黄伞的交配型性状研究

以两个黄伞子实体为材料, 经担孢子弹射, 稀释分离获得两组Ⅰ和Ⅱ分别为27和104株单核体。通过采用三轮杂交系统研究,确定黄伞为四极性异宗配合的担子菌;实验还发现单核体不同类型在群体中的比例显示出明显的偏向性分布。     

Conditions favoring anticipatory and reactive displays deflecting predatory attack

Deflective displays direct predatory attacks to body parts thatare relatively invulnerable or can be lost without disastrousconsequences. Usually, these behaviors are directed to predatorspoised to attack at very close quarters. In contrast to suchreactive deflection is anticipatory deflection in situationsthat entail a high risk of being ambushed. Because a predatorcan draw nearer during display, reactive deflection is feasibleonly when the predator is already close. A graphical model showslines relating probability of death to distance from the predatorwhen the prey displays and when it flees without display. Reactivedeflection decreases the probability of death when the predatoris closer than the intersection of these lines, but increasesthe probability of death beyond the intersection. If the predatoris detected when far enough away, the best option is to fleewithout displaying. Anticipatory deflection may increase theprobability of surviving ambush immediately after arriving ata new location but increase the risk of attracting the attentionof other predators. This risk increases with time since stoppingas more predators arrive that did not detect the prey movingto its new location. Anticipatory deflection can be selectivelyfavored only during a brief interval immediately after the preyarrives. The interval increases with benefit of display to survivalif ambushed. It decreases with increases in probabilities ofbeing detected and killed due to display. Examples of thesedisplays and other taxa in which they may be sought are discussed.