The type of life cycle will vary with the insect-pest. However, most pests have certain weak points during their life cycle when they are the most vulnerable to manage. Some insect are predators, either as larvae or in both larval and adult stages. The decomposition of organic waste, such as dung and manures are an important ecosystem process which is largely provided by insects. Insect as food for animals and human being. The knowledge regarding immature stages of insect-pests and understand site of oviposition, site of pupation and larval behaviour can allow for timely and effective management, thus we can reduction in the qualitative and quantitative losses of yield and increase the profit.

1. Wel come.....

2. Assignment on Importance of study of
immature stage of insects
in agriculture
Submitted to
Dr. A. H. Barad
Asst. Professor,
College of Horticulture,
AAU, Anand
ENT 602: Immature stages of insects (1+1)
Presented by
Sanju S. Thorat
Reg. No. 1010120027
1st Sem.
In-service Ph.D.
BACA, AAU, Anand

3. Contents
• Introduction
• Biodiversity of Insects
• Importance of immature stage of insects in agriculture
• Conclusion
• References
1

4. Immature insects’ adaptations for finding the highest quality food
and optimal environmental conditions are critical to maximizing a
species’ success.
Optimal food and environmental conditions during immature
development increase the insects’ survival and shorten their
development time; these conditions also result in earlier
reproduction and more rapid growth of the insect population.
Introduction
2

5. Immature-stage mobility is important in finding suitable food and
environment, building shelters, thermoregulating behavior, and
evading, escaping, or defending against natural enemies.
The immature stages can move distances ranging from a few
centimeters to a few hundred meters; whereas adults that can fly
can move distances of a few, hundreds, or even thousands of
kilometers.
Mobility gives immature insects greater access to available food.
Neonate larvae often must move large distances to find their first
meal or they perish. 3

6.  Number of species of Insects:
Approximately 15 lac species
have been described during the
period from 1758 to 1940 (Metcalf,
1940).
 This would make the insect
occupy almost 80% of the species
of the whole animal kingdom.
4
Graph from Fossil Focus by Ben J.
Slater. Estimates based on data
presented by Purvis and Hector 2000.

7.  Immature stages occupy a large
part of the life cycle : The egg stage
usually lasts but a few days,
sometimes even shorter, or the egg
may hatch before it is laid, as is the
case in the aphids.
 Many insects hibernate in the egg
stage in which event the egg period
may last several months.
 The growing stage is usually much
longer than the other stages.
5
Development of Immature
stages according to
season

8.  The nymph of the periodical cicada, Magicicada
septendecim (L.) lives underground from 13 to 17
years as compared with the 30 to 40 days of its
adults life and 6 to 7 weeks of its egg stages.
 While some May flies live as adults for only a few
hours, their nymphal stage believed to occupy
three years.
 Many insects spend their winter time in the pupal
stages.
 In general, insects spend considerably more time
in their immature stages than they do as adults.
6

9.  Larva and nymph are heavier feeders:
When a survey of the feeding habits of insects is
made, the nymphs are usually found to take the
same kind of food as their adults.
Larvae on the other hand, usually feed differently
and consume much more than their adults.
Take the order lepidoptera as a good example: the
caterpillars eat a large quantity of food while a
good number of moths do not feed at all.
7

10. Biodiversity of Insects
 We do not know the exact number of all species on earth, but
the estimated number of species is 5-15 million species. (Dirzo
and Raven, 2003).
 Arthropods have existed for more than 400 million years and
survived the Permian and Cretaceous mass extinctions (Kim,
(1993)).
There are about 1 million species of known insects, but only
around 7 - 10% of insects are scientifically described.
Since many insect species are not yet identified, it is estimated
that there could be around eight million species of insects on
earth (Samways, 2005).
8

11. Modern hexapod diversity representing the summation of over 400 million
years of high speciation rates and low levels of natural extinction (©Grimaldi
and Engel, Evolution of the Insects, Cambridge University Press). 9

12. Importance of immature stage of
insects in agriculture
10

13. 11
Identifying windows of opportunity for
insect-pest management
All types of pests have a life cycle or set of
developmental events that occur during their life
time.
The type of life cycle will vary with the pest.
However, most pests have certain weak points or
“windows of opportunity” during their life cycle
when they are the most vulnerable to manage.
For insects, these windows are often during the
immature life stages.

