Search Results (4)

Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), a true omnivorous insect, poses a significant threat to agriculture in the Neartic region. Understanding the feeding behavior of L. lineolaris is crucial for developing integrated pest management strategies. This study aimed to evaluate the effects of different diets on the fitness of L. lineolaris, with a focus on the diet source, feeding regime (phytophagy, zoophagy, and phytozoophagy), and number of diet items. The experimental design in the laboratory investigated the impacts of strawberry, canola and buckwheat flowers, as well as spider mites and aphids to explore relationships found in a conventional strawberry field. Results reveal that diet source, feeding regime, and the number of diet items influence L. lineolaris performance (i.e., survivorship rate, developmental time, and adult weight and length). Improvements in fitness are indicated by higher nymphal survival, shorter developmental time, and larger adults. Immature stages of L. lineolaris show improved fitness when provided with diets rich in canola compared to strawberry flowers and spider mites. Furthermore, the inclusion of multiple diet items in phytozoophagous regimes enhances insect performance. The findings emphasize the significance of understanding L. lineolaris’ nutritional requirements and the biodiversity of target ecosystems for modeling energy flows and designing effective IPM strategies against this pest. This research contributes to the knowledge base for biological control programs targeting L. lineolaris in agricultural systems. Full article

Trophic resource partitioning is one of the main ecological mechanisms of adaptive radiation. The Garra is a highly specialized periphyton feeder that has widened jaws equipped with a horny cutting scraper. In a river located in the Ethiopian Highlands in East Africa, a diversification of Garra composed of six sympatric ecomorphs which were strikingly diverse in trophic morphology was revealed. A hypothesis on trophic resource partitioning was tested using data on diet composition, gut length, and stable isotopes. The obtained results confirmed the trophic diversification of Garra ecomorphs. Three feeding modes were revealed: (i) periphytonophagy, (ii) mixed periphytonophagy and zoophagy, and (iii) zoophagy. The periphyton feeders had a long gut and were enriched in δ¹³C values compared to the shorter gut and lowered δ¹³C values in the zoophagous ecomorphs. Therefore, Garra could respecialize out of its ancestral specialization. This finding does not support the generalists-to-specialists hypothesis on the origin of specializations, and suggests that Liem’s paradox is a more common phenomenon. In the case of specialists, we assume that new ecological opportunities can be ‘visible’ to specialists if they are preceded by relaxed selection constrains that lead to the widening of the ecological/morphological plasticity to jump out of a canalized mode of ancestral specialization. Full article

Zoophytophagous predators provide biocontrol services in various major crops of modern horticulture due to the combination of its predatory capacity and the induction of plant defenses derived from its phytophagy. However, under certain conditions of prey scarcity, these natural enemies can inflict plant damage. Exploitation of genetic variation and subsequent selective breeding on foraging traits is a potential alternative to overcome this inconvenience. In this study, we quantified the genetic variation of phytophagy and zoophagy of Nesidiocoristenuis (Reuter) (Hemiptera: Miridae), a zoophytophagous predator widely used in tomato crops to suppress key pests. We compared nine isofemale lines on their capacity to produce necrotic rings and wilting on tomato plants as a proxy for phytophagy, as well as their efficacy to prey on Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs, as a proxy for zoophagy. Differences between isofemale lines in phytophagy and zoophagy indicated a genetic basis. Variation found in the zoophagy levels was larger than that in phytophagy levels. Our results showed that there is a genetic basis for the variation observed in the feeding behavior of isofemale lines of N.tenuis, highlighting the potential importance of selective breeding for such traits of biocontrol interest. Full article

Zoophytophagous predators provide benefits in agroecosystems when feeding on pests, but they can also cause crop damage. Optimizing the use of zoophytophagous predators as biocontrol agents would require improving pest control and/or limiting damage. Populations of a zoophytophagous species can be composed of a mix of individuals diverging in their level of diet specialization. Consequently, depending on their level of zoophagy, individuals would vary widely in the benefits and risks they provide to pest management. We tested the hypothesis that manipulating the composition of the population of a zoophytophagous insect, the mullein bug, Campylomma verbasci (Hemiptera: Miridae), towards an increased zoophagy would increase their net benefit in an apple orchard. We compared the inherent benefits and risks of two different isogroup lines of mullein bug that genetically differed in their level of zoophagy. In spring, when damage occurs, both strains infrequently punctured apple fruit, which rarely lead to damage and therefore represented a low risk. During summer, only the highly-zoophagous line impacted the spider mite population, while the lowly-zoophagous line did not differ from the control treatments. We concluded that manipulating the composition of the zoophytophagous predator population provided extra net benefits that improved pest control. Full article