Biology subjects

Vallejo-Marin, M.

Publications and source records attributed to Vallejo-Marin, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Divergence in wilt tolerance across the range of Mimulus guttatus in the absence of stomatal regulation

Whether phenotypes and environments predict performance under stress is central to ecology and evolution and can reveal species' vulnerability to global change. We sampled Mimulus guttatus range-wide to test whether reproductive, morphological, and physiological traits predict drought responses. Surprisingly, we find that stomatal response, a key mediator of water balance, did not change as drought intensified. Climate, however, predicted survival after turgor loss: plants from regions with large daily relative to seasonal temperature ranges survived wilting longer. Stress responses also depended on life history: where summers are dry, perennials withstood lower water potentials, whereas annuals increased leaf cooling as they wilted. Known trait associations were not fixed: although many baseline traits tracked climate, none predicted drought responses. Drought performance therefore cannot be inferred from traits measured under well-watered conditions. Lacking stomatal regulation, riparian drought escapers like M. guttatus may be vulnerable if shorter growing seasons bring drought before reproduction.

plant biology↗

bioRxiv2025

First direct quantification of floral handling costs in bees

Floral handling can be energetically costly for bees, yet these costs are rarely measured. We provide the first direct quantification of the metabolic cost of floral buzzing in bumblebees and evaluate its ecological significance. Using flow-through respirometry synchronised with laser vibrometry, we measured carbon dioxide production during buzzing by Bombus terrestris and compared it with flight take-off, which is powered by the same thoracic muscles. Buzzing required high muscular effort, with [~]0.10 J per event and mass-specific power [~]293 W kg-{superscript 1}, and overall costs comparable to take-off because buzzing bouts are longer even though the metabolic rate is lower. Absolute metabolic rate increased with body mass, whereas intertegular span did not, implying that transient load rather than structural size better explains energetic demand in short, high-intensity behaviours. Metabolic traits were repeatable within individuals, and colony identity explained additional variance, consistent with genetic or shared environmental effects. Converting costs to nectar equivalents showed that buzzing required slightly more nectar than take-off and that requirements rose as nectar sugar concentration declined. We conclude that floral buzzing is a major, previously unquantified component of bee energy budgets that is likely to shape nectar supplementation, flower sequencing, and plant-pollinator interaction strength.

animal behavior and cognition↗

bioRxiv2025

Nuances of floral mimicry in Queen of Sheba orchids

O_LIBackground and Aims Floral deception can range from finely tuned mimicry of specific rewarding plants (Batesian mimicry) to a general resemblance of the rewarding community (generalised food deception). We focused on two species in the deceptive Thelymitra variegata complex (Queen of Sheba orchids) to examine whether pollination is consistent with generalised food deception or with specific mimicry of co-flowering buzz-pollinated tinsel lilies (Calectasia spp.). C_LIO_LIMethods We assessed i) overlap in flower colour and scent between orchids, tinsel lilies, and other flowers in the rewarding community, ii) pollinator sharing between orchids, tinsel lilies and other species, and ii) quantified orchid reproductive success in relation to abundance of tinsel lilies and other rewarding species. C_LIO_LIKey Results We found that T. speciosa matches flower colour and scent of its co-flowering tinsel lily, C. gracilis, while T. porphyrosticta partly overlaps with co-flowering C. demarzii in both traits. The orchids and tinsel lilies shared flower visitors, and the only visitor observed to transfer orchid pollen was Anthoglossa plumata bee (Colletidae) that displayed a behaviour associated with buzz pollination. This species was also observed to buzz-pollinate tinsel lilies. In T. speciosa, fruit production increased with abundance of both tinsel lilies and other rewarding species with similar flower colour, suggesting a combination of mimicry and magnet effects. However, relationships were driven by a single population. There was no association between rewarding community and reproductive success in T. porphyrosticta. C_LIO_LIConclusions The results are partly consistent with mimicry towards the co-flowering tinsel lily for both orchids. Specific mimicry is strongly supported by a close resemblance involving multiple floral traits, and by bee behaviour associated with the buzz-pollinated model. However, this contrasts with the lack of consistent effects of tinsel lily abundance on orchid reproductive success. The findings further suggest that shared floral scent may reinforce visual similarity and highlight that scent may be important in food mimicry systems. More generally, the T. variegata complex offers an interesting system for studying nuances between specific mimicry and generalised deception. C_LI

ecology↗

bioRxiv2024

The fate of pollen in two morphologically contrasting buzz-pollinated Solanum flowers

