Shalu entomophily

Entomophily and role of insect pollinators in agriculture

1. SUBMITTED BY:
 SHALINI SHUKLA(Ag/063/17)
B.Sc.(Hons.) Agriculture 6
th
Sem
SUBMITTED TO:
 Dr. MAIMOM SONIYA
Faculty Entomology
RLBCAU, Jhansi
ENTOMOPHILY AND ROLE OF INSECT
POLLINATORS IN AGRICULTURE
MANAGEMENT OF BENEF ICIAL INSECT S

RANI LAKSHMI BAI CEN TRAL AGRICULTURAL UNIVERSIT Y

2. TOPIC: ENTOMOPHILY

 Pollination by insects in layman language is called as entomophily.
 It can be defined as pollination of a flower in which the pollen is carried on an insect.
 Entomophily began in Mesozoic period (252-66million years).
 Gymnosperms:
all pinales – anemophilous
Cycadales; coleopteran & thysanoptera
Gnetales: flies and moth
 First diversification of insects: beginning of Mesozoic period (labandiera & sepkoski,1993)
 Second phase was initiated by spread of angiosperms and the diversification of anthophilous insects
(living at the expense of flowers by feeding on nectar or pollen).
 These insects present- convergent evolutionary innovation (mainly in Hymenoptera, Lepidoptera
& Diptera) such as transformation of buccal pieces into tubular tongues.
 Anthophilous insects-
 large and good flyers.
 Bear hairs that can be modified so as to facilitate pollen collection, in particular in the hymenoptera
apoidea (Rodet, 2013).
 Most common pollinators are bees, others are; ants, flies, butterflies and wasps.
 In this, both get benefitted: insects- food and plants- pollination.
 Pollination is most vital for plants as it allows them to reproduce.
 Entomophilous flowers- usually bright colored & scented & often secrete nectar.
 Primulas- structural difference between the flowers to ensure that cross- pollination occurs.
 Other examples: Orchids & Antirrhinums.
 Epigyny: protection of ovules from probing animals.
 Some Modern Pollinators are as follows:
Beetles- Coleopteran
Flies- Diptera
Moths- Lepidoptera
Ants- Hymenoptera
Butterflies- Lepidoptera
Bees- Hymenoptera
 Primitive type of insect pollination appears to be beetle or fly pollination.
 The real relationship between plants and insects began in the early cretaceous, and it was because
of beetle pollinated gymnosperms.
 Beetles led the way in insect pollination followed by flies.
 There are 12 living families of basal angiosperms in which six are pollinated by flies, 5 by beetles
& only one by bees.
 But traits such as sapromyophily evolved independently in several unrelated angiosperm families.
 Ideal pollinating insect- hairy & spends time exploring flower so that pollination can occur.

3. MECHANISMS:

1) BEETLE POLLINATION:
 As per some sources, they were among the first insects to visit flowers and they are still essential
pollinators today.
 They were flower visitors of earliest angiosperms.
 They eat their way through petals and other floral parts.
 They are called as mess and soil pollinators as it is said that they defecate within flowers.
 They are capable of color-vision.
 beetles first visit the female cones of conifer to feed on pollination droplet exudates.
 This exudate helps in capturing the wind-blown pollen shift as food attractant for beetle as in
welwitsehia.
Flower Characteristics:
 Bowl shaped with sexual organs exposed.
 usually have numerous parts which serve as food for chewing beetles.
 Pale or dull color (white to dull white or green) but with strong odor – spicy (crab apples), fruity
(chimonananthus), rotten smell/fermented (calycanthus).
 Open during the day
 Moderate nectar producers
 May be in clusters of small flowers (Goldenrods, Spirea) or large solitary flowers (magnolias, pond
lilies)
 E.g.: Araceae- Cyclocephala beetle, soldier beetles, jewel beetles, blister beetles, long-horned
beetles, checkered beetles, tumbling flower beetles, soft-winged flower beetles, scarab beetles, sap
beetles, false blister beetles, and rove beetles.













