Behavioral observations of codling moth, Cydia pomonella, in orchards permeated with synthetic pheromone

Mating disruption of codling moth, Cydia pomonella, was studied in apple orchards treated with the main pheromone compound codlemone, (E,E)-8,10-dodecadienol, and a blend of codlemone and codlemone acetate, (E,E)-8,10-dodecadienyl acetate, a strong pheromone antagonist. Codlemone alone and the pheromone/antagonist-blend had a similar effect on the behavior of males emerging into air-permeated orchards. Male flights within tree canopy and upwind orientation along tree rows were strongly enhanced by both formulations, compared to untreated plots. However, the codlemone/codlemone acetate-blend increased the rate of cross-wind and downwind flights within the orchard, compared to codlemone alone. The major difference between these two formulations was that males from nearby, untreated orchards were attracted towards orchards treated with codlemone, but not towards treatments with codlemone/codlemone acetate. Additional tests were done with an equilibrium blend of codlemone and its geometric isomers. Aerial pheromone concentrations in the orchards were recorded by the field electroantennogram technique. Decreasing pheromone concentrations towards the upper part of the tree canopy, together with the stimulation of male flight activity by synthetic pheromone explains failures to control codling moth at high population densities with current dispenser formulations.     

Stock Identification of Gag, Mycteroperca microlepis, Along the Southeast Coast of the United States

The gag grouper Mycteroperca microlepis is an important component of commercial and recreational fisheries along the South Atlantic coast of the United States and in the Gulf of Mexico. Over the past two decades, this species has experienced significant declines in abundance and an increasing skew in sex ratios. Analysis of microsatellite DNA variation in this species shows mosaic patterns of population subdivision and significant departures from Hardy-Weinberg equilibrium in all sampling locations. Given the length of the pelagic stage (egg and larvae), the prevailing current patterns, and the migratory capabilities of the adults, it is unlikely that these observations are the result of restricted gene flow among genetically differentiated populations. The apparent structure of gag populations most likely reflects inbreeding in size-limited populations. Population declines, skewed sex ratios, and perhaps variance in female fecundity appear to have acted in concert to limited the number of individuals that contribute to a given year class. These data are reinforced by studies of other fish stocks that have experienced precipitous declines over the past two decades. Received April 13, 1998; accepted September 30, 1998.     

黄瓜茎端ABA/GA_4比值与花芽性别分化的关系(英文)

在同一环境条件下,单雌性株茎端ABA含量显著高于雌雄同株的,而GA_4水平却正好相反。 较高的ABA/GA_4比值有利于黄瓜雌性分化,反之则有利于雄性分化。促进黄瓜雄性分化的生长物质GA_3和AgNO_3会引起黄瓜茎端ABA/GA_4比值的下降,而促进其雌性分化的生长物质乙烯利(Ethrel)则会引起ABA/GA_4比值的上升。     

Birth sex ratios relate to mare condition at conception in Kaimanawa horses

Several hypotheses have been proposed to explain variation inbirth sex ratios, based on the premise that variation is expectedwhen the profitability of raising sons and daughters variesbetween individual parents. We tested the Trivers-Willard hypothesisthat mothers in better condition produce relatively more sonsand that mothers in poorer condition produce relatively more daughterswhen male reproductive success is more variable. We examinedbirth sex ratios in relation to mare body condition at conceptionin horses in which male reproductive success is differentiallyhelped by slight advantages in condition. Horses meet the assumptionsof the Trivers-Willard hypothesis better than many species onwhich it has been tested and in which sex ratio biases are notconfounded by sexual size dimorphism such that one sex is more likelyto die in utero in females in poor condition. Mares that hada female foal were in poorer condition at conception than thosethat had a male foal, and mares that had foals of differentsexes in different years were in significantly poorer conditionwhen they conceived their female foal. There was no relationshipbetween offspring sex and mid-gestation condition, and therewas no difference in foaling rates in relation to body conditionat conception. Consequently, sex ratio deviations are not explainedby fetal loss in utero. Furthermore, differential fetal lossof the less viable sex cannot explain the greater proportionof males produced by mares in better condition. Therefore, ourresults suggest that sex ratio modification occurs at conceptionin wild horses.     

Influence of resource level on maternal investment in a leaf-cutter bee (Hymenoptera: Megachilidae)

Fisher's (1930) prediction of equal investment for each sexin a panmictic population is influenced by a number of ecologicalfactors, among which resource availability plays a major role,particularly when the population exists under changing resource availability.Rosenheim et al. proposed a multifaceted parental investment modelbased on the underlying assumption that individual females determine theirsex investment according to resource availability and oocyte availabilityto maximize reproductive success. The model predicts that greater availabilityof resources used for provisions will lead to (1) an increasein the proportion of females produced (when the female is thelarger sex) and (2) an increase in the amount of provisionsper offspring and thus an increase in offspring size. I testedthese predictions by a controlled experiment using a leaf-cutterbee, Megachile apicalis. I presented two levels of food resourcesto the nesting females, which were allowed to forage and nestin cages. The experimental results supported these parentalinvestment model's predictions.     

