Cheng Xuan, Umina Paul A, Hoffmann Ary A
Bio21 Institute, School of BioSciences, The University of Melbourne, Victoria, Australia.
cesar, Victoria, Australia.
J Econ Entomol. 2018 Apr 2;111(2):680-688. doi: 10.1093/jee/tox368.
In the evolution of phytophagous arthropods, adaptation to a single type of host plant is generally assumed to lead to a reduction in fitness on other host plant types, resulting in increasing host specialization. While this process is normally considered to be genetically based, short-term effects acting within one generation (plasticity) or across two generations (cross-generation variation) could also play a role. Here, we test these effects in the redlegged earth mite, Halotydeus destructor (Tucker) (Prostigmata: Penthaleidae), a major agricultural pest of multiple crop plants. Field populations of mites were collected from grasses, legumes, and broad-leaf weeds and placed into enclosures with different plant types. The survival, net reproductive output (Ro), and feeding damage of each mite population were assessed across two generations. The interaction between the origin of mites and plant type had a significant effect on parental survival, Ro, offspring development, and feeding damage. Mites collected from legumes showed higher parental survival on all host types; however, Ro, offspring development and feeding damage were all higher when mites were placed onto the same plant type from which they were collected. These patterns point to the ability of H. destructor to perform well on host plants even in the absence of genetically differentiated host races, but also the likelihood of performance trade-offs when populations are forced to rapidly change hosts within and across sequential generations.
在植食性节肢动物的进化过程中，通常认为适应单一类型的寄主植物会导致在其他寄主植物类型上的适合度降低，从而导致寄主专一性增强。虽然这个过程通常被认为是基于遗传的，但在一代内起作用的短期效应（可塑性）或跨两代的效应（跨代变异）也可能发挥作用。在这里，我们在红腿土螨（Halotydeus destructor (Tucker)，前气门目：戊螨科）中测试这些效应，红腿土螨是多种作物的主要农业害虫。从禾本科植物、豆科植物和阔叶杂草上采集螨类的田间种群，并将它们放置在具有不同植物类型的围栏中。在两代中评估每个螨类种群的存活率、净繁殖率（Ro）和取食危害。螨类的起源与植物类型之间的相互作用对亲代存活率、Ro、子代发育和取食危害有显著影响。从豆科植物上采集的螨类在所有寄主类型上亲代存活率都较高；然而，当螨类被放置在它们所采集的相同植物类型上时，Ro、子代发育和取食危害都更高。这些模式表明，即使在没有遗传分化的寄主种群的情况下，红腿土螨也有能力在寄主植物上表现良好，但当种群被迫在连续世代内和世代间迅速更换寄主时，也存在性能权衡的可能性。
