The research team, led by Paraguayan herpetologists including Pier Cacciali, set out to measure how much the two lizards actually overlap in their ecological niches. According to the classic framework of Colwell and Futuyma, niche overlap describes the shared use of resources by two taxa, but true interspecific competition can only be inferred when that sharing trends toward the displacement or exclusion of one species. To evaluate this, the authors compared diet, activity patterns, habitat preferences, reproduction, defense, and communication between the two lizards, drawing on published literature, museum specimens from the Museo Nacional de Historia Natural del Paraguay, and thousands of observational records from the citizen science platform iNaturalist.

The biological comparison revealed that the two species share remarkably few traits. Both are insectivorous, both tolerate life near human dwellings, and both rely primarily on mimesis, aided by caudal autotomy, as a defensive strategy. Beyond that, their lives diverge sharply. Notomabuya frenata is diurnal, ovoviviparous, and communicates through visual and chemosensory behavior, while Hemidactylus mabouia is nocturnal, oviparous, and adds acoustic displays to its repertoire. Most tellingly, the skink climbs using claws and cannot scale smooth surfaces, whereas the gecko’s adhesive lamellae allow it to exploit walls, glass, and metal that are entirely inaccessible to its alleged victim.

Dietary analysis produced nuanced results. Using literature data from sympatric populations in Valinhos, São Paulo, Brazil, the researchers found substantial overlap in prey items at the order level, yet a chi-square test revealed a highly significant difference in the frequency of prey consumption (χ² = 92.89, DF = 23, p < 0.001). The gecko consumes more arachnids and a large share of flying insects attracted to artificial lights, such as beetles of the family Elateridae, mayflies, dipterans, and moths. The skink, by contrast, ingests substantial quantities of termites along with terrestrial, diurnal arthropods including jumping spiders and orthopterans. Notably, ants, a staple for many lizards, were not a significant component of either species’ diet.

Stomach contents from museum specimens collected in Asunción added further detail, though the small sample size of eight geckos and five skinks limited statistical power. The prey of both species in the city coincided in the ingestion of spiders, coleopterans, and homopterans, and rarefaction curves showed similar dietary structure, with the confidence interval of the skink entirely encompassed by that of the gecko. This suggests that in the urban environment, where resources may be limited, the diets do coincide. Intriguingly, the gecko stomachs also contained sand, fabric fibers, and remnants of shed skin, presumably its own, items never found in the skink specimens and a reflection of foraging in a heavily built-up setting.

The temporal record told its own story. The last museum voucher of Notomabuya frenata in Asunción dates from 1986, with only two additional iNaturalist records, one from 1995 and one from 2017. Hemidactylus mabouia, by contrast, has a voucher from 2016 and fifteen iNaturalist records between 2013 and 2022, with observations becoming notoriously frequent from 2017 onward. A significant data gap from 1996 to 2012 complicates the picture, but the pattern is consistent with the gecko colonizing Asunción and Ciudad del Este after its oldest verified Paraguayan record from Concepción in January 1983, a dispersion facilitated by human-modified environments since the species likely first entered South America in northeastern Brazil around 1640.

Microhabitat data from iNaturalist proved decisive. After removing records of deceased, handled, or collected animals, the researchers compared 98 observations of the skink with 791 of the gecko. Most skink records came from grass or other natural substrates (30%) or from trees and shrubs (27%), with only about 11% each on brick and wooden walls and 9% on tile floors. The gecko showed the opposite profile: 71% of records came from smooth and brick walls, including 3% on metal and glass surfaces never used by the skink. Wooden walls were the only microhabitat used with roughly equal frequency by both species, at about 10%. The two lizards, in other words, live side by side in the city but barely share the same surfaces.

The authors emphasize that sharing a resource does not automatically imply competition. When a resource is abundant or oversupplied, species may coexist without conflict, and the enormous diversity of insects available in Paraguay suggests that food is not the limiting factor. Prior work by Rocha and Anjos in Brazil found that even when H. mabouia shares food with native diurnal lizards such as Tropidurus itambere and N. frenata in wild areas, interspecific competition remains low because activity patterns and microhabitat preferences differ. The study’s conclusion follows the scenario described by Ricciardi and MacIsaac, in which many invasions succeed primarily by occupying available niches rather than by outcompeting residents. The architectural features of urban development, tall smooth walls, electric installations offering shelter, and artificial lights concentrating nocturnal prey, coincide precisely with the gecko’s requirements while being unsuitable for skinks.

