Zera A J., Larsen A
School of Biological Sciences, University of Nebraska, 68588, Lincoln, NE, USA
J Insect Physiol. 2001 Sep;47(10):1147-1160. doi: 10.1016/s0022-1910(01)00096-8.
The flight-capable morph of the wing-polymorphic cricket, Gryllus firmus, accumulated a substantially greater quantity of total lipid and triglyceride, compared with the obligately flightless morph, during the first five days of adulthood. Increased lipid accumulation in the flight-capable morph was genetically based, and was produced when ovarian growth is substantially reduced in that morph. Temporal changes in lipid levels suggest that the higher triglyceride reserves in the flight-capable morph fed a high-nutrient diet were produced by elevated lipid biosynthesis. By contrast, on a low-nutrient or high carbohydrate diet, increased lipid levels in the flight-capable morph appeared to result primarily from decreased lipid utilization. Increased biosynthesis or retention of triglyceride (the major flight fuel in Gryllus) by the flight-capable morph may significantly divert nutrients from egg production and hence may be an important physiological cause of its reduced ovarian growth. The obligately flightless morph allocated a greater proportion of total lipid to phospholipid than did the flight-capable morph. No functionally-significant differences in total lipid or triglyceride were produced between morphs during the last nymphal stadium. A second flightless morph, derived from the flight-capable morph by histolysis of flight muscles during adulthood, also had reduced amounts of total lipid and triglyceride but increased ovarian growth compared with the flight capable morph on the standard (high-nutrient) diet. Important qualitative and quantitative aspects of lipid metabolism differ genetically between the flight-capable and flightless morphs of G. firmus and likely contribute importantly to their respective adaptations for flight capability vs. reproduction. This is the first study to document genetically-based differences in energy reserves between morphs of a complex (phase, caste, flight) polymorphism in which morphs also differ genetically in key life history traits.
翅膀多态的蟋蟀——坚强 Gryllus firmus 的飞行型形态，在成年后的头五天内，与完全不能飞行的形态相比，积累了大量更多的总脂质和甘油三酯。飞行型形态中脂质积累的增加是基于遗传的，并且是在该形态中卵巢生长大幅减少时产生的。脂质水平的时间变化表明，飞行型形态在高营养饮食下较高的甘油三酯储备是由脂质生物合成增加产生的。相比之下，在低营养或高碳水化合物饮食下，飞行型形态中脂质水平的增加似乎主要是由于脂质利用减少。飞行型形态中甘油三酯（Gryllus 中的主要飞行燃料）生物合成或保留的增加可能会显著转移用于产卵的营养物质，因此可能是其卵巢生长减少的一个重要生理原因。完全不能飞行的形态比飞行型形态将更大比例的总脂质分配给磷脂。在最后一个若虫阶段，不同形态之间的总脂质或甘油三酯没有产生功能上的显著差异。第二种不能飞行的形态是在成年期通过飞行肌肉的组织溶解从飞行型形态衍生而来的，与标准（高营养）饮食下的飞行型形态相比，其总脂质和甘油三酯的量也减少了，但卵巢生长增加。G. firmus 的飞行型和不能飞行型形态在脂质代谢的重要定性和定量方面存在遗传差异，这可能对它们各自适应飞行能力与繁殖能力起到重要作用。这是第一项记录复杂（阶段、等级、飞行）多态性形态之间基于遗传的能量储备差异的研究，其中形态在关键生活史特征上也存在遗传差异。
