This document discusses the population of natural enemies (Chrysoperla carnea, spiders, and Geocoris bugs) on Bt and non-Bt cotton hybrids in field studies conducted in Ludhiana, India. The results show that the mean number of C. carnea and spiders per plant was higher on Bt cotton hybrids compared to non-Bt hybrids, indicating that Bt cotton supported greater abundance of these natural enemies. The population of Geocoris bugs was also higher on Bt cotton compared to non-Bt cotton in some observations. Overall, the study found that Bt cotton enhanced the biological control function by preserving natural enemy populations.

1. Submitted By:
JAYANT YADAV
(2017A39D)
Transgenics versus Bio-Control

2. Introduction
 According to ‘World Health Organization’
“Transgenic crop are crops derived from organisms whose genetic
material (DNA) has been modified in a way that does not occur
naturally, i.e. through the introduction of gene (Cry, CpTI etc.) from a
different organisms”
 Transgenic crops are also described by different names:
 Genetically Modified crops
 Genetically Engineered crops
 Biotech crops
2

3.  Early commercial transgenic crops expressed single Cry
proteins with specific activity against lepidopteron pests,
eg:
 Bollgard I cotton expressing Cry1Ac - Monsanto
 maize expressing Cry1Ab– Syngenta
 Subsequently, other lepidopteron active Bt toxins are
Cry1F and Cry2Ab2
 Bollgard II cotton expressing Cry1Ac +Cry2Ab2 developed by Monsanto
 In addition to the Bt proteins found in Bollgard
II, Cry1Ac and Cry2Ab, Bollgard III contains a third
protein, Vip3A for the control of Helicoverpa spp.
 Protease inhibitors (PIs) and lectins, whose ranges of
insecticidal activity are generally broader than those of Bt
toxins, are also being used in many experimental crops
3

4. Gene type/Transgene products/
Bacillus thuringiensis toxins
Crop
Cry1Ab Maize ,rice, sugar cane, potato, broccoli, cabbage, cauliflower
Cry1Ac Cotton, soybean, rice, tomato, persimmon, poplar, broccoli
Cry1Ac9 potato
Cry1B maize , cabbage
Cry1Ba white clover
Cry1C broccoli
Cry2Ab cotton
Cry3A potato , sweet potato, eucalypts
Cry3B eggplant
Cry3Bb1 maize
Cry5 Potato
Cry9Aa cauliflower
Cry11A1 potato
Vegetative insecticidal protein 3A cotton
Some Genetically Modified Insect Resistance Plant

5. Protease inhibitors (PIs) Crop
Serine PIs
Aprotinin white clover, maize
Arabidopsis cysteine PI Populus alba
Arrowhead PI cotton
Barley trypsin inhibitor (TI) wheat
Bovine spleen TI tobacco , Chinese cabbage
Cowpea TI
Strawberry, poplar, cotton
rice, Chinese cabbage
PI II (Pin2) Populus deltoides x P. nigra
Potato PI II Rice, sugar cane
Soybean PIs
eggplant
tobacco, potato
Wing bean TI rice
Some Genetically Modified Insect Resistance Plant

6. Cysteine PIs Crop
Corn cystatin rice
Oryzacystatin potato
Potato cysteine PI maize
Lectins
Galanthus nivalis agglutinin (snowdrop lectin) Rice, wheat, sugar cane, potato
Jackbean lectin potato
Pea lectin cotton
Wheatgerm agglutinin Indian mustard
Others
Avidin Apple, tobacco, maize
Baculovirus enhancin tobacco
Cholesterol oxidase tobacco
Germin maize
Maize cysteine protease maize
Spider insecticidal peptide birch

7. Benefits and Impacts
Potential Benefits Potential Impacts
1. Reduction of pesticide use
2. Easier Management of Pests
and weeds
3. Simplification of farming
practices
4. Eliminate dependence on
weather
1. Erosion of genetic diversity
2. Promotion of secondary pests
3. Enhancement of monoculture
paradigm
(Garcia and Altieri 2005)
7

8. Natural Enemies
8
 The term Natural Enemy refers to living organisms
that are normally found in the same habitat as
the target pest. They keep the pest numbers
down
Natural enemies, also called beneficial organisms,
can be grouped mainly into two types:
Parasitoid -- an organism that lives and feeds in or
on a host. The host is killed
Predator -- a living organism that feeds upon other
organisms that are smaller and weaker than itself

