丽斗蟋翅二型雄虫食物消化能力及消化酶活性比较

Comparison of digestive capability and digestive enzyme activities in male adults of the wing-dimorphic cricket Velarifictorus ornatus(Orthoptera:Gryllidae)

【目的】丽斗蟋Velarifictorus ornatus具明显的翅二型现象,为探讨翅型分化对丽斗蟋翅二型雄虫消化能力及中肠内消化酶活性产生的影响,对长翅型与短翅型雄虫食物消化能力及中肠内消化酶活性进行了检测比较。【方法】我们采取重量营养指数测定了羽化后12 d内丽斗蟋两型雄成虫增长量、相对增长率、取食量、食物利用率、近似消化率和食物转化率。为进一步明确丽斗蟋翅二型成虫食物消化能力与中肠内消化酶活性的关系,我们采用4种专用底物测定了中肠内用于分解蛋白质、脂肪和碳水化合物的总蛋白酶、胰蛋白酶、脂肪酶和淀粉酶的活性。【结果】结果表明,丽斗蟋两型雄虫取食量、食物转化率、食物利用率与增长量均无统计差异,但中肠内消化酶活性变化规律不同。成虫羽化后4 d时,长翅型雄虫中肠内总蛋白酶与胰蛋白酶活性显著高于短翅型雄虫,相反,羽化后0 d时,短翅型雄虫中肠内总蛋白酶与胰蛋白酶活性则显著高于长翅型雄虫,而羽化后12 d时,虽然短翅型雄虫总蛋白酶活性高于长翅型雄虫,但胰蛋白酶活性在两型雄虫间并无差异。成虫羽化后0 d时,两型雄虫脂肪酶活性无差异,但无论是羽化后4或12 d,长翅型雄虫中肠内脂肪酶活性皆显著大于短翅型雄虫。成虫羽化后4 d时,短翅型雄虫中肠内淀粉酶活性显著高于长翅型雄虫,而羽化后0与12 d时,两型雄虫间无显著差异。【结论】丽斗蟋翅二型雄虫食物消化能力无显著差异,但羽化后不同时间,中肠内消化酶活性存在差异,该差异可能与成虫羽化后不同时期,翅二型雄虫在飞行与繁殖投资中对不同能源物质的需求有关。

[ Aim] The cricket species Velarifictorus ornatus displays distinct wing dimorphism. In order to understand the effect of wing dimorphism on the digestive capability and digestive enzyme activities, we investigated the food utilization efficiency and digestive enzyme activities in long-winged （LW） and short- winged （SW） male adults. [ Methods ] To evaluate the food utilization efficiency of males in V. ornatus, we calculated the gravimetric nutritional indexes of male adults of V. ornatus in the first 12 days after last molt, including food consumption （CR）, growth （GR）, relative growth （RGR）, approximate digestibility （AD）, efficiency of conversion of ingested food to body matter （ECI）, and efficiency of conversion of digested food to body matter （ECD）. In order to further explore the relationship between food utilization efficiency and digestive enzyme activities, we analyzed the activities of four enzymes （ total protease, trypsin, lipase, and amylase） that are primary enzymes for protein, fat, and carbohydrate processing, respectively, by using four special substrates. [ Results ] No significant difference was observed in all the gravimetric nutritional indexes between LW and SW males of V. ornatus, but the activities of digestive enzymes showed difference between LW and SW males. Total protease activity was significantly higher in SW males than in LW males on day 0 and day 12 after emergence, but lower in SW males than in LW males on day 4 after emergence. Lipase activity was similar in both LW and SW males on day 0 after emergence, but increased significantly higher in LW males afterwards. Amylase activity was significantly higher in SW males than in LW males on day 4 after emergence, but not significantly different between them on day 0 or day 12 after emergence. [ Conclusions] Our findings indicated that there is no difference in digestive capability between LW and SW male adults of V. ornatus, but obvious difference exists in digestive enzyme activities between them, which might be correlated with the different resource needs for the development of flight muscles and reproductive organs at different period after adult emergence.