14. 12

15. Source: http://www.tjprc.org/ 13

16.  Larval pupation behaviour and
characteristics of the pupal
chamber in S. exigua.
 a-j: the process of building a
chamber by a larva;
 k: emergence hole remaining in the
chamber wall;
 l: emergence hole was ex-panded
and remained of pupa exuviae in
the chamber after emergence;
 m: shape of the pupal chamber;
 n-o: white multi-layers of silk on the
inner wall of the pupal chamber,
 (n) interior and (o) exterior views.
Source:
https://www.researchgate.net/publication/268369651_Pu
pation_behaviour_depth_and_site_of_Spodoptera_exigu
a [accessed Jan 31 2021]. 14

17. Immature insect as predators
In the insect orders Odonata (dragon flies) and Neuroptera
(lacewings and ant lions) all the insect species are predators,
while a large percentage of species in the orders Hemiptera
(bugs), Coleoptera (beetles), Diptera (flies) and Hymenoptera
(wasps, bees and ants) are predators, either as larvae or in
both larval and adult stages.
15

18. Lady beetles (Family: Coccinellidae)
It is very common and voracious predators of
aphids.
The adults and larvae are predacious.
Lady beetles also feed on caterpillars, moth
eggs, scales, mites, and they may also be
cannibalistic if prey is scarce.
Tiger beetles (Family: Carabidae)
Generally, they have large eyes, long legs, and
large, powerful jaws for grabbing prey.
The adults and larvae are predacious, but larvae
live in the soil and have a smaller search range.
16

19. Green lacewings (Family: Chrysopidae)
Adults feed on nectar, pollen, and honeydew
and are commonly observed flying around
lights after dark.
The larvae are wingless; therefore, they crawl
around on plant leaves in order to search for
prey.
They are mainly predators of aphids, but will
also eat small caterpillars or beetle larvae.
Green lacewing larvae can eat between 100 and
150 aphids in their lifetime. 17

20. Robber flies (Family: Asilidae)
Robber flies larvae develop in the soil, but are
also predacious, feeding on insect eggs, other
larvae, and soft bodied, soil dwelling insects.
Syrphid flies (Family: Syrphidae)
Syrphid fly larvae voracious predators of
aphids, scales, thrips, and small caterpillars.
Once the blind and legless larvae hatch, they
go to work crawling around and sucking the
bodily fluids out of their prey. 18

21. Decomposition of agriculture west by
insects
The decomposition of organic waste, such as dung and
carrion is an important ecosystem process which is largely
provided by insects.
There are about 4000 documented dung beetle species
which play an important role in the decomposition of
manure.
19

22. Dung beetles contribute to soil health by increasing nitrogen,
phosphorous, potassium, calcium and magnesium or total
proteins content (Macfadyen, et al., 2015)).
Dung beetles also contribute to the carbon cycle, reducing GHG
emissions by between 7 and 12% (Nichols, et al., 2008).
Soil insects such as ants, beetles, larval of cutworms, crickets,
collombola, make tunnels in soil and facilitate aeration in soil.
They become good manure after death and enrich soil.
20

23. 21
Beetle larvae, flies, ants and
termites clean up dead plant
matter and break it down for
further decomposition by
microbes.
Ants and termites, the soil
macrofauna in dry and hot
regions, play an important role in
the increase of mineral nitrogen
in the soil (Evans, et al., 2011).

24. Wood beetles are nature’s recyclers
Larvae of longhorn beetle feeding on
pine stump.
Huhu beetle (Prionoplus
reticularis) larvae contribute to the
decomposition of dead pine wood.
22

25. Insect as a delicious food
Insect as food for animals and human being.
For animals- aquatic insects used as fish food.
Grasshoppers, termites, pupae of moths. They have been
used as food by human beings in different parts of the
world.
23

26.  In the European Union, the use of seven
insect species as feed in aquaculture has been
permitted since July 1, 2017.
Black soldier fly (Hermetia illucens),
House fly (Musca domestica),
Mealworm (Tenebrio molitor),
Lesser mealworm (Alphitobius diaperinus),
House cricket (Acheta domesticus),
Tropical house cricket (Gryllodes sigillatus),
as well as Field cricket (Gryllus assimilis).
The inclusion of black soldier flies in the feed
of farmed fish had positive results and showed
no differences in taste or texture of the fish.
24

