Woodring Joseph, Weidlich Sandy
Department of Animal Ecology II, University of Bayreuth, Bayreuth, Germany.
Department of Animal Ecology I, University of Bayreuth, Bayreuth, Germany.
Arch Insect Biochem Physiol. 2016 Nov;93(3):121-128. doi: 10.1002/arch.21346. Epub 2016 Jul 22.
In Gryllus bimaculatus, the size of the caecum decreases in the latter half of each instar to a stable minimal size with a steady minimal rate of digestive enzyme secretion until feeding resumes after ecdysis. The higher the percent protein in the newly ingested food, the faster and larger the caecum grows, and as a consequent the higher the secretion rate of trypsin and amylase. When hard boiled eggs (40% protein) are eaten the caecum is 2× larger, the trypsin secretion is almost 3× greater, and amylase 2.5× greater then when fed the same amount of apples (1.5% protein). Only dietary protein increases amylase secretion, whereas dietary carbohydrates have no effect on amylase secretion. The minimal caecal size and secretion rate must be supported by utilization of hemolymph amino acids, but the growth of the caecum and increasing enzymes secretions after the molt depend upon an amino acid source in the lumen. This simple regulation of digestive enzyme secretion is ideal for animals that must stop feeding in order to molt. This basic control system does not preclude additional regulation mechanisms, such as prandal, which is also indicated for G. bimaculatus, or even paramonal regulation.
在双斑蟋中，盲肠的大小在每一龄的后半期会减小至稳定的最小尺寸，消化酶分泌速率也稳定在最低水平，直到蜕皮后恢复进食。新摄入食物中的蛋白质百分比越高，盲肠生长得越快且越大，相应地，胰蛋白酶和淀粉酶的分泌速率也越高。当食用煮熟的鸡蛋（蛋白质含量40%）时，盲肠大小是食用等量苹果（蛋白质含量1.5%）时的2倍，胰蛋白酶分泌量几乎是其3倍，淀粉酶分泌量是其2.5倍。只有膳食蛋白质会增加淀粉酶分泌，而膳食碳水化合物对淀粉酶分泌没有影响。盲肠的最小尺寸和分泌速率必须通过利用血淋巴中的氨基酸来维持，但蜕皮后盲肠的生长和消化酶分泌的增加取决于肠腔内的氨基酸来源。这种对消化酶分泌的简单调节对于那些必须停止进食以进行蜕皮的动物来说是理想的。这种基本控制系统并不排除其他调节机制，比如也适用于双斑蟋的餐时调节，甚至是超常调节。
