Effect of Ivermectin on Oviposition Site Selection, Egg Hatchability, and Larvicidal Activity of Housefly Musca domestica Linnaeus, 1758 (Diptera: Muscidae)

Abstract

Ivermectin is a broad-spectrum antiparasitic agent widely used in the treatment of 
parasitic infections caused by helminths, including hookworm and whipworm, as well as 
ectoparasitic and human diseases such as intestinal strongyloidiasis, onchocerciasis, 
and scabies. Houseflies, Musca domestica Linnaeus (Diptera: Muscidae), are important 
mechanical vectors of numerous pathogens, including bacteria, viruses, and parasites, 
thereby posing significant public health and veterinary risks. This study investigated 
the effects of ivermectin on oviposition site selection, egg hatchability, and larval 
development of M. domestica. Oviposition preference was assessed by exposing 30 
sexually mature houseflies within a controlled wooden enclosure (30 × 30 × 30 cm) to 
chicken waste substrate treated with graded ivermectin concentrations of 160.00, 
80.00, 40.00, 20.00, 10.00, 5.00, 2.50, and 0.00 mg/L. Parameters evaluated included 
the Oviposition Activity Index (OAI), percentage Effective Repellency (ER), egg 
hatchability, and larval mortality rates. The highest mean number of egg batches was 
recorded at 80.00 mg/L (8.67 ± 2.60), significantly exceeding the control value (4.33 ± 
0.88). This concentration also exhibited the greatest oviposition attraction, with an ER 
value of −100 and an OAI of 0.38. Hatchability assays revealed a concentration
dependent inhibitory effect of ivermectin, with egg hatching declining from 98% in the 
control to 1% at 160.00 mg/L. Similarly, larval mortality increased progressively with 
concentration, ranging from 60% at 2.50 mg/L to complete mortality (100%) at 160.00 
mg/L. Toxicity analysis yielded LC50 and LC95 values of 1.21 mg/L and 59.32 mg/L, 
respectively, for third instar larvae. The findings demonstrate that ivermectin 
functions both as an oviposition attractant and a potent developmental disruptor in M. 
domestica, highlighting its potential application in integrated housefly management 
strategies aimed at minimizing nuisance and pathogen transmission in human and 
livestock environments.