Sea buckthorn, Hippophae rhamnoides, is a woody plant of ecological and economic importance across temperate Eurasia, and the fruit fly R. batava is a highly specialized pest whose larvae feed inside its fruits. Females insert eggs into developing berries, and the resulting larvae damage the pulp, contributing to softening, deformation, discoloration and desiccation. In severe outbreaks reported for susceptible cultivars and poorly managed orchards, infestation can exceed 80%, with nearly all marketable fruit lost under the worst conditions.

The regional survey examined natural stands, ecological plantations and cultivated orchards across Altay, Aksu, Kizilsu Kirgiz, Kashgar, Urumqi, Ili and Changji, with 2,700 plants inspected using three plots at each of 30 sites. The species identification combined measurements of females from geographically separated Altay and Akqi populations with the diagnostic characters used for P. carinata, including the shape of the head behind the compound eyes, antennal structure, forewing venation, the first metasomal tergite, hind legs and ovipositor sheath. The measured ranges overlapped extensively between the two populations.

Independent examination by Cornelis van Achterberg confirmed the identification, and a search of regional revisions, catalogues and public biodiversity databases found no reliable prior record from China. This identification matters because P. carinata resembles the related P. concolor but can be distinguished through a combination of structural characters rather than a single trait. Host association was demonstrated more directly than through collection alone.

All tephritid adults emerging from the relevant rearing batches were identified as R. batava, and no other tephritid species were recovered. Adult P. carinata emerged from those puparia, while a separate dissection series of more than 900 fly larvae and puparia repeatedly revealed parasitoid immature stages inside intact hosts. These observations showed that P. carinata is a solitary larval–pupal koinobiont endoparasitoid: its host continues feeding and developing after parasitism, leaves the fruit and forms a puparium, within which the wasp completes its immature development.

Dissections before and after winter also established that the parasitoid overwinters as a pupa inside the fly puparium. Of 8,260 R. batava puparia maintained from Altay and Akqi, 457 produced adult P. carinata, and another 138 contained immature parasitoids when the remaining puparia were opened. The resulting apparent parasitism estimate was 7.57% in Altay, 6.50% in Akqi and 7.20% across the pooled sample.

At a fixed 12-hectare plantation in Burqin County, where no chemical insecticides were applied, Malaise traps operated from April through November in 2024 and 2025. Both the fly and wasp showed one concentrated period of adult activity in each year, with the parasitoid peak occurring later than that of its host. That timing does not necessarily indicate a mismatch between host and parasitoid.

Adult fly emergence and oviposition precede the larval period in which parasitism occurs, so later wasp activity can reflect the arrival of suitable host stages. Together with the fly’s known univoltine cycle in the study region, pupal overwintering by the wasp and the single annual activity period, the two-year monitoring supported a univoltine life cycle for P. carinata at the Altay site. The study was designed around sea buckthorn habitats in Xinjiang, however, and did not test whether the wasp has other hosts there or occurs outside this host–plant system.

The regional parasitism percentages describe apparent infection in collected puparia and should not be interpreted as a measured reduction in fruit damage. A fully factorial laboratory experiment involving 720 wasps examined how temperature, diet and sex affected adult longevity. Newly emerged adults were held individually at four separate temperature treatment levels—15°C, 20°C, 25°C and 30°C—with water or one of two honey concentrations supplied continuously.

Longevity declined consistently as temperature rose from 15°C to 30°C. Model-estimated longevity at 20°C, 25°C and 30°C was 63.0%, 35.2% and 23.2% of the estimate at 15°C, respectively. Females generally outlived males, and all three factors had significant effects on log-transformed longevity.

A diet-by-sex interaction was also significant, while the temperature-by-diet, temperature-by-sex and three-way interactions were not. Carbohydrate access produced a marked difference. At 15°C, females given water lived an average of 12.40 ± 0.70 days, compared with 45.80 ± 1.96 days under 15% honey and 46.17 ± 2.38 days under 30% honey.

Males given water averaged 10.20 ± 0.61 days, versus 28.40 ± 1.75 and 29.30 ± 2.01 days under the two honey diets. Mean survival was broadly similar between 15% and 30% honey, indicating little additional longevity benefit from the higher concentration under laboratory conditions. The experiment measured survival rather than reproductive output or host-searching performance, so the field significance of these nutritional and thermal effects remains to be established.

Whole-genome sequencing of a morphologically confirmed female produced a complete, circular mitochondrial genome of 15,633 base pairs, deposited as GenBank accession PX579120. The genome contained the standard 37 insect mitochondrial genes—13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes—plus an 809-base-pair control region. Its overall adenine-plus-thymine content was 82.7%, with thymine more abundant than adenine and guanine more abundant than cytosine.

The control region had the highest adenine-plus-thymine content at 91.4%, followed by the ribosomal RNA genes at 88.9%, transfer RNA genes at 86.8% and protein-coding genes at 80.1%. All 13 protein-coding genes used canonical initiation codons, and the relative use of synonymous codons was strongly biased toward those ending in A or U. Comparisons with the available mitogenomes of P. concolor, P. humilis, P. lounsburyi and P. incisi showed that protein-coding and ribosomal RNA genes retained the same relative positions and transcriptional orientations in the homologous regions examined.

