Obtaining copulation solicitation displays in female canaries without estradiol implants

Female domesticated canaries (Serinus canaria) respond to conspecific song with copulation solicitation display (CSD) between 22 and 27 days after their first offspring has hatched. This period could be used to investigate the acoustical preferences of female canaries. This non-invasive method respects the natural reproductive cycle and could be an alternative to the invasive method of estradiol implants.     

Female canaries display to songs of early isolated males

We tested the sexual responsiveness of female canaries,Serinus canaria, to two sets of different types of male conspecific songs. In each set, three of the male songs had been recorded in a young bird which was isolated at an early age from conspecifics. Each bird was recorded during three stages of the song ontogeny (early plastic songs, late plastic songs and crystallized songs). We used copulation solicitation displays (CSD) as an index of female sexual response. Playbacks were performed during a period of natural sexual responsiveness of the females to song. We demonstrated that, in both experiments, very weak sexual displays of female canaries were recorded to the two stages of isolate plastic songs. Each of the two different types of isolate crystallized songs elicited high levels of CSD. These levels are not significantly different from the adult domesticated control song. Taken together, these results suggest that even isolate songs may convey sexual information. We discuss prominent acoustic features that must be present to ensure female sexual responses.     

Behavioral and neuronal mechanisms of cricket phonotaxis

Summary The auditory communication of crickets provides a model system for the analysis of the neuronal mechanisms underlying complex behavior. The song of male crickets attracts females. The necessary and sufficient parameter of the song for the female phonotaxis has been determined by a quantified behavioral analysis. Neuronal correlates of this pattern recognition exist in the cricket brain and give rise to a hypothesis on the mechanism of song pattern recognition. Causal relationships between the orientation of a cricket during phonotaxis and the activity of single identified neurons were found by monitoring and deactivating single neurons during behavior. The different roles of various identifield neurons for sound localization have been tested by this method. The plasticity of the auditory system at both the behavioral and at the neuronal level has been studied after ampytation of one ear, and a mechanism for sound localization with only one ear is proposed.     

Hormonal control of pheromone responsiveness in the male black cutwormAgrotis ipsilon

In Lepidoptera, reproduction is linked to chemical communication between conspecific partners. When exposed to the female sex pheromone, males respond by exhibiting typical sexual behaviour which leads to mating. Here we show that presence of the juvenile hormone producing gland (corpora allata) of the male black cutworm,Agrotis ipsilon, is necessary for pheromone responsiveness. Allatectomized males do not show any sexual behaviour, although their antennal olfactory system is functional. Allatectomized males implanted with active corpora allata recover full pheromone receptivity. It is suggested that reproductive processes are synchronized in males and females through endocrine control; timing of the mating activity could serve as an adaptive strategy linked to the migratory behaviour of this species.     

The role of sex steroid in two avian song behaviours differing in ontogenetic process

The male Bengalese finch,Lonchura striata, has two types of song behaviour (directed song, DS and undirected song, US). DS and US share a basically identical syllable repertoire, sequence pattern and tempo, but differ in the time course of appearance during the maturational process. In order to examine whether this results from a difference in testosterone (T) dependency, we studied developmental changes in the fecal T level and the amounts of DS and US during the 2–4 month period (N=7). DS appeared between 83 and 94 days of age, 4–16 days after a rise in the fecal T level. In contrast, US appeared earlier and at high frequency even when T was still at a very low level. These results suggest that DS is more dependent on the T level than US, and is not activated until the T level rises during the maturational process.     

Egg-species recognition in cannibalistic hatchlings of the land snailsArianta arbustorum andHelix pomatia

Summary Laboratory experiments were conducted to determine whether cannibalistic hatchling of the land snailsArianta arbustorum andHelix pomatia discriminate between eggs of the two species. Hatchlings from both species showed a significant choice for conspecific eggs and consumed on average 1 egg in 4 days. Eggs from the other species were only occasionally eaten.     