Pollen transfer efficiency (PTE) and pollen deposition patterns on a pollinators body significantly influence plant reproductive success. However, studies on pollen fates (i.e., the destination of pollen grains after anther dehiscence) in animal-pollinated species offering pollen as the sole reward are limited. This study investigated pollen fates in two nectarless, buzz-pollinated Solanum species with contrasting floral morphology. Experimental trials were conducted involving one pollen donor and four recipient flowers of Solanum rostratum Dunal or S. dulcamara L., using captive Bombus terrestris L. as pollinator. The number of pollen grains remaining in the anthers, deposited on stigmas, placed on the pollinator, and falling to the ground was quantified. Both species produced a relatively high number of pollen grains as expected for buzz-pollinated plants. Pollen deposition curves followed exponential decay patterns, with a higher number of pollen grains deposited for S. dulcamara, and a similar rate of decline for both species. PTE was similar between species (0.86 % vs. 1.00 %, for S. rostratum and S. dulcamara, respectively) but these values could be 25 % higher if we were to measure pollen deposition in 20 recipients rather than four as in the present study. Although both species had similar PTE values, their pollen fates differed: pollen was mainly lost on the ground in S. rostratum and due to bee grooming in S. dulcamara, potentially explained by their different floral architectures. These findings suggest that species with different flower morphology could exhibit different pollen fates without impacting pollen transfer to conspecific stigmas.

plant biology↗

bioRxiv2024

Traits related to pollination and mating result in diverse reproductive strategies in angiosperms

O_LIFlowering plants have many modes of sexual reproduction, notably varying from selfing to outcrossing, and from bisexual flowers to individuals with separate sexes (dioecy). These reproductive modes are associated with floral and life-history traits that have evolved together, making it difficult to interpret correlations between traits. C_LIO_LIWe analysed variation in 21 traits related to flowers, pollination, mating, sexual systems and life history from 361 species representative of flowering plant diversity. C_LIO_LIOutcrossing was mainly found among long-lived, large-stature plants, but hermaphroditic outcrossers and dioecious species appeared as largely non-overlapping strategies in the trait space. Level of floral investment was the main difference between these strategies, with dioecious species having generally smaller, less rewarding flowers, a pattern that also occurred in biotically pollinated species. C_LIO_LIThis multi-trait study shows that pollination can be achieved in many, often contrasting, ways. Despite extensive variation in reproductive traits, dioecy stands out as being linked to floral traits primarily, while correlations with lifespan and dispersal traits appear spurious. We provide a conceptual framework based on lifespan, floral investment, and sexual separation that can be used to integrate pollination, reproduction and plant growth in future research on plant evolution and ecology. C_LI

evolutionary biology↗

bioRxiv2024

Biomechanical properties of defence vibrations produced by bees

AbstractBees use thoracic vibrations produced by their indirect flight muscles for powering wingbeats in flight, but also during mating, pollination, defence, and nest building. Previous work on non-flight vibrations has mostly focused on acoustic (airborne vibrations) and spectral properties (frequency domain). However, mechanical properties such as the vibrations acceleration amplitude are important in some behaviours, e.g., during buzz pollination, where higher amplitude vibrations remove more pollen from flowers. Bee vibrations have been studied in only a handful of species and we know very little about how they vary among species. Here, we conduct the largest survey to date of the biomechanical properties of non-flight bee buzzes. We focus on defence buzzes as they can be induced experimentally and provide a common currency to compare among taxa. We analysed 15,000 buzzes produced by 306 individuals in 65 species and six families from Mexico, Scotland, and Australia. We found a strong association between body size and the acceleration amplitude of bee buzzes. Comparison of genera that buzz-pollinate and those that do not suggests that buzz-pollinating bees produce vibrations with higher acceleration amplitude. We found no relationship between bee size and the fundamental frequency of defence buzzes. Although our results suggest that body size is a major determinant of the amplitude of non-flight vibrations, we also observed considerable variation in vibration properties among bees of equivalent size and even within individuals. Both morphology and behaviour thus affect the biomechanical properties of non-flight buzzes. Summary statementAnalyses across 65 bee taxa in three continents indicates that body size is a major determinant of the acceleration amplitude but not the oscillation frequency of non-flight thoracic vibrations.

