This study is an in-depth analysis of intersexual, intraspecific, and interspecific variability in larvopupal developmental time, pupation site preference, and larval and pupal survival of a number of isofemale lines of the speciesDrosophila mauritiana, D. melanogaster, D. sechellia, D. simulans, D. teissieri, andD. yakuba. There was no significant sex differences in pupation height, but females eclosed significantly earlier than males in all species. In addition, the suggestion of a strong negative correlation between larval developmental time and pupation height could not be confirmed in this study. The hypothesis that differences in pupation height provide a basis for niche partitioning between closely related species with overlapping distributions was tested by three planned orthogonal contrast analyses of variance. First, the two speciesD. teissieri andD. yakuba, with largely overlapping distribution, were significantly different in pupation height. Second, the two allopatric, nonoverlapping island speciesD. mauritiana andD. sechellia did not significantly differ in pupation height. However, the absence of a significant difference in the final contrast between the two cosmopolitan speciesD. melanogaster andD. simulans, which are often found together, makes us cautious to accept the hypothesis. 相似文献
We examined the locomotor activity ofDrosophila melanogaster for the existence of circadian rhythms, using the wild type and two mutants of theperiod (per) gene,pero andpers. This was accomplished using a newly described apparatus for the recording and measurement of larval path lengths over a 96-h test period. None of the larvae examined exhibited appreciable diel rhythms under cycling conditions of light or temperature. Larvae were also not rhythmic under free-running conditions. Our results suggest that theper gene does not influence an observable locomotor behavioral phenotype in the larval stage of development. 相似文献
Forty-four buffalo bulls, used for artificial insemination, were studied to develop libido, mating ability and sexual behavior indices for selection purposes. For each index, 5 categories (i.e., excellent, very good, good, fair and poor) were established. The sexual behavior index was found to be more reliable than the libido and mating ability indices. Buffalo bulls in good to excellent categories were considered acceptable sires.
Reaction time, sexual aggressiveness, and scores of libido, mating ability and sexual behavior differed significantly among the various categories of the 3 indices. Libido significantly correlated with mating ability (r=0.89; P<0.001). Sexual behavior expressed significant relationship with age (r=0.41; P<0.01) and body weight (r=0.48; P<0.01), but was nonsignificant with the scrotal circumference (r=0.28; P>0.05) of buffalo bulls. However, these relationships were absent (P>0.05) in the acceptable sires. Semen production was correlated with sexual behavior in only the fair and poor categories of buffalo bulls (r=0.84; P<0.005). Sexual behavior had no relationship with the fertility rate of buffalo bulls (r=0.44; P>0.05). It is concluded that the sexual behavior index can be used successfully for the selection of buffalo bulls. Excellent- to good bulls should be used in an artificial breeding program if they qualify in the other selection indices. 相似文献
Behavior-based and person-based perspectives are integrated to summarize approaches for dealing with the human element of ecosystem health. Behavior is selected by its consequences, and therefore interventions are needed to decrease the natural reinforcing consequences (e.g., convenience, efficiency) of environment-destructive behaviors and to increase the reinforcing consequences of environment-protective behaviors. An ABC Model (for Activator-Behavior-Consequence) can be applied effectively to design intervention programs for benefiting the human behavior aspects of ecosystem health. However, intervention agents are needed to implement positive behavior-change techniques, and this requires people to actively care enough to emit other-directed (or altruistic) behaviors for the health of the ecosystem. Person factors which influence one's propensity to actively care include: self-esteem, belongingness, and empowerment, influenced by perceptions of self-efficacy (I can do it), personal control (I am in control), and optimism (I expect the best). Strategies are reviewed for increasing these person states or expectancies. The health of our ecosystem depends upon people changing their behaviors and attitudes regarding the environment. Behavior-based psychology offers the technology for changing behaviors and attitudes in desirable directions; person-based psychology offers the states or expectancies needed in people to increase their willingness to actively care for the environment. By applying the theory and principles from these subdisciplines of applied psychology, the critical human element of our ecosystem can be accounted for and managed effectively. 相似文献
