The document summarizes research on the resistance of different maize varieties to flour beetles. The objectives were to study the importance of maize crops, varietal resistance to Tribolium confusum and Tribolium castaneum flour beetles, and observe survival rates and larval development periods. Maize varieties tested included Neelam, Popcorn, Kachan, and White Maize. Popcorn was found to be the most resistant with the lowest infestation, survival rates, and weight loss. Neelam and Kachan were the most susceptible. Larval growth and survival rates were highest on Neelam and Kachan. Future work will further study infestation rates and resistance mechanisms

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3. Research Scholar: Sabeeta Kumari Lohana
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1ST M.PHIL SEMINAR

4. Objectives
 The main objectives of this research work are to know importance of Maize
crop and varietal resistance of maize varieties by flour species
“Tribolium confusum” and “Tribolium castaneum”
 To observe the survival rate of both species.
 Larval developmental period of Confused flour beetle and Red flour beetle
in each variety of maize (i.e. from 1st instar to adult).
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5. Varietal of maize varieties against Flour Beetles
( Red flour beetles and confused flour beetles)
Coleoptera: Tenebrionidae
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7.  Maize is the highest yielding cereal crop in the world. It has significant
importance in different countries of the world (Smith C et al. 2004). More
than seventy countries (including 15 developed and 58 developing) produce
maize having more than 1, 00,000 ha (Boyer and Shannon 1987).
 Maize is the 3rd most important cereal crop after wheat and rice in Pakistan
and mostly consumed as human food and animal feed and provides raw
material for food industry.
 The Red flour beetles and confused flour beetles are found in all tropical
and sub-tropical areas of the world (Alanko et al. 2000). These beetles are
the most common pest of wheat flour (Karunakaran et al., 2004).
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8.  These beetles have chewing mouthparts, but do not bite or sting. The
red flour beetle may elicit an allergic response (Alanko et al. 2000), but
is not known to spread disease and does not feed on or damage the
structure of a home or furniture.
 The red and confused flour beetles live in the same environment and
compete for resources (Willis and Roth 1950, Ryan et al. 1970).
 These beetles also cause serious damage upon dried fruits, pulses and
prepared cereal foods, such as cornflake, pasta, biscuit, beans, nuts etc
(Karunakaran et al, 2004).
 Eggs, larvae, and pupae from both species are very similar and are
found in similar environments (Ryan et al. 1970).
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Neelam
Popcorn
Godown
Field Collection Pictures

11. Laboratory Materials
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Weight Machine Hygrometer
Binocular Microscope
Reared VarietiesLamp

12.  Infested and non infected maize varieties were
collected from the Market.
 Samples of maize varieties such as Kachan,
Neelam, White Maize and Popcorn were
procured from Tower Market and Fakir jo Pirh
(Hyderabad). This allows us to assess any
resistance variability which may have been
attributable to genetic difference between
existing varieties. The Maize varieties were
screened for susceptibility to the T. castaneum
and T.confusum.
 Maize samples were cleaned and
preconditioned at 5°C for two weeks.
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13.  The grain samples with beetle eggs were kept in
jars of 150g capacity and covered on top with
muslin cloth.
 All experiment were conducted under laboratory
conditions (27±2°C and 60±5% RH and a
Photoperiod of 10 hours) during the months of
Sep 2015 to Jan 2016.
 The samples were reweighed to determine weight
loss. Weight loss was determined by subtracting
the value of infested maize from that of the
control.
 Insects reared in the laboratory for maize grain
resistance studies.
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15. Classification
 Kingdom Animalia (Animals)
 Phylum Arthropoda (Arthropods)
 Subphylum Hexapoda (Hexapods)
 Class Insecta (Insects)
 Order Coleoptera (Beetles)
 Family Tenebrionidae (Darkling Beetles)
 Tribe Triboliini
 Genus Tribolium (Flour Beetles)
 Species Tribolium .castaneum (Red Flour Beetle)
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16. Life stages No: of
Larvae at
each stage
Mortality
Rate
Mortality% Survival Rate Survival %
larvae 25 5 20% 20 80%
Pupae 20 8 40% 12 60%
Adult 12 _ _ _
Total
Survival
----- ---- ---- ---- 48%
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Table 1.1: Showing survival % of different life stages of Flour Beetles on
Neelam variety from Sep 2015 to Feb 2016