Red neck false blister beetle

Locust borer beetle on golden rod

4. 2) FLY POLLINATION:
 They are not as hairy as bees and as efficient in carrying the pollen, but some of the are good
pollinators.
 Carrion/dung flies have special pollinations system(sapromyophily) with no reward- they are
actually attracted to have a safe place for egg laying.
Flower Characteristics:
 Pale and dull to dark brown or purple (sometimes flecked with translucent patches).
 Putrid odor- rotting meat, carrion, dung, humus, sap and blood.
 No nectar guide available.
 Pollen producers.
 Flowers are funnel shaped or like compels traps.
Bee Mimics:
 Yes! Correctly written!
 There are flies which mimic bees such as Syrphids, masquerade as bees & wasps respectively.
How to Differentiate?
 Look at wings: one pair (flies) two pairs (bees and wasps).
 Bee flies (Bombylids) are extremely hairy, comical & robust, some of them tongues as long as their
bodies.
Putrid Odor:
 Putrid smelling blossoms – an adaptation to attract certain fly pollinators.
 Even male mosquitoes pollinate orchids.
 Long tongued flies (Syrphids, Bombylids)- feed on same flower types that bees do.
 Short tongued flies- feed on flowers that imitate the main source of food for flies.
 Flies may be trapped for a time in the flower while they feed; E.g.: Stapelia, Dutchman’s pipe.


Female valley elderberry longhorn beetle

5. Hairy legged fly (Trichopoda pennipes)

Syrphid fly- a bee mimic

Tachinid fly- similar to bees or wasps

Bee fly- a good bee mimic

Jack in the pulpit- fungal gnats
Skunk cabbage- carrion fly

6. 3) BEE POLLINATION:
 The champion pollinators.
 Most important group of flower pollinators.
 Attracted to flower mainly for food (pollen, nectar, oil etc.).
 All bees have very high energy needs for their survival.
 They need pollen and nectar.
 Many bees need water in addition to nectar.
Nesting Habitat: they used to make nests from different materials available.
 Mason bees: from mud
 Leafcutter bees- wrapper of leaves, resin and sand.
 Carder bees harvest plant fibers.
 Mostly they excavate their nest tunnels in sunny patches of bare ground.
 Some go for abandoned beetle borrows in dead tree trunks or branches.
 Majority of bees are solitary while some like sweat bees, bumblebees, & honey bees, are social.
Flower Characteristics:
 Brightly colored- white, blue, yellow generally not red as THEY CAN’T SEE RED.
 Have strong UV light patterns.
 Full of nectar
 Sweetly aromatic or have a minty fragrance (perfumes, pheromones).
 Open in day time.
 Provide landing platforms.
 Often bilaterally symmetrical and tubular with nectar at base of tube.
Nectar Guides:
 Many bee flowers have a low reflectance near the center of each petal.
 This shows that bees can detect it.
 This contrasting UV pattern is called a nectar guide, helping in quickly locating the flowers center.
 This adaptation benefits both the flower & the bee.
Bee Mimic: Many insects such as flies and wasps mimic true bees.

Blow fly or green bottle fly

Tachinid fly on catnip



Tachinid on catnip

7. 4) WASP POLLINATION:
 Most common ones are under the group ACULEATA (ovipositors modified into sting but not in
all, some have different functions too).
 They look like bees but no fuzzy hairs present over body.
 Therefore, less efficient pollination.
 Have very high energy needs like bees- met from nectar & pollen.
Fig Wasps:
 All fig trees are pollinated by very small wasps of family Agaonidae.
 When the female flowers inside the immature fruit are ready for pollination- an enticing aroma is
released to attracts wasps (female only).
 While getting inside the wasps loose its wings & antennae.
 It lays eggs inside the ovary and pollinate the flower that has been brought from other flowers.
 Except the ovaries where eggs have been laid all the seeds form and the wasps dies completing her
life’s mission.
Honey bee on mustard flowers

