School of Biological Sciences, The University of Western Australia, Perth 6009, Western Australia, Australia; CSIRO Health and Biosecurity, Floreat, Western Australia 6014, Australia.
School of Biological Sciences, The University of Western Australia, Perth 6009, Western Australia, Australia; CSIRO Health and Biosecurity, Floreat, Western Australia 6014, Australia.
Sci Total Environ. 2024 Oct 1;945:174050. doi: 10.1016/j.scitotenv.2024.174050. Epub 2024 Jun 19.
Anthelmintic residues in livestock dung can adversely affect beneficial organisms. Targeted selective treatment (TST) of a reduced proportion of livestock with anthelmintics can slow resistance development in gastrointestinal nematodes by providing residue-free dung which could also benefit non-target organisms. We tested effects of TST on survival and reproduction of the dung beetle Onthophagus taurus (Scarabaeidae) in a factorial glasshouse experiment (Experimental treatments: five TST levels, 0.00, 0.25, 0.50, 0.75, 1.00 x four ivermectin concentrations, 125, 250, 375, 500 ppb). Each mesocosm comprised a 60 L bin containing sand, four dung pats and six pairs of adult beetles (F0 generation). No effects of TST level and ivermectin concentration on mortality of F0 adults after one week were observed. F0 adult brood ball production was affected by TST level, particularly at high ivermectin concentrations. Brood ball production increased as more untreated pats became available, with greater increases at higher ivermectin concentrations. We tested for evidence of a reported attraction of dung beetles to ivermectin-treated dung using a novel glitter-marker to trace the origin of dung used in brood balls. Where mesocosms contained both dung types, the proportion of brood balls created from untreated dung showed no statistical difference from the null expectation based on untreated dung availability in the mesocosm. Emergence of F1 adults was affected by the increase in TST, with this effect dependent on concentration. Treatments with concentrations of 250-500 ppb had the lowest emergence rates (ca. 5-20 % in mesocosms where all dung pats were treated) but emergence rates increased with TST level, reaching 68-88 % emergence where no dung pats were treated with ivermectin. Ivermectin-induced mortality occurred predominantly at egg and first instar stages. TST can provide refuges for dung beetles offering a strategy for livestock producers to maintain livestock welfare whilst benefiting from ecosystem services provided by important insects.
家畜粪便中的驱虫剂残留会对有益生物产生不利影响。用驱虫剂对少量家畜进行有针对性的选择性处理（TST），可以通过提供无残留粪便来减缓胃肠道线虫的耐药性发展，这也有利于非目标生物。我们在一个因子温室实验中测试了 TST 对蜣螂 Onthophagus taurus（蜣螂科）生存和繁殖的影响（实验处理：五个 TST 水平，0.00、0.25、0.50、0.75、1.00 x 四种伊维菌素浓度，125、250、375、500 ppb）。每个中尺度包含一个 60 升的箱子，其中包含沙子、四个粪便垫和六对成虫（F0 代）。在一周后，没有观察到 TST 水平和伊维菌素浓度对 F0 成虫死亡率的影响。TST 水平对 F0 成虫的卵囊生产有影响，尤其是在高伊维菌素浓度下。随着未处理的粪便垫数量的增加，卵囊产量增加，在高伊维菌素浓度下增加更多。我们使用一种新型闪光标记物来测试对报道的蜣螂对伊维菌素处理粪便的吸引力的证据，以追踪用于卵囊的粪便的来源。在中尺度包含两种粪便类型的情况下，来自未处理粪便的卵囊的比例与中尺度中未处理粪便的可用性的零假设没有统计学差异。F1 成虫的出现受到 TST 增加的影响，这种影响取决于浓度。用 250-500 ppb 浓度处理的处理方法具有最低的出现率（在所有粪便垫都用伊维菌素处理的中尺度中约为 5-20%），但随着 TST 水平的增加，出现率增加，在没有用伊维菌素处理粪便垫的情况下，出现率达到 68-88%。伊维菌素诱导的死亡率主要发生在卵和第一龄期。TST 可为蜣螂提供避难所，为畜主提供了一种在维持家畜福利的同时受益于重要昆虫提供的生态系统服务的策略。
