IntroductionIn Australia, as well as many other regions of the world, European honey bees Apis mellifera are an introduced species and may harm native bee fauna by competing with them for food resources. Field studies have revealed negative associations between honey bee and native bee abundance, but whether this translates to fitness costs for native bees is unclear.MethodsUsing drilled wooden-block trap nests, we evaluated whether honey bee abundance is associated with fitness parameters (number of nests, provisioned cells per nest, offspring number, mortality rate, sex ratio, and body size) of cavity-nesting native bees over 2 years. We also conducted palynological analyses to measure pollen resource overlap and evaluate whether this impacts native bee fitness.Results and discussionGreater honey bee abundance was associated with a male-biased sex ratio in the native bee progeny across years and an increased mortality rate of native bee progeny in the first year. Most non-significant associations were also in the directions predicted from honey bees adversely impacting native bee fitness. In the first year, greater pollen morphospecies overlap was associated with fewer provisioned cells. In conclusion, we demonstrated that honey bees have the potential to have harmful consequences for native bee fitness.

Flowers represent intricate microcosms shaped by their chemical and micrometeorological properties. Notable examples include thermogenic flowers that create a warm microclimate for visitors and residents. We document a distinct microclimate within the large flowers of both wild and domesticated squashes (Cucurbita spp.). Unlike thermogenic flowers, squash flower temperatures remain near ambient, but their humidity consistently exceeds ambient levels from bud to senescence, resulting from stomatal and petal transpiration rather than nectar evaporation. Experimentally reducing humidity in greenhouse-grown male squash flowers results in significant pollen tube rupture, directly impacting plant fitness. To explore the role of floral humidity within a broader ecological context, we performed similar humidity manipulations on squash farms to assess impacts on the behavior of their specialist squash bee pollinator (Xenoglossa pruinosa), generalist pollinators (bumblebees, honeybees), and specialist herbivores (cucurbit beetles). Experimentally reduced floral humidity lower visitation frequency by squash bees but have no effect on generalist pollinators. Manipulation of floral humidity did not influence the foraging duration of any pollinators but impacted the residence of male squash bees in wilted flowers compared with unmanipulated flowers. Finally, there was a positive correlation between the dryness of the ambient air and the abundance of squash bees and cucurbit beetles residing in the humid wilted floral chambers. In conclusion, our findings showcase squash flowers as a humid microhabitat that influences reproductive success directly by affecting pollen viability and indirectly by altering interactions with squash bees, their specialist pollinators. ### Competing Interest Statement The authors have declared no competing interest.

Temperature regimes within flowers and inflorescences are not well studied but have been shown to be important in plant sexual reproduction (pollination). We report for the first time the effects of ambient air temperatures and insolation (sunny vs. cloudy vs. night) on temperatures within the various sizes of the complex flowering head of teasel ( Dipsacus fullonum ). Blossom temperatures influence pollination in various ways, notably through the growth and maturation of the sexual organs and by being perceived by and influencing pollinator behaviour. We report that the inflorescences of common teasel become warmed above the adjacent ambient air by absorbing solar radiation and trapping heat. Inflorescence size, time of day and insolation have notable impacts on temperatures within teasel inflorescences. Large inflorescences (about 50 mm long × 30 mm in diameter) become as much as 8 C warmer than the ambient air at the time of day when the sun was strongest (ca. 10:00–14:00 EST), mid-sized ones (about 30 mm long × 20 mm diameter) about 5 C and small ones (about 20 mm long × 10 mm diameter) about 3 C. Temperature excesses observed under sunny conditions are abolished at night and under cloud. Pollinator activity, mostly by bumblebees ( Bombus ) on teasel heads follows the same trends as the temperature regimes, being most intense in warm sunny conditions. That correlation may reflect some relationships between floral biology and pollinator behaviour, such as floral heat, effects on nectar secretion, viscosity and availability, pollen presentation, and maturation of florets.