Intrageneric variation instead centered on transfer RNA genes. All five Psyttalia species shared the cox2–trnD–trnH–trnK–atp8 and nad2–trnW–trnY–trnC–cox1 clusters, but the nad4L–nad6 region contained two local arrangements. P. carinata and P. incisi shared nad4L–trnT–trnP–nad6, whereas P. concolor, P. humilis and P. lounsburyi shared nad4L–trnP–trnT–nad6.

These differences identify candidate structural characters for studying mitochondrial evolution, but their direction cannot be resolved from the five sampled species. Maximum-likelihood and Bayesian analyses of all three codon positions in the 13 mitochondrial protein-coding genes produced identical relationships within Psyttalia. The sampled species formed a strongly supported monophyletic group, and P. carinata was recovered as the sister lineage to the clade containing P. concolor, P. humilis and P. lounsburyi, with a posterior probability of 0.97 and 100% maximum-likelihood bootstrap support.

P. incisi was placed as sister to the other four species. The discordance between sequence relationships and gene order—P. carinata shared the complete trnT–trnP arrangement with P. incisi but was not its closest sampled relative—shows that local gene-order similarity need not identify the closest relationship. Denser species sampling and independent nuclear markers will be needed to distinguish ancestral retention, lineage-specific change and independent convergence.

Subject of Research: First Chinese record, host association, biology and comparative mitogenomics of the parasitoid wasp Psyttalia carinata

Article Title: Biology and Comparative Mitogenomics of Psyttalia carinata, Newly Recorded From China as a Parasitoid of Rhagoletis batava

Article References: Li, K., Ge, Z., Zhang, Z., Guo, W., & Hu, H. (2026). Biology and Comparative Mitogenomics of Psyttalia carinata , Newly Recorded From China as a Parasitoid of Rhagoletis batava. Ecology and Evolution, 16(10), Article e74415. https://doi.org/10.1002/ece3.74415

Image Credits: AI Generated

DOI: 10.1002/ece3.74415

Keywords: Psyttalia carinata, Rhagoletis batava, parasitoid wasp, Xinjiang, sea buckthorn, host association, overwintering, adult longevity, mitochondrial genome, gene order, phylogenetics, biological control

Sea buckthorn, Hippophae rhamnoides L., is a deciduous shrub native to the Xinjiang region of China and now widely distributed across Asia, Europe and Canada. Its berries are loaded with carbohydrates, polysaccharides, polyphenols, vitamins and amino acids, and have been linked to antioxidant, anticarcinogenic, anti-inflammatory, antimicrobial and hepatoprotective effects. Proanthocyanidins, or PAs, are oligomeric and polymeric flavonoid polyphenols that accumulate in the fruit peel, seeds and stems. They are prized for potent antioxidant activity, cardiovascular protection, anti-obesity potential through pancreatic lipase inhibition, and enhancement of microvascular integrity. Yet most research has focused on PAs from the pulp, while the seed, leaf and peel fractions, which are routinely discarded during processing, have been largely ignored.

Extracting PAs from plant matrices is technically difficult because plant cell walls resist penetration and polyphenols degrade easily. Conventional approaches such as high-pressure extraction, supercritical carbon dioxide and ultrasonic-assisted extraction all suffer from high equipment costs, heavy organic solvent consumption, large energy inputs and secondary pollution risks. The Chinese team turned instead to deep eutectic solvents, or DESs, a class of designer solvents formed when a hydrogen bond donor and a hydrogen bond acceptor combine into a eutectic mixture. Typically built from cheap, biodegradable and environmentally benign components, DESs can dissolve polyphenols through hydrogen-bonding networks that are stronger than the interactions between water and the solutes themselves, loosening the binding forces that hold phenolic compounds inside the plant matrix.

The researchers tested five choline chloride-based solvent systems in which choline chloride served as the hydrogen bond acceptor, paired with five different donors: 1,4-butanediol, citric acid, lactic acid, urea and malonic acid. Water content proved critical, producing a characteristic bell-shaped yield curve. At low water levels the solvent is too viscous to penetrate the seed matrix efficiently; moderate water addition disrupts inter-solvent hydrogen bonds and lowers viscosity, boosting diffusivity. But beyond an optimum, added water competes with the PAs for hydrogen-bonding sites and hydrates the solvent components, weakening the DES-PA interactions that drive extraction. All five solvent systems significantly outperformed 75 percent ethanol, and the champion, choline chloride with 1,4-butanediol at 50 percent water, reached an absorbance of 0.255, a full 201.2 percent higher than the ethanol control.

