Effect of the Drosophila endosymbiont Spiroplasma on parasitoid wasp development and on the reproductive fitness of wasp-attacked fly survivors.
Effect of the Drosophila endosymbiont Spiroplasma on parasitoid wasp development and on the reproductive fitness of wasp-attacked fly survivors.
复制标题
果蝇内共生螺原体对寄生蜂发育和受黄蜂攻击的苍蝇幸存者的繁殖适应性的影响。
DOI：
10.1007/s10682-010-9453-7
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发表时间：
2011
影响因子：
1.9
通讯作者：
Mateos,Mariana
中科院分区：
文献类型：
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作者：
Xie,Jialei;Tiner,Bethany;Vilchez,Igor;Mateos,Mariana
在以前的研究中，我们发现螺旋体是一种经母体传播的果蝇内共生细菌，当受到寄生小蜂的产卵攻击时，可以提高寄主幼虫到成虫的存活率。螺旋质提高寄主存活率的机制尚未阐明。为了更好地理解这一机制，我们比较了感染和未感染螺旋体的宿主中黄蜂幼虫的生长情况。我们的结果表明，在感染螺旋体的宿主中，黄蜂胚胎孵化并正常生长约2天，之后与在未感染宿主中发育的黄蜂相比，其生长严重受损。因此，尽管在感染螺旋体的宿主中完成发育的能力降低，但发育中的黄蜂可能会对宿主施加适应性成本，这在宿主出现后表现出来。这些费用的严重程度将影响这种保护机制在多大程度上有助于螺旋体D的长期存在。海迪亚。因此，我们检查了感染螺旋体的果蝇在黄蜂治疗后存活到10天大的成虫阶段和繁殖力。我们的结果表明，黄蜂攻击对感染螺旋体的成年果蝇的寿命有不利影响。然而，与暴露在黄蜂中的无螺旋体的苍蝇相比，暴露在黄蜂中的螺旋体感染的苍蝇从幼虫到成虫的存活率是10天成虫的大约5倍。黄蜂感染螺旋体的雌虫的相对繁殖力是未感染螺旋体的雌虫的~71%。我们的综合存活和雌性繁殖力结果表明，在高寄生率下，感染螺旋体的果蝇的繁殖适合度可能是未感染雌性的~3.5倍，这可能与螺旋体自然种群的持续存在有关。海迪亚。有趣的是，感染螺旋体的雄性在黄蜂袭击中幸存下来，在接受检查的3天内实际上是不育的。这一观察结果与人们的预期一致，即作为母体传播的共生体，螺旋体几乎没有选择压力来增强其雄性宿主的生殖适合度。
In a previous study, we showed thatSpiroplasma, a maternally transmitted endosymbiotic bacterium ofDrosophila hydei, enhances larval to adult survival of its host when exposed to oviposition attack by the parasitoid waspLeptopilina heterotoma. The mechanism by whichSpiroplasmaenhances host survival has not been elucidated. To better understand this mechanism, we compared the growth of wasp larvae inSpiroplasma-infected and uninfected hosts. Our results indicate that wasp embryos inSpiroplasma-infected hosts hatch and grow normally for ~2 days, after which their growth is severely impaired, compared to wasps developing in uninfected hosts. Thus, despite their reduced ability to complete development inSpiroplasma-infected hosts, developing wasps may exert fitness costs on their hosts that are manifested after host emergence. The severity of these costs will influence the degree to which this protective mechanism contributes to the long-term persistence ofSpiroplasmainD. hydei. We therefore examined survival to 10-day-old adult stage and fecundity ofSpiroplasma-infected flies surviving a wasp treatment. Our results suggest detrimental effects of wasp attack on longevity ofSpiroplasma-infected adult flies. However, compared toSpiroplasma-free flies exposed to wasps,Spiroplasma-infected flies exposed to wasps have ~5 times greater survival from larva to 10 day-adult. The relative fecundity of wasp-attackedSpiroplasma-infected females was ~71% that of un-attackedSpiroplasma-free females. Our combined survival and female fecundity results suggest that under high wasp parasitism, the reproductive fitness ofSpiroplasma-infected flies may be ~3.5 times greater than that of uninfected females, so it is potentially relevant to the persistence ofSpiroplasmain natural populations ofD. hydei. Interestingly,Spiroplasma-infected males surviving a wasp attack were effectively sterile during the 3-day period examined. This observation is consistent with the expectation that, as a maternally transmitted symbiont, there is little selective pressure onSpiroplasmato enhance the reproductive fitness of its male hosts.