LOCAL ADAPTATION TO REGIONAL CLIMATES IN PAPILIO-CANADENSIS (LEPIDOPTERA, PAPILIONIDAE)
LOCAL ADAPTATION TO REGIONAL CLIMATES IN PAPILIO-CANADENSIS (LEPIDOPTERA, PAPILIONIDAE)
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DOI：
10.2307/2937146
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发表时间：
1994-11-01
影响因子：
6.1
通讯作者：
SCRIBER, JM
中科院分区：
文献类型：
--
作者：
AYRES, MP;SCRIBER, JM
与密歇根州北方相比，加拿大凤蝶在阿拉斯加内陆的夏天更短，更凉爽：平均热总和为583对985摄氏度-天（10摄氏度基准）;平均日温度为14.4对18.8度。加拿大披碱草的温度生理可能是进化上保守的，或者该物种可能是区域适应种群的组合。我们通过比较阿拉斯加和密歇根的加拿大大蠊在实验室温度范围内的发育生理学来评估这些假设，并保持较高的温度通常会导致更快的幼虫发育，但这种影响因昆虫种群和宿主而异。在低温（12度）下，阿拉斯加幼虫比密歇根幼虫生长得更快（五龄幼虫在5.8天内比9.1天内增加了一倍），主要是由于40%的高消费率。在高温（30度）下，阿拉斯加幼虫生长得更慢，更快，或与密歇根幼虫相同，这取决于宿主。在高温下，寄主质量的影响最大。阿拉斯加幼虫的呼吸费用升高（比密歇根幼虫高35%），使它们在高温下对宿主质量特别敏感。干物质消化率和氮利用效率不同主机，但没有种群之间或跨温度。蜕皮占发育时间的35- 51%。阿拉斯加的幼虫在12度（11.8对17.8天）比密歇根的幼虫更快地完成了第五次蜕皮，但在30度（3.1对2.9天）时没有。在这两个种群中，蜕皮在低温下比生长更敏感（Q（10）为5.65 vs. 3.04从12到18度），但在高温下温度敏感性较低（Q（10）为1.60 vs. 2.06从18到30度）。在理想的晒太阳条件下，幼虫的体温可以比环境温度高出大约10度，但这种情况在阿拉斯加很少见，幼虫通常接近环境温度。阿拉斯加的幼虫在选择高辐射的微型地点或将太阳辐射转化为热量方面并不比密歇根的幼虫好。在野外和实验室条件下，以相同的叶片和相同的日平均气温饲养加拿大大蠊幼虫，其生长速率是相同的。我们将加拿大大蠊对温度的反应纳入生活史发育模型，然后利用48年的气候记录来评估对阿拉斯加夏季表观适应的适合度贡献。在一个好的主机，在阿拉斯加的温度下，阿拉斯加P. canadensis有一个估计的健身3.0倍以上的密歇根州P. canadensis。此外，在阿拉斯加的温度下，密歇根种群预计将在48年中的31年内灭绝。生长温度反应的变化作出了最大的贡献，以提高健身在阿拉斯加，其次是新生儿的质量增加，在低温下的蜕皮能力增强，并降低了尺寸阈值化蛹。对适应性权衡的分析表明，极端的夏季在形成适应性反应方面比平均夏季更重要。对气候的区域性适应使加拿大云杉能够保持比其他可能的更广泛的地理分布，但北方的分布范围可能仍然受到夏季温度的限制。
Papilio canadensis encounters shorter, cooler summers in interior Alaska than in northern Michigan: average thermal sums are 583 vs. 985 Celsius degree-days (10 degrees C base); mean daily temperature is 14.4 vs. 18.8 degrees. The temperature physiology of P. canadensis could be evolutionarily conserved, or the species may be a composite of regionally adapted populations. We evaluated these hypotheses by comparing the developmental physiology of P. canadensis from Alaska and Michigan across a range of temperatures in the laboratory and held.Higher temperatures generally resulted in more rapid larval development, but the effects varied with insect population and host. At low temperatures (12 degrees), Alaskan larvae grew faster than Michigan larvae (fifth instars doubled their fresh mass in 5.8 vs. 9.1 d), primarily due to 40% higher consumption rates. At high temperatures (30 degrees), Alaskan larvae grew slower, faster, or the same as Michigan larvae, depending upon host. Effects of host quality were greatest at high temperatures. Elevated respiratory expenses in Alaskan larvae (35% higher than Michigan larvae) made them especially sensitive to host quality at high temperatures. Dry matter digestibility and nitrogen use efficiency differed across hosts, but not between populations or across temperatures. Molting accounted for 35-51 % of development time. Alaskan larvae completed their fifth molt faster than Michigan larvae at 12 degrees (11.8 vs. 17.8 d), but not at 30 degrees (3.1 vs. 2.9 d). In both populations, molt was more temperature sensitive than growth at low temperatures (Q(10) of 5.65 vs. 3.04 from 12 to 18 degrees), but less temperature sensitive at high temperatures (Q(10) of 1.60 vs. 2.06 from 18 to 30 degrees). Survival differed across temperatures, but not between populations.Under ideal basking conditions, larvae in the held were able to elevate body temperatures approximate to 10 degrees above ambient, but such conditions were rare in Alaska and larvae were usually near ambient temperature. Alaskan larvae were no better than Michigan larvae at selecting high radiation microsites or converting solar radiation into heat. Growth rates of Alaskan larvae were the same in the field and laboratory when fed the same foliage and exposed to the same mean daily air temperature.We incorporated P. canadensis temperature responses into a life history development model, then used a 48-yr climatic record to evaluate the fitness contributions of apparent adaptations to Alaskan summers. On a good host, at Alaskan temperatures, Alaskan P. canadensis had an estimated fitness 3.0 times greater than Michigan P. canadensis. Furthermore, the Michigan population was predicted to go extinct in 31 of 48 yr at Alaskan temperatures. Changes in growth temperature responses made the greatest contribution to enhanced fitness in Alaska, followed by increased mass of neonates, enhanced molting abilities at low temperatures, and a reduced size threshold for pupation. Analysis of fitness trade-offs suggested that extreme summers have been more important than average summers in shaping adaptive responses. Regional adaptation to climate allows P. canadensis to maintain a broader geographic distribution than would otherwise be possible, but northern distribution limits are probably still constrained by summer temperatures.