1. Conserving Pollinator Populations in the Era of Neonicotinoids
V.V. Belavadi
Department of Entomology
University of Agricultural Sciences, Bangalore
1st IAC 2016
07/11/2016

2. Why plants need insects for pollination?
How this relationship evolved and is sustained?
How many species of bees are there?
Is there a decline in bee populations?
If so how?
What are neonecotinoids & why should we be concerned?

3. Sex has always been difficult for plants, because they cannot move.
If one cannot move, then finding a suitable partner for reproduction becomes almost impossible!
135 mya, plants discovered wind pollination.

4. Wind pollinated plants produce a large number of pollen - success rate is low and great majority of pollen goes waste
Nature seldom tolerates waste, and it was only a matter of time before the plants arrived at a better solution in the form of insects.

5. Pollen is nutritious.
Some winged insects soon began feeding on it and before long some became specialists in eating pollen.
Flying from plant to plant in search of their food, these insects accidentally carried pollen grains upon their bodies, trapped amongst hairs or in the joints between their segments.

6. When the occasional pollen grain fell off the insect on to the female parts of a flower, that flower was pollinated.
And so insects became the first pollinators or sex facilitators for plants.
Although much of the pollen was consumed by the insects, this was still a vast improvement over their dependence on wind.

7. But still there was a problem – the early pollinators had difficulty in spotting the flowers, since the flowers were no different from the surrounding vegetation!
In order to attract insects, they had to get better & “advertise” their flowers with a different colour than the surrounding vegetation!
Thus began the longest marketing campaign in history, with the early lilies and magnolias the first plants to evolve petals, conspicuously white against the forests of green.

8. With this new reliable means of pollination, insect-pollinated plants became enormously successful and diversified.
Competition for pollinators resulted in evolving bright colors, patterns and elaborate shapes.
In this battle to attract pollinators, some flowers evolved an additional trick — they began producing sugar-rich nectar as an extra reward – possibly to save pollen!

9. As these plants proliferated, so the opportunities for insects to specialize grew; butterflies & some flies evolved long, tubular mouthparts to suck up nectar.
The most specialized and successful group to emerge were the bees, the masters of gathering nectar and pollen to this day.
The first true bees appeared around 130 mya.

11. Today, the majority of flowering plants use insects, mostly bees, to carry their pollen.
Bees have one clear advantage over wind: they can track down another flower of the same species, so a plant species need not produce huge amounts of pollen.
This was the basis for the theory about the rise of angiosperms: pollination was more efficient.

12. The Flower does not dream of a bee, it blossoms and the bee comes
The bees come for the rewards that they get – pollen and Nectar

13. We take pollination for granted
Myth : Plants bear flowers which become fruits
We take pollination for granted

14. How many flowering plants ?
There are an estimated 352,000 species of flowering plants in the world (Paton, 2008)
Of these, 87.5% (3,06,000) species entirely or partially depend on flower visitors for successful seed set (Ollerton et al., 2011)

15. 87 of the 115 global food crops depend upon insects for pollination,
35 percent of global food production.
Klein, 2007
Annual economic value of pollination service worldwide is about € 153 billion
Gallai et al., 2009

16. Importance of pollinators
Number of Crops
(Klein, 2007)

17. Change in relative yield over years for pollinator dependent,
crops with high Pollinator dependence and
pollinator non dependent crops
Basu et al., 2011

18. We take pollination for granted
"Not a single bee has ever sent you an invoice. And that is part of the problem –
because most of what comes to us from nature is free,
because it is not invoiced,
because it is not priced,
because it is not traded in markets,
We tend to ignore it."
- Pavan Sukhdev,
The Economics of Ecosystems & Biodiversity
UN Report
We take pollination for granted

19. Pollination: Why is it important?
Pollination is an essential service to crops and wild plants
Pollinators are Vectors of genetic exchange
Essential in obligate mutualisms
Provide other ecosystem services
Biodiversity value

20. Myth : When we think of bees we think of only honey bees!!
20,139 species of bees in the world
(estimate: 25000);
800 species in India
How many bees?
Ascher & Pickering, 2016
There may be several more species
Myth : When we think of bees we think of only honey bees!!

21. Are Bee Populations Declining?
Late 1990s : An indication of reducing bee populations
1996 :
Reasons : ???

22. Are we forgetting pollinators?
Excessive use of chemicals
Monoculture
Deforestation
Habitat destruction
Loss of flora that sustain pollinator populations
have lead to decline in pollinator populations in cultivated systems as well
Pesticides
Are we forgetting pollinators?

23. Agriculture is almost impossible without insecticides
SOME BASIC FACTS
Agriculture is almost impossible without insecticides
Most insecticides do not discriminate between useful and harmful insects
Insecticides belonging to the group of Neonicotinoids are blamed for the decline in bee populations!
Goulson, 2013

24. If Pollinators are not there…..
Cresswell, 2016
If Pollinators are not there…..

25. The Neonicotinoids
By 1980s many insect pests had become resistant to most available insecticides
Neonicotinoids were becoming popular
Selective toxicity to insects
High persistance and systemic
High water solubility, lower impacts on fish and other vertebrates
Versatility in application – SL, WG, seed treatment, etc.

