Plants produce diverse chemical defenses with contrasting effects on different insect herbivores. Deploying herbivore‐specific responses can help plants increase their defensive efficiency. Here, we explore how variation in induced plant responses correlates with herbivore species, order, feeding guild, and level of specialization. In a greenhouse experiment, we exposed 149 plants of Salix fragilis (Linnaeus, 1753) to 22 herbivore species naturally associated with this host. The insects belonged to four orders (Coleoptera, Lepidoptera, Hemiptera, and Hymenoptera), three feeding guilds (external leaf‐chewers, leaf‐tying chewers, and sap‐sucking), and included both dietary specialists and generalists. Following herbivory, we quantified induced changes in volatiles and nonvolatile leaf metabolites. We performed multivariate analyses to assess the correlation between herbivore order, feeding guild, dietary specialization, chewing damage by herbivores, and induced responses. The volatile composition was best explained by chewing damage and insect order, with Coleoptera and Lepidoptera eliciting significantly different responses. Furthermore, we recorded significant differences in elicited volatiles among some species within the two orders. Variation in nonvolatile leaf metabolites was mainly explained by the presence of insects, as plants exposed to herbivores showed significantly different metabolites from controls. Herbivore order also played a role to some extent, with beetles eliciting different responses than other herbivores. The induction of volatile and nonvolatile leaf metabolites shows different levels of specificity. The specificity in volatiles could potentially serve as an important cue to specialized predators or parasitoids, increasing the efficacy of volatiles as indirect defenses. By contrast, the induction of nonvolatile leaf metabolites was largely unaffected by herbivore identity. Most nonvolatile metabolites were downregulated, possibly indicating that plants redirected their resources from leaves in response to herbivory. Our results demonstrate how diverse responses to herbivores can contribute to the diversity of plant defensive strategies.

Plants produce volatile organic compounds (VOCs) in response to herbivory. Such signals mediate plant interactions with herbivores and their natural enemies. Different herbivores can elicit distinct responses in plants, influencing predator attraction. While invertebrate predators primarily rely on chemical cues, birds often use visual cues in addition to olfactory signals. We conducted a field experiment on two abundant willow species, Salix cinerea and Salix fragilis , to test whether herbivore‐specific elicitors induce changes in VOC emissions and if these changes affect predation rates. Treatments included insect‐derived extracts from beetles and caterpillars, and mechanical damage. We measured VOC emissions, leaf reflectance, and predator attack rates on plasticine caterpillar models. We detected 22 VOCs in total. Out of these, all were detected in S. fragilis and 19 in S. cinerea. We found species‐specific responses and predator interactions: In S. fragilis , treatments induced distinct VOC blends and individual compounds, such as ( E )‐β‐farnesene, which correlated with invertebrate predation. In S. cinerea , treatment‐specific effects were limited to individual VOCs, while variation in background VOCs influenced bird predation. In S. cinerea, leaf reflectance did not significantly vary with treatments but correlated with bird predation. Our findings highlight that specificity in plant responses to herbivory translates into differences in predator attraction under natural field conditions. We show that closely related plant species with contrasting defence strategies route top‐down control through different predator guilds, where inducible VOCs in S. fragilis recruit invertebrate predators, while constitutive chemical and visual traits in S. cinerea attract birds. Our findings provide a mechanistic explanation for variation among previous reports on VOC‐mediated predator attraction and show that some plant species rely on herbivore‐specific induction to attract predators of their herbivores while others employ alternative or constitutive defence cues. Read the free Plain Language Summary for this article on the Journal blog.

The principle and the techniques applied in DNA extraction play a pivotal role in the obtention of a purified genetic material. The present study investigates the efficiency of eight protocols in the DNA extraction of Hypostomus commersoni, an essential component of South American freshwater ichthyofauna. The quality of samples was assessed through spectrophotometry, gel electrophoresis, and PCR-RAPD markers amplification. The efficiency of DNA extraction was influenced both by the method applied and the target-tissue of choice. Higher concentrations and yield of DNA were obtained from ocular tissue, with a positive spectrum of incubation in lysis buffer for up to 36 hours after sample collection, using fresh tissues and in the presence of a high concentration of Proteinase K (20 mg.ml-1). In these conditions, samples were successfully amplified. To date, there is no record of description for the parameters analyzed in this work, neither the description of RAPD markers for the species H. commersoni.