Life history strategies of hemi metabola

1. COMPARATIVE STUDIES IN LIFE HISTORY STRATEGIES OF
HEMIMETABOLA INSECTS
Prepared by,
M.LOGESWARAN,
2023505006

2. HEMIMETABOLA METAMORPHOSIS
• It is also known as Incomplete metamorphosis.
• Wings develop externally called Exopterygota , either on later
juvenile instars or during pre-pupal and pupal stages.
What is the characteristic feature of
Hemimetabola insects ?

3. HEMI METABOLA INSECTS
• Cockroaches ( Order – Blattodea)
• Crickets and Grasshoppers ( Order- Orthoptera)
• Stick insects ( Order- Phasmatodea)
• Praying mantis ( Order- Mantodea)
• Termites ( Order- Isoptera)
• Dragonflies and Damselflies ( Order-Odonata)
• Earwigs ( order-Dermaptera)
• Stink bugs ( order- Hemiptera)

4. LIFE CYCLE OF COCKROACHES

5. REPRODUCTION
• Development of the ovary of P. americana occurs after eclosion of the nymph
into an adult.
• The main features of the ovary are oocyte differentiation and vitellogenesis,
parthenogenesis and gametogenesis.
EGGS
The American cockroach lays 12 to 16 eggs each time.
Mature eggs are expelled sequentially and encased individually with
secretions produced by the colleterial glands, eventually forming an ootheca .
The developmental threshold temperature of eggs is 15.8 °C, reaching an
effective accumulated temperature of 415.8 ± 38.5 degree-days before hatching.

6. NYMPHAL DEVELOPMENT

7. PARENTAL CARE
• Subsociality has been found among many cockroach species, and
there is considerable variation in care, such as
1)tending and protecting their young,
2)feeding young on body fluids and
3)progressive provisioning (Nalepa and Bell 1997).

8. LIFE CYCLE OF GRASS HOPPERS

9. REPRODUCTION
• Male and female grasshoppers mate as summer changes to
autumn.
• Males fertilize the females, who deposit the eggs that will
become the grasshopper population next summer.
• The female drives its elongated abdomen into the ground for
a cluster of eggs to deposit.

10. EGGS
Each Egg Pod consists of roughly 10-300 rice-shaped eggs. In the
autumn and winter seasons the eggs remain dormant for nearly ten
months. The eggs hatch into Nymphs (offspring) by the spring or early
summer.
PROTECTION
The eggs are coated with a sticky substance that helps protect
them during the winter as they lie dormant underground.

11. NYMPHS
• Nymphs undergo 5 - 6 moults before becoming adults, and change
their shape and structure. This process of moulting is called
Incomplete Metamorphosis.
ADULT
• The Wings are fully developed after 25 – 30 days, and the Nymphs
ripen into adults. By the time an egg ripens to an adult, the
Grasshopper is about 11 months old.

12. LIFE CYCLE OF STICK INSECTS

13. REPRODUCTION
Walking sticks are one of many species that can reproduce
parthenogenetically.
EGG
Females lay eggs that look like seeds, and they have
numerous egg-laying mechanisms to keep predators away.
PROTECTION
Some females lay eggs in places that are hidden or hard to get
to. Others drop eggs one by one on the ground so they’re not all in one
place for a predator to find.

14. ADULT
Newly hatched walking sticks reach adult size once they’ve
undergone several molts.
They reach maturity between three months and one year, and
usually live up to two years.

15. LIFE CYCLE OF PRAYING MANTIS

16. REPRODUCTION
The female praying mantis will bite off the male’s head and if
mating has already begun, the males will have very vigorous
movements while delivering the sperm.
The male attempts to engage the female in a courtship dance .
To mate after the courtship dance, the male praying mantis will
leap onto the females back.
Once the collapsing is done, he then bends his abdomen to place
his sperm into a cavity that is located on the tip of the female’s
abdomen.

