Sagata Katayo, Gibb Heloise
Department of Zoology, La Trobe University, Melbourne, VIC 3086, Australia.
Papua New Guinea Institute of Biological Research, Goroka, Eastern Highlands Province, Papua New Guinea.
PLoS One. 2016 Jul 19;11(7):e0155131. doi: 10.1371/journal.pone.0155131. eCollection 2016.
Global temperature increases are significantly altering species distributions and the structure of ecological communities. However, the impact of temperature increases on multi- species interactions is poorly understood. We used an ant-Hemiptera-plant interaction to examine the potential outcomes of predicted temperature increases for each partner and for the availability of honeydew, a keystone resource in many forest ecosystems. We re-created this interaction in growth cabinets using predicted mean summer temperatures for Melbourne, Australia, for the years 2011 (23°C), 2050 (25°C) and 2100 (29°C), respectively, under an unmitigated greenhouse gas emission scenario. Plant growth and ant foraging activities increased, while scale insect growth, abundance and size, honeydew standing crop per tree and harvesting by ants decreased at 29°C, relative to lower temperatures (23 and 25°C). This led to decreased scale insect infestations of plants and reduced honeydew standing crop per tree at the highest temperature. At all temperatures, honeydew standing crop was lower when ants harvested the honeydew from scale insects, but the impact of ant harvesting was particularly significant at 29°C, where combined effects of temperature and ants reduced honeydew standing crop to below detectable levels. Although temperature increases in the next 35 years will have limited effects on this system, by the end of this century, warmer temperatures may cause the availability of honeydew to decline. Decline of honeydew may have far-reaching trophic effects on honeydew and ant-mediated interactions. However, field-based studies that consider the full complexity of ecosystems may be required to elucidate these impacts.
全球气温上升正在显著改变物种分布和生态群落结构。然而，气温上升对多物种相互作用的影响却鲜为人知。我们利用蚂蚁 - 半翅目昆虫 - 植物的相互作用，来研究预测的气温上升对每个参与者以及蜜露（许多森林生态系统中的关键资源）可利用性的潜在影响。我们在生长箱中重现了这种相互作用，分别采用了澳大利亚墨尔本在未减缓温室气体排放情景下，2011年（23°C）、2050年（25°C）和2100年（29°C）的预测夏季平均温度。与较低温度（23°C和25°C）相比，在29°C时，植物生长和蚂蚁觅食活动增加，而蚧虫生长、数量和大小、每棵树的蜜露存量以及蚂蚁的采集量均下降。这导致在最高温度下，植物上的蚧虫侵染减少，每棵树的蜜露存量降低。在所有温度下，当蚂蚁从蚧虫采集蜜露时，蜜露存量都会降低，但蚂蚁采集的影响在29°C时尤为显著，此时温度和蚂蚁的综合作用使蜜露存量降至可检测水平以下。尽管未来35年气温上升对该系统的影响有限，但到本世纪末，气温升高可能会导致蜜露的可利用性下降。蜜露的减少可能会对蜜露和蚂蚁介导的相互作用产生深远的营养级影响。然而，可能需要开展考虑生态系统全部复杂性的实地研究来阐明这些影响。
