Dangles O, Carpio C, Barragan A R, Zeddam J L, Silvain J F
Pontificia Universidad Católica del Ecuador, Facultad de Ciencias Exactas y Naturales, Laboratorio de Entomología, Quito, Ecuador.
Ecol Appl. 2008 Oct;18(7):1795-809. doi: 10.1890/07-1638.1.
Invasive species are a major threat to the sustainable provision of ecosystem products and services, both in natural and agricultural ecosystems. To understand the spatial arrangement of species successively introduced into the same ecosystem, we examined the tolerance to temperature and analyzed the field distribution of three potato tuber moths (PTM, Lepidoptera: Gelechiidae), that were introduced in Ecuador since the 1980s. We studied physiological responses to constant temperatures of the three PTM species under laboratory conditions and modeled consequences for their overall population dynamics. We then compared our predictions to field abundances of PTM adults collected in 42 sites throughout central Ecuador. Results showed that the three PTM species differed with respect to their physiological response to temperature. Symmetrischema tangolias was more cold tolerant while Tecia solanivora had the highest growth rates at warmer temperatures. Phthorimaea operculella showed the poorest physiological performance across the range of tested temperatures. Overall, field distributions agree with predictions based on physiological experiments and life table analyses. At elevations >3000 m, the most cold-tolerant species, S. tangolias, was typically dominant and often the only species present. This species may therefore represent a biological sensor of climate change. At low elevations (<2700 m), T. solanivora was generally the most abundant species, probably due to its high fecundity at high temperatures. At mid elevations, the three species co-occurred, but P. operculella was generally the least abundant species. Consistent with these qualitative results, significant regression analyses found that the best predictors of field abundance were temperature and a species x temperature interaction term. Our results suggest that the climatic diversity in agricultural landscapes can directly affect the community composition following sequential invasions. In the tropical Andes, as in other mountain ecosystems, the wide range of thermal environments found along elevational gradients may be one reason why the risks of invasion by successively introduced pest species could increase in the near future. More data on potential biological risks associated with climatic warming trends in mountain systems are therefore urgently needed, especially in developing nations where such studies are lacking.
入侵物种对自然和农业生态系统中生态系统产品和服务的可持续供应构成重大威胁。为了解相继引入同一生态系统的物种的空间分布情况，我们研究了三种自20世纪80年代起引入厄瓜多尔的马铃薯块茎蛾（PTM，鳞翅目：麦蛾科）对温度的耐受性，并分析了它们在田间的分布情况。我们在实验室条件下研究了这三种PTM物种对恒温的生理反应，并对其总体种群动态的后果进行了建模。然后，我们将预测结果与在厄瓜多尔中部42个地点采集的PTM成虫的田间丰度进行了比较。结果表明，这三种PTM物种对温度的生理反应存在差异。Symmetrischema tangolias更耐寒，而Tecia solanivora在较温暖的温度下生长速率最高。Phthorimaea operculella在测试温度范围内的生理表现最差。总体而言，田间分布与基于生理实验和生命表分析的预测结果一致。在海拔>3000米处，最耐寒物种S. tangolias通常占主导地位，且往往是唯一存在的物种。因此，该物种可能代表气候变化的生物传感器。在低海拔（<2700米）地区，T. solanivora通常是最丰富的物种，这可能是由于其在高温下的高繁殖力。在中等海拔地区，这三种物种共存，但P. operculella通常是数量最少的物种。与这些定性结果一致，显著的回归分析发现，田间丰度的最佳预测因子是温度和物种×温度交互项。我们的结果表明，农业景观中的气候多样性可直接影响相继入侵后的群落组成。在热带安第斯地区，与其他山地生态系统一样，沿海拔梯度发现的广泛热环境可能是未来相继引入的害虫物种入侵风险可能增加的原因之一。因此，迫切需要更多关于山地系统气候变暖趋势相关潜在生物风险的数据，尤其是在缺乏此类研究的发展中国家。
