Piston mechanism of pollination


  • The Bull Thistle (Cirsium vulgare)—Foraging
  • The Bull Thistle Cirsium vulgare —Foraging He that has a good harvest must be content with some thistles—Spanish Proverb Bull thistle Cirsium vulgare photo by Nina Munteanu On my daily walks to the local marshy stream by a large meadow, a cluster of Bull thistles has recently burst into brilliant purple-pink flower. Attracted to its beautiful flowers, I decided to inspect it more closely. But this stunning deep purple-pink flowered plant is as sharp as it is beautiful.

    Almost the entire plant is covered in very sharp spiny bristles that easily penetrate all but the most sturdy materials. Bull thistle flower head Capitula and involucre photo by Nina Munteanu Bull thistle flower head showing hundreds of tubular florets and style coated with white pollen photo by Nina Munteanu Like the aster, the Bull thistle is a composite plant with a dome-like flower head or capitulum of up to hundred tubular florets together called an inflorescence ; flower heads may occur solitarily or in terminal clusters of two or three on a single plant.

    Unlike asters, the Bull thistle flower head contains only disk not ray florets. Each floret is bisexual containing female stigma and style and male anthers.

    The pink corolla flower petals , longer than the floret tube itself, have throats with five lobes from which emerges the long style. The style is tightly surrounded by five stamens, shorter than the style.

    CABI tells us that white-flowers are rare worldwide but have been spotted in Canada, especially in British Columbia and in Ontario, where I currently reside. The flower head sits on a narrow vase-shaped involucre collection of bracts which surrounds and protects the enclosed achene-pappus units the dry seeded fruit and protective calyx. Emerging flower head from the spiny involucre of the Bull thistle photo by Nina Munteanu The involucre consists of hundreds of grayish-green bracts modified leaves or phyllaries, armed with very sharp, stiff yellow spines.

    The spines help guard the thistle against insects wishing to climb the stem in search of the nutritious seeds achenes.

    The upper bracts normally curve up towards the flower head reflexed and the lower ones bend down decurrent. Cross-section of Bull thistle, showing receptacle thistle heart inside the protective involucre and on which the seeds are embedded photo by Nina Munteanu Inside the protective shell of bracts, the ovaries of each floret attach to the receptacle, the widest part of the involucre and a fleshy part of the flower-base. The achene of the thistle is called a cypsela—a fruit that looks like a seed.

    Lancelate leaf of Bull thistle showing sharp spines photo by Nina Munteanu The stem and leaves of the Bull thistle are also protected by sharp prickles. In fact, the bull thistle can be distinguished from other thistles by the covering of the short, sharp prickles on the upper, dark green surface of each highly lobed lanceolate leave blade.

    The style pushes the stigmas out from between the pollen-carrying anthers that surround it. The anthers release their pollen on the inside and as the style and stigma push past, they collect pollen from the dehisced anthers. The globs of sticky pollen are then ready to be picked up by pollinators searching for the nectar inside the tiny flowers.

    As the insects move from one flower to the next, they release some pollen on the sticky stigma; the pollen then travels down the tube to fertilize the egg at the base. The fertilized egg develops into an achene or seed among many others embedded in the receptacle inside the protective shell of the involucre collection of bracts below the flower head awaiting dispersal.

    The branched pappus acts as a parachute to reduce the terminal velocity of the falling achene so that wind can disperse it farther. The branching hairs also help to loosen the achenes from the capitulum when captured by the wind. Since this species can tolerate adverse environmental conditions and adapt to different habitats, it continues to spread and occupies new areas despite control measures.

    High seed production, variation in seed dormancy, and vigorous growth make this species a serious invader. It competes with other species in pastures, rangelands and agricultural fields and causes both wool fault and physical injury to animals. Bull Thistle Ecology Although it is considered an invasive species and weed, the Bull thistle still contributes beneficial ecosystem services such as serving as nectar sources for pollinators such as honey bees Apis spp. Bumble bee feeding on a Bull thistle photo by Nina Munteanu The Bull thistle also provides seeds to granivores consumers of grains and seeds such as goldfinches.

    The goldfinch is particularly attracted to the thistle. Not only does the goldfinch pull the seeds out to eat; it also uses the thistle down the pappus to line its nest. The Bull thistle was used by early humans as a warm medicinal tea.

