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1.
Ann Bot ; 2024 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-39223914

RESUMEN

BACKGROUND AND AIMS: Flower-visitor interactions comprise a continuum of behaviors, from mutualistic partners to antagonistic visitors. Despite being relatively frequent in natural communities, florivory remains unexplored, especially when comprising abiotic factors, spatio-temporal variations and global environmental changes. Here, we addressed the variation of florivory driven by changes in elevation and temporal flower availability. We expect decreased floral resources as elevation increases -due to environmental constraints- which may affect plant-florivore interactions. Yet, if floral resources decrease but florivores remain constant, then we may expect an increase in florivory with increasing elevation in the community. METHODS: The flowering phenology of plant individuals was recorded in the Neotropical campo rupestre vegetation, in southeastern Brazil. Damages by florivores were recorded in plots at elevations ranging from 823 to 1411 m using two response variables as a proxy for florivory: the proportion of attacked flowers per plant and the proportion of petal removal on single flowers. KEY RESULTS: Flower attack increased with elevation and damages were intensified in species with longer flowering periods. Conversely, longer flowering periods resulted in higher levels of petal removal when decreasing elevation. The temporal availability of flowers affected florivory, with the proportion of attacked flowers being more intense when there are less flowered individuals in the community. Petal removal on single flowers was intensified in plots with a larger number of individuals flowering, and with more species co-flowering. CONCLUSIONS: This study brings one of the broadest records of a commonly neglected interaction of insects feeding on floral structures, quantifying the combined effect of floral display and availability along an elevation gradient in a highly biodiverse mountaintop community. These findings contribute to filling in the gap in the understanding of florivory dynamics, focusing on a tropical mountaintop scenario facing imminent environmental changes and excessive natural resource exploitation.

2.
Bull Entomol Res ; 114(1): 124-133, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38268108

RESUMEN

Neotropical cyclocephaline beetles, a diverse group of flower-loving insects, significantly impact natural and agricultural ecosystems. In particular, the genus Cyclocephala, with over 350 species, displays polymorphism and cryptic complexes. Lacking a comprehensive DNA barcoding framework, accessible tools for species differentiation are needed for research in taxonomy, ecology, and crop management. Moreover, cuticular hydrocarbons are believed to be involved in sexual recognition mechanisms in these beetles. In the present study we examined the cuticular chemical profiles of six species from the genus Cyclocephala and two populations of Erioscelis emarginata and assessed their efficiency in population, species, and sex differentiation. Overall we identified 74 compounds in cuticular extracts of the selected taxa. Linear alkanes and unsaturated hydrocarbons were prominent, with ten compounds between them explaining 85.6% of species dissimilarity. Although the cuticular chemical profiles efficiently differentiated all investigated taxa, only C. ohausiana showed significant cuticular profile differences between sexes. Our analysis also revealed two E. emarginata clades within a larger group of 'Cyclocephala' species, but they were not aligned with the two studied populations. Our research underscores the significance of cuticular lipid profiles in distinguishing selected cyclocephaline beetle species and contemplates their potential impact as contact pheromones on sexual segregation and speciation.


Asunto(s)
Escarabajos , Animales , Escarabajos/genética , Ecosistema , Hidrocarburos , Feromonas/química , Lípidos/análisis
3.
Oecologia ; 204(1): 47-58, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38091102

RESUMEN

Two of the major factors that control the composition of herbaceous plant communities are competition for limiting soil resources and herbivory. We present results from a 14-year full factorial experiment in a tallgrass prairie ecosystem that crossed nitrogen (N) addition with fencing to exclude white-tailed deer, Odocoileus virginianus, from half the plots. Deer presence was associated with only modest decreases in aboveground plant biomass (14% decrease; -45 ± 19 g m-2) with no interaction with N addition. N addition at 5.44 and 9.52 g N m-2 year-1 led to increases in biomass. There were weak increases in species richness associated with deer presence, but only for no or low added N (1 and 2 g N m-2 year-1). However, the presence of deer greatly impacted the abundances of some of the dominant perennial forb species, but not the dominant grasses. Deer presence increased the abundance of the forb Artemisia ludoviciana by 34 ± 12 SE g m-2 (94%) and decreased the forb Solidago rigida by 32 ± 13 SE g m-2 (79%). We suggest that these changes may have resulted from trade-offs in plant competitive ability for soil N versus resistance to deer herbivory. Field observations suggest deer acted as florivores, mainly consuming the flowers of susceptible forb species. The preferential consumption of flowers of forbs that seem to be superior N competitors appears to create an axis of interspecific niche differentiation. The overpopulation of white-tailed deer in many tallgrass reserves likely structures the abundance of forb species.


