Ngomane Nomalizo C, Terblanche John S, Conlong Des E
Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch 7600, Western Cape, South Africa.
South African Sugarcane Research Institute, 170 Flanders Drive, Mount Edgecombe 4300, KwaZulu-Natal, South Africa.
Insects. 2022 Mar 23;13(4):314. doi: 10.3390/insects13040314.
Various combinations and concentrations of cholesterol (C) and stigmasterol (S) were added into a base diet developed for Eldana saccharina. Survival of inoculated neonate was high on all diets (>92% at day 20 and >95% at day 27). Fastest larval development occurred on the minimum specification (MS) (+1.0 gS) and MS (+0.2 gC: 0.2 gS) diets (72 and 70% pupation respectively at day 20). Significantly slower development (15% pupation) occurred on the control diet at day 20. Female pupal weight increased when larvae fed on the MS (+0.1 gC), (+0.1 gS) and (+0.2 gC:0.2 gS) diets (0.2143 ± 0.00 g, 0.2271 ± 0.01 g and 0.2252 ± 0.01 g, respectively) as compared with the control diet (0.1886 ± 0.00 g). Adult emergence was significantly higher (100%) from the MS (+0.1 gS) and MS (+0.2 gC:0.2 gS) diets, as compared with the remaining sterol (95%) and control diets (97%). To potentially increase E. saccharina’s cold tolerance, inclusion of cryoprotectants L-proline (P) and trehalose (T) into the MS diet was investigated. Males from the MS (0.2 gP:0.2 gT), MS (0.5 gP:0.5 gT) and MS (1.0 gT) diets recovered fastest from chill coma treatment (204 ± 44 s, 215 ± 7 s and 215 ± 9 s, respectively) than those from the remaining cryoprotectant diets (305 ± 22 s). The addition of cryoprotectants severely reduced female fertility (<44%) when mated with non-chill coma exposed males. In contrast, eggs from females not exposed to chilling treatment were 84% fertile when mated with males from the same source. The MS (0.2 gC:0.2 gS) diet is the preferred choice to replace the currently used diet, reducing the larval growth period by 60% without negative effects on key life cycle parameters of E. saccharina.
将胆固醇（C）和豆甾醇（S）的各种组合及浓度添加到为甘蔗蛀茎蛾（Eldana saccharina）研制的基础日粮中。在所有日粮上接种的新生幼虫存活率都很高（第20天>92%，第27天>95%）。在最低规格（MS）（+1.0 gS）和MS（+0.2 gC:0.2 gS）日粮上幼虫发育最快（第20天分别有72%和70%化蛹）。在第20天，对照日粮上的发育明显较慢（15%化蛹）。当幼虫取食MS（+0.1 gC）、（+0.1 gS）和（+0.2 gC:0.2 gS）日粮时，雌蛹重量增加（分别为0.2143±0.00 g、0.2271±0.01 g和0.2252±0.01 g），而对照日粮为（0.1886±0.00 g）。与其余甾醇日粮（95%）和对照日粮（97%）相比，MS（+0.1 gS）和MS（+0.2 gC:0.2 gS）日粮的成虫羽化率显著更高（100%）。为了潜在提高甘蔗蛀茎蛾对低温的耐受性，研究了在MS日粮中添加冷冻保护剂L-脯氨酸（P）和海藻糖（T）的情况。来自MS（0.2 gP:0.2 gT）、MS（0.5 gP:0.5 gT）和MS（1.0 gT）日粮的雄虫从冷昏迷处理中恢复得最快（分别为204±44秒、215±7秒和215±9秒），比来自其余冷冻保护剂日粮的雄虫（305±22秒）恢复得快。当与未经历冷昏迷的雄虫交配时，添加冷冻保护剂会严重降低雌虫的繁殖力（<44%）。相比之下，未经过冷处理的雌虫与来自同一来源的雄虫交配时，其卵的受精率为84%。MS（0.2 gC:0.2 gS）日粮是替代目前使用日粮的首选，可将幼虫生长期缩短60%，且对甘蔗蛀茎蛾的关键生命周期参数没有负面影响。
