Effect of Abamectin on Reproduction and Development of an Avian Tick, Argas (Persicargas) arboreus (Ixodoidea: Argasidae)

Abstract

Entomology Journal publishes original research papers and reviews from any entomological discipline or from directly allied fields in ecology, behavioral biology, Topical application of a single dose (10µl/tick or egg batch) of different concentrations of abamectin (an avermectin) has lethal and biological effects on the engorged mated adult female, immatures and egg of Argas (Persicargas) arboreus that induced 100% mortality at 25,15 and 10 ppm, respectively. Abamectin treatment at lower concentrations of 1-10 ppm interfered with the female reproduction, nymphal and egg development.Abamectin topical (3-10 ppm) application on mated engorged adult female A. (P.) arboreus at different intervals of its reproductive cycle reduced fecundity and fertility of the female, prolonged its preoviposition, oviposition and the egg incubation periods. The effects were most prominent during vitellogenesis and the least at the start of oviposition.Abamectin treatment of the newly moulted fed 2 nd nymphal instar, delayed its moulting and of the resulted 3 rd instar and reduced adult emergence. The treatment caused paralysis and various deformities (15.6-28.6%) as missing legs at the coxal level, changes in colour and failure to moult or to detach the old exuvia in the resulted 3 rd nymphal instar.Egg batch treatment by dipping the freshly deposited eggs for 20 seconds in an aqueous solution of 1-5 ppm abamectin was more effective in reducing normal hatching, increasing unhatching and total inhibition of egg development than topical treatment. However, both methods of treatment similarly prolonged the egg incubation periods and caused abnormal hatching, malformations, and anomalies in the eggs and embryos.

The Effect of Abamectin on Some Biochemical Components in Argas (Persicargas) Arboreuseggs During Embryogenesis

“…The topical application of the LC50 abamectin causing 50% unhatching [17] on the newly deposited eggs on the day of oviposition (day 0 POP) was found to change the concentrations of total protein and DNA and disturbed the patterns of electrophoretically separated protein fractions during embryogenesis in A. (P.) arboreus (days 0-8 POP) in the present study.…”

“…(P.) arboreus eggs reduced the amount of DNA to about 75-84% of that in normal. Also, Aboutaleb et al [17] reported that the treatments with abamectin induced concentration-dependent ovicidal effects, and caused distortions of the eggshell and abnormality of hatching, which were attributed to probable defects in chitinization of the eggshell and fully developed embryos. In conclusion, this study provides valuable insights into the biochemical impact of abamectin on tick eggs and its potential role as an effective tick control measure.…”

“…It was dissolved in distilled water to prepare the concentration used in the present study. Mated, engorged females were placed individually in glass vials under laboratory condition of rearing the tick and the freshly deposited eggs of untreated and topically treated with 1.0 µL of 5 ppm abamectin, which is the LC50 causing 50% unhatching [17] when applied per egg batch (60 eggs). The treated eggs were collected on different days post-treatment and post-oviposition (0, 3, 5 and 8 days POP).…”

“…AVMS caused mortality, paralysis, inhibited feeding, reduced digestion, delayed oviposition, and prevented growth and development in the treated arthropods as in the mosquitoes Aedes aegypti [13] , Anopheles arbiensis [14] , and the argasid tick Argas persicus [15,16] . In Argas (P.) arboreus, abamectin application decreased egg production and hatching, interfered with nymphal molting, and produced malformations and abnormalities during development [17] . Furthermore, AVMS were found to inhibit chitin synthesis in the brine shrimp [18] , disturb immunity, decrease protease activity in Culex pipiens [19] , and interfere with DNA synthesis in some other organisms (fungi) [20] .…”