Asunto(s)
Ciervos , Ecosistema , Animales , Herbivoria , Pradera , Nitrógeno , Plantas , Suelo
4.
Oecologia ; 203(1-2): 151-165, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37794240

RESUMEN

Although it is well recognized that the strength of plant-herbivore interactions can vary with the plant sex, the distance, and the density of conspecific neighbors, no study has yet assessed their combined influence. Here, we filled this knowledge gap by focusing on the dioecious palm Chamaerops humilis L., and its two main herbivores, the invasive moth Paysandisia archon Burmeister and the feral goat Capra hircus L. We evaluated levels and spatial patterns of herbivory, as well as those of plant size and number of inflorescences in two palm populations in Mallorca (Balearic Islands, Spain). Our spatial point pattern analyses revealed that palms not affected by moth herbivory or goat florivory were spatially aggregated, goats fed more strongly upon inflorescences in palms with more neighbors, but they consumed more leaves in isolated palms. Interestingly, we could reveal for the first time that plant sex is a key plant trait modulating neighborhood effects. For instance, whereas aggregated female palms experienced lower intensity of goat florivory than isolated ones, male palms showed the opposite pattern. Palm size and number of inflorescences also showed sex-related differences, suggesting that sexual dimorphism is a key driver of the observed neighborhood effects on herbivory. Our study highlights the importance of considering relevant plant traits such as sex when investigating plant neighborhood effects, calling for further research to fully understand the dynamics governing plant-herbivore interactions in dioecious systems.


Asunto(s)
Arecaceae , Mariposas Nocturnas , Animales , Herbivoria , Hojas de la Planta , Cabras , Características del Vecindario
5.
Environ Entomol ; 52(6): 1082-1094, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37827520

RESUMEN

Host-plant phenology can directly and indirectly mediate the abundance of insect herbivores. Our objective was to determine how host-plant flowering phenology shapes a facultative ant-lycaenid mutualism. The focus of our research was the hops azure, Celastrina humulus Scott & D. Wright, a rare species whose larvae feed on the pollen-bearing inflorescences of Humulus lupulus var. neomexicanus. We used several approaches to evaluate the role of host-plant flowering phenology in this system. First, we monitored larvae over three study years (2020-2022) to parse the role of host-plant flowering phenology and other factors in shaping the likelihood of ant tending. Second, we tested larval performance at various phenological stages of the host plant. We also quantified variation in soluble proteins and secondary metabolites among inflorescences at varying phenological stages. Lastly, we treated artificial sugar-protein baits with extracts from different phenological stages of the host plant; this allowed us to assess how chemical variation among stages could impact ant recruitment. Monitoring results revealed that the likelihood of ant tending was lowest for larvae on host plants with early-stage inflorescences. These floral stages had the greatest concentrations of both soluble proteins and α-acids (humulone and cohumulone), and in the feeding trial, early-stage flowers enabled greater weight gain for larvae. However, extracts from early-stage flowers reduced ant recruitment to sugar-protein baits. Altogether, these results suggest that early-stage inflorescences enhance larval growth while also reducing the recruitment of mutualist ants. This shows an indirect mechanism whereby changing host-plant phenology can mediate herbivore populations through interactions with ants.


