Distribution and spacing of Drosophila mycetophaga flies on bracket fungi used as mating arenas

Abstract.

• 1 To understand the nature of male aggregations in Drosophila mycetophaga, data were collected on male and female distribution and male spacing on bracket fungi used as mating arenas in cool rainforests of south-eastern Australia.
• 2 Both males and females appeared to be aggregated among bracket fungi that were used as mating arenas. Females were associated with large male aggregations. The probability of a fungus being occupied increased with its area. However, a multiple Poisson regression analysis suggested that fungus area did not affect female distribution when male number was controlled.
• 3 The presence of female breeding and feeding resources did not determine where aggregations were formed, because there were aggregations on fungi without resources, and fungi with resources were not used more often than those without them.
• 4 D.mycetophaga males did not select and defend territories within bracket fungi, and did not determine female access to areas. However, males were more evenly spaced than expected on the basis of a random distribution, suggesting that males kept apart from each other.
• 5 The distribution of the different sexes and male spacing pattern supports the interpretation that D.mycetophaga has a lek mating system.

     

A test for preference of association in a color polymorphic poeciliid fish: laboratory study

Synopsis The ecological and evolutionary forces maintaining genetic polymorphism within populations is of continuing interest to evolutionary biologists. Male pygmy swordtails,Xiphophorus pygmaeus, are polymorphic at a Y-linked locus controlling body color. Fish with the + and cp alleles have blue bodies; those with the con allele have bright gold bodies. Male and female fish were tested in the laboratory to determine if there were any preferences for association with groups of male fish based on color. Single test fish were presented with two groups of males of different phenotypes, and times in which the test fish spent in proximity to each group were recorded. Males of different phenotypes showed no differences in preference, nor did phenotype of the males in the groups affect the behavior of the test fish. Females also showed no preference for males of a particular phenotype. Finally, female test fish showed no preference for groups containing a male with the rare phenotype compared to a group containing all males of the same phenotype.     

Aggression in adult male primates: A comparison of confined Japanese macaques and free-ranging olive baboons

The frequencies and types of adult male aggressive behavior of confined Japanese macaques (Macaca fuscata)and free-ranging olive baboons (Papio anubis)were compared. The baboons, which do not have a mating season, were more aggressive to conspecific males than were the macaques during their nonmating season. The baboons also solicited aid during aggressive encounters more frequently than the macaques. However, during their mating season, the macaques were more aggressive to conspecific females than were the baboons. The macaques were also involved in more triadic sequences of aggression, and the frequency of occurrence of these patterns supported Chase’s theory of dominance hierarchy formation and maintenance. The differences in aggressive behavior appeared to be related to the seasonal reproductive cycle of the macaques.     

Lycopersicon esculentum: Trifoliate plants recovered from anther cultures of heterozygous tftf plants

The effects of the genotype and growth medium composition on callus induction and shoot regeneration from tomato (Lycopersicon esculentum Mill) anthers were studied. Five male sterile varieties, homozygous for the recessive gene ms 10³⁵, their isogenic fertile counterparts, and nineteen sterile mutants from an F₂ population segregating for ms 10³⁵, were tested. Callus induction and shoot formation were found to be affected by the genotype. The presence of the mutant gene ms 10³⁵ greatly increased callus induction. A significant interaction concerning callus induction was found between the ms 10³⁵ gene and the general genetic background. In most of the plants shoot regeneration from the anthers was associated with various degrees of callus production. However, there was no correlation between callus production and the ability to regenerate plants from that callus. Anthers isolated from plants which were heterozygous for the recessive leaf marker trifoliate, regenerated diploid plants with trifoliate leaves. The plants retained the trifoliate phenotype for over six months in culture under non-aseptic condition. Since the trifoliate phenotype appears only in the homozygous recessive state, the evidence that these trifoliate plants are doubled haploids of sporogenic origin is discussed.     

Hydroxycinnamic acid amides in fertile and cytoplasmic male sterile lines of maize

Hydroxycinnamic acid (HCA) amides in fertile and cytoplasmic male sterile lines of maize were determined in reproductive organs, developing grains and cobs. HCA amides occurred in large amounts in the anthers of fertile plants (line F7N) and were absent from the anthers of cytoplasmic male sterile lines (lines F7T and F7C). Restoration of fertility was associated with the production of these compounds (line FC31). Considerable variations were observed in the concentrations of HCA amides at different stages of growth and grain maturation. Changes of HCA amides in the grains which were to produce sterile plants followed a pattern similar to that obtained with the grains which were to produce fertile plants. Accumulation of HCA amides was substantially higher in fertile lines whatever their genotype (F7N, FC31 and F7T x FC31) than in sterile lines. Marked changes occurred in the HCA amide content of embryo and endosperm during grain development. Many changes in HCA amides were observed in cobs during development and maturation, but no substantial differences could be observed between fertile and sterile lines.     