    The roots were also good against poor digestion and helped treat stomach cramps. The leaves were used to treat neuralgia. Eflora describes several uses of thistle from tinder seed fluff and papermaking using the inner bark to medicinal uses in teas and poultices e. How to Identify the Bull Thistle You can identify the Bull thistle by several features: Flower head or capitula larger than Canada thistle often gumdrop-shaped, containing hundreds of tiny purple flowers, all being disk florets no ray florets.

    Fluted shape of the involucre below the flower head not rounded like the Scotch thistle more slender and usually more numerous than in Nodding thistle or Plumeless thistle. The phyllaries involucral bracts are each tipped with a very sharp, stiff yellow spine. The upper bracts normally curve up towards the flower head and the lower ones bend down. Hairs that look like cobwebs lie scattered among the series of phyllaries.

    Its stem is light green with dense white hair on its angular circumference, punctuated by a series of winged spines. Sharply lobed leaves, each with a stiff spine at its tip, that are coarse on the top with spines and soft on the bottom. What we normally eat of the artichoke are the soft pads inside the bracts that surround the flower cluster, and the receptacle the heart to which the florets attach.

    After watching two videos about parts of the Bull thistle being edible e. The trick was convincing my naturalist friend Merridy to join in the experiment… Collecting thistle heads photo by Merridy Cox Cutting away spiny involucre to expose the heart photo by Merridy Cox EatTheWeeds demonstrated that a sharp knife could cut away the spines of a leaf, leaving the edible leaf rib in tact.

    What would the goldfinches do then? However, The Northwest Forager demonstrated how one can easily harvest a few flower heads for a taste of thistle hearts. Merridy was curious enough to join me and we left for the thicket by the marsh meadow.

    First we collected late-blooming flowerheads that had fairly sizable involucres—and therefore large receptacles inside. We collected about ten then returned to our outside lab to process them. Removing the achenes and pappus, revealing the thistle heart photo by Merridy Cox Thistle heart photo by Nina Munteanu The next step was to cut away the involucre near the stem and remove the florets with the pappas and achenes.

    As instructed by The Northwest Forager, we then boiled the hearts for 10 minutes then drained and followed by frying the hearts in butter with some sea salt for a few minutes.

    Frying up the thistle hearts photo by Nina Munteanu Merridy and I then simply took each tiny thistle heart and gnawed on it with our teeth. I was overjoyed by a lovely subtle nutty kohlrabi-like flavour. They were thrown on the patio and very soon a curious chipmunk came to test them.

    Chipmunk checks out thistle seeds photo by Merridy Cox Cutting off the involucre and pulling apart the florets to reveal the receptacle was a bit of work; but it was worth it for me to discover and appreciate more about this complex plant. References: Cronodon. Reviews of Weed Science, 6: De Jong, T. Grime et al. A functional approach to common British species. Holm et al. Johnston, Brian. Reproductive and vegetative biology of Cirsium vulgare Savi Ten. Compositae: Cynareae. New Zealand Journal of Botany Moore and Frankton.

    Sheldon, J. The dispersal effectiveness of the achene-pappus units of selected compositae in steady winds with convection. New Phytol. The Northwest Forager. Visit www. Share this:.

    Hide and flirt: observed behavior of female jaguars Panthera onca to protect their young cubs from adult males Abstract Common across various taxa, infanticide is a highly variable phenomenon present from insects to birds to mammals. In felids, antagonistic sexual coevolution led to the development of female counterstrategies to infanticide spanning particular sexual behavior, physiology, and social strategies. Numerous protective behaviors are well documented for large felids such as lions, cheetahs, and pumas that rely on cooperative defenses and polyandrous mating to protect their cubs from infanticide.

    Nevertheless, little is known about other wildcat species adopting such behaviors. Solitary and enigmatic, jaguars Panthera onca are the largest cat existing in the Americas. Here, field observations in two major wetland ecosystems of South America show new and unique findings on female jaguar counterstrategies towards male infanticide.

    Our findings suggest that, like their big cat relatives in Africa, jaguars have evolved behavioral counterstrategies to protect their young in response to antagonistic sexual coevolution.

    Invasive Italian wall lizards outcompete native congeneric species in finding food in a Y-maze Abstract Though biological invasions constitute one of the biggest threats for global biodiversity, our understanding of the mechanisms that enable invasive species to outperform native species is still limited, especially, in terms of behavior.

