Survival and reproduction of Onthophagus landolti (Coleoptera: Scarabaeidae) exposed to ivermectin residues in cattle dung.
Two bioassays were conducted in parallel to assess the effects of cattle treated with either 1% ivermectin (IVM) or 3.15% IVM (dosed at 0.2 and 0.63 mg kg-1, respectively) on reproduction and survival of Onthophagus landolti Harold. Adult beetles were exposed 10 days to faeces of treated cattle starting at: one day before treatment (controls), 3, 6, 14, 28 and 35 days post-treatment. Adult survival of O. landolti was not affected by either of the two treatments. Faecal residues of 1% IVM almost completely suppressed fecundity of beetles at 3, 6 and 14 days post-treatment (dPT), and reduced fecundity of O. landolti at 28 dPT ( 38.3%), relative to controls. Meanwhile, IVM residues after treatment with 3.15% IVM almost completely suppressed fecundity of beetles at 3, 6, 14 and 28 dPT, and reduced fecundity of O. landolti at 35 dPT (80.9%), relative to controls. Larval survival was significantly reduced only at 3 dPT with 1% IVM. Meanwhile, treatment with 3.15% IVM significantly reduced larval survival at 6, 14 and 28 dPT. Larval mortality was recorded only in L-I and L-II instars. Moreover, in both bioassays, most of the L-I and L-II specimens that survived showed signs of toxicity. In conclusion, residual IVM in cattle faeces after treatment with injectable IVM has a detrimental effect on the fecundity of adult O. landolti up to 4 weeks post-treatment and on the subsequent larval survival.
Facultad de Medicina Veterinaria y Zootecnia,Universidad Autónoma de Yucatán,Km. 15.5 carretera Mérida-Xmatkuil. C.P. 97100,Yucatán,México.
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Pérez-Cogollo
Facultad de Medicina Veterinaria y Zootecnia,Universidad Autónoma de Yucatán,Km. 15.5 carretera Mérida-Xmatkuil. C.P. 97100,Yucatán,México.
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Rodríguez-Vivas
Centro de Investigaciones Regionales "Dr Hideyo Noguchi".Av. Itzaes No. 490 × 59 Col. Centro. C.P. 97000,Yucatán,México.
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Reyes-Novelo
Facultad de Medicina Veterinaria y Zootecnia,Universidad Autónoma de Yucatán,Km. 15.5 carretera Mérida-Xmatkuil. C.P. 97100,Yucatán,México.
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Delfín-González
Facultad de Ingeniería Química,Universidad Autónoma de Yucatán,Periférico Norte Km. 33.5,Tablaje catastral 13615,Colonia Chuburná de Hidalgo Inn. C.P. 97203,Yucatán,México.
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Muñoz-Rodríguez
D000818:Animals; D001517:Coleoptera / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D005243:Feces / Q000737:chemistry; D007306:Insecticides / Q000494:pharmacology*; D007559:Ivermectin / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D008136:Longevity / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects
D007306:Insecticides; D007559:Ivermectin
dung beetle; macrocyclic lactone; non-target effect; toxicity test