17. Life stages No: of
Larvae at
each stage
Mortality Mortality% Survival Survival %
larvae 25 12 48% 13 52%
Pupae 13 12 90% 1 4%
Adult 1 _ _ _
Total
survival
--- ---- --- --- 4%
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Table 1.2: Showing survival % of different life stages of Flour Beetles on Popcorn
variety from Sep 2015 to Feb 2016

18. Life stages No: of
Larvae at
each stage
Mortality
Rate
Mortality% Survival Rate Survival %
larvae 25 15 60% 10 40%
Pupae 10 6 60% 4 40%
Adult 4
Total
Survival
----- ---- ---- ---- 16%
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Table 1.1: Showing survival % of different life stages of Flour Beetles on
White Maize from Sep 2015 to Feb 2016

19. Life stages No: of
Larvae at
each stage
Mortality
Rate
Mortality% Survival Rate Survival %
larvae 25 15 20% 10 80%
Pupae 10 5 50% 5 50%
Adult 5
Total
Survival
----- ---- ---- ---- 20%
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Table 1.1: Showing survival % of different life stages of Flour Beetles
on Kachan Maize variety from Sep 2015 to Feb 2016

20. 48%
4%
20%
16%
Neelam Popcorn Kachan White Maize
Neelam Popcorn Kachan White Maize
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Fig#1: Showing the survival % of the Flour Beetles on different varieties of maize

21. No. of
Adults
Month Name of Varieties
Neelam Popcorn Kachan White Maize
Total
Weight
Weight
loss
Total
Weight
Weight
loss
Total
Weight
Weight
loss
Total
Weight
Weight
loss
20 Sep 100g 99g 100g 99.85g 100g 99g 100g 99g
20 Oct 100g 95.72g 100g 99.70g 100g 95.72g 100g 95.47g
20 Nov 100g 94.25g 100g 99.65g 100g 94.25g 100g 93.24g
20 Dec 100g 94g 100g 99.50g 100g 94g 100g 94.22g
20 Jan 100g 92.26g 100g 98g 100g 92.26g 100g 93.25g
20 Feb 100g 90.25g 100g 97g 100g 90.25g 100g 92g
Total
Mean
- 94.24g 98.95g 94.24g 93.636g
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Table 2.1: Showing the weight loss of different Maize varieties against Red
Flour Beetles from Sep 2015 to Feb 2016

22. 94.24667
98.95
94.99333
94.24667
Neelam Popcorn Kachan White Maize
Mean
Neelam Popcorn Kachan White Maize
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Fig#2.1: Showing the weight loss in Mean of different Maize varieties against
Flour Beetles from Sep 2015 to Feb 2016

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Neelam
Kachan
White Maize
Popcorn
Neelam

24. 2.9915
1.172
2.9915
2.6736
Neelam Popcorn Kachan White Maize
Standard Deviation
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Fig#2.2: Showing the standard deviation of weight loss on different Maize varieties
against Flour Beetles from Sep 2015 to Feb 2016

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S.D= 2.9915
Mean and Standard deviation of weight loss in Neelam Variety

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Mean and Standard deviation of weight loss in PopcornVariety

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S.D= 2.9915
Mean and Standard deviation of weight loss in KachanVariety

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Mean and Standard deviation of weight loss in White MaizeVariety

29. Table# 3.1:Developmental Period Of Flour Beetles on different varieties of Maize
(Days)
Varieties Months Developmental
Period
Temperature Relative
Humidity
Jeewan Sept to Oct 2015 48days 27±2 60±5
Popcorn Oct to Nov 2015 38 days 27±2 60±5
Kachan Nov to Dec 2015 33 days 20±2 65±5
White Maize Dec to Feb 2016 51 days 20±2 65±5
Total Mean 42.5 days
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30. 0
10
20
30
40
50
60
Jeewan Popcorn Kachan White Maize
Developmental Period ( days)
Jeewan
Popcorn
Kachan
White Maize
48 days
38 days
33 days
51 days
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Fig# 3.1:Developmental Period Of Flour Beetles on different varieties of Maize
(Days)

