Sexual behavior mutants revisited: molecular and cellular basis of Drosophila mating

The study of Drosophila melanogaster by a combination of forward genetics with specific mutants, and reverse genetics, in which a given gene is expressed in an appropriate brain area to test its effect on behavior, provides a unique opportunity to explore the causal relationship between a particular gene, its function in the cell and the behavioral outcome at the organismic level. Enhanced male-to-male courtship has been shown to occur as a result of mutations in several different genes. For example, the Voila mutant exhibits intense GAL4 reporter expression in the tarsal gustatory sensilla, suggesting the importance of tapping by a male on the female abdomen with his forelegs. Feminization of parts of the antennal lobe and mushroom body by targeted expression of a female-determining gene transformer ⁺ (tra ⁺) drives the male to court other males. Mutations in the tra target gene fruitless (fru), which is expressed in the antennal lobe as well as the suboesophageal ganglion (the gustatory inputs are processed here), also induce homosexual courtship in males. These results suggest that sensory inputs mediated and/or processed by the tarsal receptors, suboesophageal ganglion, antennal lobe and mushroom body contribute to the regulation of male–female courtship. Mosaic analysis localized the neural center for male courtship behavior to the posterior dorsal brain, in which the sensory information processed by the aforementioned neural structures may be integrated. Another mosaic study mapped the neural center for female sexual behavior, as measured by her receptiveness to copulation, to the anterior dorsal brain. The issue as to how the mutations that reduce female sexual receptiveness, e.g. dissatisfaction (dsf), spinster (spin) and chaste (cht), affect the structure and/or function of this neural center deserves to be addressed urgently. Received 27 April 1999; received after revision 21 June 1999; accepted 8 July 1999     

Accumulation of phenylpropanoids in the rectal glands of males of the Oriental fruit fly,Dacus dorsalis

Summary Two phenylpropanoid compounds, 2-allyl-4,5-dimethoxyphenol(II) and coniferyl alcohol(III), were characterized from body tissue of wild males of the Oriental fruit fly,Dacus dorsalis. These compounds accumulated in the rectal glands only when laboratory-reared males were fed with methyl eugenol. Compound II was released into the air during dusk, which coincides with the fly courtship period. Pheromonal and allomonal effects of the phenylpropanoids were examined.     

Variation in the improtance of acoustic stimuli inDrosophila melanogaster courtship

Summary These is genotype-dependent variation in the importance to females of the courtship song relative to other nale generated courtship stimuli.This work was supported by a grant from the Science Research Council of Great Britain.     

Age-related perseveration of the precopulatory behaviour in maleDrosophila melanogaster

Summary In response to an interruption of their courtship, males ofD. melanogaster exhibit a lasting sexual arousal (up to 30–60 min), expressed behaviourally by characteristic wing displays. A study of this effect centered on two memory mutants of different ages suggests that it can be related to an ageing-dependent perseveration, rather than to modifications in memory processing.Acknowledgments. This research was supported by an exchange grant of the Royal Society. We are grateful to Dr Linda Partridge for advice and loan of apparatus.     

Biological studies onPseudohypocera kerteszi (Phoridae,Diptera)

Summary 15 couples ofPseudohypocera kerteszi were introduced into individual tubes containing culture medium, maintained at 22–28°C and 45–55% relative humidity. The courtship and the behaviour of males and females before and after the copula are described for the first time; the number of eggs laid by each female during the oviposition period and the sexual rate in offspring were registered in each tube. The relative viability from egg to imago was determined in 8 of the 15 tubes.This study was made possible by a grant of the State of São Paulo Research Foundation (FAPESP).     

Evidence for an aphrodisiac pheromone of femaleDrosophila

Summary We report here direct evidence for the involvement of a pheromone in the induction of male wing vibration, an important fixed action of theDrosophila melanogaster courtship pattern. This chemical stimulus is produced by mature females but not by mature males. The behavioral response is proportional to the pheromone concentration.Acknowledgments. Thanks are due to Drs Y. Hotta, S. Benzer and C. Descoins for stimulating discussions at the beginning of this work. Most of it was performed in the Centre de Génétique Moléculaire du C.N.R.S. We want to acknowledge their financial support.     

