Silicon can enhance plant resistance to herbivores, but its practical value depends on whether effective doses remain robust across herbivore species, plant water states, time after application and host genotypes. We tested a prespecified minimum-effective silicon rule in durum wheat against Sitobion avenae and Rhopalosiphum padi under well-watered and water-deficit conditions. In cv. Karim, 0, 1, 2 and 4 mM sodium metasilicate were compared, and the lowest treatment satisfying cross-species suppression and plant-performance criteria was frozen for subsequent experiments. The 2 mM treatment reduced observed day-7 cell-mean aphid abundance by 54.19
Pollination studies generally emphasize bees, although flies are abundant flower visitors and may remain active under conditions in which bees do not forage. Pollination success depends not only on how much pollen is carried but also on whether the pollen is carried on body surfaces likely to contact flower stigmas. We compared exposed pollen load and its body placement on 527 bee (Hymenoptera) and fly (Diptera) specimens collected in a commercial apple orchard. Pollen was quantified by direct microscope counts for 376 specimens and hemocytometer wash counts for an additional 151 specimens. Pollen concentrated within scopae and corbiculae, which is less available for transfer, was excluded from our counts. High pollen loads among apid and megachilid bees contrasted with low loads among chironomid flies. Bees carried nearly four times more exposed pollen than flies, averaging 426 grains per specimen compared with 108 for flies. Megachilidae and Apidae carried the largest pollen loads among bees, whereas Muscidae carried the largest pollen loads among flies. Bees were more likely to carry pollen on the head and thorax, body regions well positioned for stigma contact, whereas flies were more likely to carry pollen on the legs and wings, regions whose relative effectiveness for pollen transfer is less well established. Whereas flies carried substantial exposed pollen loads, bees carried nearly four times more pollen and were more likely to carry it on the head and thorax, where it may be more likely to contact floral stigmas.
Floral traits associated with floral display that likely enhance pollinator attraction may inadvertently increase attractiveness to antagonists such as pre-dispersal seed predators, yet direct tests of this trade-off within closely related species remain scarce. We investigated this relationship in three threatened grass aloes - Aloe albida, A. craibii, and A. chortolirioides - that differ markedly in floral colour, display, morphology, and flowering ecology. We quantified fruit and seed damage, identified predator and parasitoid assemblages, and tested whether independently measured floral and plant traits predicted fruit and/or seed utilisation within each species. Substantial reproductive loss occurred in all three species, with fruit utilisation ranging from 45 to 79
Pollination syndromes are often used to guide pollinator conservation and ecosystem restoration, but their effectiveness in predicting main pollinators is contested. This study characterized floral traits and pollination syndromes of 69 plant species in a Mixed Ombrophilous Forest fragment and assessed whether observed floral visitors matched the expected syndromes. Floral attributes (anthesis, color, odor, size, shape, symmetry, orientation, stamen position, nectar guides, resources) and plant characteristic (habit, sexual system, plant status, and occurrence) were recorded. Syndromes were inferred using literature, and insect visitors were collected and identified. The main visitor group (bee, beetle, butterfly, moth, fly, or wasp) was determined by highest visitation frequency. Logistic regression, subsampling, and sensitivity analyses were used to test the effects of monitoring time, the stability of main visitor groups, and alternative treatments of ties. Only 39.4
Sixteen rapeseed (Brassica napus L.) genotypes were evaluated for cabbage aphid (Brassica napus) infestation under natural field conditions at one research station in the 2024–2025 season, using two sowing dates and five observation dates. Genetic diversity was assessed using ISSR, SRAP, and SCoT markers. Descriptive infestation indices were comparatively low for SRL-1400-4 and high for SRL-1400-13, but resistance stability has not been established beyond this environment. The marker assays yielded 567 scored bands, including 377 polymorphic bands. Previously reported dominant-marker polymorphism information content (PIC) values include an inadmissible value of 0.52 and therefore require recalculation from the original band-presence matrix before marker informativeness can be ranked. Reported Mantel correlations (SCoT 0.521, SRAP 0.412, ISSR 0.346) cannot be interpreted without documenting compatible distance-matrix construction and permutation significance testing. The present evidence supports descriptive germplasm characterization, not validated resistance mechanisms or marker–trait associations.