Autoradiographic study of the penetration of non-histone chromatin proteins into differentiating cells

Summary Attention has previously been drawn to a specific effect of NHCP on embryonicPleurodeles cell differentiation. With a modified NHCP labelling technique, autoradiography has revealed a cytoplasmic concentration of labelled NHCP and has not revealed any difference between homospecific and heterospecific NHCP penetration.This work has been supported financially by research grants from the C.N.R.S. (ERA No. 327 and ATP No. 4310 on the cellular differentiation), and INSERM (No. 711019).The authors wish to extend their thands to Dr.Mazarguil who kindly initiated us in the techniques of enzyme binding. Many thanks are also due to Mr.Hawks for most valuable help in correcting the English.     

Oestrus induction in unisexually grouped mice by multiple short-term exposures to males

Oestrus induction and synchronization (the Whitten effect) were achieved in unisexually grouped female mice by short-term (10 and 30 min) exposure to conspecific males.     

Un nouveau type de détermination chromosomique du sexe chez les mammifèresEllobius lutescens Th. etMicrotus (Chilotus) oregoni Bachm. (Muridés-Microtinés)

Summary (1)Ellobius lutescens andMicrotus oregoni show the same type of sex-chromosomes. The diploid number is odd in both sexes, seventeen.(2) The odd element ofEllobius is morphologically alike in the male and in the female. InM. oregoni, the odd element of the male is acrocentric, that of the female metacentric.(3) Following a hypothesis ofWhite, it seems very probable that the heterochromosome of the male is built of the primitiveY (short arm) and the primitiveX (long arm) linked together. In the female of the same species (M. oregoni), the sex-chromosome represents both theX fused together.(4) Only the half of the Zygotes may develope, the other half being lethal.(5) The close kinship betweenEllobius andM. oregoni is certain, a parallel evolution appearing as highly improbable.     

Two related butterfly species avoid oviposition near each other's eggs

Summary Some butterfly species avoid egg-laying on plants which already bear conspecific eggs, and thus reduce food competition between their offspring. In twoPieris species the females produce in their accessory glands an oviposition-deterring pheromone (ODP), which is combined with the egg during oviposition. The ODP collected from eggs or accessory glands ofP. brassicae inhibits oviposition byP. rapae and vice versa. The ODP of either species stimulates tarsal receptors in both species. The antennae of the two pierids respond to the volatiles of their own and each other's eggs. Thus the ODPs of the two species may reduce not only intraspecific, but also interspecific food competition between their larvae.     

Phylogeny and rapid Northern and Southern Hemisphere speciation of goldfinches during the Miocene and Pliocene Epochs

Mitochondrial cytochrome b (cyt b) from 25 out of 31 extant goldfinches, siskins, greenfinches and redpolls (genus Carduelis) has been sequenced from living samples taken around the world, specimens have also been photographed. Phylogenetic analysis consistently gave the same groups of birds, and this grouping was generally related to geographical proximity. It has been supposed that Pleistocene glaciations played a crucial role in the origin of extant diversity and distribution of Northern Hemisphere vertebrates. Molecular comparison of most extant songbird species belonging to the genus Carduelis does not support this assertion. The fossil record of chicken and pheasant divergence time has been used to calibrate the molecular clock; cyt b DNA dendrograms suggest that speciation in Carduelinae birds occurred during the Miocene and Pliocene Epochs (9 – 2 million years ago) in both the Northern and Southern Hemispheres. Only about 4% average amount of nucleotide substitution per lineage is found between the most distant Carduelis species; this suggests a remarkably rapid radiation when compared with the radiation of other passerine songbird genera. In addition, a continuum of small songbird speciation may be found during the Miocene Epoch in parallel with speciation of other orders (i.e. Galliformes, chicken/pheasant). Pleistocene glaciations may have been important in subspeciation (i.e. Eastern European grey-headed goldfinches/Western European black-headed goldfinches) and also in ice-induced vicariance (isolation) (i.e. siskin in Western Europe vs. siskin in Far East Asia) around the world. European isolated Serinus citrinella (citril finch) is not a canary, but a true goldfinch. South American siskins have quickly radiated in the last 4 million years coinciding with the emergence of the Isthmus of Panama; probably, a North American siskin related to C. notata invaded a suitable and varied biotope (the South American island) for Carduelis birds. North American goldfinches may be renamed as siskins, because they have a distant genetic relationship with European goldfinches. Genus Acanthis could be dropped, and thus redpolls should be separated from twite and linnet, the latter (Europeans) probably being related to American goldfinches. Also, reproductive barriers are observed between closely related species and not between other more distant ones. Finally, a tentative classification for genus Carduelis species is suggested. Received 6 March 1998; received after revision 3 July 1998; accepted 7 July 1998     

