Survival rate in Z. tau adults exposed to high temperatures for a short duration
The survival rate in Z. tau adults was affected by the different short-term high-temperature treatments. At 38, 40, and 42 °C, the survival rate of both females and males was significantly lower than that at the control temperature (females: F4,19 = 246.4550, P = 0.0001; males: F4,19 = 111.3460, P = 0.0001). The survival rate of both males and females decreased as the treatment temperature increased, and females was higher than that of males (Table 1). The LT50 value determined for the males was 38.02 °C, which was 1.12 °C lower than that of females (Table 2).
Table 1
Survival rate in Z. tau adults exposed to different short-term high-temperature treatments for 12 h.
Temperature (°C)
|
Females
|
Males
|
25
|
100.00 ±0.00a
|
100.00 ±0.00a
|
34
|
99.02 ±0.98a
|
96.80 ±1.62a
|
38
|
75.28 ±4.31b
|
58.91 ±8.12b
|
40
|
33.14 ±3.95c
|
20.01 ±3.49c
|
42
|
5.44 ±0.72d
|
5.16 ±1.85d
|
Data are presented as mean±SE. The different lowercase letters within the same column indicate significant differences (P < 0.05)
Table 2
LT50 values of Z. tau adults after 12 h of exposure to different high-temperature treatments.
|
Regression equation
|
Correlation coefficient (r)
|
LT50 (95% confidence interval)
|
Females
|
Y = 49.284 X-78.491
|
0.931
|
39.143 (38.583–39.572)
|
Males
|
Y = 38.239 X-60.420
|
0.954
|
38.022(37.644–38.351)
|
Effect of different short-term high-temperature treatments on reproductive behaviors in Z. tau
Mating rate in Z. tau adults exposed to different short-term high-temperature treatments
The short-term exposure to high temperatures was observed to exert a significant effect on the mating rate in Z. tau. In addition, the mating rate of females was different from that of males at the same temperature. In comparison to the control temperature of 25 °C, the high temperatures of 34 °C and 38 °C resulted in a significantly increased mating rate (34 °C: F3,15 = 24.4930, P = 0.0001; 38 °C: F3,15 = 14.1660, P = 0.0003). At these two temperatures, the control♀-treatment♂ combination exhibited the highest mating rate increases of 60.00 % and 53.25 %, respectively, followed by the treatment♀-treatment♂ and treatment♀-control♂ combinations. At 40 °C, the mating rates of all mating combinations were lower than that of the control, except for the treatment♀-control♂ combination (F3,15 = 0.4980, P = 0.6908). At 42 °C, no mating occurred between males and females (Fig. 1).
Pre-mating period in Z. tau adults exposed to different short-term high-temperature treatments
After short-term exposure to high temperatures, the Z. tau adults exhibited a shortened pre-mating period. As the treatment temperature increased, the pre-mating period demonstrated a trend of an initial shortening followed by prolonging. All mating combinations had the shortest pre-mating period at 38 °C (F3.15 = 9.2900, P = 0.0001), and the order was as follows: treatment♀-treatment♂ (39.00 min), treatment♀-control♂ (66.47 min), control♀-treatment♂ (78.59 min), and control♀-control♂ (123.40 min). Among the different mating combinations (Table 3), treatment♀-treatment♂ had the shortest pre-mating period in all short-term high-temperature treatment groups (F3,15 = 8.3580, P = 0.0002).
Table 3
Pre-mating period of Z. tau adults exposed to different short-term high-temperature treatments for 12 h.
Temperature
(°C)
|
Pre-mating period (min)
|
Treatment♀-control♂
|
Control♀-treatment♂
|
Treatment♀-treatment♂
|
Control♀-control♂
|
34
|
97.27 ±7.79ABab
|
109.67 ±11.82ABab
|
85.00 ±10.05BCb
|
123.40 ±12.91a
|
38
|
66.47 ±6.67Bb
|
78.59 ±7.15Bb
|
39.00 ±9.76Cc
|
123.40 ±12.91a
|
40
|
98.75 ±12.77ABa
|
100.00 ±8.66ABa
|
93.75 ±9.87ABa
|
123.40 ±12.91a
|
25
|
123.40 ±12.91A
|
123.40 ±12.91A
|
123.40 ±12.91A
|
—
|
Data are mean±SE. The different lowercase letters after the same row data indicate significant differences between different mating combinations at the same temperature, and the different uppercase letters after the same column data indicate significant differences between the same mating combinations at different temperatures (P< 0.05). The same is below.
