Death of Cydia pomonella larvae and damage to apple fruit, after field application of codling moth granulosis virus

In field experiments, larvae of codling moth Cydia pomonella (L.) rarely acquired granulosis virus on hatching from the egg, but picked up most later, on the tree surface. Deposits of virus sprayed in 1.0% w/v skimmed milk did not affect neonate larval behaviour. Larvae died, usually in the first instar, after entering treated fruit, but they frequently entered via the calyx or near the base of the stalk or through cracks in the skin, where little feeding damage by first-and sometimes second-instar larvae was seen.

---

Résumé En verger, la pulvérisation d'oeufs de carpocapse avec du virus de la granulose en suspension dans l'eau (additionnée de lait écrémé dilué à 1%) n'a pas modifié la survie des chenilles avant pénétration dans le fruit; par contre la pulvérisation des arbres a provoqué une forte mortalité. Bien que des chenilles consommant des poils et la surface des feuilles aient été observées avant leur pénétration dans le fruit, ce qui aurait pu provoquer leur contamination par le virus, il semble que la contamination létale provienne des fruits seuls.La présence de produit n'a modifié ni le comportement larvaire, ni le taux de pénétration dans les fruits; la mortalité y a lieu ensuite, généralement au premier stade. Dans 74 à 78% des cas, les chenilles ont pénétré dans le fruit par le calice ou près de la base du pédoncule — aucun dégât provenant de larves du premier stade n'y était visible, de même que dans le calice pour les larves du deuxième stade. Par contre, toute pénétration par la surface du fruit était repérable dès le premier stade. Il est possible que la répartition des lieux de pénétration dans le fruit influe sur la létalité due au virus et explique les variations d'efficacité observées en verger. Un système de classification des dégâts, provoqués lors de la pénétration dans le fruit, de chenilles du premier au troisième stade est proposé pour évaluer l'efficacité des essais en verger.

     

Isozyme studies in provenance research of forest trees

Summary The nature and origin of the isozymes and the techniques for their detection in forest trees are briefly reviewed. The theories used to interpret the isozyme variation are summarized. Recent isozyme variation studies in provenance research are discussed in relation to known variation pattern detected by classical nursery and field tests. The populations of a tree species can be sometimes, but not always, distinguished by their isozyme patterns. For a number of species, relationships between environment of origin of the provenances and some isozyme frequencies have been statistically established. In one case (Picea sitchensis) where direct comparison between the variation pattern detected by isozymes and the genetic variation of silviculturally important traits was possible, no meaningful relationships between both patterns could be detected. Nei's genetic distances and indices of gene diversity do not appear to be useful in provenance research. The concept of genetic distance based on gene frequencies is probably not very useful in provenance research either.     

The possible involvement of polyamines in the development of tomato fruits in vitro

The apparent involvement of ornithine decarboxylase (ODC) and putrescine in the early stages of fruit growth in tomato (Lycopersicon esculentum Mill.) has been previously described. Further evidence presented here supports the direct involvement of ODC and putrescine in the cell division process in tomato fruits. In tomato fruits grown in vitro, in which basic growth processes are inhibited, the activity of ODC and arginine decarboxylase (ADC) and the level of free polyamines were reduced. While ODC and ADC activity was correlated with the period of cell division in the tomato fruit, the free polyamine content was correlated with the DNA content, cell size, and fruit fresh weight. The addition of exogenous putrescine, however, did not restore the basic growth processes in the fruits grown in vitro.     

Ecdysteroid levels and integument changes in post-embryonic stages of Anastrepha suspensa