17. EGG
Egg clusters are protected inside papery cases called ootheca. In
the Fall these are left attached to small twigs or branches.
NYMPH
Eggs hatch in spring and hundreds of Nymphs emerge.Nymphs are
cannibalistic so they hould not be confined together.
ADULT
Nymphs will undergo several molt and the adult begin to appear
in the late summer.

18. LIFE CYCLE OF TERMITES

19. REPRODUCTION
The termite community does this through species with wings.
Mating takes place when termites are in flight. The laying of eggs is in
the nesting chamber below ground or inside fallen trees.
EGGS
The fertilized termite eggs are called ootheca.
NYMPHS
Once termite hatch from egg shell, it resembles tiny termites.
ADULTS
Adults live for many years

20. LIFE CYCLE OF DRAGONFLIES AND DAMSELFLIES

21. REPRODUCTION
• To mate, the male first grabs a female by the back of her neck with
claspers at the end of his abdomen .
• From here, the pair can fly around together in tandem.
• If the female is sexually receptive, she will lift her abdomen up to
bring her "vagina" in contact with his "penis," allowing the male to
transfer his sperm.
• In some species, the pair will remain in this wheel position for only a
minute.

22. EGGS
• The eggs may be dropped into water or other partially submerged
objects and are deposited in gelatinous masses.
• Dragonfly - lay their eggs on the surface of the aquatic plants. i.e
Exophytic.
• Damselfly - Insert their eggs into the stem of aquatic plants. i.e
Endophytic.
• The male guard the ovipositing females and chase off other males
that comes near.

23. NAIADS
• Differ from adult by habit and habitat.
• The wing and reproductive organ are not promptly developed .
• In may fly the naiad has biting type of mouthpart and they breath
through bilateral abdominal gills. It also consists caudal filament
between cerci.
• Sub imago is the stage between naiad and adult which is dull colour
opaque wing and not properly developed legs and cerci and covered
by fine set of hair called pellicle.

24. Dragon fly naiad has :
 rectal gill
 internal gill
 jet propulsion mechanism
Damsel fly naiad has :
Caudal gill
External gill
No jet propulsion
mechanism

25. DRAGON FLY ADULT
• Compoud eyes are holoptic.
• Both the wings are unequal and hind
wings are broader than fore wings.
• Wings are laterally spread at the rest.
• Males have 3 terminal abdominal
appendages.
• Strong fliers.
DAMSEL FLY ADULT
• Compound eyes are dichoptic.
• Both the wings are equal.
• Wings are held at an angle.
• 4 terminal abdominal
appendages.
• Weak fliers.

27. LIFE STAGES IN HEMIMETABOLOUS INSECTS
EGG Laid in
water mainly
setteled at
bottom
NAIADare
aquatic and
mainly
predator in
nature and
indicator of
water
pollution
ADULT
Are aerial
strong fliers
and predator
in nature

28. MAYFLY ADULT
• Sub imago stage is present.
• But the adult has well developed wings and legs called imago.
• Adults are terrestrial in nature .
• Adults have atrophied mouth part.
• Adults deposit the eggs to the water and subsequently swims to the
bottom.

29. ADULT COLOURATION
Genetic basis
Opsin gene is responsible for adult and naiad coloration.
Physical basis
Irrediscent colouration Redox value in ommachrome

30. DEFENCE MECHANISMS
• Presence of hydrofuge hairs in ephemeroptera.
• Reflecting colouration in odonata.
• Strong flying capacity

31. Behavioural defensive mechanism
• Drifting
• Swimming
• Crawling away and hiding
• Scorpion position in mayfly naiad
• Timing of activities
(mass emergence, mating swarms)

32. REFERENCES
• Biparental care in insects: paternal care, life history, and the function
of the nest – Seizi Suzuki. J Insect Sci. 2013.
• Borror and Delong’s Introduction to the study of insects – Charles. A.
Triplehorn , Norman.F.Johnson
• https://www.britannica.com
• https://www.vigyanvarta.com
• https://pubmed.ncbi.nlm.nih.gov

33. THANK YOU!