Asunto(s)
Hormigas , Mariposas Diurnas , Humulus , Animales , Simbiosis , Larva , Plantas , Azúcares
6.
Plant Biol (Stuttg) ; 25(7): 1071-1082, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37703504

RESUMEN

The chemical composition of plant individuals can vary, leading to high intraspecific chemodiversity. Diversity of floral chemistry may impact the responses of flower-feeding insects. Tanacetum vulgare plants vary significantly in their leaf terpenoid composition, forming distinct chemotypes. We investigated the composition of terpenoids and nutrients of flower heads and pollen in plants belonging to three chemotypes - dominated either by ß-thujone (BThu), artemisia ketone (Keto) or a mixture of (Z)-myroxide, santolina triene, and artemisyl acetate (Myrox) - using different analytical platforms. We tested the effects of these differences on preferences, weight gain and performance of adults of the shining flower beetle, Olibrus aeneus. The terpenoid composition and diversity of flower heads and pollen significantly differed among individuals belonging to the above chemotypes, while total concentrations of pollen terpenoids, sugars, amino acids, and lipids did not differ. Beetles preferred BThu over the Myrox chemotype in both olfactory and contact choice assays, while the Keto chemotype was marginally repellent according to olfactory assays. The beetles gained the least weight within 48 h and their initial mortality was highest when feeding exclusively on floral tissues of the Myrox chemotype. Short-term weight gain and long-term performance were highest when feeding on the BThu chemotype. In conclusion, the beetles showed chemotype-specific responses towards different T. vulgare chemotypes, which may be attributed to the terpenoid composition in flower heads and pollen rather than to differences in nutrient profiles. Both richness and overall diversity are important factors when determining chemodiversity of individual plants and their consequences on interacting insects.


Asunto(s)
Escarabajos , Tanacetum , Animales , Tanacetum/química , Tanacetum/metabolismo , Flores/química , Terpenos/metabolismo , Insectos , Plantas , Aumento de Peso
7.
Oecologia ; 202(4): 783-794, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37596431

RESUMEN

Discovering how organisms respond to the combinations of stressors they face in their environment is an enduring challenge for ecologists. A particular focus has been how natural enemies and abiotic stressors faced by plants may interact in their effect on the ecology and evolution of plant defense strategies. Here, we report on the results of an experiment measuring how reproduction in the clonal herbaceous plant horsenettle (Solanum carolinense) is affected by damage by leaf-feeding and by flower-feeding herbivores-as well as how horsenettle's tolerance of these different types of herbivory may be altered by nutrient stress. Leaf herbivory by lace bugs reduced horsenettle's seed production and root growth, and the relative impacts were greater in fertilized than in nutrient-stressed plants. In contrast, simulated-floral herbivory reduced seed production to a similar degree in fertilized and nutrient-stressed plants. However, compensation for floral herbivory through increased root growth occurred to a much greater extent in the fertilized than in the nutrient-stressed plants. These results can be explained in terms of the limiting resource model of plant tolerance, with leaf damage interpreted as exacerbating carbon limitation in the fertilized plants and floral damage ameliorating carbon limitation in the fertilized plants. These results can be extended to predicting patterns in the field: Although plants in a nutrient-poor environment may have overall low fitness, they are likely to be more tolerant of leaf herbivores-though this benefit may be countered by lower tolerance of any floral herbivores that share the environment.


Asunto(s)
Herbivoria , Semillas , Carbono , Nutrientes , Plantas
8.
Animals (Basel) ; 13(6)2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36978662

RESUMEN

The role of lizards as potential pollinators on islands has been documented for either one or a few plants in different parts of the world, but it has never been assessed for an entire plant community. Here, we quantified interaction rate by lizards and evaluated intraspecific differences in the use of flowers on Cabrera Gran (Cabrera archipelago, Balearic Islands) by means of visual observations, automated cameras and the analysis of pollen grain samples. Overall, we recorded interactions of the Balearic wall lizard (Podarcis lilfordi) with flowers of 44 plant species, 72.7% of which were unknown to date. Although florivory occurs in some of these species (35%), the majority of visits were legitimate (65%); in addition, we found intraspecific differences in the interactions related to the sex and age of lizards. Our findings support the role of Balearic wall lizards as potential pollinators across the entire plant community, and their contribution to particular plant species, for instance the endangered Cistus heterophyllus carthaginensis. This study also documents the first record of another sympatric lizard (Tarentola mauritanica) visiting flowers and contributes to the few existing records of flower interactions involving geckos in the Paleartic ecozone.

