Valera F, Casas-Crivillé A, Calero-Torralbo M A
Estación Experimental de Zonas Aridas (CSIC), General Segura 1, E-04001, Almería, Spain.
Parasitology. 2006 Aug;133(Pt 2):179-86. doi: 10.1017/S0031182006009899. Epub 2006 Apr 20.
Prolonged diapause is usually interpreted as an adaptation to unpredictable environmental conditions and resource availability. Many parasites usually face highly unpredictable environments, therefore prolonged diapause should be common among these organisms. Here we examine the occurrence and frequency of prolonged diapause in the ectoparasite Carnus hemapterus (Diptera: Cyclorrhapha, Acalyptratae). We found that the studied population is polymorphic with respect to diapause duration. Emergence of carnid flies after 2 and 3 wintering seasons was therefore detected in around 17% and 21% of the samples respectively. The number of flies with prolonged diapause ranked 0.88-50% with respect to the number of flies emerging during the first spring. Both the occurrence of prolonged diapause and the number of flies with a long life-cycle are related to the number of flies emerging during the first spring. The emergence pattern of flies with prolonged diapause was very similar to that observed for flies with a short cycle and occurred in synchrony with the occurrence of hosts. Prolonged diapause has been frequently reported in plant-feeding insects and in some host-parasitoid systems, but this is, to our knowledge, the second report ever on prolonged diapause in true parasites of animals. We discuss the reasons for the apparent rarity of prolonged diapause among these organisms.
长期滞育通常被解释为对不可预测的环境条件和资源可用性的一种适应。许多寄生虫通常面临高度不可预测的环境，因此长期滞育在这些生物中应该很常见。在这里，我们研究了体外寄生虫肉蝇（双翅目：环裂亚目，无瓣蝇类）中延长滞育的发生情况和频率。我们发现，所研究的种群在滞育持续时间方面具有多态性。因此，分别在约17%和21%的样本中检测到肉蝇在经历2个和3个越冬季节后出现。与第一个春季出现的苍蝇数量相比，滞育延长的苍蝇数量占0.88 - 50%。滞育延长的发生情况和生命周期较长的苍蝇数量都与第一个春季出现的苍蝇数量有关。滞育延长的苍蝇的出现模式与短周期苍蝇观察到的模式非常相似，并且与宿主的出现同步发生。长期滞育在植食性昆虫和一些宿主 - 寄生蜂系统中经常被报道，但据我们所知，这是关于动物真正寄生虫中延长滞育的第二篇报道。我们讨论了这些生物中延长滞育明显罕见的原因。