Flowers represent intricate microcosms shaped by their physical, chemical, and micrometeorological properties. Both thermogenic and non-thermogenic flowers (passively heated by insolation) that present a warm microclimate have been shown to attract pollinators, but emerging evidence suggests that floral humidity can also serve as an attractive cue. Here, we document a distinct microclimate within the flowers of both wild and domesticated squashes (Cucurbita spp.). Squash flower temperatures remain near ambient, but their humidity consistently exceeds ambient levels from bud to senescence. Experimental manipulations of the floral microclimate increased the occurrence of pollen tube rupture in a germination medium assay, highlighting a direct impact on plant fitness. To explore the role of the floral microclimate within a broader ecological context, we perforated squash flowers in farms to assess impacts on the behavior of their specialist squash bee pollinator (Xenoglossa pruinosa), generalist pollinators (bumblebees and honeybees), and specialist herbivores (cucurbit beetles). Perforated male flowers with reduced humidity received fewer visits from squash bees but not from generalist pollinators. Floral manipulations did not influence the foraging duration of any visitor but decreased the occupancy of male squash bees and cucurbit beetles in wilted flowers compared with controls. There was a positive correlation between ambient air dryness and the abundance of squash bees and cucurbit beetles residing within the humid wilted floral chambers. Our findings showcase squash flowers as humid microhabitats that influence reproductive success directly by affecting pollen viability and indirectly by altering interactions with the specialists, squash bees and cucurbit beetles.

Evidence is widespread that many species of Bombus are in population and biogeographical decline in response to adverse effects of global climate warming. The complex interactions of the mechanisms at the root of the declines are poorly understood. Among the numerous factors, we posit that heat stress in the nests could play a key role in the decline of bumblebee species. The similarity of the optimum temperature range in incubating nests is remarkable, about 28–32 °C regardless of species from the cold High Arctic to tropical environments indicates that the optimal temperature for rearing of brood in Bombus spp. is a characteristic common to bumblebees (perhaps a synapomorphy) and with limited evolutionary plasticity. We do note that higher brood rearing temperature for the boreal and Arctic species that have been tested is stressfully high when compared with that for B. terrestris. The Thermal Neutral Zone (TNZ), temperatures over which metabolic expenditure is minimal to maintain uniform nest temperatures, has not been studied in Bombus and may differ between species and biogeographic conditions. That heat stress is more serious than chilling is illustrated by the Thermal Performance Curve Relationship (TPC) (also sometimes considered as a Thermal Tolerance Relationship). The TPC indicates that development and activity increase more slowly as conditions become warmer until reaching a plateau of the range of temperatures over which rates of activity do not change markedly. After that, activity rates decline rapidly, and death ensues. The TPC has not been studied in eusocial bees except Apis dorsata but may differ between species and biogeographic conditions. The importance of the TPC and the TNZ indicates that environmental temperatures in and around bumblebee nests (which have been rarely studied especially in the contexts of nest architecture and substrate thermal characteristics) are factors central to understanding the adverse effects of heat stress and climatic warming on bumblebee populations, health, and biogeographical decline.

Dr. Pieter Oomen, born in 1946, a prominent and inspirational scientist in many areas of the biosafety of pesticides, most notably ecotoxicology, regulatory, risk assessment and bioassays, passed away peacefully on 19th of January 2024. His efforts have had a great and long-lasting impact on bee risk assessment and have improved bee protection. While we will miss a very warm and brilliant person; his many contributions to science and our ability to detect and mitigate risks to the environment remain.

Apivectoring, or bee vectoring, employs managed bees to distribute powders containing disease and pest-fighting biocontrol agents during pollination flights to crops. Our research introduces a novel application of this concept, termed inspensing, which leverages bee vectoring for hive-based benefits. In inspensing, bees traverse through a carrier powder combined with products aimed at combating pathogens or pests within the hive. To facilitate this, we developed the ProtectaBEE® system, an innovative beehive-entrance technology that guides bees through a compartment inoculated with an inspensing powder. This system facilitates the application of beneficial agents into the hive without the need for beekeepers to open the hive, thereby streamlining the treatment process and reducing hive disturbance. To analyze the effectiveness of the system, we employed a fluorescent tracer in a powder formulation for tracking distribution throughout the hive. Complementing this, we inspensed a living dry powder-formulated biocontrol agent, Beauveria bassiana, an entomopathogenic fungus known to reduce Varroa mite populations, and detected its presence in the hive using PCR. The fluorescent powder was detected in 78.8% of the samples while B. bassiana was confirmed in up to 86.2% of larvae and 91.7% of mites. Our results underscore the system's efficacy in delivering material throughout the hive and affirm the potential for inspensing dry-powder-formulated biocontrol agents to manage Varroa destructor. Inspensing paves new paths for optimizing bee health and pest control strategies, streamlining disease management, simplifying hive maintenance, and minimizing beekeeper intervention, all contributing to sustainable apiculture.