    Most available studies have examined behavioral traits which favor invasive species on the later stages of invasion, however, our knowledge on earlier stages, namely, when alien species face novel environments and must exploit new resources, remains obscure.

    Here, we focus on one crucial behavioral trait, finding food. The Italian wall lizard Podarcis siculus has been widely introduced and established viable populations in S. Europe and N. We examined whether P. We performed a Y-maze experiment, in which we varied arm markings in a standard way to prevent learning.

    Podarcis siculus was more efficient than its congenerics in finding and consuming food. This exploitative superiority was persistent, more frequent and repetitive. Interesting behavioral differences were also detected within the native species. Some P. Our results suggest that the invasive P. This provides further support to the idea that behavior plays a crucial role in animal invasions. Time-activity budget of urban-adapted free-ranging dogs Abstract The domestic dog Canis lupus familiaris is known to have evolved from gray wolves, about 15, years ago.

    They frequently exist as free-ranging populations across the world. They are typically scavengers and well adapted to living among humans. Most canids living in and around urban habitats tend to avoid humans and show crepuscular activity peaks.

    In this study, we carried out a detailed population-level survey on free-ranging dogs in West Bengal, India, to understand the activity patterns of free-ranging dogs in relation to human activity.

    Using sightings of dogs, over a period of 1 year, covering the 24 h of the day, we carried out an analysis of the time activity budget of free-ranging dogs to conclude that they are generalists in their habit.

    They remain active when humans are active. Their activity levels are affected significantly by age class and time of the day. In addition, we provide a detailed ethogram of free-ranging dogs. This, to our knowledge, is the first study of this kind, which might be used to further study the eco-ethology of these dogs.

    Interspecific nest destruction in the Tropical Kingbird Tyrannus melancholicus: kleptoparasitism or competition? Abstract Bird nest destruction and nest material kleptoparasitism i. Here, I present the first account of nest material kleptoparasitism in the Tropical Kingbird Tyrannus melancholicus followed by nest destruction, which occurred on a Variegated Flycatcher nest Empidonomus varius.

    I explore the implications of these behaviors for both the kleptoparasite and the victim species and, due to the lack of basic information on the general behavior of both species, I point out some directions to guide future researches on the subject.

    Primary nectar robbing by Apis mellifera Apidae on Pyrostegia venusta Bignoniaceae : behavior, pillaging rate, and its consequences Abstract The interactions between plants and their pollinators are the result of convergent evolution of floral attributes reflecting pressure exerted by pollinators. Nonetheless, the strategies employed by floral visitors to collect floral resources are extremely complex, and commonly involve theft or robbery in addition to pollination.

    We describe here the behavioral repertory of Apis mellifera during the collection of the floral resources, and evaluated the robbing rates of A. We recorded the behaviors exhibited by foraging bees while collecting floral resources, quantified the numbers of floral buds and flowers with perforations in their corolla tissues, and determined whether that damage reduced nectar production.

    The evaluations were conducted during two distinct periods: during the period of intense flowering of P. Nectar robbing was observed during The robbing of floral buds and flowers was most intense during the period of heavy flowering. Flowers that had been intensely robbed secreted significantly less nectar than those non-robbed. The unusual nectar robbing activities of A. Our results therefore point to a major limitation of nectar per floral unit during the intense flowering period of P.

    What do we know about flamingo behaviors? A systematic review of the ethological research on the Phoenicopteridae — Abstract We provide a systematic review of the current scope of published behavioral research on flamingos Phoenicopteridae , to answer the following questions: 1 what is the profile of ethology and behavioral research on flamingos, 2 which are the behaviors displayed by flamingos already observed and described in nature and captivity, and 3 what are the prospects in the ethological research of the group?

    Eighty-eight studies, from to , met our inclusion criteria and were analyzed. Most involved maintenance and social behaviors in the context of ecology and welfare. Furthermore, most studies were performed on animals in captivity and controlled conditions, but there was a recent trend of studies in the field, mainly in South America and the Caribbean. The most studied species were greater and American flamingos, but there is a recent rise in studies on Chilean and Andean flamingos in Latin America.

    Behavior description can also help in comparative studies between flamingo species and other water birds. Ethological research can help identify the threats and measure the impacts on these species, which can be useful for setting up management plans and conservation actions to mitigate the damage and avoid extinction.

    Lateralization at the individual and population levels of European green lizard in Slovak Karst Abstract Lateralization is one of the specific characteristics of animals, occurring in both invertebrates and vertebrates.

