Biology subjects

Keasar, T.

Publications and source records attributed to Keasar, T..

4 recordsLinked to original sources

bioRxiv2026

Rapid estimation of insect biodiversity using AI assisted image analysis:a cost-effective tool for monitoring and ecological assessmen

Protection of natural areas and environmentally friendly management of anthropogenic landscapes require reliable tools for monitoring and comparing biodiversity. Bioindicator-based approaches can support large-scale ecological assessment, but insect monitoring remains constrained by the taxonomic expertise required for species identification. Here, we propose an AI-supported index for estimating the biodiversity of flying insects, based on the diversity of visual features of insect bodies. Flying insects were captured using yellow sticky traps across agricultural and natural habitats, seasons, crops, and sites in Israel's Mediterranean region. Traps were scanned at high resolution and uploaded to a dedicated image database. A machine learning model was used to detect and delineate insects, after which engineered visual features representing body size, color, and shape were extracted. Biodiversity was estimated from distances among feature vectors and compared with taxonomic diversity derived from expert identification of a representative validation set. The AI-derived diversity index correlated strongly with expert-based taxonomic diversity, supporting the hypothesis that morphological variation in insect images can provide a proxy for taxonomic diversity. Applying the index to the full dataset revealed a negative relationship between insect abundance and diversity, while diversity also varied across habitats and sampling seasons. Our results demonstrate the potential of AI-based image analysis to provide rapid and cost-effective assessments of insect biodiversity without requiring complete taxonomic identification. This approach may facilitate biodiversity monitoring and support timely ecological assessment and decision-making in sustainable agricultural and landscape management.

ecology↗

bioRxiv2026

Manuscript, raw data, and R code: Ziziphus spina-christi as a Refuge and Resource for Parasitoids in Arid Ecosystems

1. Climate change is increasing aridity in dryland ecosystems, potentially threatening parasitoid wasps through reduced resource availability and environmental stress. Native drought-adapted plants may help sustain parasitoid communities by providing floral resources and refuge habitats. The tree Ziziphus spina-christi (L.) tolerates drought and heat stress, making it a promising candidate species for desert afforestation and dryland restoration. Its abundant flowering attracts a wide range of insects, supports honey production, and provides valuable forage resources for pollinators. 2. In this two-year study, we investigated the role of Ziziphus spina-christi in supporting parasitoid wasps across four sites that span a 200-600 mm annual rainfall gradient. Parasitoid abundance, diversity, community composition, and sugar-feeding frequency were assessed on Z. spina-christi and compared with surrounding vegetation. 3. Parasitoid abundance was consistently higher on Z. spina-christi than in the surrounding vegetation, especially during the hot and dry summer. Parasitoid diversity and community composition varied among sites along the aridity gradient. Mymarid wasps dominated some sites, mostly in autumn. Eulophids, braconids and scelionids were prominent in summer, and braconids became most dominant in autumn. The proportion of sugar-fed individuals increased during periods of greater flower availability. 4. These findings suggest that Z. spina-christi serves as an important nutritional resource and ecological refuge for parasitoid wasps, highlighting the potential of native drought-adapted plants to support beneficial insects and conservation biological control in dryland ecosystems.

ecology↗

bioRxiv2024

Do flowers with specialized morphologies produce more nectar and pollen?

Premise of the studyFlower morphology influences the wiring of plant-pollinator interaction networks. Flowers with deep corolla tubes and bilateral symmetry have a narrower pollinator range, hence are considered more specialized than shallow radial flowers. Past inter-specific comparisons revealed positive correlations between flower depth and nectar production rates in a few plant communities, suggesting that specialized flowers may allocate more resources into food rewards for pollinators. MethodsTo evaluate this hypothesis, we compiled a global dataset of flower morphology vs. nectar sugar production rates (n = 494 plant species) and per-flower pollen counts (n = 164 species). We applied phylogenetically controlled mixed models to examine the effects of symmetry and tube length on floral rewards. Key resultsCorolla tube lengths, symmetry type and their interaction significantly predicted nectar production rates, with the larger effect attributed to tube length. Neither tube length nor symmetry predicted pollen number. Both nectar and pollen production were affected by phylogeny in a larger dataset that included 854 nectar-producing and 1040 pollen-producing species. Plant genus explained more of the variation in nectar production, and less of the variation in pollen production, than plant family. ConclusionsOur findings suggest that visual signals associated with specialized flowers honestly advertise nectar production, but not pollen rewards. Other visual and chemical family-specific floral displays potentially advertise pollen availability to pollinators. We propose experiments to test whether nectar foragers indeed use flower depth as a visual signal that guides their choices of nectar sources.

ecology↗

bioRxiv2024

Spillover of managed bumble bees from Mediterranean orchards during mass flowering causes minor short-term ecological impacts

Commercial bumble bee colonies are routinely used for crop pollination in greenhouses, and are increasingly introduced into orchards as well. Bumble bee spillover to natural habitats neighboring the orchards may interfere with local wild bees and impact the pollination of non-crop plants. Concurrently, foraging in natural habitats may diversify the bumble bees diets and improve colony development. To evaluate these potential effects, we placed commercial Bombus terrestris colonies in blooming Rosaceae orchards, 25-125 m away from the margins. We recorded the colonies mass gain, population sizes, composition of stored pollen, and temperature regulation. We monitored bee activity, and seed sets of the non-crop plant Eruca sativa, along transects in a semi-natural shrubland up to 100 m away from the orchards, with managed bumble bees either present or absent. Rosaceae pollen comprised [~]1/3 of the colonies pollen stores at all distances from the orchard margins. Colonies placed closest to the margins showed prolonged development, produced fewer reproductive individuals, and had poorer thermoregulation than colonies closer to the orchards center. Possibly, abiotic stressors inhibited the bumble bees development near orchard borders. Wild bees were as active during the colonies deployment as after their removal. E. sativas seed sets decreased after bumble bee removal, but similar declines also occurred near a control orchard without managed bumble bees. Altogether, we found no short-term spillover effects of managed bumble bees on nearby plant-bee communities during the orchards two-week flowering. The colonies prompt removal after blooming can reduce longer-term ecological risks associated with managed bumble bees.

ecology↗