The role of olfactory cues in mother–pup,groupmate, and sex recognition of lesser flat‐headed bats,Tylonycteris pachypus

Tylonycteris pachypus is a gregarious bat species with tens of individuals in a colony. The mechanisms by which mother bats recognize their pups and adult bats recognize each other are not clear. We hypothesized that such recognition is achieved by chemical discrimination and performed experiments to test the hypothesis. Results showed that mother bats were much more attracted to the scent from their own pups. For adult bats, females were attracted to the scent from both male and female groupmates but had a higher preference to the scent from female than from male groupmates. Male bats were much more attracted to the scent from male groupmates while showed no preference to the scent from female groupmates. Within a group, both female and male bats had no difference in preference to the scent from the same or opposite sex. These results suggest that mother–pup and groupmate recognition of T. pachypus can be achieved by olfactory cues.     

Estrogen‐regulated developmental neuronal apoptosis is determined by estrogen receptor subtype and the Fas/Fas ligand system

Adult sexual dimorphism in neuronal cell number is controlled by estrogen exposure during a tightly defined period of rat brain development. The mechanisms of estrogen's effect are unknown; one possibility is regulation of programmed cell death (apoptosis). In this study we have shown that estradiol can function as a neuroprotective agent or an inducer of apoptosis, depending on the estrogen receptor‐subtype present in the cell. Thus, ERα has a neuroprotective effect, while ERβ mediates the induction of apoptosis in neuronal cells. Moreover, we show that estrogen‐induced apoptosis through ER‐β requires the expression of Fas‐ and Fas ligand (FasL) proteins, since the absence of FasL in neurons prevents this effect. Furthermore, we demonstrate that microglia‐secreted products induce the expression of FasL necessary to mediate estradiol–ERβ apoptotic effect. These findings may explain the dichotomous effect of fetal estradiol on the adult neuronal number. © 2000 John Wiley & Sons, Inc. J Neurobiol 43: 64–78, 2000     

Brief communication: Gender and sex: Vive la difference

The distinction prevalent in the social sciences between the terms sex and gender is a useful one and ought to be preserved. Sex refers to the anatomical or chromosomal categories of male and female. Gender refers to socially constructed roles that are related to sex distinctions. Use of these terms as synonyms is becoming increasingly frequent in physical anthropology, especially among bioarchaeologists and primatologists. A failure to make the distinction between gender and sex is analytically incapacitating in a field such as physical anthropology, whose strength lies in the integration of biological and cultural information. Am J Phys Anthropol 106:255–259, 1998. © 1998 Wiley-Liss, Inc.     

An adolescent female Neanderthal mandible from Montgaudier Cave,Charente, France

In 1974, an incomplete human mandible was discovered in the site of Montgaudier Cave, along the Tardoire (Charente), France. The mandible was found in association with stone tools and animal bones in geological deposits referable to the very end of the Middle Pleistocene or the beginning of the Upper Pleistocene. The mandible preserves much of the anterior part of the body and three permanent teeth: left lateral incisor, canine and first molar. Estimates based on tooth eruption of modern humans, as well as occlusal wear and root development, suggest an age at death of between 12.5 and 14.5 years. Morphologically, the fossil possesses features, such as a lack of a chin and multiple mental foramina, which have been observed on immature Neanderthal mandibular specimens from Europe. Comparison with these immature European Neanderthals indicates that the jaw and teeth of the Montgaudier mandible are small for its chronological age, suggesting it was that of a female. Am J Phys Anthropol 103:507–527, 1997 © 1997 Wiley-Liss, Inc.     

The evolution of the life cycle of brown seaweeds

The brown seaweeds (Phaeophyta) are well-suited for testing theories of the evolution of the sexual alternation of haploid and diploid generations because of the great diversity of life cycles within the phylum. Three theories are investigated in this paper. (1) Diploid growth evolves because it has the effect of complementing deleterious recessive mutations. This is rejected because (a) ancestral haplonty is not a parsimonious inference from current phylogenies; (b) the exaggeration of diploid growth does not evolve in a comb-like fashion; (c) forms with predominantly haploid growth have evolved from smaller isomorphic ancestors; and (d) there is no correlation between haploid growth and monoecy. (2) Diploid growth evolves when gamete dimorphism leads to intense sexual selection, favouring the production of genetically diverse gametes through meiosis. This is rejected because diere is no correlation between the dominance of the diploid generation and the degree of gamete dimorphism. It is possible to show that gamete dimorphism itself has evolved in the Phaeophyta through the increase in size of the macrogamete in forms that have evolved larger sporophytes. (3) Microthalli become specialized as gametophytes because fusion is promoted by releasing gametes into the boundary layer; macrothalli become specialized as sporophytes because dispersal is promoted by releasing zoospores into the water column. This is consistent with the sexual and reproductive biology of Phaeophyta. The classic sexual cycle can then be interpreted as evolving from an asexual alternation of microthallus and macrothallus, governed largely by environmental factors, through selection for the appropriate association of ploidy with vegetative size. The exceptions to this general rule are forms in which gametes are released from macrothalli, where a different suite of sexual characters has evolved.