Duration of copulation in Z. tau adults exposed to different short-term high-temperature treatments
The duration of copulation in Z. tau adults after short-term exposure to high temperatures was evaluated, and a general increasing trend was observed. At 38 °C, the duration of copulation was significantly greater than that observed for the control (F3,15 = 4.3800, P = 0.0069). The longest durations of copulation for the treatment♀-control♂ and treatment♀-treatment♂ combinations were 648.07 min and 678.00 min, respectively, both of which were observed at 38 °C (treatment♀-control♂: F3,15 = 2.3110, P = 0.0436; treatment♀-treatment♂: F3,15 = 4.8960, P = 0.0051). The longest duration of copulation for the control♀-treatment♂ combination was 640.00 min which was observed at 34 °C (F3,15 = 2.1810, P = 0.0981) (Table 4).
Table 4
The duration of copulation duration of Z. tau adults exposed to different short-term high-temperature treatments for 12 h.
Temperature
(°C)
|
Duration of copulation (min)
|
Treatment♀-control♂
|
Control♀-treatment♂
|
Treatment♀-treatment♂
|
Control♀-control♂
|
34
|
627.42 ±16.87ABa
|
640.00 ±18.43Aa
|
622.47 ±11.29Ba
|
595.47 ±16.23a
|
38
|
648.07 ±14.82Aa
|
637.81 ±9.03Aa
|
678.00 ±18.67Aa
|
595.47 ±16.23b
|
40
|
609.50 ±12.75ABa
|
626.00 ±14.33Aa
|
599.83 ±15.95Ba
|
595.47 ±16.23a
|
25
|
595.47 ±16.23B
|
595.47 ±16.23A
|
595.47 ±16.23B
|
—
|
Fecundity in Z. tau adults exposed to different short-term high-temperature treatments
Mating after short-term exposure to high temperatures exerted an evident effect on fecundity in Z. tau adults. At 34 °C and 38 °C, the fecundity of control♀-treatment♂ was the largest, with the values of 1004.11 eggs and 1016.75 eggs, respectively (34 °C: F3,15 = 16.0720, P = 0.0001; 40 °C: F3,15 = 5.6660, P = 0.0044). At 40 °C, the fecundity decreased significantly (F3,15 = 6.3760, P = 0.0036). The fecundity of treatment♀-control♂ reached the minimum level of 293.25 eggs at 40 °C (F3,15 = 3.3450, P = 0.0345) (Table 5).
Table 5
Fecundity of Z. tau adults exposed to different short-term high-temperature treatments for 12 h.
Temperature
(°C)
|
Fecundity per females
|
Treatment♀-control♂
|
Control♀-treatment♂
|
Treatment♀-treatment♂
|
Control♀-control♂
|
34
|
411.25 ±62.97ABb
|
1004.11 ±77.80Aa
|
541.33 ±69.62Ab
|
545.29 ±35.48b
|
38
|
385.8 ±38.80Bb
|
1016.75 ±116.53Aa
|
538.60 ±41.84Ab
|
545.29 ±35.48b
|
40
|
293.25 ±45.62Bb
|
373.50 ±52.70Bb
|
299.50 ±55.98Bb
|
545.29 ±35.48a
|
25
|
545.29 ±35.48A
|
545.29 ±35.48B
|
545.29 ±35.48A
|
—
|
Hatching rate in Z. tau adults exposed to different short-term high-temperature treatments
Mating after short-term exposure to high temperature affected the hatching rate in Z. tau adults. The hatching rate decreased to different degrees in different treatment groups, among which the hatching rate of treatment♀-control♂ was the lowest (34 °C: F3,15 = 3.0090, P = 0.0456; 38 °C: F3,15 = 0.9680, P = 0.4205; 40 °C: F3,15 = 9.9470, P = 0.0003). The lowest hatching rate of treatment♀-control♂, only 25.71%, was observed at 40 °C (F3,15 = 7.0480, P = 0.0010). The hatching rate of control♀-treatment♂ continued to increase as the treatment temperature increased, with the maximum value of 82.25% reached at 40 °C, and this value was close to that of the control (F3,15 = 2.8630, P = 0.0453). The hatching rate of treatment♀-treatment♂ decreased as the treatment temperature increased (F3,15 = 1.1530, P = 0.3491) (Table 6).