In order to determine the critical period(s) during which estrogen alters sexually dimorphic behavior and neuroanatomy in zebra finches (Poephila guttata), nestlings were injected daily 20 μg estradiol benzoate (EB) during posthatching week 1, week 2, week 3, or weeks 1, 2, and 3. At 7 months of age, birds were implanted with testosterone propionate and tested with female partners for singing, dancing, and copulatory mounting. Brains were subsequently processed for morphometry, and the volumes of the song system nuclei HVC, area X, and RA and the soma sizes and densities of neurons in RA were determined. Males given EB during week 1 failed to mount. Females given EB during week 1 were fully masculinized with respect to dancing and RA neuron soma size and density, and were partially masculinized with respect to song nuclei volumes and singing. Treatment beginning after week 1 was ineffective or less effective for all measures. Only for RA neuron measures was treatment for all three weeks more effective than week 1 treatment. Thus the first post-hatching week is the most influential period of those tested for effects of exogenous estrogen on sexual differentiation in this species, and is a period during which both masculinization of females and demasculinization of males is possible. 1994 John Wiley & Sons, Inc. 相似文献
A simple behavioral model is used to investigate whether differences in the specific-mate-recognition system (SMRS), occur within species of the Drosophila genus. This model takes into account, and overcomes, the distorting effect of vigor differences on experimental results. Analysis shows significant deviations from the expected values under the assumption of identical SMRSs in around one fifth of the multiple-choice experiments performed with natural strains of twelve different Drosophila species. Different selection procedures raise the number of significant assortative mating results between strains of D. melanogaster and D. pseudoobscura from 3.0% to 32.8%. Finally, sub- or semispecific taxa show variations in their SMRS even more frequently (74.5%). Differences in male vigor and female receptivity are also found. These results show that a classification of Drosophila species based on SMRS stability, as proposed by the “Recognition concept of species”, is virtually impossible. 相似文献
Homing to a more or less permanent scar after each foragingexcursion is a common movement pattern among intertidal gastropodsand chitons; however, details of the timing and spacing of foragingactivity have been investigated only in a few species. The presentstudy analyzes the short-term behavior of the limpet Patellarustica along the Tyrrhenian coast, Italy, using a motographictechnique to assess the fine organization of its foraging duringfavorable periods of sea roughness. P. rustica becomes activeonce the upper midlittoral is well splashed. It alternates foragingexcursions and resting at home with a periodicity slightly longerthan 12 h, suggesting a tidal-diel pattern. However, periodogramanalysis of the sea level oscillations during the study periodsrevealed no such rhythmicity because tidal oscillations werehidden by irregular variations caused by waves. As a resultof this time partitioning, limpets move, on average, less than50% of their potential activity time. Time partitioning maybe highly adaptive in reducing potential risks. Nevertheless,in the absence of clear external driving cues, the significanceof a very regular and apparently tidal pattern, fairly synchronousamong the different specimens, remains to be explained. Theactivity of P. rustica during each excursion is organized intothree parts: the outgoing journey during which grazing activityprogressively increases, a central part characterized by intensegrazing, and the return characterized by fast displacement anda more or less consistent trail following. Limpets head forrandom directions to reach foraging grounds in successive excursions,showing only a slight avoidance of the direction taken duringthe previous outward journey. This pattern produces a spatialscattering of grazing activity, allowing efficient exploitationof grazing areas distributed radially around home during subsequentexcursions. 相似文献
Colonies of honeybees (Apis mellifera L.) were established thatvaried in the proportions of their workers that were of Europeanand hybrid (Africanized x European) descent. Colony defensiveresponses increased with higher proportions of hybrid workers.Colonies consisting exclusively of hybrid workers did not differin their response from "pure" Africanized colonies, suggestingthat the strong defensive behavior of Africanized workers isgenetically dominant. European workers became more defensivein colonies that also contained hybrid workers, whereas hybridworkers became less defensive in the same mixed colonies. Inmixed colonies hybrid workers were individually more likelythan Europeans to sting a leather target but not more likelyto guard the entrance. 相似文献