Effects of hunger level and nutrient balance on survival and acetylcholinesterase activity of dimethoate exposed wolf spiders

Abstract

The influence of two nutritional factors (food quantity and quality) on the responses of a wolf spider, Pardosa prativaga (L.K.), to a high dose of the insecticide dimethoate, was investigated in a fully factorial experimental design. Spider groups with different (good and bad) nutrient balance were created by feeding them fruit flies of either high or low nutrient content for 28 days. Both groups were then split into satiated and 14 days starved subgroups. Each of these was further divided into insecticide treated and control halves. Survivorship and acetylcholinesterase (AChE) activity measured on the survivors were used as response variables. Survivorship after topical dimethoate exposure (LD50; 48 h) was influenced by spider body weight, nutrient balance, and starvation. Furthermore, AChE activity was significantly inhibited by dimethoate exposure. A significant interaction between nutrient balance, starvation, and dimethoate exposure revealed synergistic effects of starvation and nutrient imbalance on AChE inhibition by dimethoate in surviving spiders. These results show that the tolerance of non‐target arthropods to dimethoate may vary depending on the nutritional history of the animal.

Impact of cypermethrin on feeding behaviour and mortality of the spider Pardosa amentata in arenas with artificial ‘vegetation’

“…This may not be the case for stronger concentrations of this chemical8 and further research into application rates and number of applications is required. Longevity was not significantly reduced by exposure to a single application of cypermethrin, which is despite starving spiders prior to the experiment, a technique that can increase pesticide impacts 26. The occurrence of ataxia and paralysis of the fourth pair of legs were expected and are in accordance with previous studies that exposed spiders to pyrethroid insecticides 8, 27.…”

Spiders (Araneae) in the pesticide world: an ecotoxicological review

“…Nutritional condition probably affects a spider's ability to cope with many stress factors. Starved lycosid Pardosa prativaga (L Koch, 1870) juveniles exhibited higher mortality after the application of dimethoate than satiated ones 77. This is a crucial finding, as spiders are believed to be starved in the field,78 and mortality in the field can be higher than that observed in the laboratory using satiated spiders.…”

“…The susceptibility of spiders to neurotoxic compounds can be caused either by their inability to produce detoxification enzymes or deficiency to regenerate acetylcholinesterase. The ability to regenerate acetylcholinesterase was found to be affected by the nutritional condition of the lycosid P. prativaga 77. Nielsen et al 100 studied levels of detoxification enzymatic activity of glutathione‐ S ‐transferase and glutathione peroxidase in the lycosid P. amenata after exposure to cypermethrin.…”

Dimethoate, fenvalerate and their mixture affects Hylyphantes graminicola (Araneae: Linyphiidae) adults and their unexposed offspring

“…The effects of pesticides observed on spiders are not limited to their impact on abundance but also include sublethal effects such as a reduction in prey capture ability, body mass and reproductive rate (Deng et al, 2007;Desneux et al, 2007), and changes at the cellular level such as the inhibition of acetylcholinesterase (AChE) or carboxylesterase (CarE) (Pedersen et al, 2002;Babczynska et al, 2006). AChE is an enzyme found at the junction of nerve cells.…”