Table 6
Hatching rate in Z. tau adults exposed to different short-term high-temperature treatments for 12 h.
Temperature
(°C)
|
Hatching rate (%)
|
Treatment♀-control♂
|
Control♀-treatment♂
|
Treatment♀-treatment♂
|
Control♀-control♂
|
34
|
58.07 ±7.59Bb
|
61.62 ±5.19Bb
|
72.09 ±5.86Aab
|
82.98 ±3.77a
|
38
|
68.26 ±6.27ABa
|
74.05 ±7.49Aba
|
68.99 ±4.41Aa
|
82.98 ±3.77a
|
40
|
25.71 ±2.97Cb
|
82.25 ±5.21Aa
|
65.78 ±9.92Aa
|
82.98 ±3.77a
|
25
|
82.98 ±3.77A
|
82.98 ±3.77A
|
82.98 ±3.77A
|
—
|
Effect of short-term exposure to high temperatures on the physiological enzyme activities in Z. tau
Antioxidant enzyme activities in Z. tau insects exposed to different short-term high-temperature treatments
Short-term exposure to high temperatures was observed to affect the activities of antioxidant enzymes in Z. tau, and the females and males exhibited differences in their enzyme activities (Fig. 2). With the increase in treatment temperature, the SOD activity of both females and males exhibited a trend of an initial increase followed by a decline. The highest SOD activity was observed at 38 °C, with the females and males exhibiting 3.64 times and 3.10 times the SOD activity, respectively, compared to control. (females: F3.11 = 202.3730, P = 0.0001; males: F3.11 = 210.9200, P = 0.0001). At 40 °C, the SOD activity in males was lower than that in the control and significantly lower than that in the females (F1,5 = 19.6660, P = 0.0114) (Fig. 2a). The highest POD activity was observed at 40 °C, and at this temperature, the activities of females and males were increased by 0.82 times and 0.24 times, respectively, compared to the control (females: F3,11 = 56.4710, P = 0.0001; males: F3,11 = 16.7520, P = 0.0008) (Fig 2b). The CAT activity in females was the highest at 40 °C, and at this temperature, the activity was increased by 0.44 times compared to the control (F3,11 = 27.2690, P = 0.0001). The CAT activity in males decreased as the treatment temperature increased (F3,11 = 18.2520, P = 0.0001) (Fig. 2c).
Activities of detoxifying enzymes in Z. tau insects exposed to different short-term high-temperature treatments
As the treatment temperature increased, the activity of the detoxifying enzymes in Z. tau first increased and then decreased, with differences between females and males (Fig. 3). The AchE activity of females and males was the highest at 38 °C and 34 °C, respectively, and at this temperature, the activities in females and males were increased by 1.04 times and 1.25 times, respectively, compared to the control (females: F3,15 = 161.3250, P = 0.0001; males: F3.15 = 181.6750, P = 0.0001) (Fig. 3a). The CarE activity was higher in the short-term high-temperature treatment groups compared to the control, with the highest activity observed at 38 °C. At 38 °C, the CarE activities of females and males were increased by 7.81 times and 1.69 times, respectively, compared to the control (females: F3.11 = 83.3130, P = 0.0010; males: F3,11 = 101.2170, P = 0.0001). At both control and high temperatures, the CarE activity in males was significantly higher than that in females (25 °C: F1,5 = 208.8800, P = 0.0261; 34 °C: F1,5 = 116.2940, P = 0.0004; 38 °C: F1,5 = 122.4470, P = 0.0004; 40 °C: F1,5 = 35.2140, P = 0.0040) (Fig. 3b). The GST activity in females and males was the highest at 38 °C and 34 °C, respectively, and at these temperatures, the activities in females and males were increased by 1.75 times and 1.29 times, respectively, compared to the control (females: F3,15 = 8.7750, P = 0.0038; males: F3,15 = 14.4580, P = 0.0014). The GST activity in males was higher than that in females at 25 °C and 34 °C, while the activity of females was higher than that of males at 38 °C and 40 °C (25 °C: F1,5 = 0.9160, P = 0.3926; 34 °C: F1,7 = 8.6110, P = 0.0261; 38 °C: F1,7 = 30.9230, P = 0.0051; 40 °C: F1,7 = 59.9920, P = 0.0015) (Fig. 3c).