9.
Am J Bot ; 110(1): e16101, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36371765

RESUMEN

PREMISE: Floral traits are frequently under pollinator-mediated selection, especially in taxa subject to strong pollen-limitation, such as those reliant on pollinators. However, antagonists can be agents of selection on floral traits as well. The causes of selection acting on spring ephemerals are understudied though these species can experience particularly strong pollen-limitation. I examined pollinator- and antagonist-mediated selection in a narrowly endemic spring ephemeral, Trillium discolor. METHODS: I measured pollen limitation in T. discolor across two years and evaluated its breeding system. I compared selection on floral traits (display height, petal size, petal color, flowering time) between open-pollinated, and pollen-supplemented plants to measure the strength and mode of pollinator-mediated selection. I assessed whether natural levels of antagonism impacted selection on floral traits. RESULTS: Trillium discolor was self-incompatible and experienced pollen limitation in both years of the study. Pollinators exerted negative disruptive selection on display height and petals size. In one year, pollinator-mediated selection favored lighter petals but in the second year pollinators favored darker petals. Antagonist damage did not alter selection on floral traits. CONCLUSIONS: Results demonstrate that pollinators mediate the strength and mode of selection on floral traits in T. discolor. Interannual variation in the strength, mode, and direction of pollinator-mediated selection on floral traits could be important for maintaining of floral diversity in this system. Observed levels of antagonism were weak agents of selection on floral traits.


Asunto(s)
Flores , Polinización , Selección Genética , Fitomejoramiento , Polen
10.
Ecology ; 104(3): e3900, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36315032

RESUMEN

Encounters between flowers and invertebrates are key events for the functioning of tropical forests. Assessing the structure of networks composed of the interactions between those partners leads to a better understanding of ecosystem functioning and the effects of environmental factors on ecological processes. Gathering such data is, however, costly and time-consuming, especially in the highly diverse tropics. We aimed to provide a comprehensive repository of available flower-invertebrate interaction information for the Atlantic Forest, a South American tropical forest domain. Data were obtained from published works and "gray literature," such as theses and dissertations, as well as self-reports by co-authors. The data set has ~18,000 interaction records forming 482 networks, each containing between one and 1061 interaction links. Each network was sampled for about 200 h or less, with few exceptions. A total of 641 plant genera within 136 different families and 39 orders were reported, with the most abundant and rich families being Asteraceae, Fabaceae, and Rubiaceae. Invertebrates interacting with these plants were all arthropods from 10 orders, 129 families, and 581 genera, comprising 2419 morphotypes (including 988 named species). Hymenoptera was the most abundant and diverse order, with at least six times more records than the second-ranked order (Lepidoptera). The complete data set shows Hymenoptera interacting with all plant orders and also shows Diptera, Lepidoptera, Coleoptera, and Hemiptera to be important nodes. Among plants, Asterales and Fabales had the highest number of interactions. The best sampled environment was forest (~8000 records), followed by pastures and crops. Savanna, grasslands, and urban environments (among others) were also reported, indicating a wide range of approaches dedicated to collecting flower-invertebrate interaction data in the Atlantic Forest domain. Nevertheless, most reported data were from forest understory or lower strata, indicating a knowledge gap about flower-invertebrate interactions at the canopy. Also, access to remote regions remains a limitation, generating sampling bias across the geographical range of the Atlantic Forest. Future studies in these continuous and hard-to-access forested areas will yield important new information regarding the interactions between flowers and invertebrates in the Atlantic Forest. There are no copyright restrictions on the data set. Please cite this data paper if the data are used in publications and teaching events.


