Sublethal and Transgenerational Effects of Abamectin on the Biological Performance of the Predatory Thrips Scolothrips longicornis (Thysanoptera: Thripidae)

Abstract

Determination of sublethal and transgenerational effects of pesticides on natural enemies is necessary for successful implementation of biocontrol in integrated pest management programs. In this study, these effects of abamectin on the predatory thrips Scolothrips longicornis Priesner fed on Tetranychus urticae Koch were estimated under laboratory conditions in which adult predators were exposed to pesticide residues on bean leaves. The estimated values of LC50 for female and male predators were 0.091 and 0.067 µg a.i./ml, respectively. Low-lethal concentrations (LC10, LC20 and LC30) of abamectin severely affected fecundity and longevity of treated females of S. longicornis. In addition, transgenerational effects on reproductive and life table parameters of the subsequent generation were observed. The results from this research can be used to develop guidelines for the use of abamectin to minimize the impact on S. longicornis.

Assessment of ecological risks of agrochemicals requires a new framework.

“…Examples include the lower fecundity of the pea aphid (Acyrthosiphon pisum) exposed to sublethal concentrations of Margosan-O extracts (active ingredient, azadirachtin) [66] and that of the cotton aphid (Aphis gossypii) exposed to cycloxaprid [67], both of which can help reduce the populations of those pests and achieve their effective long-term control. However, similar negative effects can be observed in beneficial, predatory and parasitoid arthropod species, such as the decrease in fecundity of predatory Coleomegilla maculata lady beetles after exposure to commercial formulations of 2,4-D and dicamba herbicides [68] and reduced ovipositions of Eriopis connexa lady beetles exposed to the insecticides teflubenzuron and cypermethrin [69]; the severe reduction in fecundity of predatory thrips (Scolothrips longicornis) exposed to abamectin [70]; or the reduced fecundity of the generalist predatory bug Orius armatus exposed to spinosad [71], amongst many others. Other non-target organisms also experience impaired reproductive effects; for example, the reduced fecundity of queen honey bees (Apis mellifera) exposed to sublethal doses of bifenthrin and deltamethrin [72] or to field relevant residues of imidacloprid [73,74]; the reduced spawning of Australian crimson-spotted rainbowfish (Melanotaenia fluviatilis) and medaka fish (Oryzias latipes) exposed to sublethal concentrations of esfenvalerate insecticide in water [75,76]; or the reduced population growth rate of Daphnia spp.…”

Sublethal Effects of Emamectin Benzoate on Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

“…In N. lugens, LC 10 and LC 25 abamectin significantly inhibited the fecundity of brachypterous [38]. LC 10 , LC 20 and LC 30 abamectin severely affected the fecundity of predatory mite, Phytoseius plumifer (Canestrini and Fanzago) and Scolothrips longicornis Priesner [39,40]. Similar, the fecundity of T. absoluta treated with LC 10 and LC 30 abamectin was significantly lower than the control [41].…”

“…In this study, sublethal concentrations of EMB significantly increased the mortality rates of pupae and pre-adults; reduced the larval and pre-adult stage development times, longevity of male, oviposition period, and fecundity of FAW; and prolonged pupal periods. Similarly, these transgenerational sublethal effects of Abamectin and EMB were found in Tetranychus urticae Koch, P. plumifer, Phytonemus pallidus (Banks), T. absoluta, and S. longicornis, when the parental generation exposed to low lethal concentrations [39][40][41][42]49]. Some hypotheses sought to explain this phenomenon in the offspring generation.…”

“…LC 30 values of EMB significantly reduced the longevity of H. armigera female and male [43]. Low-lethal concentrations (LC 10 , LC 20 and LC 30 ) of abamectin significantly reduced the longevity of predatory thrips S. longicornis [40]. The longevity of T. absoluta female and male exposed to the LC 10 and LC 30 treatment of abamectin was significant lower than the control [41].…”

A “Population Dynamics” Perspective on the Delayed Life-History Effects of Environmental Contaminations: An Illustration with a Preliminary Study of Cadmium Transgenerational Effects over Three Generations in the Crustacean Gammarus

“…Life-history trait alterations after parental exposure to chemicals are frequently documented in F1 generations, notably in arthropods [ 16 , 17 , 18 , 19 ], and the proposals for considering F1 generations in standard toxicity protocols are increasing [ 4 , 20 ]. Nevertheless, few long-term studies in aquatic ecotoxicology have specifically demonstrated transgenerational effects, i.e., effects in generations that were never exposed at any stage of their life, including germ cell and embryo stages.…”