Arthropod-Plant Interactions最新文献

Soybean (Glycine max) is a valuable crop in agricultural production. Our previous study showed that extract from the cyanobacterium strain Desmonostoc alborizicum is toxic as demonstrated by sequencing the mcyD and mcyG genes of the microcystin synthetase (mcy) cluster. We hypothesized that bioactive compounds from Desmonostoc alborizicum would enhance the defense responses of soybean to cowpea aphids (Aphis craccivora Koch), a severe pest of leguminous crops. Results showed that inoculation with cowpea aphid affected oxidative stress in soybean leaves. A potent production of superoxide anion radical (O₂·⁻) was observed in 30 aphids 12 h post infestation (hpi), while the highest amount of hydrogen peroxide (H₂O₂) was observed in 30 aphids 96 hpi without treatment of cyanobacteria extract. Results of enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) showed that they were intensely stored to decrease the toxic effects of reactive oxygen species (ROS). The highest generation of SOD and CAT was observed in 30 and 20 aphids 96 hpi and 24 hpi with treatment of cyanobacteria extract, while the highest amount of GPx (36.95 nkat mg⁻¹ protein) was observed in aphids 96 hpi, respectively, without treatment of cyanobacteria extract.

When exposed to cyanobacteria extract, the production of O₂·⁻ and H₂O₂, as well as the activity of GPx, were significantly reduced, leading to a substantial decrease in oxidative damage. However, the activity of SOD and CAT showed a remarkable increase in the leaves infested with cowpea aphids when treated with cyanobacteria extract. This suggests that the application of cyanobacteria extract may have a novel impact on the antioxidative response of soybean plants in the context of their interaction with cowpea aphids. Incorporating the effect of cyanobacteria extract into current research data can enhance our understanding of the soybean–aphid interaction.

Avocado is a pollinator-dependent crop rich in fiber, monounsaturated oils, vitamins, and minerals, which is seeing an increase in global demand. While some studies have shown that insect pollination improves avocado fruit set, the effects of pollinators on fruit quality and the nutritional profile remain unclear. Furthermore, it remains untested whether a potential pollination deficit can be compensated by the supplementation of farms with extra pollinators. We quantified the contribution of insect pollination on fruit and seed weight, and oil, protein, carbohydrate, and phytochemical (flavonoid and phenolics) contents, and assessed if the supplementation of pollinators on farms can improve fruit parameters. The experiment was conducted in 36 smallholder avocado farms of which 18 farms were supplemented with two Apis mellifera bee hives, while 18 were used as controls. Four manipulative pollination treatments were conducted: hand, open, self- and wind pollination. We observed that avocado fruit weight was significantly higher (213.7 g) for insect pollinated flowers than in case of wind- (107.8 g) or self-pollination (95.1 g).

Insect pollination resulted in heavier seeds (29.5 g) as well as higher oil contents, clearly showing that insect pollination was required to reach a high seed yield and quantity of oil. Honey bee supplementation on farms enhanced the avocado fruit weight by 18%, and increased avocado oil content by 3.6%. As the marketability of avocado directly depends on fruit size and oil content, a sustainable management of bee communities may be of key importance for the long-term profitability of avocado agriculture.

Cerrado is one of the most diverse savannahs on the planet in terms of plant species and insect herbivores, as well as in hotspot in the diversity of plant–galling insect interactions. The aims of the study were as follows: characterize the diversity of host plants (HP) and their associated gall-inducing insects (GII) in the Brazilian Cerrado; estimate the species richness of GII for the Cerrado vegetation; determine if GII species richness is shaping the plant species richness, taxa size, and the taxon age; to analyze the number of species per HP communities, and estimate the number of GII (co-threatened) in endangered plants. We used a comprehensive database compiling information available in 32 inventories on GII and their HP from several areas of the Cerrado. We find 994 morphospecies associated with 505 HP. Additionally, we estimated a total of 11,745 GII for the Cerrado, of which 8,574 were cecidomyiid species. More than 58% of the HP harbored a single GII, while 42% had more than two GII, corroborating the high specialization of the GII on their HP. Finally, we detected nine threatened HP hosting 27 species of GII, which are considered super-hosts. Our study is the first to analyze the assemblages of HP and their GII in the Cerrado vegetation at a regional scale. Our findings indicate a high regional diversity of both HP and GII, and we highlight the importance of plant species richness, taxon size, and the taxon age as factors shaping the diversity of GII in the Cerrado.

Fifty years have passed since the first descriptions of the “floral oil syndrome” by Stefan Vogel. Over those past decades, substantial knowledge was obtained mainly on the taxonomic distribution, morphologies and phylogenetics involved in floral oil-mediated interactions. Many studies have also extended the understanding of several ecological and evolutionary aspects of these interactions over the last two decades, mainly in neotropical environments, where oil bee–oil flower interactions are more diverse and abundant. Although researchers worldwide have been inspired by Vogel’s work, the Brazilian research on oil-collecting bees and oil-secreting plants has particularly played a crucial role for this expansion. Here, we review the findings on floral oil systems and organize them in an illustrative timeline, containing a representative picture of important studies since Vogel’s first discoveries. We summarize not only the structural biology and taxonomic groups involved, but also the ecological, evolutionary and conservation aspects addressed to date. In addition, we indicate future directions for a broader understanding of these interactions.

The interaction between Botanophila flies and Epichloë fungi is one of the few interactions in which grass-associated fungi are ‘pollinated’ by flies. We analysed the gains and losses for both interaction partners and the time factors determining cost dynamics. A hypothesis regarding the relationship between changes in the severity of grass infection with Epichloë fungus, size of fungal sexual structures (stromata), and fly presence (expressed as egg and larvae numbers) was tested. During a 3-year study conducted on permanent field plots, fungal infection of wild grass tussocks of Holcus lanatus and fly visits to fungal stromata were monitored. An increase in the number of shoots with stromata and a reduction in stromata size were observed. From one year to another, flies deposited fewer eggs on stromata, and larval body mass decreased. We explain these results by the deterioration of grass condition due to increased Epichloë infection, which resulted in higher maintenance costs for the fungal parasite.