The evidence points instead to habitat transformation as the driver of the skink’s decline. Where Notomabuya frenata has disappeared from Asunción, the streets are paved, the walls are tall and smooth, and green areas are few, hindering dispersal and isolating individuals. Where urban gardens still allow connections among populations, the skink persists regardless of the gecko’s presence. Satellite imagery of the corridor between the botanical garden and Parque Guasu Metropolitano shows the expansion of concrete structures between 2003 and 2023 and the corresponding loss of gardens, green areas, and unpaved roads. The same anthropogenic changes that harm the skink likely benefit the human-commensal gecko, making the displacement a consequence of human activity rather than a biological invasion.

The researchers are careful not to declare the gecko harmless in general. In regions where H. mabouia has been introduced elsewhere, it has demonstrably displaced native geckos through competition and predation, and its aggressive behavior and high reproductive rates make it a formidable invader in some contexts. In Paraguay, however, the species remains mostly confined to cities, and no direct negative effects on native lizards have yet been recorded. Interestingly, in the riverine town of Bahía Negra, the native gecko Phyllopezus przewalskii occupies human dwellings where the exotic gecko is absent, suggesting that a native species with similar body size, activity, and microhabitat use can resist colonization. Yet recent reports of local extinction of the endemic gecko Phyllopezus heuteri in areas now occupied by H. mabouia leave open whether human activity preceded the exotic gecko or direct competition occurred. The team calls for continuous monitoring, supported by citizen science platforms like iNaturalist, while cautioning that conspicuous wall-dwelling geckos are easier to photograph than skinks, a recording bias that must be acknowledged when interpreting such databases. This study marks the first step toward understanding the exotic gecko’s true effect on Paraguay’s fauna, and it clears the Amberé’s accused rival of the charge that made it famous.

Subject of Research: Niche overlap between the exotic gecko Hemidactylus mabouia and the native skink Notomabuya frenata in Paraguay

Article Title: Guilty or innocent? Could the exotic lizard Hemidactylus mabouia ( Squamata , Gekkonidae ) be responsible for the displacement of the native species Notomabuya frenata ( Squamata , Mabuyidae ) in anthropic environments?

Article References: Cacciali, P., & Maneyro, R. (2024). Guilty or innocent? Could the exotic lizard Hemidactylus mabouia (Squamata, Gekkonidae) be responsible for the displacement of the native species Notomabuya frenata (Squamata, Mabuyidae) in anthropic environments?. Herpetozoa, 37, 319-326. https://doi.org/10.3897/herpetozoa.37.e133456

Image Credits: AI Generated

DOI: 10.3897/herpetozoa.37.e133456

Keywords: Hemidactylus mabouia, Notomabuya frenata, invasive species, niche overlap, urban ecology, Paraguay, Asunción, lizard competition, microhabitat use, citizen science, iNaturalist, habitat loss

Amphibians are among the most threatened vertebrate groups worldwide, with population declines driven by climate change, habitat degradation and the spread of emerging infectious diseases. Bd, the causative agent of chytridiomycosis, was first described in 1999 as the agent behind massive amphibian die-offs, but its presence in Mexico dates back to the 1970s. The pathogen is now widespread, particularly in the central and southern regions of the country, and has been reported to infect at least 50 amphibian species in Mexico. Hylidae and Plethodontidae are among the most affected families, with the genera Hyla, Ambystoma and Pseudoeurycea ranking as the most impacted, their species concentrated across central and southern Mexico.

Mexico is a global hotspot of amphibian diversity and endemism, hosting approximately 3.69 percent of the world’s anuran species. The country’s most diverse amphibian family, Plethodontidae, comprises 140 species that primarily inhabit high-elevation forests in the Trans-Mexican Volcanic Belt, the Sierra Madre Oriental and the montane regions of the Sierra Madre del Sur, the Balsas Depression and Oaxaca. Hylidae is the second most diverse family with approximately 101 species, while Ambystomatidae, though lower in species richness with 12 to 18 species depending on the taxonomic framework, includes 16 endemic species, making Mexico the centre of diversity for the group.