Plants, animals, and fungi display a rich tapestry of colors. Animals, in particular, use colors in dynamic displays performed in spatially complex environments. Although current approaches for studying colors are objective and repeatable, they miss the temporal variation of color signals entirely. Here, we introduce hardware and software that provide ecologists and filmmakers the ability to accurately record animal-perceived colors in motion. Specifically, our Python codes transform photos or videos into perceivable units (quantum catches) for animals of known photoreceptor sensitivity. The plans and codes necessary for end-users to capture animal-view videos are all open source and publicly available to encourage continual community development. The camera system and the associated software package will allow ecologists to investigate how animals use colors in dynamic behavioral displays, the ways natural illumination alters perceived colors, and other questions that remained unaddressed until now due to a lack of suitable tools. Finally, it provides scientists and filmmakers with a new, empirically grounded approach for depicting the perceptual worlds of nonhuman animals.

Plant structures that enclose trapped air are morphologically and taxonomically diverse. They range from pubescence (trichomes) on various parts of plants to flowers, inflorescences, stems, culms (above-ground jointed stems of grasses), petioles, peduncles, scapes, fruits, bracts, leaves, galls, algal pneumatocysts, moss sporophytes, lichen podetia, and fungal fruiting bodies. Despite being familiar, such structures have not been studied systematically until recently when their complex thermodynamic functionality as microgreenhouses has been recognized. We propose the term “heliocaminiform” (Greco-Latin origin for “sun-room”) provides an umbrella term that describes form and function. Almost all the hollow structures we have examined have elevated internal temperatures of several degrees C above the surrounding air in sunshine, but those are abolished under cloud or at night. The potential importance for the additional heat is presumed to be in growth, maturation, reproduction, sexual function, and overall fitness of the plants. There seem to be no experimental studies on those effects even though they may help explain aspects of plants’ responses to climate change and to phenological mismatches with symbionts (mutualists and herbivores) as ecologically co-dependent partners. Our review and observations opens a remarkably new and hitherto surprisingly neglected avenue in botany which we hope others will explore.

The cultivation of strawberries within greenhouse environments is an increasingly common area of agricultural productivity, affording consistent fruit production of an otherwise highly seasonal crop. However, due to its relative novelty, few management tools have been identified, assessed or registered to date for control of the many known pests of greenhouse grown strawberry crops. This includes evaluation of biocontrol strategies such as apivectoring, whereby microbial agents known to suppress crop pests are dispersed by commercially available pollinating bumblebees, Bombus impatiens (Cresson 1863) (Hymenoptera: Apidae). Towards addressing the need for such tools, this study evaluated the impacts of three periods of apivectoring in a commercial greenhouse strawberry production facility to determine how well the conidia of entomopathogen, Beauveria bassiana (Bals.-Criv. Vuill 1912), would be disseminated for control of crop pests such as the western flower thrips, Frankliniella occidentalis (Pergrande) (Thysanoptera: Thripidae). Our results indicate that bumblebees effectively dispersed a formulation of B. bassiana throughout the greenhouse crop, with the entomopathogen being detected on multiple flowers, leaves, and fruit. Furthermore, the impact of this tool on the quality of fruit produced, as well as possible adverse effects of the entomopathogen on carrier bumblebees were also evaluated. The B. bassiana formulation had minimal impacts on bumblebee populations, with under 16% mortality attributed to infection by B. bassiana. Through population monitoring, we found that naturally occurring thrips were being suppressed by the apivectoring biocontrol strategy, with up to 75% of Frankliniella occidentalis collected from some treatment zones testing positive for infection by B. bassiana.

Willis Chan, is an excellent compendium of knowledge on the broadly understood process of pollination.Pollination is an extremely important ecosystem service provided by insects, therefore a comprehensive understanding of the diverse relationships between plants and pollinators requires a great deal of knowledge.This publication, prepared by many prominent specialists in pollination, offers readers a state of the art overview on the subject.It shows the secrets of the mechanisms developed by plants in order to encourage insects to visit their flowers and make effective cross-pollination.This is especially important in the case of cultivated plants, but also wild ones.In addition, it indicates the current threats to pollinating insects (climate change, diseases and pests, and the impact of pesticides) and methods of preventing adverse phenomena affecting the well-being of pollinators.The book also considers the phenomenon of interspecific competition of insects in ecosystems.In bringing this research together, the book highlights the need to protect ecosystem-valuable pollinators so that they can fulfil their role in the environment.It also gives growers practical tips on good pollinator care behaviour.In conclusion, this is an extremely valuable and much-needed publication for the whole of society.