ecology↗

bioRxiv2022

POLLINATOR GROOMING BEHAVIOR ALTERS POLLEN LANDSCAPES ON BEES BODIES AND INCREASES POLLEN CARRYOVER TO OTHER FLOWERS

Pollen participates both as the carrier of male gametes in the reproduction of flowering plants and as a key resource exploited by floral visitors, especially bees. Pollinator behavior significantly alters the patterns of pollen removal and deposition, often called pollen fates. To date, few theoretical investigations have attempted to jointly model patterns of pollen transfer and pollinator behavior, and empirical studies are restricted to species to which pollen movement can be tracked. Here we use a spatially explicit agent-based modeling approach, to determine how bee grooming behavior may alter pollen fates and affect plant reproduction. Specifically, we asked whether pollen mixing and removal during pollen grooming may change the "pollen landscape" on a bees body consequently affecting both pollen export by the anthers and deposition onto stigmas. Our model shows that both mixing and removal behaviors restructure the "pollen landscape" on the bees body, increasing pollen carryover (deposition in consecutive visits), and increasing pollen diversity (number of pollen donors) onto stigmas in sequential flower visits. Our results counterintuitively show that pollen grooming may have a positive effect on both male and female finesses during plant reproduction.

ecology↗

bioRxiv2022

Trait-dependent diversification in angiosperms: patterns, models and data

Variation in species richness across the tree of life, accompanied by the incredible variety of ecological and morphological characteristics found in nature, has inspired many studies to link traits with species diversification. Angiosperms are a highly diverse group that has fundamentally shaped life on earth since the Cretaceous, and illustrate how species diversification affects ecosystem functioning. Numerous traits and processes have been linked to differences in species richness within this group, but we know little about how these interact and their relative importance. Here, we synthesized data from 152 studies that used state-dependent speciation and extinction (SSE) models on angiosperm clades. Intrinsic traits related to reproduction and morphology were often linked to diversification but a set of universal drivers did not emerge as traits did not have consistent effects across clades. Importantly, dataset properties were correlated to SSE model results - trees that were larger, older, or less well-sampled tended to yield trait-dependent outcomes. We compared these properties to recommendations for SSE model use and provide a set of best practices to follow when designing studies and reporting results. Finally, we argue that SSE model inferences should be considered in a larger context incorporating species ecology, demography and genetics.

evolutionary biology↗

bioRxiv2021

Anther cones increase pollen release in buzz-pollinated Solanum flowers

The widespread evolution of tube-like anthers releasing pollen from apical pores is associated with buzz pollination, in which bees vibrate flowers to remove pollen. The mechanical connection among anthers in buzz-pollinated species varies from loosely held conformations, to anthers tightly held together with trichomes or bio-adhesives forming a functionally joined conical structure (anther cone). Joined anther cones in buzz-pollinated species have evolved independently across plant families and via different genetic mechanisms, yet their functional significance remains mostly untested. We used experimental manipulations to compare vibrational and functional (pollen release) consequences of joined anther cones in three buzz-pollinated species of Solanum (Solanaceae). We applied bee-like vibrations to focal anthers in flowers with ("joined") and without ("free") experimentally created joined anther cones, and characterised vibrations transmitted to other anthers and the amount of pollen released. We found that joined anther architectures cause non-focal anthers to vibrate at higher amplitudes than free architectures. Moreover, in the two species with naturally loosely held anthers, anther fusion increases pollen release, while in the species with a free but naturally compact architecture it does not. We discuss hypotheses for the adaptive significance of the convergent evolution of joined anther cones.

evolutionary biology↗

bioRxiv2021

Reduced visitation to the buzz-pollinated Cyanella hyacinthoides in the presence of other pollen sources in the hyperdiverse Cape Floristic Region

Many plant species have floral morphologies that restrict access to floral resources, such as pollen or nectar, and only a subset of floral visitors can perform the complex handling behaviours required to extract restricted resources. Due to the time and energy required to extract resources from morphologically complex flowers, these plant species potentially compete for pollinators with co-flowering plants that have more easily accessible resources. A widespread floral mechanism restricting access to pollen is the presence of tubular anthers that open through small pores or slits (poricidal anthers). Some bees have evolved the capacity to remove pollen from poricidal anthers using vibrations, giving rise to the phenomenon of buzz-pollination. These bee vibrations that are produced for pollen extraction are presumably energetically costly, and to date, few studies have investigated whether buzz-pollinated flowers may be at a disadvantage when competing for pollinators attention with plant species that present unrestricted pollen resources. Here, we studied Cyanella hyacinthoides (Tecophilaeaceae), a geophyte with poricidal anthers in the hyperdiverse Cape Floristic Region of South Africa, to assess how the composition and relative abundance of flowers with easily accessible pollen affect bee visitation to a buzz-pollinated plant. We found that the number of pollinator species was not influenced by community composition. However, visitation rates to C. hyacinthoides were negatively related to the abundance of flowers with more accessible resources. Visitation rates were strongly associated with petal colour, showing that flower colour is important in mediating these interactions. We conclude that buzz-pollinated plants might be at a competitive disadvantage when many easily accessible pollen sources are available, particularly when competitor species share its floral signals.