The research team selected 13 amphibian species based on endemism, conservation status and ecological relevance within the montane regions of central Mexico. The selection included three Hyla species (H. euphorbiacea, H. eximia and H. plicata), three Ambystoma species (A. altamirani, A. lermaense and A. velasci) and seven Pseudoeurycea species (P. altamontana, P. gadovii, P. juarezi, P. lineola, P. longicauda, P. smithi and P. werleri). All are endemic to Mexico, and most inhabit high-elevation cloud forests or temperate montane ecosystems that are particularly susceptible to climate change, habitat loss and emerging diseases. The species span a broad spectrum of IUCN Red List categories: four are listed as Least Concern, one as Vulnerable, seven as Endangered and one, P. smithi, as Critically Endangered.

Notably, most Pseudoeurycea species included in the study are extremely data deficient. For several of them, only presence records are available, with almost no information on their population sizes, ecology, reproductive behaviour or physiological tolerances. This scarcity of data results in their exclusion from many broad-scale conservation initiatives, despite the likelihood that they are among the most vulnerable to environmental disturbance and chronic infections. By including this taxonomically and ecologically diverse group, ranging from broadly distributed species to microendemics with only a handful of records, the study aimed to provide a more integrative evaluation of the potential impacts of Bd across a gradient of conservation statuses and research gaps.

Methodologically, the researchers compiled occurrence records from online databases including GBIF, iNaturalist and CONABIO, while Bd records were obtained from a previous study and its associated Dryad data repository, covering the period from 2000 to 2022. Records were filtered to remove coordinate errors, duplicates and points outside known geographic ranges, then spatially rarefied to retain only one occurrence per square kilometre, an approach shown to reduce model overfitting. Nineteen bioclimatic variables at roughly one kilometre resolution were obtained from WorldClim, along with elevation and land-cover variables derived from satellite imagery. A Pearson correlation analysis eliminated highly correlated variables, retaining seven final land-cover layers: percentage cover of agriculture, arid vegetation, grassland, fir forest, pine forest, oak forest and cloud forest.

Two distinct modelling methodologies were employed to facilitate comparative analysis. The first used the maximum entropy algorithm implemented through the ENMeval package in R, testing regularisation multipliers and feature class combinations, with 100,000 background points randomly generated to characterise the environmental background. A block method partitioned occurrence data geographically based on latitude and longitude, ensuring that training and evaluation datasets were separated across space. The second approach constructed an ensemble model with the biomod2 package, combining ten algorithms including generalised linear models, random forest, Maxent and XGBOOST, each run ten times with different selections of training and testing datasets. Model performance was assessed using the area under the curve of receiver operating characteristic plots, partial ROC analyses and the true skill statistic.

The results showed that the maximum temperature in the warmest month, the minimum temperature in the coldest month and precipitation in the wettest and driest months were the most important environmental variables for the amphibian species. For most Ambystoma species, the optimal habitat suitability fell between roughly minus two and ten degrees Celsius for the coldest month, while A. lermaense presented an optimum temperature range of 15 to 25 degrees. For Bd, the maximum temperature in the warmest month was positive within a range of approximately 15 to 35 degrees, and the minimum temperature of the coldest month was a negative variable. The optimal temperature range for Bd was found to lie between 10 and 25 degrees, aligning with observations from European studies. Elevation was a positive variable for all species, and pine, oak and cloud forest percentages were positive for nearly all species.

According to the tenth percentile training presence threshold, Bd had the greatest potential distribution among all species studied, covering 267,557 square kilometres, while the most restricted species, P. altamontana, covered just 9,982 square kilometres. Niche overlap analysis revealed that Bd and A. altamirani showed relatively higher overlap values (Schoener’s D = 0.423; Hellinger’s I = 0.572), suggesting a greater degree of environmental similarity compared to other species pairs. In contrast, A. lermaense exhibited the lowest overlap with Bd (D = 0.038; I = 0.178). Barplot analysis indicated that P. juarezi, P. longicauda and P. altamontana exhibited the highest percentage of spatial overlap with Bd, all exceeding 70 percent of their distribution ranges, while A. velasci and H. eximia had the lowest overlap, below 40 percent.