Professor Dan Eisikowitch (Dini), one of the greatest researchers in 10 pollination and botany, has passed away (1936-2022). Dini died on 19 July, 2022 at 11 the age of 86. An obituary.

Plants, animals, and fungi display a rich tapestry of colors. Animals, in particular, use colors in dynamic displays performed in spatially complex environments. In such natural settings, light is reflected or refracted from objects with complex shapes that cast shadows and generate highlights. In addition, the illuminating light changes continuously as viewers and targets move through heterogeneous, continually fluctuating, light conditions. Although traditional spectrophotometric approaches for studying colors are objective and repeatable, they fail to document this complexity. Worse, they miss the temporal variation of color signals entirely. Here, we introduce hardware and software that provide ecologists and filmmakers the ability to accurately record animal-perceived colors in motion. Specifically, our Python codes transform photos or videos into perceivable units (quantum catches) for any animal of known photoreceptor sensitivity. We provide the plans, codes, and validation tests necessary for end-users to capture animal-view videos. This approach will allow ecologists to investigate how animals use colors in dynamic behavioral displays, the ways natural illumination alters perceived colors, and other questions that remained unaddressed until now due to a lack of suitable tools. Finally, our pipeline provides scientists and filmmakers with a new, empirically grounded approach for depicting the perceptual worlds of non-human animals.

The first fossil flowers of Neotropical Urticaceae (Boehmerieae) are described from the Dominican Republic and Mexico as belonging to a new genus, Ekrixanthera. Ekrixanthera hispaniolae sp. nov. from Dominican amber has pentamerous staminate flowers on short pedicels with a pilose pistillode and heteromorphic pilose tepals: two are clavate and three linear. Ekrixanthera ehecatli sp. nov. has pentamerous staminate flowers lacking pedicels, a pistillode with greatly reduced pilosity, glabrous and heteromorphic tepals with two linear and three wedge-shaped with truncate tips. The presence or absence of a pedicel, heterotrophic condition of the tepals, and the presence or absence of pilosity of the pistillode and tepals separate the two species. Those characters, together with the pentamerous flowers separate both fossil species from extant genera. The floral structures indicate explosive pollen release and pollination by wind (anemophily). Pistillate flowers have not been found for this usually dioecious tribe. Lepidopteran herbivory is suggested by a damaged stipule in one specimen and a nymphalid butterfly (Vanessa-like) caterpillar that may have used Ekrixanthera as a food plant is illustrated. The fossils establish an early lineage of Boehmerieae with characteristic explosive pollen release and perhaps associated herbivorous insects in the West Indies and North America during the mid-Tertiary.

This paper presents an in situ calibration method for an uncooled thermal camera to reduce bias and root mean square error (RMSE) for the observed surface temperatures of Gerbera jamesonii plants. Surface temperature bias and RMSE were quantified for the calibrated camera constants and compared with respect to the default constant statistics. The averaged calibrated camera constant bias and RMSE values decreased by at least 89.1% relative to the averaged default camera constant bias and RMSE values for individual plant stems and flowers. This calibration approach has the potential to be suitable for other uncooled thermal cameras in fields beyond horticultural applications.

Near-ground temperatures strongly influence Arctic plant growth, reproduction, maturation and phenological relations with pollinators and herbivores. Those temperatures become further elevated within plant parts through passive solar heating, e.g. dish-shaped blossoms that focus insolation and heat-trapping pubescent structures. Other Arctic plants gain heat in hollow structures that possibly function as microgreenhouses. Arctic plants with hollow flowers in which intrafloral temperatures and temperature excesses (i.e. above nearby air) were recorded are Silene sorensenis and S. uralensis (Caryophyllaceae) with globose syncalyces, and Pedicularis langsdorfii and P. capitata (Orobanchaceae) with sympetalous corollas. The flowers heated passively, as microgreenhouses, in sunshine but not under cloudy conditions. Lateral orientation to insolation maximizes intrafloral heating in Pedicularis spp. Temperature excesses up to about 6 °C probably accelerate development of the plants’ reproductive organs (gynoecium, androecium, fruits, seeds) through 25% additional heat units (growing degree days above 0°C) over the High Arctics short, cool, active season. How these phenomena exacerbate the effects of climate change remains to be assessed.