ecology↗

bioRxiv2021

Transmission of vibrations in buzz-pollinated plant species with disparate floral morphologies

In buzz-pollinated plants, bees apply vibrations produced by their thoracic muscles to the flower, causing pollen release from anthers, often through small apical pores. During floral buzzing, bees grasp one or more anthers with their mandibles, and vibrations are transmitted to the focal anther(s), adjacent anthers, and the whole flower. Because pollen release depends on the vibrations experienced by the anther, the transmission of vibrations through flowers with different morphologies may determine patterns of release, affecting both bee foraging and plant fitness. Anther morphology and intra-floral arrangement varies widely among buzz-pollinated plants. Here, we compare the transmission of vibrations among focal and non-focal anthers in four species with contrasting anther morphologies: Cyclamen persicum (Primulaceae), Exacum affine (Gentianaceae), Solanum dulcamara and S. houstonii (Solanaceae). We used a mechanical transducer to apply bee-like artificial vibrations to focal anthers, and simultaneously measured the vibration frequency and displacement amplitude at the tips of focal and non-focal anthers using high-speed video analysis (6,000 frames per second). In flowers in which anthers are tightly held together (C. persicum and S. dulcamara), vibrations in focal and non-focal anthers are indistinguishable in both frequency and displacement amplitude. In contrast, flowers with loosely arranged anthers (E. affine) including those in which stamens are morphologically differentiated within the same flower (heterantherous S. houstonii), show the same frequency but higher displacement amplitude in non-focal anthers compared to focal anthers. Our results suggest that stamen arrangement affects vibration transmission with potential consequences for pollen release and bee behaviour.

biophysics↗

bioRxiv2020

Rapid local adaptation in both sexual and asexual invasive populations of monkeyflowers (Mimulus spp.)

Background and AimsTraditionally, local adaptation has been seen as the outcome of a long evolutionary history, particularly in sexual lineages. In contrast, phenotypic plasticity has been thought to be most important during the initial stages of population establishment and in asexual species. We evaluated the roles of adaptive evolution and phenotypic plasticity in the invasive success of two closely related species of invasive monkeyflowers (Mimulus) in the United Kingdom (UK) that have contrasting reproductive strategies: M. guttatus combines sexual (seeds) and asexual (clonal growth) reproduction while M. x robertsii is entirely asexual. MethodsWe compared the clonality (number of stolons), floral and vegetative phenotype, and phenotypic plasticity of native (M. guttatus) and invasive (M. guttatus and M. x robertsii) populations grown in controlled environment chambers under the environmental conditions at each latitudinal extreme of the UK. The goal was to discern the roles of temperature and photoperiod on the expression of phenotypic traits. Next, we tested the existence of local adaptation in the two species within the invasive range with a reciprocal transplant experiment at two field sites in the latitudinal extremes of the UK, and analysed which phenotypic traits underlie potential local fitness advantage in each species. Key ResultsPopulations of M. guttatus in the UK showed local adaptation through sexual function (fruit production), while M. x robertsii showed local adaptation via asexual function (stolon production). Phenotypic selection analyses revealed that different traits are associated with fitness in each species. Invasive and native populations of M. guttatus had similar phenotypic plasticity and clonality. M. x robertsii presents greater plasticity and clonality than native M. guttatus, but most populations have restricted clonality under the warm conditions of the south of UK. ConclusionsOur study provides experimental evidence of local adaptation in a strictly asexual invasive species with high clonality and phenotypic plasticity. This indicates that even asexual taxa can rapidly (< 200 years) adapt to novel environmental conditions in which alternative strategies may not ensure the persistence of populations.

evolutionary biology↗

bioRxiv2020

The evolution of thermal performance in native and invasive populations of Mimulus guttatus