Asunto(s)
Himenópteros , Lepidópteros , Humanos , Animales , Ecosistema , Invertebrados , Bosques , Plantas , Flores , Polinización
11.
Biol Lett ; 18(10): 20220373, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36285463

RESUMEN

Certain plants exhibit rapid movement in response to mechanical stimulation; however, the ecological functions of this behaviour are largely unknown. Here, we show that the rapid flower closure of Drosera tokaiensis (Droseraceae) in response to mechanical stimulation functions as a physical defence against a specialist herbivore Buckleria paludum (Pterophoridae) caterpillar. Following feeding damage on fruits, flowers, flower stalks and buds by B. paludum, D. tokaiensis closed its flowers nine times faster than during natural circadian closure. The extent of damage to ovules was significantly reduced when the flowers were able to close compared with the condition in which closure was physically inhibited by the application of a resin. Nonetheless, flower closure had no effect on the feeding damage to stamens and styles and promoted further damage to petals. Given that feeding on petals, stamens and styles had no significant effect on the number of mature seeds, rapid flower closure leading to the protection of ovules had an overall positive effect on the reproductive success of D. tokaiensis. Our study showed rapid plant movement as a novel case of induced physical defence against herbivory.


Asunto(s)
Drosera , Drosera/fisiología , Herbivoria , Flores , Plantas , Semillas
12.
Curr Biol ; 32(21): 4688-4698.e6, 2022 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-36198321

RESUMEN

Angiosperm flowers and their animal visitors have co-evolved for at least 140 Ma, and early flowers were likely used mainly as mating and feeding sites by several groups of insects, including beetles, flies, true bugs, and thrips. Earlier studies suggested that shifts from such neutral or antagonistic relationships toward mutualistic pollination interactions between flowers and insects occurred repeatedly during angiosperm evolution. However, the evolutionary mechanisms and adaptations, which accompanied shifts toward effective pollination, are barely understood, and evidence for such scenarios has been lacking. Here, we show that Syngonium hastiferum (Araceae), a Neotropical representative of an otherwise beetle-pollinated clade, is pollinated by plant bugs (Miridae; Heteroptera), which are florivores of Syngonium schottianum and other Araceae species. We found that S. hastiferum differs in several floral traits from its beetle-pollinated relatives. Scent emission and thermogenesis occur in the morning instead of the evening hours, and its pollen surface is spiny instead of smooth. Furthermore, the floral scent of S. hastiferum includes a previously unknown natural product, (Z)-3-isopropylpent-3-en-1-ol, which we show to have a function in specifically attracting the plant bug pollinators. This is the first known case of a specialized plant bug pollination system and provides clear evidence for the hypothesis that the adoption of antagonistic florivores as pollinators can drive flower diversification. VIDEO ABSTRACT.


Asunto(s)
Araceae , Escarabajos , Heterópteros , Animales , Polinización , Flores , Insectos , Polen
13.
Am J Bot ; 109(9): 1331-1345, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36048829

RESUMEN

The awn of grasses is a long, conspicuous outgrowth of the floral bracts in a grass spikelet. It is known to impact agricultural yield, but we know little about its broader ecological function, nor the selective forces that lead to its evolution. Grass awns are phenotypically diverse across the extant ~12,000 species of Poaceae. Awns have been lost and gained repeatedly over evolutionary time, between and within lineages, suggesting that they could be under selection and might provide adaptive benefit in some environments. Despite the phylogenetic context, we know of no studies that have tested whether the origin of awns correlates with putative selective forces on their form and function. Presence or absence of awns is not plastic; rather, heritability is high. The awns of grasses often are suggested as adaptations for dispersal, and most experimental work has been aimed at testing this hypothesis. Proposed dispersal functions include soil burial, epizoochory, and aerial orientation. Awns may also protect the seed from drought, herbivores, or fire by helping it become buried in soil. We do not fully understand the fitness or nutrient costs of awn production, but in some species awns function in photosynthesis, providing carbon to the seed. Here we show that awns likely provide an adaptive advantage, but argue that studies on awn function have lacked critical phylogenetic information to demonstrate adaptive convergent evolution, are taxonomically biased, and often lack clear alternative hypotheses.