26. Nicotine-like insecticides
Neonicotinoids or Nitroguanidine compounds
Nicotine-like insecticides
Structure and MoA similar to Nicotine: nACH agonist
More toxic to insects than to humans

27. NICOTINE AND NEONICOTINOIDSH 3
Nicotine
Imidacloprid

28. Neonicotinoids prefentially bind to a unique insect α4β2 nAChR subtype
Humans are thought to be protected from neonicotinoid toxicity because of the poor permeability of the blood-brain barrier to these compounds
These two differences provide the neonicotinoids with a potentially more favourable toxicological profile

29. 2009: Global neonicotinoid market 2. 63 billion $ - 41
2009: Global neonicotinoid market 2.63 billion $ % was imidacloprid
2010: Global insecticide market share of neonicotinoids 27 %
Neonicotinoids are registered globally in more than 120 countries

30. How are bees affected? How do bees get these chemicals?
Being systemic, they get into all parts of the plant, including pollen and nectar
Seed treatment
Thiamethoxam seed dressing of oilseed rape – all pollen and nectar samples had residues (3.26 ng/g in pollen; 3.20 ng/g in nectar) (Bonmatin et al., 2014; Botias et al., 2015)
Foraging bees
Brought back contaminated nectar (71.8 ng/day)
(Botias et al., 2015)

31. Some properties of Imidacloprid
Systemic and Nonvolatile
Anaerobic Half-life 33 to 44 days
Aerobic Half-life days
Rapidly moves through plant tissue after application; detectable in leaves, vascular fluids and pollen

32. Imidacloprid Toxicity for bees:
Contact LD50 = 0.078μg a.i./bee
Oral LD50 = μg a.i./bee.
sub-lethal doses 1-24μg/kg & ng/bee
Williamson et al., 2013

33. Residues in Pollen & Nectar after Seed treatment
Crop
Compound
Application Rate
Pollen
(ug/kg)
Nectar
Oil-seed Rape
Clothionidin
600 g ai/Cwt seed
<0.5 to 6.2
<0.5 to 8.6
400 g ai/Cwt seed
1.7
0.8
Imidacloprid
454 g ai/Cwt seed
1.3 to 3.0
0.3 to 3.0
Sunflower
0.7 mg ai/seed
<0.5 to 3.4
<0.5 to 1.9
(Dively & Kamel, 2012)

34. Residues in Pumpkin Pollen after spray application or soil drenching
Insecticide
Treatment
Residue in
Pollen ng/g
Nectar ng/g
Imidacloprid
Soil Drenching
4.90
0.40
Foliar spray (twice)
60.90
11.20
Dinotefuran
Through Drip
57.50
9.20
88.30
7.50
Thiamethoxam
68.00
9.50
92.50
8.20
(Dively & Kamel, 2012)

35. Negative effect of Clothianidin seed treatment on colony growth of Bumble bee

36. Reduced nesting of solitary bee Osmia bicornis
(Rundlof et al., 2015)

37. What is Colony Collapse Disorder
Sudden loss of adult worker bees
Few or no dead bees found in the hive
Presence of immature
Small cluster of bees with the live queen
Pollen and honey stores in hive
One of the factors attributed – sublethal dose of Neonicotinoids!

38. At sublethal levels Neonicotinoids act in two ways:
Foragers get addicted
Visit the sprayed / contaminated plants repeatedly and carry contaminated pollen and nectar to their hives
May result in mortality of brood
Affect their memory, forget their way back home, and get lost

39. Effect of sublethal doses on homing
½ of LD50
¼ of LD50
% of successful homing flights
Topical application
Matsumoto, 2013

40. Evidence of neonicotinoid damage is “conclusive”
BBC reports: Widespread impacts of neonicotinoids ‘impossble to deny’ called ‘today’ s DDT’ BBC News, June 23, 2014
Xerces Society and American Bird Conservancy reviewed 200 studies showing harm to bees and birds from neonicotinoids Xerces Soc report

41. To conclude
There is evidence to show that neonicotinoids are extremely harmful to bees – not only honey bees but also other non-Apis bees.

42. Decisions at International level
US is phasing out use by end of 2016 covering over 150 million ha
European Union including Germany, France, Italy and Switzerland have banned
UK had banned the use of neonics between 2012 and 2015 but has lifted the ban for use against selected crops

43. How to conserve pollinators in the era of Neonicotinoids?
Restrict use of Neonicotinoids – if needed get basic data on Neonicotinoids from India.
Recommendations on different crops may have to be revised
Conserve natural habitats of bees
Develop local bee flora calendars
Identification of bee species and their floral hosts

44. Rachel Carson must be stirring in her grave!!
Thank you