Field image- honey bee on mustard flowers

Male carpenter bee on Penstemon

Bee and snapdragon

8.  The pollen from male flowers- eggs will grow into grubs and after development males and females
emerge.
 Male wasps emerge first but they do not have wings.
 As soon as they emerge they try to fertilize the female wasps and after this they too die.
 When females emerge they are already fertilized so they start moving outside.
 At this stage male flowers inside that fruit gets loaded with pollen and thus in this way female
carries pollen from the male flowers.
 This pollen is used for pollinating the female flowers inside the another immature fruit.
E.g.: potter wasps (golden rod)
























potter wasp (mason wasp)

Fig- wasp life cycle
yellow jacket wasp

9. 5) ANT POLLINATION:
 social insects
 Lovers of nectar.
 They being wingless crawl into each flower to reach the energy rich nectar.
 Some are not important pollinators even if they carry the pollen on their body.
 They visit inconspicuous flowers close to the stem.
Flower Characteristics:
 Low growing
 Small inconspicuous flowers.
 Very close to stem.
Ant Guardians:
 These are tropical plants having nectar outside to attract ants.
 They rely on the defensive capabilities of ants to protect them from various kinds of attack from
other insects including nectar robbers.
 Plants that secrete nectar outside of the flower & on their leaves have ant- guard system that
prevents other insects from robbing nectar.
E.g.: Formica argentea worker ants have been observed carrying pollen grains between flowers of
cascade knotweed, also known as Polygonum cascadense.

















Ant on aster
Ant on euphorbia

10. 6) BUTTERFLY POLLINATION:
 Very active during day but are less efficient than bees at moving pollen between plants.
 resting on their thin legs, they do not pick up much pollen on their bodies and lack any specialized
structure for collecting it.
 They taste with their feet.
 Found on every continent but Antarctica.
 Many butterflies produce scents that attract the opposite sex.
 They probe for nectar (their flight fuel).
 Have good vision but bad sense of smell.
 Unlike bees, they can see red.
Flowers Characteristics:
 Usually in clusters.
 Provide landing platforms.
 Brightly colored (red, orange, yellow).
 Open during the day.
 Produce much nectar but its hidden.
 Butterflies & milkweed:
 Many caterpillars feed on the sap of milkweed.
 This juice makes the caterpillars and butterflies distasteful to birds and other predators.
















Monarch butterfly on milkweed
Sulfur tailed butterfly on aster
Checker spot butterfly on cone flowers
Fritillary butterfly
Pale swallow tail butterfly
monarch larva on milkweed

11. 7) MOTH POLLINATION:
 They are active during night (most of them).
 Some are active during day too.
 Nocturnal flowers with pale or white flowers heavy with fragrance and copious dilute nectar attract
these moths.
Flower Characteristics:
 In clusters and they also provide landing platforms.
 White or dull color.
 Open late afternoon or night.
 Ample nectar producers (deeply hidden)
Yucca Moth:
 Yucca plant is dependent on yucca moth for their survival & reproduction.
 The pistil ends in a three lobed stigma.
 female moth gathers pollen from the flower anthers using her specially adapted mouthparts.
 She makes a boll out of those sticky pollen.
 This boll is stuffed or combed into the stigma of flowers she visits.
 Without this process, no seed formation can take place.
 When the female moth visits the flower, she backs up to the flower base and inserts her ovipositor
to lay egg in one or more of six chambers.
 By the time the egg hatches into a microscopic caterpillar, the yucca will have begun to develop a
pod with little seeds.
 Both get benefitted in this relationship.
E.g.: Orchids such as Angraecum sesquipedale, dependent on a particular hawk moth, Morgan's sphinx.,
Tegeticula maculata (yucca moth).











White lined sphinx moth

Clear wing moth
Humming bird hawk moth on bougainvillea

12. 8) MIDGE POLLINATION:
 Without midges- there would be no chocolate.
 Ceratopogonidae and Cecidomyiidae families of midges are the only known pollinator of
cocoa.
 Most active at dusk & dawn.
 This seems to be in synchronization with cocoa tree which fully open right before sunrise.