Identification and biological significance of 4-methyl-3Z,5-hexadienoic acid produced by males of the gall-forming tephritidsUrophora cardui (L.) andUrophora stylata (Fab.) (Diptera: Tephritidae)

Summary A new natural substance has been identified in the rectal ampullae of gall-forming fruit flies. The substance was found to be the only volatile compound in the rectal ampulla of maleUrophora cardui andUrophora stylata. GC-MS methods were used to characterize its structure as 4-methyl-3Z,5-hexadienoic acid. Physiological parameters such as the amount of the acid at different ages and under different conditions were investigated. The biological significance of the new volatile as an arresting pheromone was tested in several bioassays. The arrestant function could not be established, but the results gave hints of a territorial function between conspecific males. The results are discussed with respect to gland morphology and predictions of communication models among fruit flies.     

Identification of an oviposition-regulating pheromone in the European grapevine moth,Lobesia botrana (Lepidoptera: Tortricidae)

The oviposition of the European grapevine moth (EGVM)Lobesia botrana can be deterred by an extract of conspecific eggs corresponding to 20 egg equivalents. The reduction of the oviposition behavior is dose-dependent. Nine chemicals have been extracted from the eggs and identified as straight chain fatty acids and esters of fatty acids. A mixture of these rather simple molecules induces the same levels of deterrence as the total extract. It might be possible to use oviposition regulating pheromone in the future for the control of EGVM populations.     

Biochemical genetic differentiation among seed chalcid species of genusMegastigmus (Hymenoptera: Torymidae)

The degree of genetic variability and the taxonomic status of adults of 14 seed chalcid species of the genusMegastigmus was analyzed using electrophoresis on horizontal starch gel. Variability of chalcid populations with host tree was observed in 21 host species. A total of 13 enzyme loci were considered. Seven of the loci were found to be polymorphic. The electrophoretic data strongly supported the adaptation of each chalcid species to a limited number of congeneric hosts, and confirmed the morphologically-based taxonomy of the genus. The resulting dendrogram separated the chalcid species into three distinct groups, infesting 1) Pinaceae spp., 2) Cupressaceae spp., and 3) Angiosperm spp., respectively. The highest level of overall genetic similarity was observed among the chalcid populations infesting conifers of the generaPseudotsuga andAbies. The genetic identity values observed among populations infesting 5 differentAbies species tended to reflect the occurrence of conspecific populations rather than that of distinct chalcid species. Genetic identity was similarly important among the chalcid species infesting seeds of Cupressaceae. By contrast, a large genetic distance was observed between two seed chalcids attacking a same host,Rosa montana.     

Cysteine oxidase and cysteine sulfinic acid decarboxylase in developing rat liver

Summary The patterns of development of cysteine oxidase (CO) and cysteine sulfinic acid decarboxylase (CSD) in rat liver are not similar. It was observed that CO is not under sex control as CSD is. The results obtained agree with the idea that, in liver, as well as in brain, CSD is the limiting factor for the regulation of taurine biosynthesis.Acknowledments: The authors thank CEA for financial support for the purchasing of labelled substrates.     

Habitat marking: males attracted to residual odors of twoDrosophila species

Summary We have found that males of the sibling speciesD. melanogaster andD. simulans are preferentially attracted to sites marked by the residual odors of conspecific females, especially if non-virgin. In natural populations, this could enhance sexual selection among males, and cause some isolation at the microhabitat level.     