Paternal allocation of sequestered plant pyrrolizidine alkaloid to eggs in the danaine butterfly,Danaus gilippus

Summary Pyrrolizidine alkaloid sequestered by adult maleDanaus gilippus from plants is transferred in large measure to the female at mating, and by the female to the eggs. The eggs, presumably, are protected as a result. The male's courtship pheromone, danaidone, derived from the sequestered alkaloid, may function to advertise the male's alkaloid-donating capacity.Acknowledgments. Paper Nr. 89 of the series Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908 and AI-12020; Predoctoral Traineeship to DED), Hatch funds (191-7416), the Bache Fund (National Academy of Sciences, to DED), and the Theodore Roosevelt Memorial Fund (American Museum of Natural History, to DED). We thank M. Weingarner and J. Miller forD. gilippus collection, J. Boggan for technical assistance, and the staff of the Archbold Biological Station, Lake Placid, Florida, for assistance and hospitality. One of us (DED) is indebted to M. D. Achey, who by demonstrating nuptial cardenolide transfer in the monarch butterfly [Honors Thesis, Amherst College, Amherst, Massachusetts (1979)] raised the possibility that other plant metabolites might be similarly transferred in danaines.Deceased July, 1985. This paper is affectionately dedicated to his memory.     

Paternal allocation of sequestered plant pyrrolizidine alkaloid to eggs in the danaine butterfly, Danaus gilippus

Pyrrolizidine alkaloid sequestered by adult male Danaus gilippus from plants is transferred in large measure to the female at mating, and by the female to the eggs. The eggs, presumably, are protected as a result. The male's courtship pheromone, danaidone, derived from the sequestered alkaloid, may function to advertise the male's alkaloid-donating capacity.     

Molecular and neural mechanisms regulating sexual motivation of virgin female Drosophila

Cellular and Molecular Life Sciences - During courtship, multiple information sources are integrated in the brain to reach a final decision, i.e., whether or not to mate. The brain functions for...     

Effects of the light-dark cycle and scheduled feeding on behavioral and reproductive rhythms of the cyprinodont fish, Medaka, Oryzias latipes

Medaka were maintained on a 16:8 light-dark cycle and fed once daily on one of 5 different feeding schedules. The daily rhythm of agonistic behavior rapidly entrained to the scheduled feeding time and maintained this entrainment during a 3-day starvation period. In contrast the daily rhythms of egg laying and courtship stayed entrained to the L:D cycle regardless of the feeding schedule. Thus, temporal integration of this fish with its daily environment can involve multistimuli which concurrently and differentially entrain externally expressed circadian systems.     

Effects of the light-dark cycle and scheduled feeding on behavioral and reproductive rhythms of the cyprinodont fish,Medaka,Oryzias latipes

Summary Medaka were maintained on a 168 light-dark cycle and fed once daily on one of 5 different feeding schedules. The daily rhythm of agonistic behavior rapidly entrained to the scheduled feeding time and maintained this entrainment during a 3-day starvation period. In contrast the daily rhythms of egg laying and courtship stayed entrained to the L:D cycle regardless of the feeding schedule. Thus, temporal integration of this fish with its daily environment can involve multistimuli which concurrently and differentially entrain externally expressed circadian systems.We thank Mark Goodrich and Steve Huber for fish maintenance and technical assistance; and Don Dovala for aid in developing the automatic feeder. The research was funded in part by NIH, AM 25191 and NIEHS, ES No. 01985.     

Cytotaxonomy of the myobatrachid frogs of the genusLimnodynastes

Summary 4 of the 5 species ofLimnodynastes of theperoni group show 2n=24. Onlysalmini has 2n=22, thus resembling the species ofPlatyplectron (thedorsalis andornatus complexes) which all show 22 chromosomes. This 2nd group also includes species (ornatus) with very low DNA amounts. From a karyological point of view, the species of thePlatyplectron (plus eventuallysalmini) group appear more differentiated than the species of theperoni group, from which they have probably arisen.Research partly supported by a contribution from C.N.R., Rome.     

New contribution to the study of chromosomes of the European Cryptocephalinae (Coleoptera,Chrysomelidae)

Summary The chromosomes of three species ofPachybrachis and nine ofCryptocephalus chrysomelids were analyzed. The male meiotic bivalent formula ofP. azureus Suffr.,P. catalonicus Burl. andP. petitpierrei Daccordi is 7^II+Xy_r.Cryptocephalus sexmaculatus Ol. andC. vittula Suffr. have 13^II+Xy_p,C. bipunctatus L. 14^II+Xy_r,C. ochroleucus Steph. andC. ocellatus Drap. 14^II+Xy_p,C. crassus 01. 15^II+Xy_r,C. sulphureus 01. 15^II+Xy_p, the same number as inC. fulvus Goeze with 2n=32 chromosomes, whileC. primarius Har. has 19^II+Xy_p. The modal chromosome number inCryptocephalus is 2n=30 (about 60% of spp.), and most species are characterized their small chromosomes. The low variation found in the karyotypes of Cryptocephalinae along with their possible interrelationships with allied chrysomelid subfamilies are also discussed.     