By integrating spatial exposure information with IUCN Red List categories, the researchers developed a composite vulnerability index that ranked P. altamontana, P. longicauda and P. juarezi as the most vulnerable species. A principal component analysis of vulnerability patterns revealed distinct species clusters, with the first two components accounting for 92.3 and 7.7 percent of the variance respectively. Species richness maps showed that amphibian diversity peaks in the central highlands of Mexico, particularly in regions overlapping with the Trans-Mexican Volcanic Belt, where richness values reach up to nine species per pixel, and the overlay analysis demonstrated that Bd suitability was notably high in these same regions. The authors emphasise the urgency of implementing targeted conservation actions, including long-term monitoring, early detection of infections, identification of resistant or tolerant populations and regulation of ecotourism in vulnerable regions. They also highlight the potential importance of range break zones, such as Oaxaca and the Altiplano Sur, as natural barriers that could limit Bd spread, and note that community-based conservation initiatives and voluntary reserves managed by indigenous people offer an opportunity to expand protected areas and implement habitat restoration programmes.

Subject of Research: Ecological niche overlap between the chytrid fungus Batrachochytrium dendrobatidis and endemic amphibians in Mexico's Central-Southern Highlands

Article Title: Mapping Risk Zones: niche overlap between Batrachochytrium dendrobatidis and endemic amphibians in Mexico’s Central-Southern Highlands

Article References: Heredia-Bobadilla, R. L., Manjarrez, J., Gómez-Benítez, A., Reyes-Velázquez, E. A., Carmen-Cristobal, J. M., Sánchez-Lara, A. J., Martínez-Alva, G., Bolom-Huet, R., & Sunny, A. (2026). Mapping Risk Zones: niche overlap between Batrachochytrium dendrobatidis and endemic amphibians in Mexico’s Central-Southern Highlands. Nature Conservation, 63, 299-335. https://doi.org/10.3897/natureconservation.63.163964

Image Credits: AI Generated

DOI: 10.3897/natureconservation.63.163964

Keywords: Batrachochytrium dendrobatidis, chytridiomycosis, amphibian conservation, ecological niche modelling, Mexico, Trans-Mexican Volcanic Belt, Sierra Madre del Sur, Pseudoeurycea, Ambystoma, Hyla, niche overlap, biodiversity hotspots

The ecological niche is one of the foundational concepts in ecology, but its definition has been contested for a century. Charles Elton in 1927 framed the niche as a species’ functional role within a community, emphasizing interactions with other species. Joseph Grinnell in 1928 instead defined it as the physical space in which a species lives. The most widely used formulation came from G. Evelyn Hutchinson in 1957, who described the niche as a hypervolume in an n-dimensional environmental space, roughly spanning biotic and abiotic factors. Hurlbert later compiled more than twenty different definitions of the niche, and the debate continues. Crucially, almost all of these definitions operate at the species level or above, treating variation among individuals as noise around an ecological optimum.

That species-level focus is now recognized as a serious limitation. Foundational work over recent decades has shown that many species contain distinct phenotypes linked to age, sex, morphology, or behavior, and that consistent individual differences appear in cognition, antipredator behavior, breeding behavior, and responses to chemical cues. The Niche Variation Hypothesis, proposed by Van Valen in 1965, holds that the width of a species’ niche is driven by among-individual variation, a relationship demonstrated empirically across multiple taxa. Individual-level differences therefore matter for population-level dynamics, species coexistence, and the indefinite persistence of species. The term individualized niche emerged in the early 2010s to describe individual niche specialization, and it inherits the plasticity of the broader niche concept, which is precisely why its quantification has been considered a laborious task.