Preferential destruction of chloroplast nucleoids in zygotes in green algaeDictyosphaeria cavernosa andAcetabularia calyculus

Summary The preferential destruction of chloroplast nucleoids in young zygotes in the coenocytic algaDictyosphaeria cavernosa and the giant unicellular algaAcetabularia calyculus was studied by high resolution epifluorescent microscopy. The chloroplast nucleoids (DNA) in the chloroplast from one of the parents were preferentially destroyed soon after the mating of male and female gametes.     

Hobbes on natural philosophy as “True Physics” and mixed mathematics

In this paper, I offer an alternative account of the relationship of Hobbesian geometry to natural philosophy by arguing that mixed mathematics provided Hobbes with a model for thinking about it. In mixed mathematics, one may borrow causal principles from one science and use them in another science without there being a deductive relationship between those two sciences. Natural philosophy for Hobbes is mixed because an explanation may combine observations from experience (the ‘that’) with causal principles from geometry (the ‘why’). My argument shows that Hobbesian natural philosophy relies upon suppositions that bodies plausibly behave according to these borrowed causal principles from geometry, acknowledging that bodies in the world may not actually behave this way. First, I consider Hobbes's relation to Aristotelian mixed mathematics and to Isaac Barrow's broadening of mixed mathematics in Mathematical Lectures (1683). I show that for Hobbes maker's knowledge from geometry provides the ‘why’ in mixed-mathematical explanations. Next, I examine two explanations from De corpore Part IV: (1) the explanation of sense in De corpore 25.1-2; and (2) the explanation of the swelling of parts of the body when they become warm in De corpore 27.3. In both explanations, I show Hobbes borrowing and citing geometrical principles and mixing these principles with appeals to experience.     

Nouvelles contributions à la cytogénétique desMus Africains du sous-genreLeggada

Summary The author describes four new chromosome complements in the African pigmy-mice (Mus, subgenusLeggada). (1) One form from Angola has 18 metacentric chromosomes (N.F.=36) in both sexes. In contrast toMus minutoïdes minutoïdes Smith from South Africa, whose females have the same chromosome complement while the males show an acrocentric and shortY-chromosome, we have here a metacentricY. It is a confirmation of the hypothesis that theY ofM. m. minutoïdes was primarily of translocated type (TR) but lost a big intercalary segment of the autosomic arm. (2) In another species from Angola 2N=34;N.F.=36. It is the first case in the subgenus where a Robertsonian fusion occurs between autosomes before the transformation of the sex-chromosomesPR into sex-chromosomesTR. This observation is a confirmation that the complement 2N=36;N.F.=36 is the primitive one, being found in the three groups of species,minutoïdes, bufo-triton andtenellus. (3) Indeed, from Ghana, I have got specimens ofM. tenellus. We have here to deal with the primitive chromosome complement: 2N=36;N.F.=36. (4) In a sample of 12Leggada from the region of Bukawu (Congo), there are 5 and 7 . 4 show a total deletion of the short arm of theX-chromosome. In spite of the absence of X _dc -Y and of X _dc -X _dc in the sample, it is probable that neither of these complements is lethal.     

Hydroxyproline-rich glycoproteins in plant reproductive tissues: structure, functions and regulation

The plant reproductive process of pollination involves a series of interactions between the male gametophyte (the pollen grain or pollen tube) and extracellular matrix (ECM) molecules secreted by different cell types along the pollen tube growth pathway in the female organ, the pistil. These interactions are believed to signal and regulate the pollen tube growth process to effect successful delivery of the sperm cells to the ovules where fertilization takes place. Hydroxyproline-rich glycoproteins secreted by plant cells are believed to play a broad range of functions, ranging from providing structural integrity to mediating cell-cell interactions and communication. The pistil and pollen tube ECM is enriched in these highly glycosylated proteins. Our discussions here will focus on a number of these proteins for which most information has been available, from Nicotiana tabacum, its self-incompatible relative N. alata, and Zea mays. In addition, the regulation of the synthesis and glyco-modification of one of these proteins, TTS (transmitting tissue-specific) protein from N. tabacum will be discussed in the light of how differential glycosylation may be used to regulate molecular interactions within the ECM.