On the irreversible agglutination of the sperm of the sea-urchins caused by the sperm extract

Zusammenfassung Eine neue Methode der Extrahierung von «Antifertilizin» aus den Samenzellen von Seeigeln,Paracentrotus lividus undArbacia lixula, wurde beschrieben. Der Extrakt zeigte folgende Wirkungen: Neutralisierung des Fertilizins, nicht umkehrbare Agglutinierung der Samenfäden und der Eier bei beiden Seeigelarten.     

Alexis Fontaine's ‘Fluxio-differential method’ and the origins of the calculus of several variables

Alexis Fontaine des Bertins (1704–1771) was the first French mathematician to introduce what we would now regard as results in the calculus of several variables. One example is Fontaine's theorem nF = (?F/?x)x + (?F/?y)y of 1737 for homogeneous expressions F of degree n in x and y. Many years later Fontaine indicated this particular result to have been ‘a continuation of the method of solution’ introduced by him in 1734 to solve the problem of the tautochrones. It is tempting to disregard this announcement, since the method applied to the tautochrones was a method of variations and not manifestly an exercise in the calculus of several variables. Do we have just another case of a mathematician's confusion about the origins of his earlier work? In this paper I describe Fontaine's possible intentions in his remarks.     

Forecasting for the generation of trading signals in financial markets

In this paper we show that optimal trading results can be achieved if we can forecast a key summary statistic of future prices. Consider the following optimization problem. Let the return r_i (over time i=1, 2, ..., n) for the ith day be given and the investor has to make investment decision d_i on the ith day with d_i=1 representing a ‘long' position and d_i=0 a ‘neutral' position. The investment return is given by r=Σⁿ_i=1r_id_i−cΣⁿ⁺¹_i=1∣d_i−d_i−1∣, where c is the transaction cost. The mathematical programming problem of choosing d₁, ..., d_n to maximize r under a given transaction cost c is shown to have an analytic solution, which is a function of a key summary statistic called the largest change before reversal. The largest change before reversal is recommended to be used as an output in a neural network for the generation of trading signals. When neural network forecasting is applied to a dataset of Hang Seng Index Futures Contract traded in Hong Kong, it is shown that forecasting the largest change before reversal outperforms the k‐step‐ahead forecast in achieving higher trading profits. Copyright © 2000 John Wiley & Sons, Ltd.     

Photoreactivable sectors and the systematics of the genusPichia

Zusammenfassung Es wird der Beweis erbracht, dass photoreaktivierungsfähige Sektoren von Zellen einen zusätzlichen Affinitätsparameter zwischer Hefen der GattungenHansenula undPichia bilden und vielleicht wertvolle Daten für die endgültige Erschliessung der intragenerischen Phylogenie derPichia liefern.

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These studies were aided in part by a contract No. AT (11-1)-1772 with the U.S. Atomic Energy Commission.     

Application of the linear partial information model to forecasting the Swiss timber market

Most often, statistical analyses only provide partial information about the appropriateness of different models, structures and parameters which may underlie the dynamic process that has generated a time series. Linear partial information (LPI), in particular, consists of linear restrictions such as LPI: p_a> p_b, p_a> p_c where p_a denotes the probability that structure a holds. Fuzzy information of this type can be put to use for decision-making by LPI analysis. In this paper, LPI analysis is applied to answer the question of whether subsidizing price, given an abnormal disturbance on the timber market, would contribute to continuous forest management, a stated goal of Swiss environmental policy.     

myo-Inositol in the biosynthesis of benzylpenicillin by the mycelial suspensions ofPenicillium chrysogenum

Résumé Lemyo-Inositol, en concentration de 0,2%, active la biosynthèse de la benzylpénicilline par des suspensions mycéliales deP. chrysogenum dans le tampon de phosphate et d'acétate de phényl. L'action stimulante est inhibée par le 2,4-dinitrophénol, cyanure ou arsénite en concentrations de 0,0006M, 0,005M et 0,005M respectivement. Lemyo-Inosose-2 en concentration de 0,2% est comparable à l'inositol en sa stimulation de biosynthèse de la pénicilline; laD-glucuronolactone ne présente aucun effet notable en concentration de 0,2%, mais à 0,5%, elle a un effet stimulant. LeP. chrysogenum est capable d'accroissement dans un milieu synthétique contenant 2% d'inositol comme seule source de carbonne et le polysaccharide du mycelium fournit après hydrolyse presque uniquement du glucose.