Stimulatory Sublethal Response of a Generalist Predator to Permethrin: Hormesis, Hormoligosis, or Homeostatic Regulation?

Abstract

The assessment of pesticide effects in arthropods historically have relied heavily on acute lethal effects. Although the sublethal responses to such compounds are sometimes neglected, stimulatory effects associated with low doses of compounds toxic at higher doses, such as pesticides, have been widely reported in recent years and recognized as a general toxicological phenomenon. Evidence of such stimulatory response has also been reported among mites and a few insect pest-species exposed to pesticides and recognized as a one of the potential causes underlying pest resurgence and secondary pest outbreaks. However, fitness parameters and its implications were seldom considered in these studies and natural enemies are not usually target of attention. Here, we reported the stimulatory effect of sublethal doses (ranging from 0.02 to 172.00 ppb in addition to the control) of the pyrethroid permethrin topically applied to third instar nymphs of the spined soldier bug, Podisus distinctus (Stål) (Heteroptera: Pentatomidae). The parameters estimated from the fertility tables of insects exposed to the increasing doses of insecticide indicated a slight increase in the mean survival time for doses > or = 0.20 ppb and a peak in the net reproductive rate at 1.72 ppb. This trend is coincident and correlated with the intrinsic rate of population growth (n = 18, r = 0.78, P = 0.0001), which also shows a peak at 1.72 ppb, leading to higher reproductive values of insects exposed to this dose. The phenomenon is consistent with insecticide-induced hormesis, for which the potential implications are discussed.

Demonstration of an adaptive response to preconditioning Frankliniella occidentalis (Pergande) to sublethal doses of spinosad: a hormetic-dose response

“…Induction of CarE and P450s by exposure to LC 10 and LC 25 sublethal concentrations of spinosad were also found in the Spin-S and Spin-Sub strains, respectively, and the induced effects were higher at the LC 25 concentration ). These results indicate that exposure to low doses of spinosad may induce production of enzymes-like esterases and P450s that are important in detoxification processes, and these adaptive hormesis responses might help to augment the development of resistance or increased tolerance to spinosad (Guedes and Cutler 2014;Guedes et al 2009). A similar phenomenon has been reported in other sublethal-effects studies (Yin et al 2009).…”

Side Effects of Fungicides Used in Cucurbitaceous Crop on Trichogrammaatopovirilia Oatman & Platner (Hymenoptera: Trichogramatidae)

“…Studies support the idea that hormesis contributes to increasing the performance of beneficial organisms (Calabrese, 1999;Guedes et al, 2009;Zanuncio et al, 2003).…”

Sublethal Effects of Cry 1F Bt Corn and Clothianidin on Black Cutworm (Lepidoptera: Noctuidae) Larval Development

“…Regardless of the inducer, low level effects may not be caused by the same mechanism that is observed at greater concentrations (Giesy 2001). Hormesis has been observed in a wide range of cells, tissues, and species (Giesy 2001) and is well documented in the pharmacological, toxicological (Calabrese and Baldwin 2001), and entomological literature (Luckey 1968, De Leo et al 1998, Guedes et al 2009). …”

“…Hormoligosis is frequently used as a synonym of hormesis by entomologists and acarologists (Guedes et al 2009). The two terms are however not interchangeable, because hormoligosis, unlike hormesis, occurs under suboptimal growth conditions (Guedes et al 2009).…”