Intraspecific variability in response to stimuli for male and ephippia formation in Daphnia pulex

Natural clones and clones from laboratory crossings of Daphnia pulex have been tested in their response to stimuli for male and ephippia formation. The clones are from ponds in Illinois, USA, an area with both obligate and cyclical clones of D. pulex. The progeny from two types of crosses were studied: 1) crosses between an obligate clone producing males and a cyclical clone producing only females, and 2) self-fertilization within a cyclical clone producing both sexes. Both the natural and the artificial clones showed great variation in response to environmental stimuli for males. Ephippia response seems more equal among the clones, but two of the artificial clones could hardly be stimulated to produce ephippia in the induction experiments. In crowded cultures, however, they produced a few. Crossings between cyclicals and obligates yielded mostly cyclical progeny. Progeny from the selfed clone had low survival and fecundity.     

Combining pheromone-baited and food-baited traps for insect pest control: Effects of developmental period

An age-structured population dynamics model is presented that incorporates pheromone-trapping and food-trapping as control methods for an insect pest. The model yields the following results. Low rates of pest survivorship allow lower trapping rates for control. Species with long developmental periods are easier to control than those with shorter developmental periods (other factors being equal) due to lower net survival. The rates of pheromone trapping alone for effective control are usually very high. The combination of pheromone and food trapping allows control with much lower trapping rates than either method alone. Even small amounts of immigration of adult pests into the control area renders pheromone control ineffective, whereas food traps suppress both the immigrants and the resident population. Food- (or odor-) baited traps which attract both males and females are only somewhat more efficient than those which attract females alone. The existence of density-dependent population regulation assists the control program substantially, but this assistance declines as food trapping becomes a more important part of the control program. Larval competition strongly affects the required trapping rates for eradication; species in which all larvae exert strong competition are much easier to control than those in whic the younger larvae contribute little to the total competitive depression.     

Protein analysis during the ontogeny of normal and male sterile stamenless-2 mutant stamens of tomato (Lycopersicon esculentum Mill.)

The levels and synthesis of proteins during the ontogeny of normal and male sterile stamenless-2 (sl-2/sl-2) mutant stamens of tomato (Lycopersicon esculentum) were examined. The mutant stamens contained low levels of soluble protein which were related to reduction in protein synthesis. The mutant stamens, however, possessed many polypeptides similar to the normal and synthesized a 53-kd polypeptide at stages when there are abnormalities in tapetum development. The mutant stamens also possessed a 23-kd and some low molecular weight polypeptides that were considered as degradative proteins. Normal stamens exhibited the synthesis of many polypeptides not found in the mutant, from microspore mother cell to the preanthesis stages. In addition, at the time of pollen maturation there was a greater synthesis of several polypeptides, particularly those of 42 and 37 kd. Although the causative mechanisms of male sterility in the sl-2/sl-2 mutant are not known, the synthesis, and the lack, of specific polypeptides reported here appears to be associated with pollen degeneration.This work was supported by an operating grant from the Natural Sciences and Engineering Research Council of Canada to V.K.S.     

Male-male behavior and sexual dimorphism of the ear of a zaprochiline tettigoniid (Orthoptera: Tettigoniidae)

The external anatomy of the auditory system of an undescribed zaprochiline tettigoniid (Genus nov. 22 Sp. 1, Australian National Insect Collection, Canberra) shows sexual dimorphism: the male appears to have no auditory spiracle equivalent to that seen in the female. Nocturnally active males aggregate around female required nectar sources in a random manner with regard to each other. There is limited evidence, either from song interaction or from their behavior in the field, that males respond to each other by acoustic cues. Laboratory trials, testing male phonotaxis, showed that movement was random with respect to a target group of caged calling males. In the field, the only signs of agonistic behavior consisted of an increased calling rate when males were close together. Taken together, these data suggest that the male may not preceive sound in the same way as the female.     

Somatic hybridization between male sterile Nicotiana tabacum and N. glutinosa through protoplast fusion

Summary Protoplasts derived from suspension cultured cells of cytoplasmic male sterile Nicotiana tabacum (N. debneyi cytoplasm) and of fertile N. glutinosa were fused with the aid of polyethylene glycol (PEG). Out of 1,089 colonies developed from PEG-treated protoplasts, 29 restored whole plants.A somatic hybrid plant was selected on the basis of isoelectrofocusing analysis of Fraction I protein in leaves of regenerated plants. A newly created hybrid contained small subunits of both parents but only a N. glutinosa type large subunit.Male sterile character was conserved in a hybrid plant while leaf morphology was intermediate between the parents. By tobacco mosaic virus infection tests, the hybrid's leaves showed resistant symptoms, hypersensitive local lesions, which were due to N. glutinosa nuclear genome expression.Abbreviations PEG Polyethylene glycol - TMV Tobacco mosaic virus