    Lateralization exists at two levels, individual level and population level. This research is focused on the individual- and population-level lateralization of the European green lizard Lacerta viridis under laboratory conditions. Lateralization was observed experimentally in a modified T-maze without the possibility of visual control by lizards.

    Lizards were stimulated by a piston from the caudal side to simulate a predator attack from behind. The numbers of left and right choices were evaluated. Statistical analysis confirmed no statistically significant difference in lateralization at both the individual and population levels.

    The absence or presence of autotomy suggests that non-biased lizards have a better chance of escape from a predator than left- or right-biased individuals.

    In the population of L. Limited effects of traffic noise on behavioural responses to conspecific mating calls in the eastern sedge frog Litoria fallax Abstract Anthropogenic noise is a pervasive environmental feature across both urban and non-urban habitats and presents a novel challenge especially for acoustically communicating species.

    While it is known that some species adjust acoustic signals to communicate more effectively in noisy habitats, we know very little about how the receivers of these signals might be impacted by anthropogenic noise. We performed a controlled behavioural experiment whereby frogs were presented with simultaneously broadcasted attractive and unattractive calls from opposing directions, once with background traffic noise and once without. We found that females in particular chose the unattractive call significantly more often and males significantly less often when noise was being broadcast.

    This indicates that anthropogenic noise potentially affects receiver responses to acoustic signals, even when calls are not acoustically masked, with potential consequences for maladaptive mating behaviours and population outcomes. Using predator feces as a repellent for free-ranging urban capybaras Hydrochoerus hydrochaeris Abstract Biological repellents have been used as a control method to mitigate human-wildlife conflict worldwide. We aimed to evaluate the effect of jaguar Panthera onca feces as a repellent for a free-living urban population of capybaras Hydrochoerus hydrochaeris , which are considered a vertebrate pest in some regions of their range.

    Observational data were collected during two consecutive 5-day periods: control and treatment. During the treatment period, 30 g of jaguar feces were added daily every 5. Of those capybaras that did continue to visit a site, incursions into the marked perimeter were initially greatly reduced, but did rebound relatively rapidly over the trial period.

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    Podarcis siculus was more efficient than its congenerics in finding and consuming food. This exploitative superiority was persistent, more frequent and repetitive. Interesting behavioral differences were also detected within the native species. Some P.

    Our results suggest that the invasive P. This provides further support to the idea that behavior plays a crucial role in animal invasions. Time-activity budget of urban-adapted free-ranging dogs Abstract The domestic dog Canis lupus familiaris is known to have evolved from gray wolves, about 15, years ago. They frequently exist as free-ranging populations across the world. They are typically scavengers and well adapted to living among humans.

    Most canids living in and around urban habitats tend to avoid humans and show crepuscular activity peaks. In this study, we carried out a detailed population-level survey on free-ranging dogs in West Bengal, India, to understand the activity patterns of free-ranging dogs in relation to human activity.

    Using sightings of dogs, over a period of 1 year, covering the 24 h of the day, we carried out an analysis of the time activity budget of free-ranging dogs to conclude that they are generalists in their habit.

    They remain active when humans are active. Their activity levels are affected significantly by age class and time of the day. In addition, we provide a detailed ethogram of free-ranging dogs. This, to our knowledge, is the first study of this kind, which might be used to further study the eco-ethology of these dogs. Interspecific nest destruction in the Tropical Kingbird Tyrannus melancholicus: kleptoparasitism or competition? Abstract Bird nest destruction and nest material kleptoparasitism i.

    Here, I present the first account of nest material kleptoparasitism in the Tropical Kingbird Tyrannus melancholicus followed by nest destruction, which occurred on a Variegated Flycatcher nest Empidonomus varius. I explore the implications of these behaviors for both the kleptoparasite and the victim species and, due to the lack of basic information on the general behavior of both species, I point out some directions to guide future researches on the subject.

    Ktm kart engine nectar robbing by Apis mellifera Apidae on Pyrostegia venusta Bignoniaceae : behavior, pillaging rate, and its consequences Abstract The interactions between plants and their pollinators are the result of convergent evolution of floral attributes reflecting pressure exerted by pollinators.