27. Mealworms for dinner?
European Union approves first insect food
Mealworms have become the first insect
approved in Europe as a human food after
the region's food agency said that they are
safe to eat.
Despite their name, mealworms are beetle
larvae rather than worms and are already
used in Europe as a pet food ingredient.
Source:(https://www.wionews.com/entertainment/lifestyle/n
ews-mealworms-for-dinner-european-union-approves-first-
insect-food-356581)
25

28. Silk farming
Sericulture, or silk farming, is the cultivation of silkworms to
produce silk.
Although there are several commercial species of
silkworms, Bombyx mori (the caterpillar of the domestic silk moth)
is the most widely used and intensively studied silkworm.
Sericulture has become an important cottage industry in countries
such as Brazil, China, France, India, Italy, Japan, Korea, and Russia.
Today, China and India are the two main producers, with more than
60% of the world's annual production.
26

29. Conclusion
The type of life cycle will vary with the insect-pest. However, most pests have certain
weak points during their life cycle when they are the most vulnerable to manage. The
some insect are predators, either as larvae or in both larval and adult stages.
The decomposition of organic waste, such as dung and manures is an important
ecosystem process which is largely provided by insects. Insect as food for animals
and human being.
The knowledge regarding immature stages of insect-pests and understand site of
oviposition, site of pupation and larval behavior can allow for timely and effective
management, thus we can reduction in the qualitative and quantitative losses of
yield and increase the profit.
27

30. References
• Dirzo, R. and Raven, P.H. (2003). Global State of Biodiversity and Loss. Annual Review of Environment and Resources, 28, 137-167.
https://doi.org/10.1126/science.241.4872.1441
• https://en.wikipedia.org/wiki/Sericulture#:~:text=The%20silk%20is%20a%20continuous,and%20readies%20them%20for%20reeling.
• Kim, K. C. (1993). Biodiversity, Conservation and Inventory: Why Insects Matter. Biodiversity & Conservation, 2, 191-214.
https://doi.org/10.1007/BF00056668
• Samways, M. J. (1993). Insects in Biodiversity Conservation: Some Perspectives and Directives. Biodiversity & Conservation, 2, 258-282.
https://doi.org/10.1007/BF00056672.
• Zhang, Z. Q. (2011). Animal Biodiversity: An Introduction to Higher-Level Classification and Taxonomic Richness. Zootaxa, 3148, 7-12.
• Samways, M. J. (2005). Insect Diversity Conservation. Cambridge University Press, New York, 25-29.
https://doi.org/10.1017/CBO9780511614163
• Dicke, M. (2017). Ecosystem Services of Insects. In: Van Huis, A. and Tomberlin, J.K., Eds., Insects as Food and Feed: From Production
to Consumption, Wageningen Academic Publishers, Wageningen, The Netherlands, 61-76.
• Hunt, T. and Bergsten, J. (2007). A Comprehensive Phylogeny of Beetles Reveals the Evolutionary Origins of a Superradiation. Science,
318, 1913-1916. https://doi.org/10.1126/science.1146954
• Macfadyen, S., Kramer, E.A., Parry, H.R. and Schellhorn, N.A. (2015). Temporal Change in Vegetation Productivity in Grain Production
Landscapes: Linking Landscape Complexity with Pest and Natural Enemy Communities. Ecological Entomology, 40, 56-69.
https://doi.org/10.1111/een.12213
• Nichols, E., Spector, S., Louzada, J., Larsen, T., Amezquita, S. and Favila, M.E. (2008). Ecological Functions and Ecosystem Services
Provided by Scarabaeinae Dung Beetles. Biological Conservation, 141, 1461-1474. https://doi.org/10.1016/j.biocon.2008.04.011
• Evans, T.A., Dawes, T.Z., Ward, P.R. and Lo, N. (2011). Ants and termites Increase Crop Yield in Dry Climate. Nature Communications, 2,
Article No. 262. https://doi.org/10.1038/ncomms1257
• Andy Purvis & Andy Hector (2000). Getting the measure of biodiversity Nature volume 405, pages 212–219.
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31. THANK YOU