With the solvent chosen, the team optimized the process using single-factor experiments followed by a three-factor, three-level Box-Behnken response surface design. The solid-to-liquid ratio exerted the strongest influence, followed by temperature and time, and the interaction between solvent ratio and temperature was highly significant because heating thins the solvent and speeds mass transfer only when enough solvent is present, while excessive heat destroys the thermolabile PAs. The model predicted a maximum yield of 48.025 milligrams per gram at a 41:1 milligram-per-milliliter ratio, 61.11 degrees Celsius and 3.29 hours. Validation runs at practical adjusted conditions delivered 47.591 milligrams per gram, a relative error of just 0.90 percent, with a regression fit of R squared 0.9964. Purification on D101 macroporous adsorption resin lifted the extract to 69.17 percent total proanthocyanidins.

Liquid chromatography-tandem mass spectrometry then revealed exactly what the green solvent had pulled from the seeds. Monomeric catechin and epicatechin appeared at mass-to-charge ratios of 291.08 and 292.08, while the dimeric proanthocyanidins B1 through B4 showed characteristic signals at m/z 579.15 to 581.15. Notably, no trimer or tetramer peaks were detected, indicating that sea buckthorn seed PAs consist almost entirely of monomers and dimers. Antioxidant testing across three independent assays showed the extract scavenging DPPH radicals at 4.61, ABTS cation radicals at 5.53 and reducing ferric iron at 6.24 micromoles of Trolox equivalents per milligram, respectable values that trailed only slightly behind pure ascorbic acid and confirmed the extract retained strong reducing and radical-scavenging capacity.

The second half of the study tackled the compounds’ Achilles heel: poor water solubility, instability under heat, pH swings and gastrointestinal conditions, and rapid metabolism in the body. Using ionic gelation, the team encapsulated the purified PAs within a composite wall of sodium alginate and carboxymethyl cellulose, extruding the mixture into a calcium chloride bath to form microcapsules with an encapsulation efficiency of 89.015 percent. Scanning electron microscopy showed intact, roughly elliptical particles without tears or holes, their surface folds a by-product of freeze-drying that increases surface area and may aid retention.

Spectroscopic and thermal analyses confirmed that the capsule walls protect without chemically altering the payload. Fourier transform infrared spectra showed hydrogen-bond interactions between the phenolic hydroxyl groups of the PAs and the polysaccharide wall, but no new peaks and no shift in the aromatic ring vibrations, proving a non-covalent, structure-preserving association. Thermogravimetric analysis was even more dramatic: free PAs lost mass sharply between 100 and 150 degrees Celsius and left only about 8 percent residual char at 600 degrees, whereas loaded microcapsules degraded gradually like the blank wall material, retaining roughly 26 percent residue and shielding the core from direct heat exposure, a critical advantage for foods and pharmaceuticals that undergo thermal processing.

Simulated digestion told a similar story. In gastric fluid at pH 2.0, free PAs flooded out, releasing 29.58 percent within the first 30 minutes and 53.64 percent by 180 minutes, while microencapsulated PAs released only 2.86 percent early on and 21.99 percent at 180 minutes, a delay of more than 31 percentage points. The team attributes this to the pH sensitivity of alginate, whose carboxyl groups protonate in acid, shrinking the matrix and blocking penetration. In neutral intestinal fluid the balance reversed: microcapsules reached a cumulative release of 45.65 percent at 180 minutes, surpassing the free PAs at 39.57 percent and still climbing, exactly the controlled, intestine-targeted release profile desired for maximizing absorption and bioactivity.

The authors are candid about the hurdles separating bench from factory. The choline chloride-1,4-butanediol solvent is relatively viscous, complicating continuous large-scale extraction, and freeze-drying inflates production costs. They propose screening lower-viscosity ternary solvent systems, coupling extraction with ultrasound or microwaves, blending in cheaper agricultural waste-derived polysaccharides such as corn fiber or rice bran cellulose, and ultimately running in vivo trials of bioavailability, tissue distribution and long-term safety. If those steps succeed, the implications extend well beyond sea buckthorn. The integrated solvent-and-encapsulation strategy offers a reusable blueprint for converting fruit-processing residues of every kind into stabilized, deliverable nutraceutical ingredients, turning industrial garbage into functional-food gold with nothing more exotic than biodegradable chemistry.

Subject of Research: Green extraction and microencapsulation of sea buckthorn seed proanthocyanidins using deep eutectic solvents

Article Title: Extraction and purification and microcapsulation of sea buckthorn seed proanthocyanidins using deep eutectic solvent-assisted extraction

Article References: Sun, Y., Sun, D., Ahmad, M., Li, X., Huang, M., Bi, X., Han, L., & Hao, G. (2026). Extraction and purification and microcapsulation of sea buckthorn seed proanthocyanidins using deep eutectic solvent-assisted extraction. Food Chemistry: X, 39, Article 104394. https://doi.org/10.1016/j.fochx.2026.104394

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104394

Keywords: sea buckthorn, proanthocyanidins, deep eutectic solvents, microencapsulation, antioxidants, green extraction, sodium alginate, carboxymethyl cellulose, response surface methodology, in vitro digestion, food by-products, functional foods