Flashcards in Pollination Deck (21):
Roughly what percentage of angiosperms rely on pollination by insects or other animals?
Estimated at over 85%
Outline the main parts and functions of an angiosperm.
Outer sepals: usually greenish and protect the flower in bud.
Petals: often brightly coloured to attract pollinators.
Stamens: consist of an anther and filament, where pollen develops.
Carpels: fused & collectively called the gynoecium, containing the ovary. They have receptive surfaces, stigma, which receive pollen and are attached by a single stalk (style) to the ovary.
What purpose do highly coloured and/or scented flower parts serve?
They attract insects and other animals.
How does the term 'flower visitor' differ from 'pollinator'
Many species visit flowers for food, but they do not necessarily perform a pollination act (i.e. transfer pollen between members of the same species). Therefore, the term flower visitor is often used where there is uncertainty about pollination.
What does monoecious mean?
Male and female flowers occur separately on the same plant, e.g. courgette.
What kind of system would completely rule out self-pollination and inbreeding in angiosperms? What is the term for these plants?
Having unisexual flowers on different plants. These plants are called dioecious.
What are dichotomous keys?
In dichotomous keys the identification is based on couplets, one part of which agrees and the other part of which disagrees with the observed characteristic(s). You follow the answers that agree with the observed characteristics and (hopefully) arrive at the correct answer. For example, a key distinguishing true flies (Diptera) from other flying insects would ask whether the adult insect had halteres (small knobbed structures that are modified wings). If the answer is ‘yes’ you would go to the next question on flies; if the answer is ‘no’ you would follow the key further on to other insects.
Comment on the distribution and behavioural adaptations of cuckoo species of bumble bees in the British Isles.
they put their eggs in the nests of other species (the host) and do not provide food for the young. They are associated with species with a wide distribution. This is a general feature of parasitic species, which often have more restricted range than their hosts, because they need a minimum density of hosts to maintain their own local populations. There are six common cuckoo species of bumble bee.
Outline the bumble bee life cycle.
Queens emerge in spring (some as early as feb but most between March and May) they forage and initiate nesting sites with singular honey pots. Workers (female) are produced first and the colony is developed, young queens and male drones are born after workers once the hive is operational. Breeding occurs in autumn, queens over winter underground.
What is the major genetic difference between the production of males and females in ants, bees and wasps?
The males are produced from unfertilised eggs (so they are haploid). The queens are produced from fertilised eggs (i.e. they are diploid) and receive extra food.
When will you see queen bumblebees in the UK?
Spring (queens foraging after overwintering) and late summer (new queens).
Why do insects and other animals visit flowers?
Flower visitors benefit from a variety of nutritional resources available in the flower. These include well-known substances such as sugars in nectar and proteins from pollen. In addition to sugars, amino acids may be available in nectar and some species of plant have oil- or resin-secreting glands. Although it had been suggested that amino acids in nectar might be important for flower visitors, evidence was lacking.
Why is it important to take account of butterfly mass in an experiment considering the effects of diet on aspects of fecundity (such as number of eggs laid)?
Because larger females might be expected to lay more eggs and this needs to be separated out from the effect of diet on fecundity.
Define ecosystem services.
The services (to humans) provided by the whole or part of an ecosystem. These include pollination services provided by some insects or other animals, which may be important for crop production.
What percentage of global food production and what percentage of global crops are highly dependent upon insect pollination?
35% of global food production depends on pollinators and 44% of the world’s crops are heavily or completely reliant on pollinators.
Why does convergence of phenotypic characteristics provide a good test of coevolution?
Because convergence occurs in phylogenetically independent lineages and therefore shows that coevolution is not a coincidental occurrence between two species.
What three families of birds display convergent evolution as pollinators?
The New World hummingbirds, the Old World sunbirds and the Australasian honeyeaters.
Given the advantages of bat pollination, why are there not more bat-pollinated species?
Because of the higher costs associated with attracting bats to flowers (e.g. more nectar and higher sugar content). This has to work against a backdrop of primarily insect-pollinated plants.
What are the three subfamilies of hoverfly larvae based on feeding methods?
1. The Microdontinae, most species of which are found in the Neotropics, have larvae that live inside ant nests and feed on ant larvae.
2. The Syrphinae feed on sap-sucking insects, especially aphids, and number about 2000 species worldwide.
3. Members of the Eristalinae are mainly saprophages, feeding on yeasts and bacteria and contributing to the decomposition of plants and other animals.
The process of animals/insects following set routes of flowers for nectar/pollen on a daily or other regular basis.