOedipoda miniata adulte, la ponte chez les femelles et chez les mâles, un comportement sexuel très actif. Chez les témoins non opérés ou ayant subi une opération factice, la diapause reproductive persiste.