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32. Life cycle
Eggs
LarvaeAdult
Pupa
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33. Egg of flour beetles
 Freshly laid eggs were very small, whitish,
cylindrical microscopic and often have bits of flour
stuck to their surface and harden, making them
difficult to see.
 The incubation period ranged from 4 to 7 days.
The length of eggs ranged from 0.54 to 68 mm.
 The average minimum, maximum temperature and
humidity were 5.8˚C to 22.3˚C and 60.26%
respectively.
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34. 1st instar larvae
 Body creamy white in colour, translucent,
light brown head with dark brown eye and six legs.
 The last abdominal segment was partly or
completely concealed ventrally with a pair of pseudo
pods. The duration of first instar ranged from 16 to
18 days.
 The length of grub ranged from 0.94 to 0.99 mm
while the width ranged from 0.18 to 0.25 mm
respectively.
 The average (mini, max) temperatures were 4.3˚C,
28.8˚C and humidity was 46.11% respectively.
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35. Second Instar
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Second instar: Body yellowish white,
slender, and cylindrical and covered with fine
hairs.
The head was pale brown and the last
segment of abdomen had two upturn dark,
pointed structures.
The duration of 2nd instar grub ranged from
10 to 14 days.
 The length of 2nd instar grub ranged from
1.57 to 2.16 mm while the width ranged from
0.27 to0.41 respectively.
The average (mini, max) temperature and
humidity were 13.4˚C, 29.14˚C and 47, 21%
respectively

36. Third Instar
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Third instar: The third instars were
structurally similar to second instars except in
size.
The duration of third instar ranged from 8-10
days.
The dark brown patches were developed in
last two-three abdominal segments.
The length of third instar grub ranged from
1.89 to 2.79mm, while the width ranged from
0.40 to respectively.
The average minimum, maximum temperature
and humidity were 15.4˚C, 33.7˚C and 55.3%
respectively

37. Last Instar
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Fourth instar: After third moulting, the fourth
instar grub come out of the exuviate of the third
instar larvae.
The fourth instar larvae were similar to third instar
in colour but they differ in size and shape as well.
The duration of fourth instar ranged from 8 to 10
days.
The body length of fourth instar ranged from 3.10
to, while the width ranged from 0.50 to 1.16 mm
respectively.
The average minimum, maximum temperature and
humidity were 14.87˚C, 30.5˚C and 62.37%
respectively

38. Pupae
 Shortly before pupation the pupa have
dark wings, sclerotized legs and fully
developed eyes.
 The pupa did not have a cocoon and
initially it was white at first day and
then gradually turned to yellowish at
second stage then finally turned into
brown in colour.
 Its dorsal side was covered with fine
hair.
 At this stage the pupa was dormant and
not eating. The male and female pupal
period ranged from 6-7 days for male
and 7-9 days for female.
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39. Adult beetles
 Adult beetles were reddish-brown in colour,
flattish curved-sided body.
 The head was visible from above, did not
have beak and the thorax had slightly
curved sides .The antennae were enlarged
at the tip (capitates) with the last three
segments wider than preceding segments.
 The length of male was 3.06±0.03 mm and
width was 1.28±0.30 mm where as the
length and width of female beetle was
3.70±0.01 mm and1.28±0.03 respectively.
 The average minimum, maximum
temperature and humidity were 19.93˚C,
30.6˚C and 76.5% respectively.
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Popcorn
Neelam
Most resistant
varieties
Most susceptible
varieties
Kachan White Maize