The new workflow, presented by researchers building on a formal definition published by Takola and Schielzeth, distinguishes between realized and potential individualized niches, following Hutchinson’s classic separation of the fundamental and realized niches. The realized individualized niche represents the environmental space where an individual actually is found, while the potential niche represents the space where it could be found. The workflow proceeds in three stages: data preparation, analysis, and output generation. Recorded GPS locations correspond to used locations, and available locations are generated randomly within a radius set by the organism’s dispersal rates. These points are then overlaid with environmental variables, which can be measured, inferred, or calculated with the aid of remote-sensing tools and grouped by resource type such as food, soil, and weather.

The analytical core is a mixed-effects resource selection function, or RSF, fitted for each resource-type group using a binomial model with a logit link. The response variable is binary, distinguishing used from available locations. Each model contains the relevant environmental predictors along with random intercepts and random slopes for each individual. The random intercepts capture baseline differences among individuals, whereas the random slopes, also known as reaction norms, estimate individual variation in the strength of selection along each environmental gradient. The model outputs represent population-average effects that describe selection and individualized deviations that quantify consistent among-individual differences along specific environmental axes. Fitted predictions are converted from the log-odds scale back to probabilities of use, and these predicted values are then scaled into relative selection probabilities, or RSPs, which set each individual’s maximum predicted selection value to one and express all other locations relative to that maximum.

These RSPs serve as observation-level weights in the construction of individualized niche hypervolumes. For each resource type, the workflow transforms the ecological group into a standardized multidimensional environmental space and estimates a weighted hypervolume separately for each individual using Gaussian kernel density estimation with Silverman’s bandwidth estimator. Because density-estimated hypervolumes have continuous boundaries, the workflow converts them to hard boundaries by selecting the region containing 95 percent of the probability estimates. Niche breadth is then defined as the volume of each individual’s 95 percent hypervolume, roughly corresponding to the within-individual variance of the individualized niche. Pairwise niche overlap between individuals is quantified with Jaccard and Sørensen similarity indices, which provide insights into intraspecific competition and niche partitioning along different environmental axes. Notably, the breadth of a potential niche is not necessarily larger than that of the realized niche, contrary to the traditional species-level definition, a phenomenon related to the so-called zero-niche paradox in which animals survive under conditions outside their species’ fundamental niche.

A key innovation is the use of repeatability estimates to address the problem of resource availability, which strongly influences individual variation in use. Repeatability quantifies the proportion of variance attributable to between-individual differences. The workflow calculates repeatability separately for realized niches, based on the environmental conditions individuals actually use, and for potential niches, based on the conditions available to them. Higher realized than potential repeatability indicates that individuals differ in use beyond what would be expected from their opportunity sets alone, supporting an interpretation of genuine individualized selection or specialization. Similar values suggest that differences in use largely reflect differences in availability, while higher potential repeatability points to spatial or home-range segregation. The workflow implements these tests with 1,000 bootstrap replicates and 1,000 permutations to obtain empirical 95 percent confidence intervals.

The case study showcases the workflow with northern lapwing tracking data publicly available through the Movebank database, covering the Netherlands, Belgium, England, France, and Spain from April 2021 to March 2023, with between 28 and 1,266 locations per individual. The environmental variables integrated into the lapwing niches were remarkably rich: temperature, precipitation, wind speed, the normalized difference vegetation index, crop type, cropping intensity, soil water index, soil organic carbon and its stock, soil nitrogen, pesticide application rates, population density, human footprint, and earthworm abundance. The mixed-effects RSFs showed that lapwings avoided densely populated areas and frequently cropped fields but preferred certain crop types, water, and high earthworm abundance, confirming what is already known about the species’ ecology while the random slopes revealed how each of the 13 tracked birds responded differently to each environmental variable.

The lapwing results illustrate the diagnostic power of the paired niche components. In many cases, for example in the selection of soil and human-presence variables, realized niche breadth was smaller than potential niche breadth, providing evidence of stronger individual specialization. High overlap among potential niches for soil variables suggested limited potential for individual differentiation in a highly suitable environment, while high overlap among realized niches for food resources, including the soil water index, earthworm abundance, and their interaction, indicated that individuals tended to use the same resources. Repeatability values ranged from 0 to 0.55 for potential niches and from 0 to 0.83 for realized niches, and in most cases realized repeatability exceeded potential repeatability, consistent with the hypothesis that northern lapwings exhibit individual variation in space use.

