Composition and toxicity of venom produced by araneophagous white-tailed spiders (Lamponidae: Lampona sp.).

Prey-specialised spiders are adapted to capture specific prey items, including dangerous prey. The venoms of specialists are often prey-specific and less complex than those of generalists, but their venom composition has not been studied in detail. Here, we investigated the venom of the prey-specialised white-tailed spiders (Lamponidae: Lampona), which utilise specialised morphological and behavioural adaptations to capture spider prey. We analysed the venom composition using proteo-transcriptomics and taxon-specific toxicity using venom bioassays. Our analysis identified 208 putative toxin sequences, comprising 103 peptides < 10 kDa and 105 proteins > 10 kDa. Most peptides belonged to one of two families characterised by scaffolds containing eight or ten cysteine residues. Toxin-like proteins showed similarity to galectins, leucine-rich repeat proteins, trypsins and neprilysins. The venom of Lampona was shown to be more potent against the preferred spider prey than against alternative cricket prey. In contrast, the venom of a related generalist was similarly potent against both prey types. These data provide insights into the molecular adaptations of venoms produced by prey-specialised spiders.

Sensitivity of polyphagous (Plodia interpunctella) and stenophagous (Ephestia kuehniella) storage moths to residual insecticides: effect of formulation and larval age.

Pyralid moths, Ephestia kuehniella and Plodia interpunctella, are prevalent stored product pests. The insecticides are the main tool to control these moths in the stores. The data describing the response of these moths to insecticides are scarce. The lethal effect of the organophosphate, pyrethroid, and halogenated-pyrrole on moths larvae were compared in laboratory test. The hypothesis was that the very polyphagous P. interpunctella would have generally higher insecticide tolerance than that of the stenophagous E. kuehniella. Different insecticide concentrations were applied onto the inner surface of glass tube vials. Ten larvae of 14 or 21 d old of E. kuehniella and 7 or 14 d old of P. interpunctella were used by treatment. The larval mortality was checked after 24 h of exposure. The mortality was significantly influenced by age of larvae and the groups of chemicals. No differences among the efficacies of the tested formulations with identical active compounds were found, except significant different mortality of E. kuehniella on deltamethrin formulations. A comparison of analytical standards showed that P. interpunctella was less susceptible to the active ingredient pirimiphos-methyl than E. kuehniella, while E. kuehniella was less susceptible to deltamethrin than P. interpunctella. No differences between the two species were observed for chlorfenapyr. We therefore rejected the hypothesis that polyphagy/stenophagy can be a general predictor of insecticide tolerance in the two tested storage moths. The most important finding for effective use was that the young larvae of both species were more susceptible to tested insecticides than older larvae.