Diapause is a period of arrested growth or development in insects where physiological processes like differentiation and reproduction are suspended. It is represented by low metabolism and consumption of oxygen. Diapause can occur at different life stages, including eggs, larvae, pupae, and adults. It is induced by environmental cues like photoperiod and temperature and helps insects survive unfavorable conditions. Theories on hormone activity and food mobilization aim to explain the diapause process.

1. DIAPAUSE MECHANISM IN
INSECTS
Presented to:-
Mr. Snehasish Routray
Assistant Professor
(Agricultural Entomology)
Sri Sri University
Presented by:-
Bismoy Mohanty
FOA/BAG/2018-22/034
BSc. (Hons.) Agriculture

2. What is Diapause ?
• It is the period of arrested growth or development in the life cycle of the
insects during which the physiological processes like differentiation and
reproduction are suspended.
• Diapause represented by low rate of metabolism, low O2 consumption, low
body weight, low body water content, and vitamin deficiency in the blood.
• The term “diapause” was applied by Wheeler to egg stage of grasshopper,
Conocephalus ensiferum at which its development was ceased.
• Later the scope of diapause widened into various stages of insects as
“periods of arrest in ontogenetic development” by Henneguy.

3. Types
• According to seasonal Variation-
1. Aestivation(Summer Diapause)
2. Hibernation(Winter Diapause)
• According to life stages-
1.Egg (embryonic) diapause- e.g-silkworm moth (Bombyx mori)
2.Larval diapause -e.g- Euphroctis sps. ,Cotton pink bollworm(Pectinophora gossypiella)
3.Pupal diapause- e.g-Red hairy Caterpillar (Amsacta albistriga)
4.Adult diapause- e.g-Mangonut Weevil (Sternochaetus mangiferae)
• According to the influence of environmental factors-
1.Obligatory diapause e.g-silkworm moth (Bombyx mori)
2.Facultative diapause e.g-Cotton pink bollworm (Pectinophora gossypiella)
• According to physiological and ecological mechanisms of its incidence and termination-
1.Parapause
2.Oligopause
3.Eudiapause

4. Intensity of Diapause
• Diapause lasts for 9-10 months in the temperate zones, and may persist for a year
or more.
• During diapause, most insects do not feed at all or, in the case of some larvae and
adults feed very little.
• Diapause lasting more than a year is known as prolonged or extended diapause and
has been documented in 64 insect species. Yucca moth (Prodoxus y-inversus) adults
emerge after 19 years of diapause as pre-pupae.
• Another example,where larvae had been in soil up to three years followed by
emergence of wheat-blossom midges(Cantarinia tritici Kirby), whereas larvae of
wheat blossom midge (Sitodiplosis mosellana) overwintered for 12 years in the soil
before adult emergence.
• In some sawflies, diapause stage lasts for 3-4 years.

5. Factors affecting Diapause
Diapause in insects is induced or terminated in response to environmental cues & other factors.
• Photoperiod- Most important Factor
• Temperature- Woolly bear caterpillar must endure a period of chilling to trigger the
end of diapause & continuation of lifecycle.
• Food- e.g Green lace wing shows reproductive diapause when prey are less.
• Genetic factors

8. Theories related to Diapause
• Many theories are out there to explain the process of diapause.
1.Hormone theory
2.Food mobilization Hypothesis

9. Conclusion
• Different processes, such as dormancy, migration and polyphenism can be
modified by diapause.
• Diapause termination can happen by means of chemicals,hormones,oxygen
level,chromosome numbers, wounding and genetics.

10. References-
• https://en.wikipedia.org/wiki/Diapause#:~:text=Diapause%20is%20a%20
mechanism%20used,stages%20of%20arthropods%2C%20especially%20ins
ects.
• https://www.sciencedirect.com/topics/agricultural-and-biological-
sciences/diapause
• https://www.researchgate.net/publication/322701317_Insect_Diapause_A
_Review