    Nonetheless, the strategies employed by floral visitors to collect floral resources are extremely complex, and commonly involve theft or robbery in addition to pollination. We describe here the behavioral repertory of Apis mellifera during the collection of the floral resources, and evaluated the robbing rates of A. We recorded the behaviors exhibited by foraging bees while collecting floral resources, quantified the numbers of floral buds and flowers with perforations in their corolla tissues, and determined whether that damage reduced nectar production.

    Seeds that are produced are abundant and viable. What are the advantages of self-pollination and cross pollination? Self-pollination or cross pollination can be an advantage when the number of flowers is small or they are widely spaced. During self-pollination, the pollen grains are not transmitted from one flower to another. As a result, there is less wastage of pollen.

    What is the difference between cross and self-pollination which is better and why? Transfer pollen grains from the anther to the stigma of the same flower. Self-pollination increases genetic uniformity and decreases genetic variation. Cross-pollination decreases genetic uniformity and increases genetic variation. What is the difference between cross pollination and self pollination What is the evolutionary advantage of cross pollination? The disadvantage of cross pollination are: — Huge amounts of pollen grains are wasted.

    The Bull Thistle (Cirsium vulgare)—Foraging

    What is important for a1b reactor This method of pollination does not require an investment from the plant to provide nectar and pollen as food for pollinators. Is self-pollination good or bad? What is the result of cross pollination? Cross pollination is when one plant pollinates a plant of another variety.

    Sometimes cross pollinating is used intentionally in the garden to create new varieties. Why do plants prefer cross pollination? Cross pollination is advantageous because it allows for diversity in the species, as the genetic information of different plants are combined. Self pollination leads to more uniform progeny, meaning that the species is, for example, less resistant as a whole to disease. Can a flower pollinate itself? Self-pollinating — the plant can fertilize itself; or, Cross-pollinating — the plant needs a vector a pollinator or the wind to get the pollen to another flower of the same species.

    Which type of pollination is better? The Bull thistle was used by early humans as a warm medicinal tea. The roots were also good against poor digestion and helped treat stomach cramps. The leaves were used to treat neuralgia. Eflora describes several uses of thistle from tinder seed fluff and papermaking using the inner bark to medicinal uses in teas and poultices e. How to Identify the Bull Thistle You can identify the Bull thistle by several features: Flower head or capitula larger than Canada thistle often gumdrop-shaped, containing hundreds of tiny purple flowers, all being disk florets no ray florets.

    Fluted shape of the involucre below the flower head not rounded like the Scotch thistle more slender and usually more numerous than in Nodding thistle or Plumeless thistle. The phyllaries involucral bracts are each tipped with a very sharp, stiff yellow spine.

    The upper bracts normally curve up towards the flower head and the lower ones bend down. Hairs that look like cobwebs lie scattered among the series of phyllaries. Its stem is light green with dense white hair on its angular circumference, punctuated by a series of winged spines. Sharply lobed leaves, each with a stiff spine at its tip, that are coarse on the top with spines and soft on the bottom.

    What we normally eat of the artichoke are the soft pads inside the bracts that surround the flower cluster, and the receptacle the heart to which the florets attach. After watching two videos about parts of the Bull thistle being edible e. The trick was convincing my naturalist friend Merridy to join in the experiment… Collecting thistle heads photo by Merridy Cox Cutting away spiny involucre to expose the heart photo by Merridy Cox EatTheWeeds demonstrated that a sharp knife could cut away the spines of a leaf, leaving the edible leaf rib in tact.

    What would the goldfinches do then? However, The Northwest Forager demonstrated how one can easily harvest a few flower heads for a taste of thistle hearts. Merridy was curious enough to join me and we left for the thicket by the marsh meadow. First we collected late-blooming flowerheads that had fairly sizable involucres—and therefore large receptacles inside. We collected about ten then returned to our outside lab to process them. Removing the achenes and pappus, revealing the thistle heart photo by Merridy Cox Thistle heart photo by Nina Munteanu The next step was to cut away the involucre near the stem and remove the florets with the pappas and achenes.

    As instructed by The Northwest Forager, we then boiled the hearts for 10 minutes then drained and followed by frying the hearts in butter with some sea salt for a few minutes.

    Frying up the thistle hearts photo by Nina Munteanu Merridy and I then simply took each tiny thistle heart and gnawed on it with our teeth. I was overjoyed by a lovely subtle nutty kohlrabi-like flavour. They were thrown on the patio and very soon a curious chipmunk came to test them.


    Piston mechanism of pollination