9) MOSQUITO POLLINATION:
 Usually they suck blood, yup the female ones!
 Why? Because they need to suck it before laying eggs.
 But their favorite food is nectar.
 Male and female both drink nectar prior to mating.
 During this they pollinate the flowers.
 They are known to pollinate certain orchids.
E.g.: Blunt-leaved bog orchid,(Habenaria obtusata, also called Platanthera obtusata), and other rare
Arctic bog orchids.

13. ROLE OF INSECT POLLINATORS IN AGRICULTURE:
















Here are some quotes regarding the importance of pollinators in agriculture:
 “Bees have great intrinsic value to people across the UK and were widely regarded as a key symbol
of the natural world by respondents in a survey of attitudes towards nature conducted by Defra.” -
UK Department for Environment Food & Rural Affairs (DEFRA)
 “It cannot be denied that the honey bee is the greatest pollinating machine when it comes to
agriculture.” -The Nature Conservancy
 “Did you ever wonder where apples come from or how an apple tree makes apples? Actually, apples
start as flowers on the apple tree. Without the help of bees though, the flowers would bloom and
then wither and drop without ever having a chance to become an apple.” -Dr. Gloria Hoffman,
USDA Scientist
BEES
ANTS
BEETLES
SYRPHID
FLIES
FLIES
MOTH
WASPS BUTTERFLIES
MIDGE

14.  “Honey bees are the most important pollinator – about 90% of pollinator-dependent crops are
reliant on the honey bee.” -Carol Poole, SANBI Applied Biodiversity Research Division,
discussing bee pollination in South Africa
 “A decline in managed bee colonies puts great pressure on the sectors of agriculture reliant on
commercial pollination services. This is evident from reports of shortages of bees available for the
pollination of many crops.”
WORLD CROP POLLINATION:
4%
Butterflies,
Birds And
Moths
5% Wasps
& Beetles
(Each)
6.5%bats
19%Flies
73% Bees

15. CONCLUSIONS FROM RESEARCH WORK:
 Nearly 35% of crops are pollinators dependent.
 It has been found from a research that rape seed and mustard is the most pollinator dependent crop.
Its economic value of pollination is around Rs. 19355.70 crores.
 Crops undergo pollination are: cotton, brinjal, citrus, apple, guava, chilli, okra, tomato, cumin,
coriander, soybean, mustard and many more.
 Value of pollination from vegetables is Rs 19498.20 crores (11.10%), fibers (mainly cotton) Rs
17290.66 crores (23.39%) and condiments and spices at Rs 10109.43 crores (25.47%)
 Direct contribution of insect pollination to Indian agriculture is Rs 112615.73 crores (USD 22.52
billion) annually, which is approx. 8.72%.
 Buckwheat -65% dependence rate over pollinators.
 While Some crops, including blueberries and cherries- 90 per cent dependent on honey bee
pollination;
 And almonds depend entirely on insect pollination at bloom time.
 Insect pollination- main reproductive mechanism in 78 per cent of temperate flowering plants.

16. REFERENCES:
 www.sciencedirect.com
 www.fs.fed.us
 https://basicbiology.net/animal/invertebrates.entomophily
 www.oxfordreference.com
 https://www.encyclopedia.com
 www.coursesbotany.wisc.edu
 https://en.m.wikipedia.org/pollinator
 www.embibe.com
 https://www.britannica.com/science/pollination/Butterflies-and-moths
 https://www.thoughtco.com/insect-pollinators-that-arent-bees-or-butterflies-1967996
 https://www.mosquitoreviews.com/learn/mosquitoes-pollination
 https://croplife.org/wp-content/uploads/pdf_files/Role-of-Pollinators-in-Agriculture.pdf
 https://modernag.org/biodiversity/beeconomy-economic-value-pollination
 https://farmfolio.net/articles/importance-insect-pollination-agriculture
 https://www.researchgate.net/figure/Economic-value-of-animal-pollination-services-based-
on-dependence-rate-of-crops-to-Indian_tbl3_320136745
 http://www.researchjournal.co.in/online/RKE/RKE%2012(1)/12_11-14.pdf