1. The rise of globalization has spread organisms beyond their natural range, allowing further opportunity for species to adapt to novel environments and potentially become invaders. Yet, the role of climatic niche evolution in promoting the success of invasive species remains poorly understood. Here, we use thermal performance curves (TPCs) to test hypotheses about thermal adaptation during the invasion process. First, if novel temperature regimes impose strong selection in the introduced range, invasive populations may evolve distinct TPCs relative to native populations. Second, invasive species may not exhibit specialist-generalist tradeoffs and instead may be "masters-of-all" with high maximum performance and broad TPCs. Third, with sufficient time, standing genetic variation, and temperature-mediated selection, TPCs of native and invasive populations may show parallel evolution in response to thermal gradients. 2. To test these hypotheses, we built TPCs for 18 native (United States) and 13 invasive (United Kingdom) populations of the yellow monkeyflower, Mimulus guttatus. We grew clones of multiple genotypes per population across six temperature regimes in growth chambers. 3. Invasive populations have not evolved different thermal optima or performance breadths, providing evidence for evolutionary stasis of thermal performance between the native and invasive ranges after over 200 years post-introduction. Further, both native and invasive populations experienced similar specialist-generalist tradeoffs whereby broad TPCS come at the cost of lower peak performance. Inconsistent with the idea that the degree of thermal specialization varies across spatial or temperature gradients, native and invasive populations did not exhibit adaptive clines in thermal performance breadth with latitude or temperature seasonality. However, thermal optimum increased with mean annual temperature in the native range, indicating some adaptive differentiation among native populations 4. Synthesis: These findings suggest that thermal niches were static during the invasion process, and that general-purpose genotypes, rather than rapid evolution in the introduced range, may promote invasion.

evolutionary biology↗

bioRxiv2020

Pollen dispensing schedules in buzz-pollinated plants: Experimental comparison of species with contrasting floral morphologies

O_LIIn buzz-pollinated plants, bees apply vibrations to remove pollen from anthers that have small apical pores or slits. These poricidal anthers potentially function as mechanism to stagger pollen release, but this has rarely been tested across plant species differing in anther morphology. C_LIO_LIIn Solanum section Androceras, three pairs of buzz-pollinated Solanum species have undergone independent evolutionary shifts between large- and small-flowered taxa. These shifts in flower size are accompanied by replicate changes in anther morphology, and we used these shifts in anther morphology to characterise the association between anther morphology and pollen dispensing schedules. We characterised pollen dispensing schedules by applying simulated bee-like vibrations directly to anthers to elicit pollen release. We then compared pollen dispensing schedules across anther morphologies, and we further investigated how vibration velocity affects pollen release. Finally, we assessed whether particular anther traits, presented in the Buchmann-Hurley model, can predict pollen dispensing schedules. C_LIO_LIWe show that replicate transitions in Solanum anther morphology are associated with consistent changes in pollen dispensing schedules. We found that small-flowered taxa with small anthers release their pollen at higher rates than their large-flowered counterparts, showing an association between general anther morphology and pollen dispensing. Further, higher vibration velocities resulted in quicker pollen dispensing and more total pollen released, which suggested that bees that produce high-energy vibrations can access more reward than bees producing low-energy vibrations. Finally, both the pollen dispensing rate and the amount of pollen released in the first vibration were negatively related to anther wall area, but, surprisingly, we did not observe any association between pore size and pollen dispensing. C_LIO_LIOur results provide the first empirical demonstration that the pollen dispensing properties of poricidal anthers depend on both floral characteristics and bee vibration properties, and suggest that morphological modification of anthers could provide a mechanism to exploit different pollination environments. C_LI

ecology↗

bioRxiv2020

Population genomic and historical analysis reveals a global invasion by bridgehead processes in Mimulus guttatus

Humans are transforming species ranges worldwide. While artificial translocations trigger biological invasions with negative effects on biodiversity, invasions provide exceptional opportunities to generate ecological and evolutionary hypotheses. Unfortunately, imperfect historical records and exceedingly complex demographic histories present challenges for the reconstruction of invasion histories. Here we combine historical records, extensive worldwide and genome-wide sampling, and demographic analyses to investigate the global invasion of yellow monkeyflowers (Mimulus guttatus) from North America to Europe and the Southwest Pacific. By sampling 521 plants from 158 native and introduced populations genotyped at >44,000 loci, we determined that invasive North American M. guttatus was first likely introduced to the British Isles from the Aleutian Islands (Alaska), followed by rapid admixture from multiple parts of the native range. Populations in the British Isles then appear to have served as a bridgehead for vanguard invasions worldwide into the rest of Europe, New Zealand and eastern North America. Our results emphasise the highly admixed nature of introduced M. guttatus and demonstrate the potential of introduced populations to serve as sources of secondary admixture, producing novel hybrids. Unravelling the history of biological invasions provides a starting point to understand how invasive populations adapt to novel environments.