9. 9
Common predators used against different insect-pests on various transgenic crops
(Gatehouse et al., 2011)
Protein Transgenic plants Pest Natural enemies
Bt (Cry 1 Ab) Maize Orius nubilalis (Lepidoptera:
Pyralidae), Spodoptera
littoralis (Lepidoptera:
Noctuidae)
Chrysoperla carnea (Neuroptera: Chrysopidae)
Bt (Cry 1 Ab) Maize Direct feeding (Pollen) Several (Coleoptera, heteroptera, Neuroptera)
Bt (Cry 1 Ab) Maize Tetranychus urtica Stenothus punctillum (Col: Cocinellidae)
Bt (Cry 3Bb1) Maize Rhopalosiphum maidis (Hom:
Aphididae)
Coleomegilla maculate (Col: Coccinellidae)
Bt (Cry 1 Ac) Cotton Aphis gossypii (Hem. Aphididae) Chrysopa pallens (Neu: Chrysopidae)
Bt (Cry 1 Ac) Cotton Spodoptera exigua, Helicoverpa
zea (Lepidoptera: Noctuidae)
Geocoris punctipes (Het: Lygaeidae)
Bt (Cry 1 Ac) Cotton lepidopterous pests C. carnea; Orius tristicolor
(Het: Anthocoridae)
Bt (Cry 3) Potato Myzus persicae Hippodamia convergens (Col: Coccinellidae)
Bt (Cry 3A) Potato Lacanobia oleracea (Lep:
Noctuidae)
H. axyridis, Nebria brevicollis (Col: Carabidae)

10. Common parasitoids used against different insect-pests on various transgenic crops
10(Gatehouse et al., 2011)
Protein Transgenic
plants
Pest Natural enemies
Bt (Cry 1Ab) Maize Chilo partellus (Lep: Crambidae) Diaraetiella rapae (Hym: Braconidae)
Bt (Cry 1Ab) Maize Ostrinia nubilalis (Lep: Crambidae) Macrocentrus cingulum (Hym:
Braconidae)
Bt (Cry 1Ab) Maize Spodoptera frugiperda (Lep: Noctuidae) Campoletis sonorensis (Hym:
Ichneumonidae)
Bt (Cry 1Ac) Cotton Helicoverpa armigera (Lep: Noctuidae) Microplitis mediator (Hym: Braconidae)
Bt (Cry 1Ac) Cotton Pseudoplusia includens (Lep: Noctuidae) Cotesia marginiventris (Hym:
Braconidae), Copidosoma floridanum
(Hym: Encyrtidae)
Bt (Cry 1Ac) Broccoli Plutella xylostella (Lep: Plutellidae) Cotesia plutellae (Hym: Braconidae)
Bt (Cry 1Ab) Tobacco Heliothis viresecens (Lep: Noctuidae) C. sonorensis
CpTi and Bt Cotton H. armigera M. mediator

11. 11
Possibilities of Impact of Insect-Resistant GM Plants on Natural Enemies:
Exposure to Insecticidal Proteins
Insecticidal proteins expressed by GM plants are ingested by a number of non-target species.
Consequently, it becomes important to assess which organisms are exposed and at what level.
The level at which an organism is exposed to a plant-expressed insecticidal protein depends on the
(i)concentration of the toxin in the plant or environment (ii) the plant tissue in which the protein is
expressed and (iii) the feeding behaviour of the non-target organism.
The most direct route is through plant feeding. Many predators are facultative feeders of pollen and
plant sap, while both predators and parasitoids utilize extra-floral nectar.
Another important food source for natural enemies in agricultural fields is honeydew produced by
sap-feeding insects such as aphids, planthoppers and leafhoppers. If insecticidal proteins appeared in
honeydew, this could expose many natural enemies to the toxin as in case of lectins and PIs.
major route through which natural enemies are potentially exposed to plant-expressed insecticidal
proteins is through their prey or host organisms.
Romeis et al., 2008

12. Way of Exposure of Transgenes to Natural enemies
(Romeis et al., 2009)
12
Route 1- Exposure
through plant feeding
Route 3- Exposure through
honeydew
Route 4- Exposure through
predation/ parasitization-
Route 2- Exposure through
pollination

13. 13
A. Direct Toxic Effects
The Cry proteins expressed in today’s Bt-transgenic maize and cotton varieties are known to be
specific to Lepidoptera (e.g., Cry1A or Cry2A proteins) or Coleoptera (Cry3 proteins).
The currently deployed Vip3A protein has been reported to be very specific to Lepidoptera, are
likely to cause minimal non-target effects.
Experimental plants have been produced that express different proteins with insecticidal activity
such as avidin, protease or α-amylase inhibitors, or lectins.
In general these compounds have a much broader activity spectrum and consequently a higher
potential to cause direct effects to non-target organisms.
The non-target toxicity studies conducted by biotechnology companies or public research
scientists have revealed no direct toxic effects on natural enemies (Romeis et al., 2006).
Romeis et al., 2008

