Fairbairn D J, Roff D A
Department of Biology, Concordia University, 1455 de Maisonneuve Blvd., West, Montreal, Quebec, CANADA, H3G 1M8.
Department of Biology, McGill University, 1205 Dr. Penfield Avenue, Montreal, Quebec, CANADA, H3A 1B1.
Evolution. 1990 Nov;44(7):1787-1795. doi: 10.1111/j.1558-5646.1990.tb05249.x.
Migration by flight is an important component of the life cycles of most insects. The probability that a given insect will migrate by flight is influenced by many factors, most notably the presence or absence of fully-developed wings and functional flight musculature. Considerable variation has also been reported in the flight propensity of fully-winged individuals with functional flight musculature. We test the hypothesis that these components of migratory tendency are genetically correlated in a wing-dimorhic cricket, Gryllus firmus. Flight propensity and condition of the dorsal longitudinal flight muscles (DLM) are examined in fully-winged (LW) crickets from lines selected for increasing and for decreasing %LW, as well as from unselected control lines. Increased %LW is found to be associated with increased flight propensity among individuals with intact DLM, and with retention of functional DLM. The opposite is true for lines selected for decreased %LW. These results indicate both phenotypic and genetic correlations among behavioral, physiological, and morphological traits determining migratory tendency. We propose that these correlations may result from the multifunctional role of juvenile hormone, which has been reported to influence wing development, flight muscle development and degeneration, and flight propensity. Finally, we discuss the potential influence of genetic correlations for migratory traits on the evolution and maintenance of migratory polymorphisms in insects.
飞行迁移是大多数昆虫生命周期的重要组成部分。特定昆虫通过飞行进行迁移的概率受多种因素影响，其中最显著的是是否拥有发育完全的翅膀和功能性飞行肌肉组织。据报道，具有功能性飞行肌肉组织的全翅个体在飞行倾向方面也存在相当大的差异。我们在一种翅二型蟋蟀（Gryllus firmus）中检验了这样一个假设，即迁移倾向的这些组成部分在遗传上是相关的。我们对从为增加和减少全翅个体百分比（%LW）而选择的品系以及未选择的对照品系中选取的全翅（LW）蟋蟀的飞行倾向和背纵飞行肌（DLM）状况进行了研究。发现在DLM完整的个体中，%LW的增加与飞行倾向的增加以及功能性DLM的保留有关。而对于为降低%LW而选择的品系，情况则相反。这些结果表明，在决定迁移倾向的行为、生理和形态特征之间存在表型和遗传相关性。我们提出，这些相关性可能源于保幼激素的多功能作用，据报道，保幼激素会影响翅膀发育、飞行肌肉发育与退化以及飞行倾向。最后，我们讨论了迁移性状的遗传相关性对昆虫迁移多态性的进化和维持的潜在影响。