The authors emphasize that the workflow rests on explicit assumptions: individuals move in landscapes that on average match their phenotype, higher relative selection probabilities correspond to conditions providing greater expected lifetime reproductive success, and individualization is supported when realized niches show greater among-individual structure than potential niches. The framework is transferable across taxa of mobile organisms and responds to a decade of calls for incorporating individual-level variation into ecology and conservation. By quantifying individual niche variation, filtering for areas of high selection probability, and aggregating resource-use data into meaningful indices of intraspecific variation, the workflow promises more accurate and mechanistic individual-based models of wild population dynamics. Future research can focus on linking individualized niches to population growth rates, and because climatic niche breadth has been shown to predict recent range shifts across moths, butterflies, and birds, accounting for intraspecific variation may improve forecasts of persistence and redistribution under global change. As the individualized niche concept becomes established, quantifying it from movement data may prove an essential tool for behavioral ecologists seeking to draw population-level inferences from individual-level data.

Subject of Research: Individual specialization in habitat use quantified from animal movement data

Article Title: The individualized niche in motion: Quantifying individual specialisation with movement data

Article References: Takola, E. (2026). The individualized niche in motion: Quantifying individual specialisation with movement data. Individual-based Ecology, 2, Article e203247. https://doi.org/10.3897/ibe.2.203247

Image Credits: AI Generated

DOI: 10.3897/ibe.2.203247

Keywords: ecology, movement ecology, individualized niche, resource selection functions, hypervolumes, repeatability, northern lapwing, GPS tracking, niche breadth, niche overlap, individualized, niche

Researchers Rohit Rohit and Anjali Dhar of the Department of Zoology at Central University of Jammu surveyed six orchard sites spanning 1,073 to 2,302 meters above sea level during the 2025 blooming season. Using a combination of passive pan trapping with ultraviolet-bright blue, yellow, and white bowls and nearly one hundred hours of timed focal observations at flowering trees, they recorded 847 individual floral visitors belonging to 13 species across 10 families and 4 orders. The assemblage included six bee species, four species of hoverflies, and three butterflies, with the western honey bee Apis mellifera, the sweat bee Lasioglossum moroi, the Asiatic honey bee Apis cerana indica, and the drone fly Eristalis tenax together dominating the counts.

The most striking finding is the strength of the relationship between elevation and diversity. Shannon diversity declined in an almost perfectly linear fashion with altitude, with elevation explaining 91.3 percent of the variation in the diversity index. Total abundance fell by 71.8 percent across the gradient, from 238 individuals at the lowest site to just 67 at the highest, while species richness dropped from 13 to 5. The authors caution that elevation and temperature were nearly perfectly collinear in their dataset, with temperatures falling roughly 9.5 degrees Celsius over the 1,229-meter span, so the pattern reflects the composite elevational thermal environment rather than either factor alone. Temporal sampling waves, in which high sites were visited later in the season, add a further phenological confound that the team explicitly acknowledges.

Beneath the aggregate decline lies a pronounced taxonomic reshuffling. Social Apid bees, which made up 39.7 percent of visitors at low elevations, fell to 22.2 percent at high elevations, an absolute decline of 76 percent driven by losses of both honey bee species. Halictidae, represented solely by the sweat bee Lasioglossum moroi, nearly doubled their relative share, rising from 18.1 to 38.2 percent while maintaining near-stable absolute numbers. Hoverflies also held their proportional ground, and the authors attribute this resilience to multivoltine life cycles, larvae that develop in aquatic or aphid-rich habitats decoupled from orchard flowers, and the ability of several species to forage at temperatures as low as 8 to 10 degrees Celsius.