14. 14
B. Prey/Host-Quality Mediated Effects
Natural enemies can also be affected indirectly by the GM plant when they feed on sublethally
impaired herbivores (“sick prey”). Such effects appear to be caused by declines in the nutritional
quality of the host/prey organisms.
It is well established that parasitoids are especially vulnerable to changes in their host’s quality,
since they usually complete their development in a single host
In extreme cases, parasitoids attack sublethally affected hosts that die before the parasitoid
offspring completes development
When tested under confined conditions, predators have also been found to be affected by altered
prey quality when feeding on Bt-fed susceptible prey items.
The most widely cited example is that of larvae of the green lacewing, Chrysoperla carnea
(Neuroptera: Chrysopidae). When C. carnea larvae were fed lepidopteran larvae reared on Cry1Ab-
expressing maize, a significantly prolonged larval development and an increased mortality were
observed. (Hilbeck et al., 1998; Dutton et al., 2002).

15. 15
Benefits of GM Crops on Natural Enemies
1. Reduction of Insecticides
Adoption of Bt-transgenic varieties has led to substantial reductions in the use of chemical
insecticides. For the period from 1996 to 2005, use of Bt (Cry1Ac) cotton caused a 19.4% reduction in
the total volume of insecticide active ingredient in global cotton production.
Various experimental field studies of Bt crops have shown that natural enemies, with the exception
of specialist species that depend on the targeted pest either increase in abundance or remain the same
in unsprayed Bt plots compared to plots of the same crop managed with chemical insecticides (Romeis
et al., 2006).
Abundances of two generalist predators, C. carnea and Orius tristicolor (Heteroptera:
Anthocoridae), were negatively associated with the number of insecticide sprays.
Similar results were reported by Cattaneo et al. (2006) in which the reduction in insecticide use in Bt
cotton was associated with significantly higher abundances of ants and beetles.
Romeis et al., 2008

16. 16
2. Enhancement of Biological Control Function
Natural enemy activity was enhanced in Bt crops when they received fewer insecticide applications
compared to a corresponding non-transgenic crop
Head et al. (2005) reported lower populations of army worms (Spodoptera spp.) in Bt cotton fields
in South Carolina, which were attributed to enhanced abundance and activity of natural enemies due
to reduced application of insecticides
Similarly, higher predator abundance in Bt sweet corn compared to insecticide-sprayed non-Bt
crops resulted in an enhanced predation of O. nubilalis egg batches.
A number of studies have reported lower populations of aphids in Bt potato, Bt cotton and Bt maize
which were probably caused by increased biological control activity in the Bt crops.

17. 17
3. Management of Pest Resurgence
If the parasitoids and predators that normally attack a pest, are destroyed, those pests that are still
alive after insecticide residues dissipate will live in an environment with fewer natural enemies,
leading to longer pest lifetimes and higher reproduction.
Since natural enemies are in general both less exposed and less susceptible to the Bt toxins than their
herbivorous hosts/prey, i.e., the target pests, Bt plants should either be harmless to the pest’s natural
enemies or kill them at a lower rate than the pest
Thus preserve a favorable pest natural enemy ratio. Consequently, Bt crops are unlikely to induce
resurgence of target pests

18. 18
CASE STUDIES

19. Hybrids Observations
1st 2nd 3rd 4th 5th 6th 7th 8th Mean
Mean number of Chrysoperla carnea per plant
RCH 134
(Bt)
0.50 0.67 0.77 0.83 (1.35) 0.83 (1.35) 0.87 (1.36) 0.97 (1.40) 0.63 (1.28) 0.76 (1.33)
RCH 134
(Non Bt)
0.57 0.30 0.40 0.47 (1.21) 0.40 (1.18) 0.47 (1.21) 0.47 (1.21) 0.33 (1.15) 0.43 (1.19)
LHH 144 0.43 0.30 0.47 0.30 (1.14) 0.23 (1.11) 0.73 (1.32) 0.53 (1.24) 0.50 (1.22) 0.44 (1.20)
CD (p=0.05) NS NS NS (0.10) (0.15) (0.10) (0.06) (0.07) (0.03)
Mean number of Spiders per plant
RCH 134
(Bt)
0.57 1.23 1.30 2.97 (1.99) 3.47 (1.74) 2.03 (1.74) 1.83 (1.68) 1.53 (1.59) 1.87 (1.69)
RCH 134
(Non Bt)
0.50 1.07 1.13 1.83 (1.68) 1.00 (1.41) 0.97 (1.40) 0.87 (1.36) 0.97 (1.40) 1.05 (1.43)
LHH 144 0.47 0.87 1.03 1.40 (1.55) 1.40 (1.55) 1.47 (1.57) 0.93 (1.39) 1.07 (1.44) 1.08 (1.44)
CD (p=0.05) NS NS NS (0.06) (0.08) (0.11) (0.09) (0.06) (0.03)
19
Population of C. carnea and spiders on Bt and non-Bt cotton hybrids at Ludhiana
(Wadwa and Gill, 2007)