41. The result clearly indicated that the adult progeny and grain weight loss of maize
varieties caused by flour beetles individually as well as in combination varied
significantly. Both characteristics were significantly low in Popcorn and White
maize grains. However, they were significantly high in Neelam and Kachan
varieties.
In Neelam variety, Kachan and White Maize, 7% infestation rate were
recorded from Sep 2015 to March 2016.
 Larvae growth rate was higher on Neelam and kachan varieties and survival
rate was also high.
 Where as in the Popcorn variety infestation was 3% and survival of pest was
very low. Popcorn variety is resist variety of corn.
 Developmental period of larvae in Jeewan variety was (48 days), white maize
(51 days), Popcorn (38 days) ,where as in kachan variety was (33 days ).
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42. Future plan
 The rate of infestation in each variety will be observed .
 The loss of weight after infestation will be monitor fortnightly.
 The effect of temperature and relative humidity will be
observed .
 The developmental time of larval instars will be observed in
each variety.
 Analysis of data will be done by statistical program analysis of
Variance (ANOVA).
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The present study was conducted from September 2015 to March 2016 in laboratory.
Generally, flour beetles are observed to remain active during summer season.
During the observation, it was also found that flour beetles were very active
whenever we kept them at photoperiod of 10 hours .
Result reveal that their was maximum consumption of flour beetle on Neelam and
Kachan varieties also White maize grains and minimum on popcorn, 7% and 3%
respectively. Neelam, Kachan, and White maize varieties of maize were most
susceptible variety and popcorn was more resistant variety.
It was also observed that maximum survival of red flour beetle on White Maize
(16%), Kachan (20%), also Neelam (48%) and minimum on popcorn, 4%
respectively.

45. References Cited
 Bousquet Y. 1990. Beetles associated with stored products in Canada. Canadian
Government Publishing Centre, Ottawa 189-192.
 Arbogast RT, Kendra PE, Mankin RW, McGovern JE. 2000. Monitoring insect pests
in retail stores by trapping and spatial analysis. Journal of Economic Entomology
93: 1531-1542.
 Arbogast RT, Kendra PE, Mankin RW, McGovern JE. 2000. Monitoring insect pests
in retail stores by trapping and spatial analysis. Journal of Economic Entomology
93: 1531-1542.
 Atwell, W. A. 2001. Wheat flour. American Association of Cereal Chemists, Eagan
Press, St Paul, MN.
 Fasulo TR. (2002). German Cockroach and Stored Product Pests. Bug Tutorials.
University of Florida/IFAS. CD-ROM. SW 165.
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46. More
 Campbell, J. F., and D. W. Hagstrum. 2002. Patch exploitation by Tribolium castaneum:
movement patterns, distribution and oviposition. J. Stored Products Res. 38: 55– 68. CrossRef
 Campbell, J. F., and C. Runnion. 2003. Patch exploitation by female red flour beetles, Tribolium
castaneum. J. Insect Sci. 3: 1–8. BioOneAlanko K, Tuomi T, Vanhanen M, Pajari-Backas M,
Kanerva L, Havu K, Saarinen K, Bruynzeel DP. 2000. Occupational IgE-mediated allergy to
Tribolium confusum (confused flour beetle) Allergy 55: 879-882.
 Ajayi, F. A., and S. A. Rahman. 2006. Susceptibility of some staple processed meals to red flour
beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Pak. J. Biol. Sci. 9: 1744–
1748.
 Buss LJ, Fasulo TR. (2006). Stored Product Pests. UF/IFAS. SW 185. CD-ROM.
 Cotton RT. 1950. Insect damage to stored grain and its prevention. Pest Control 18: 8-10.
 CABI. (2007). Tribolium castaneum (red flour beetle) datasheet. Crop Protection Compendium,
2007 Edition. CAB International Publishing. Wallingford, UK.
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47. More
 Campbell, J. F., and C. Runnion. 2003. Patch exploitation by female red flour
beetles, Tribolium castaneum. J. Insect Sci. 3: 1–8. BioOneAlanko K, Tuomi T,
Vanhanen M, Pajari-Backas M, Kanerva L, Havu K, Saarinen K, Bruynzeel DP.
2000. Occupational IgE-mediated allergy to Tribolium confusum (confused flour
beetle) Allergy 55: 879-882.
 Ajayi, F. A., and S. A. Rahman. 2006. Susceptibility of some staple processed meals
to red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Pak.
J. Biol. Sci. 9: 1744–1748.
 Semple R.L., Hicks P.A., Lozare J.V., Castermans A. (eds.). 1992. UN Food and
Agricultural Organization. Rome, Italy. 526
 Robinson W.H. 2005. Cambridge University
Bousquet Y. 1990. Research Branch Agriculture Canada, Publication 1837.
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48. Acknowledgment
Dean, Faculty of Natural Sciences
Chairperson , Department of Zoology
All the Professors and Teachers, Department
of Zoology
All friends, Researchers
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49. Thanks
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