Abstract: 【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.

Key words: Velarifictorus ornatus, wing dimorphism, enzyme activity, food utilization efficiency, digestive enzyme, resource allocation