Life-history traits appear to explain much of this filtering. Perennial honey bee colonies demand continuous forage across a long season, conditions that collapse as elevation compresses the bloom window and thins floral diversity. In contrast, Lasioglossum moroi combines flexible sociality with ground nesting, which buffers nests against cold, and can shift to a single generation per year at altitude. Strictly solitary, univoltine bees such as Osmia cornuta and Anthophora confusa vanished from the highest site, consistent with their narrow thermal requirements for emergence. Habitat measurements reinforced the story: bare ground cover, essential nesting substrate for ground-nesting sweat bees, increased with elevation and correlated strongly with L. moroi abundance, while declining non-crop floral richness tracked the disappearance of solitary bees that need diverse forage during their brief adult lives.

At the single site where apple and apricot co-flowered under identical conditions, the team uncovered a clear division of labor. Apid bees accounted for 43.9 percent of apple visits but only 27.1 percent of apricot visits, with both honey bee species showing statistically significant preferences for apple. Hoverflies showed the mirror-image pattern, contributing 42.2 percent of apricot visits against 24.5 percent on apple, with the drone fly Eristalis tenax displaying the strongest crop preference of any species. The generalist sweat bee visited both crops in equal measure. The authors suggest that apple’s larger flowers and higher nectar sugar concentrations suit energy-hungry social bees, while apricot’s nectar volume and volatile profile may better attract olfactory-guided hoverflies, though direct floral trait measurements will be needed to confirm the mechanism.

Behavioral effectiveness scores, combining visit duration with the frequency of stigma contact, pointed to functional complementarity between the two pollinator groups. Honey bees achieved their highest scores on apple, where they contacted stigmas in 78 percent of visits compared with 62 percent on apricot, while all four hoverfly species scored higher on apricot, with E. tenax recording 16.8 versus 10.2 on apple. Overall mean scores were higher on apricot, driven by the extended visits of syrphid flies. The researchers stress these are visitation-based behavioral proxies rather than measured pollen deposition, and confirming actual pollination efficiency would require single-visit pollen assays. Even so, the pattern implies that keeping both crops in the landscape sustains two complementary pollinator guilds.

Network analysis added a structural dimension to the elevational story. High-elevation interaction networks, built from just 8 pollinator and 6 plant species, were more modular and more specialized than their low-elevation counterparts, with modularity rising from 0.38 to 0.46 and network-level specialization from 0.39 to 0.61. Niche overlap among species, measured with Pianka’s index, was significantly lower at high elevations, 0.31 versus 0.58, consistent with intensified resource partitioning when few species share scarce flowers. Within these simplified networks, Lasioglossum moroi emerged as the critical connector, showing the highest degree and species strength and the lowest specialization of any taxon, bridging network modules that would otherwise remain isolated. The authors warn that losing this single species could disproportionately fragment high-altitude pollination webs.

The conservation implications are elevation-specific rather than uniform. At low elevations, the authors recommend wildflower strips to sustain non-crop forage, careful timing of pesticide applications away from peak morning visitation hours, and preservation of dead wood and hollow stems for cavity-nesting solitary bees. At mid-elevations, maintaining a mosaic of both apple and apricot may support transition-zone communities that could serve as refugia under warming. At high elevations, where barely five or six pollinator species persist, priorities include minimizing soil disturbance to protect sweat bee nesting substrate, retaining water features and leaf litter for hoverfly larvae, and ensuring at least one wildflower species blooms throughout the compressed growing season. The strong elevation-diversity relationship also offers a quantitative baseline: repeated surveys at the same six sites could detect the upward range shifts and community disassembly expected as Himalayan winters warm and apple cultivation itself climbs ever higher in search of suitable chill.

Subject of Research: Elevational changes in insect pollinator communities and their interactions with apple and apricot trees in Himalayan orchards

Article Title: Bionomics of insect pollinators and their interaction with host trees in the orchards of Doda, Indian Himalayas

Article References: Rohit, R., & Dhar, A. (2026). Bionomics of insect pollinators and their interaction with host trees in the orchards of Doda, Indian Himalayas. Discover Ecology, 2(1), Article 24. https://doi.org/10.1007/s44396-026-00040-1

Image Credits: AI Generated

DOI: 10.1007/s44396-026-00040-1

Keywords: pollinators, Himalayas, apple orchards, apricot, elevational gradient, bees, hoverflies, plant-pollinator networks, niche overlap, pollinator conservation, Doda, bionomics