Asunto(s)
Poaceae , Semillas , Carbono , Filogenia , Poaceae/genética , Suelo
14.
Ecol Evol ; 12(3): e8686, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35309750

RESUMEN

Identifying and quantifying crop stressors interactions in agroecosystems is necessary to guide sustainable crop management strategies. Over the last 50 years, faba bean cropping area has been declining, partly due to yield instabilities associated with uneven insect pollination and herbivory. Yet, the effect of interactions between pollinators and a key pest, the broad bean beetle Bruchus rufimanus (florivorous and seed predating herbivore) on faba bean yield has not been investigated. Using a factorial cage experiment in the field, we investigated how interactions between two hypothesized stressors, lack of insect pollination by bumblebees and herbivory by the broad bean beetle, affect faba bean yield. Lack of bumblebee pollination reduced bean weight per plant by 15%. Effects of the broad bean beetle differed between the individual plant and the plant-stand level (i.e., when averaging individual plant level responses at the cage level), likely due to high variation in the level of herbivory among individual plants. At the individual plant level, herbivory increased several yield components but only in the absence of pollinators, possibly due to plant overcompensation and/or pollination by the broad bean beetle. At the plant-stand level, we found no effect of the broad bean beetle on yield. However, there was a tendency for heavier individual bean weight with bumblebee pollination, but only in the absence of broad bean beetle herbivory, possibly due to a negative effect of the broad bean beetle on the proportion of legitimate flower visits by bumblebees. This is the first experimental evidence of interactive effects between bumblebees and the broad bean beetle on faba bean yield. Our preliminary findings of negative and indirect associations between the broad bean beetle and individual bean weight call for a better acknowledgment of these interactions in the field in order to understand drivers of crop yield variability in faba bean.

15.
Curr Zool ; 68(1): 69-79, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35169630

RESUMEN

Some types of plant accumulate liquid in their inflorescences creating phytotelmata. These environments protect the flowers against florivory, although they may be colonized by aquatic or semi-aquatic florivorous insect larvae, whose effects on the fitness of the plants remain unclear. We tested the hypothesis of floral antagonism by the occupants of phytotelmata, which predicts that florivory by the occupants of the phytotelmata represents a cost to the female fitness of the plant, reducing its fecundity. We manipulated experimentally the infestation by 3 florivores larvae species occupants of phytotelmata in inflorescences of Heliconia spathocircinata (Heliconiaceae) to test for negative direct trophic effects on the fecundity of the flowering and fruiting bracts. We found that the foraging of the hoverfly (Syrphidae) and moth (Lepidoptera) larvae in the inflorescences contributed to a decline in the fecundity of the plant. While the lepidopteran impacted fecundity when foraging in both flowering and fruiting bracts, the syrphid only affected the fruiting bracts, which indicates that the nectar and floral tissue are the principal resource exploited by the hoverfly. By contrast, soldier fly (Stratiomyidae) had a neutral effect on fecundity, while foraging in flowering or fruiting bracts. These findings corroborate our hypothesis, that herbivory by the larval occupants represents cost to the host plant having phytotelmata. The negative influence of this foraging on plant fecundity will nevertheless depend on the consequences of the exploitation of resources, which vary considerably in ephemeral habitats such as the phytotalmanta of flower parts.

16.
New Phytol ; 233(1): 132-144, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34363707

RESUMEN

Florivory is an ancient interaction which has rarely been quantified due to a lack of standardized protocols, thus impairing biogeographical and phylogenetic comparisons. We created a global, continuously updated, open-access database comprising 180 species and 64 families to compare floral damage between tropical and temperate plants, to examine the effects of plant traits on floral damage, and to explore the eco-evolutionary dynamics of flower-florivore interactions. Flower damage is widespread across angiosperms, but was two-fold higher in tropical vs temperate species, suggesting stronger fitness impacts in the tropics. Flowers were mostly damaged by chewers, but neither flower color nor symmetry explained differences in florivory. Herbivory and florivory levels were positively correlated within species, even though the richness of the florivore community does not affect florivory levels. We show that florivory impacts plant fitness via multiple pathways and that ignoring this interaction makes it more difficult to obtain a broad understanding of the ecology and evolution of angiosperms. Finally, we propose a standardized protocol for florivory measurements, and identify key research avenues that will help fill persistent knowledge gaps. Florivory is expected to be a central research topic in an epoch characterized by widespread decreases in insect populations that comprise both pollinators and florivores.