20. Hybrids Observations
1st 2nd 3rd 4th 5th 6th 7th 8th Mean
Mean number of Geocoris bug per plant
RCH 134
(Bt)
1.00 0.67 (1.29) 0.70 (1.30) 0.73 (1.32) 1.47 (1.57) 0.97 (1.40) 4.10 (2.26) 1.93 (1.71) 1.45 (1.56)
RCH 134
(Non Bt)
1.07 1.40 (1.55) 1.00 (1.41) 0.57 (1.25) 0.07 (1.03) 0.40 (1.18) 1.17 (1.47) 1.43 (1.56) 0.89 (1.37)
LHH 144 0.97 0.60 (1.26) 1.67 (163) 1.03 (1.42) 0.47 (1.21) 0.90 (1.38) 1.30 (1.52) 2.00 (1.730 1.12 (1.46)
CD (p=0.05) NS (0.13) (0.10) (0.12) (0.09) (0.11) (0.08) (0.07) (0.03)
Mean number of yellow wasp per plant
RCH 134
(Bt)
0.23 (1.11) 0.17 0.17 0.13 1.00 (1.41) 1.20 (1.48) 1.07 (1.44) 1.23 (1.49) 0.65 (1.28)
RCH 134
(Non Bt)
0.03 (1.02) 0.10 0.17 0.20 0.67 (1.29) 0.80 (1.34) 0.83 (1.35) 0.83 (1.35) 0.46 (1.21)
LHH 144 0.00 (1.00) 0.03 0.10 0.13 0.37 (1.16) 1.30 (1.52) 0.87 (1.37) 0.97 (1.40) 0.47 (1.21)
CD (p=0.05) (0.06) NS NS NS (0.15) (0.10) (0.05) (0.05) (0.03)
20
Population of Geocoris bug and yellow wasp, Polistes hebraeus on Bt and non-Bt cotton hybrids at Ludhiana
(Wadwa and Gill, 2007)

21. 21
Predator population density on cotton (the red
arrow indicates the beginning of Bt cotton use)
Blue- Ladybirds
Red- Spiders
Green- Lacewings
Black- Cotton bollworm
Grey- Number of insecticide sprays for Cotton Bollworm
(Lu et al., 2012)

22. 22
Mirid bug population dynamics in Bt and non-Bt cotton with different management regimes from 2002–2009
(Lu et al., 2010)

23. Table 1: Effects on life table parameters (means 6 SE) of Chrysoperla rufilabris, fed Trichoplusia
ni larvae, reared on Cry1Ac-producing broccoli leaves or non-Bt broccoli leaves over two
generations
23
(Tian et al., 2008)

24. Table 2: Effects on life table parameters (means 6 SE) of C. rufilabris, fed T. ni larvae, reared on Cry1Ac/Cry2Ab-
producing cotton leaves or non-Bt isoline cotton leaves over two generations
24(Tian et al., 2008)

25. 25
Mean longevity of first instar C. carnea fed with different concentrations of the Cry1Ab toxin dissolved in sucrose solution
Effect of Bt-consumption on prey utilisation in C. carnea larvae
(Romeis et al., 2014)
Bacillus thuringiensis toxin (Cry1Ab) has no direct effect on larvae of the green lacewing
Chrysoperla carnea (Neuroptera: Chrysopidae)
Food
solution
L1 development
(days±SE)
L1 survival (%) L2 development
(days±SE)
L2 survival (%) L3 dry weight
(µg±SE)
Sucrose 5:1±0:08 84.7 3:4±0:09 96.0 1139±77:8
Bt-sucrose 5:1±0:06 87.9 3:4±0:08 96.1 1252±68:6