Ecdysteroid levels in larvae and pupae of Anastrepha suspensa (Diptera: Tephritidae) were measured by radioimmunoassay. These levels were correlated with histological changes throughout the development of the post-embryonic stages. Ecdysteroid levels increase rapidly throughout the last-larval instar and on the last day of this stage are 283 pg equivalents of 20-hydroxyecdysone per insect (14.5 ng/g) when wandering behaviour is initiated. At the end of this period the puparium is formed and within 24 h, the ecdysteroid rises to its highest peak (625 pg equivalents of 20-hydroxyecdysone/insect). Larval-pupal apolysis is initiated within 24 h later and the pupal cuticle is then secreted. Two days later, the ecdysteroids reach their lowest levels (75 pg equivalents of 20-hydroxyecdysone/insect or 0.6 ng/g) and most of the larval fat body and other tissues have been histolysed. In 5- to 10-day old pupae ecdysteroid levels again increase and remain relatively high throughout. During this period the larval epidermis is replaced by imaginal epidermis, imaginal discs begin to proliferate and the adult cuticle is secreted. Ecdysteroid levels finally fall 2 days prior to adult emergence. HPLC determinations indicate that 20-hydroxyecdysone is the predominant free ecdysteroid, and along with ecdysone, is readily detectable in all postembryonic stages of this species. An unusually high and unexplained peak of 20-hydroxyecdysone occurs in the pharate adult. This peak probably consists of ecdysone metabolites with retentions similar to that of 20-hydroxyecdysone and to which the antiserum is sensitive.     

From icons to symbols: Some speculations on the origins of language

This paper is divided into three sections. In the first section we offer a retooling of some traditional concepts, namely icons and symbols, which allows us to describe an evolutionary continuum of communication systems. The second section consists of an argument from theoretical biology. In it we explore the advantages and disadvantages of phenotypic plasticity. We argue that a range of the conditions that selectively favor phenotypic plasticity also favor a nongenetic transmission system that would allow for the inheritance of acquired characters. The first two sections are independent, the third depends on both of them. In it we offer an argument that human natural languages have just the features required of an ideal transmission mechanism under the conditions described in section 2.We would like to thank Robert Boyd, Noam Chomsky, Gerald Feinberg, Ken Glander, David Hull, Ernst Mayr, John Rawls, Peter Richerson, william Wimsatt and Paul Ziff for helpful comments on earlier drafts of this paper. Special thanks go to Doug Stalker who was instrumental in both the origins and development of this work.     

Variation of growth form parameters inCapsella (Cruciferae)

Growth form parameters ofCapsella bursa-pastoris populations, including a wide range of different environments, have been analyzed from random block field and growth chamber experiments. Changes in one character are often correlated with changes in another. Of special interest are correlations detected with the onset of first flowering. Variation in each of the characters is clearly influenced by both phenotypic and genotypic components. However, genotype — environment interactions are also subject to variation. Therefore, the adaptive significance of a given parameter is not found to be constant over the entire geographical range of the genus. Alpine populations tend to shift from annual to biannual life cycles.Part of a series Adaptation in life history traits of colonizing plant species. Part of a doctoral thesis by the first author. Dedicated to Prof. Dr.Karl Mägdefrau on the occasion of his 80th birthday.     

Regulatory Mechanisms of Reproductive Effort in Plants II. Plasticity in Reproductive Energy Allocation and Propagule Output of Glycine max Merr. (Leguminosae) Cultivated at Varying Densities and Nitrogen Levels

Abstract Plasticity in growth, reproductive energy allocation (RA), and reproductive output were studied in Glycine max Merr. Cv. Enrei (Leguminosae) grown under varying densities and soil nitrogen levels.
Marked plastic responses were detected in individual biomass, the patterns of resource allocation to total reproductive structures (RA) and also to propagules, reproductive outputs, and propagule weight under changing densities and soil nitrogen levels. Plants cultivated at higher densities exhibited proportionately lower individual biomass, lower RA, lower seed output, and smaller seed size in response to increasing density and decreasing soil nitrogen levels, although some deviations were observed, especially in the highest density plot with no fertilization. Differences due to different N-levels were not as great as those to changing density, which may in part be due to the fact that soybean has nitrogen-fixing bacteria in root tubercles, just as in any other Leguminosae. Fecundity was also maintained at the similar high rates of 80–97% in all plots examined, although slight but steady decreases were noted with increasing density. This resemblance in fecundity may be due to its strong inbreeding system.
Another important finding was that seed production under limited resource availability, notably lack of ample solar radiation due to strong interference at higher density plots, is exceedingly costly. This was most clearly exhibited by a sharp increase in relative energy partitioning to a single propagule in response to the increased density, the relative energy cost to a single propagule (RA) increasing from one to seven-fold. The results obtained in this study coincide well with the findings made in other plants, e.g., Helianthus annuus, Oryza sativa , and Coix ma-yuen , with the same experimental designs.