evolutionary biology↗

bioRxiv2020

Are flowers tuned to buzzing pollinators? Variation in the natural frequency of stamens with different morphologies and its relationship to bee vibrations

During buzz pollination, bees use vibrations to remove pollen from flowers. Vibrations at the natural frequency of pollen-carrying stamens are amplified through resonance, resulting in higher-amplitude vibrations. Because pollen release depends on vibration amplitude, bees could increase pollen removal by vibrating at the natural frequency of stamens. Yet, few studies have characterized the natural frequencies of stamens and compared them to frequencies of buzz-pollinating bees. Here we use laser Doppler vibrometry to characterise natural frequencies of stamens of six buzz-pollinated Solanum taxa of contrasting stamen morphology. We also compare the fundamental frequency of bumblebee buzzes produced on two Solanum species with different natural frequencies. We found that stamen morphology and plant identity explain variation in natural frequency of stamens. Our results show that medium-sized pollinators, such as bumblebees, produce buzzes of frequencies higher than the natural frequency of most (5/6) of the Solanum species we studied. However, the observed natural frequency of Solanum stamens is at the low end of the range of frequencies produced by other buzz-pollinating bees. Thus, our findings suggest that in some buzz pollination interactions, but not others, stamen resonance may play a role in mediating pollen release.

biophysics↗

bioRxiv2020

Biomechanical properties of a buzz-pollinatedflower

Approximately half of all bee species use vibrations to remove pollen from plants with diverse floral morphologies. In many buzz-pollinated flowers, these mechanical vibrations generated by bees are transmitted through floral tissues, principally pollen-containing anthers, causing pollen to be ejected from small openings (pores or slits) at the tip of the stamen. Despite the importance of substrate-borne vibrations for both bees and plants, few studies to date have characterised the transmission properties of floral vibrations. In this study, we use contactless laser vibrometry to evaluate the transmission of vibrations in the corolla and anthers of buzz-pollinated flowers of Solanum rostratum, and measured vibrations in three spatial axes. We found that floral vibrations conserve their dominant frequency (300Hz) as they are transmitted through the flower, but that vibrations in anthers and petals can gain additional harmonics relative to the pure tone of input vibrations. We also found that vibrations are generally amplified (up to >400%) as they travel from the receptacle at the base of the flower to other floral structures, and that anthers vibrate with a higher amplitude velocity than petals. Together, these results suggest that vibrations travel differently through floral structures and across different spatial axes. As pollen release is a function of vibration amplitude, we conjecture that bees might benefit from applying vibrations in the axes associated with higher vibration amplification.

plant biology↗

bioRxiv2019

Floral vibrations by buzz-pollinating bees achieve higher frequency, velocity and acceleration than flight and defence vibrations

Vibrations play an important role in insect behaviour. In bees, vibrations are used in a variety of contexts including communication, as a warning signal to deter predators and during pollen foraging. However, little is known about how the biomechanical properties of bee vibrations vary across multiple behaviours within a species. In this study, we compared the properties of vibrations produced by Bombus terrestris audax (Hymenoptera: Apidae) workers in three contexts: during flight, during defensive buzzing, and in floral vibrations produced during pollen foraging on two buzz-pollinated plants (Solanum, Solanaceae). Using laser vibrometry, we were able to obtain contactless measures of both the frequency and amplitude of the thoracic vibrations of bees across the three behaviours. Despite all three types of vibrations being produced by the same power flight muscles, we found clear differences in the mechanical properties of the vibrations produced in different contexts. Both floral and defensive buzzes had higher frequency and amplitude velocity, acceleration, and displacement than the vibrations produced during flight. Floral vibrations had the highest frequency, amplitude velocity and acceleration of all the behaviours studied. Vibration amplitude, and in particular acceleration, of floral vibrations has been suggested as the key property for removing pollen from buzz-pollinated anthers. By increasing frequency and amplitude velocity and acceleration of their vibrations during vibratory pollen collection, foraging bees may be able to maximise pollen removal from flowers, although their foraging decisions are likely to be influenced by the presumably high cost of producing floral vibrations.

animal behavior and cognition↗