Asunto(s)
Flores , Magnoliopsida , Animales , Herbivoria , Insectos , Filogenia , Polinización
18.
Naturwissenschaften ; 108(5): 39, 2021 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-34477965

RESUMEN

Florivores and rainfall generally have negative impacts on plant fecundity. However, in some cases, they can mediate fruit set. Some plants face severe pollen-limited fecundity and any additional fruit set, even if from self-pollination, can be advantageous. This is the case in some tropical deceptive orchids, such as the threatened Cyrtopodium hatschbachii. Here we test the hypothesis that florivory of the anther cap would facilitate rain-assisted autogamy in this species. In the field, we followed flowers in which the anther cap was removed by the orthopteran Stenopola sp. and found cases where pollinia self-deposited after rainfall and in one case this resulted in swelling of the column typical of fruit development. This event comprised 33% of all fruit set in the population in 2019. We then experimentally varied anther cap removal and rainfall in a factorial design and found increased fruit set in the group with cap removal (simulated florivory) followed by rain. The water absorption by pollinia makes them heavier, causing the stipe to bend. The droplet of water on the stigma then shrinks and pulls the pollinia back onto the stigma, causing self-pollination. Seeds from self-pollination have considerable viability and may allow population persistence, given that bee-mediated cross-pollination is uncertain and even absent in some years. Our study provides a unique example of how two unrelated factors (i.e., florivory and rain) that are detrimental alone may together promote fruit set.


Asunto(s)
Orchidaceae , Polinización , Animales , Abejas , Flores , Polen , Lluvia
19.
Proc Biol Sci ; 288(1953): 20210320, 2021 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-34132112

RESUMEN

Florivory (flower consumption) occurs worldwide in modern angiosperms, associated with pollen and nectar consumption. However, florivory remains unrecorded from fossil flowers since their Early Cretaceous appearance. We test hypotheses that earliest angiosperms were pollinated by a diverse insect fauna by evaluating 7858 plants from eight localities of the latest Albian Dakota Formation from midcontinental North America, in which 645 specimens (8.2%) were flowers or inflorescences. Well-preserved specimens were categorized into 32 morphotypes, nine of which displayed 207 instances of damage from 11 insect damage types (DTs) by four functional-feeding groups of hole feeding, margin feeding, surface feeding and piercing-and-sucking. We assessed the same DTs inflicted by known florivores on modern flowers that also are their pollinators, and associated insect mouthpart types causing such damage. The diverse, Dakota florivore-pollinator community showed a local pattern at Braun's Ranch of flower morphotypes 4 and 5 having piercing-and-sucking as dominant and margin feeding as minor interactions, whereas Dakotanthus cordiformis at Rose Creek I and II had an opposite pattern. We found no evidence for nectar robbing. These data support the rapid emergence of early angiosperms of florivore and associated pollinator guilds expressed at both the local and regional community levels.


Asunto(s)
Magnoliopsida , Polinización , Animales , Flores , Insectos , América del Norte
20.
J Plant Res ; 134(5): 963-970, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33866459

RESUMEN

Floral stickiness is a rare trait with unknown function, but it is common in the mega-diverse Cape genus Erica (Ericaceae). This study investigated the role of stickiness measured as adhesive strength in Erica as protection against nectar robbing and its correlation with floral traits. We compared the incidence of nectar robbing in flowers of the same species with or without experimentally added stickiness, and amongst communities of co-occurring species with flowers differing in stickiness. Additionally, we tested the relationship between stickiness and pollination syndrome, corolla shape, corolla length and sepal-corolla ratio across the whole genus. Stickiness was correlated with lower floral damage rates within and between species, indicating it functions as an anti-nectar robbing trait. Across the genus Erica, stickiness is most strongly correlated with bird and long-proboscid fly pollination, presumably because of their larger nectar rewards. Stickiness was also correlated with floral traits that are often associated with high risk of being damaged by nectar robbers: narrow-mouthed corollas, long corollas and shorter sepals. These results show that corolla stickiness defends Erica flowers against nectar robbing and thereby potentially improves fitness.


Asunto(s)
Ericaceae , Néctar de las Plantas , Animales , Aves , Flores , Polinización
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