26. Reproduction and longevity of Cryptolaemus montrouzieri fed on Ferrisia virgata,
reared on non-transgenic or transgenic (Cry1Ac + CpTI) cotton leaves
26
Weight upon moulting of different life stages of C. montrouzieri fed on F. virgata, reared on non-transgenic or transgenic cotton leaves
(Wu et al., 2014)
Cotton cultivar Preoviposition
period
(days)
Fecundity
(eggs/R)
Oviposition
rate (eggs/
R/day)
Egg hatch (%) Longevity (days)
Male Female
Non-transgenic
cotton
7.00 ±0.93 823.80±84.25 7.21±0.83 90.60±0.01 160.96±17.36 131.42±9.82
Transgenic
cotton
7.18±0.58 766.46±110.99 5.44±0.74 90.80±0.11 157.88±11.62 152.91±13.85

27. 27
Feeding performance of C. montrouzieri on F. virgata mealy bugs reared on non-transgenic or transgenic cotton
(Wu et al., 2014)

28. Bt maize expressing Cry3Bb1 does not harm the ladybird beetle predator,
Stethorus punctillum fed on spider mite, Tetranychus urticae
28
Daily fecundity of Stethorus punctillum fed Tetranychus urticae that were reared on Cry3Bb1-expressing Bt maize (MON88017) or on the
corresponding non-Bt maize for 8 weeks
Li and Romeis (2010)

29. 29
Survival of Stethorus punctillum females and males fed Tetranychus urticae that were reared on Cry3Bb1-
expressing Bt maize (MON88017) or on the corresponding non-Bt maize for 8 weeks
(Li and Romeis 2010)
• Stethorus punctillum fed on T. urticae reared on transgenic Bt-expressing maize (events Bt176 and MON810),
there was no effect on the fecundity, survival of neonate ladybird larvae and larval development
(Alfageme et al., 2008)

30. 30
Longevity of predatory coccinellid, Cheilomenes sexmaculatus on different food solutions
(Dhillon and Sharma, 2009)

31. Effects of Bt toxins on different biological parameters of the coccinellid, C. sexmaculatus
31
(Dhillon and Sharma, 2009)

32. Effects of ingesting transgenic corn pollen containing Cry3Bb toxin on
Coleomegilla maculata fitness- Development
32(Lundgren and Wiedenmann, 2005)

33. Devlopment of coccinellid, Propylea japonica fed different diets (transgenic
rice along with pollen) during larval stages
33
• KMD1 and KMD2 were transgenic Bt rice lines expressing Cry1Ab toxin in pollen
• XS11 was a nontransgenic rice line (parent variety of KMD1 and KMD2)
• The species of aphids was Myzus persicae (Bai et al.,2005)

34. Mean larval and pupal developmental time, mean adult weight and mortality (%) of
ground beetle, Poecilus cupreus fed with Spodoptera littoralis raised on Bt maize and
non-Bt maize
34
(Alvarez et al., 2009)

35. Development and survival of Orius insidiosus fed on Thrips tabaci reared on
Cry1Ac/Cry2Ab-expressing Bt cotton leaves (Bollgard-II) or its non-Bt isoline
35(Kumar et al., 2014)

36. Preoviposition and oviposition periods, fecundity, fertility, and longevity of adult O. insidiosus fed
T. tabaci larvae reared on cotton leaves of Bollgard-II and its non-Bt isoline
36(Kumar et al., 2014)

37. 37
Proportions of Parallorhogas pyralophagus females probing, drilling, and ovipositing on Mexican rice borer,
Eoreuma loftini larvae that were fed either artificial diet containing conventional (top) or transgenic
(bottom) sugarcane stem tissue
(Tomov et al., 2014)

38. Effects of Cry1Ac (Bt Transgenic cotton) on offspring of Microplitis mediator females fed on
Helicoverpa armigera
38
Liu et al., 2005

39. 39
Effect of Cry1F maize on life table parameters of Cotesia marginiventris when parasitized Cry1F
resistant Spodoptera frugiperda were reared on Cry1F maize or non-Bt maize
(Tian et al., 2014)

40. CONCLUSION
40
The End Of A Myth- Trans Genes Does Not Harm Predators And Parasitoids
Crops such as cotton or sweet corn where the introduction of Bt-transgenic varieties results in
significant reductions of insecticide applications.
Laboratory and field studies conducted thus far have shown that the currently used Bt crops do
not cause any unexpected detrimental effects on predators or parasitoids or on the biological
control function.
Consequently, Bt crops can contribute to natural enemy conservation while at the same time
protecting the crop from the targeted pests and are thus a useful component in IPM systems.