This document summarizes the order Siphonaptera (fleas) and Strepsiptera (stylopids or twisted-wing parasites). It describes their key physical characteristics, lifecycles, taxonomy, and economic importance. Fleas are small, wingless blood-sucking parasites of mammals and birds. Their lifecycle involves eggs, larvae, pupae, and wingless adults. They can transmit diseases like plague. Stylopids are endoparasites of insects that undergo hypermetamorphosis, with non-feeding larval females and winged adult males. Their lifecycle and parasitic behavior induces morphological changes in their hosts. Both orders contain medically and economically important species.

1. Presented by ,
RIFADA K
PSMO COLLEGE

2. Synonym-Aphaniptera
• Siphon= a tube or
pipe.
• aptera= wingless
• Commonly known as
‘fleas’.
• This order comprise
about1400species.

3. They are small apterous blood sucking
ectoparasites of birds and mammals (found as
attaches to hairs and feathers of hosts).
Very sensitive to body temperature of host and is
the criteria of host selection.
Body is laterally compressed , sclerotized,
bear spines and bristles.

4. CHARACTERS
 Head - Hypognathous , possess a median frontal
tubercle and genal ctenidia latero-ventrally.
Cmpound eyes are absent.2 ocelli laterally or vestigial
or absent.
Antennae -Short ,clavate lodged in antennal
Groove.
Mouthparts- Piercing sucking type,
• labrum modified to elongate groove blade
• mandibles in to elongate styles with median groove and
denticulate distal portion
•Maxillae (laciniae) to blades

5. •Maxillary palp- 4 segmented
•Labial palp- 1-5 segmented

6. Thorax – 3 segmented , pronotal comb is present,
metathorax with greatly developed epimera.
Leg – large,stout.flattened coxae,short femora,5
segmented tarsi. Adapted for jumping. (presence of
resilin cuticle in pleural arch)
Abdomen – 10 segmented,last 3 segments are
genital.9th &10th segment bear sensilium (dorsal sensory
plate) and posterior proctiger.
Male genitalia- a pair of claspers,Aedeagus present
between them.
Female genitalia is without ovipositor.
 2 pair thoracic and 8 pair abdominal spiracle.

8. BIOLOGY
Flea lifecycle;
Holometabolous development

9. • Eggs are not sticky ,fall to the ground immediately
upon being laid. Eggs hatch into larvae within
1 to 12 days.
• Larvae are ~ 3 to 5.2 mm long and are
apodous,vermiform ,semitransparent white in
color. Three larval instars are there.The larval stage
lasts from 4 to 18 days, after which larvae enter the
pupal stage under cocoon. The pupal stage may
complete within 3 days, or last as long as 1 year.

10. Adults
Adult fleas begin searching for food when they
emerge from the pupal stage. While fleas are noted for
their jumping abilities, they will remain stationery when
a suitable host is located. Females begin laying eggs
within 48 hours of the first feed, thus beginning the life
cycle again.
Order siphonaptera devided in to suborders
1. Fracticipita
2. Integricipita
CLASSIFICATION

11. Suborder Fracticipita:
Families:
o Ischnopsyllidae (Bat flea) – Head with paired
sclerotic lobes.
o Hysricopsyllidae (Mole fleas) -Metanotum lacks
marginal spinclets.
o Ceratophyllidae –Genal comb absent.
o Deptopsyllidae - Upper ocular seta above eye.
Suborder Integricipita
Families:
oPulicidae – Abdominal tergite with single row of
setae,sensilium with 14 pits.
oCtenophthalmidae-Abdominal tergites with 2 /3 rows of
setae,eyes reduced or absent.
oTungidae –Female abdomen more swollen,hind coxae
without internal bristles, sensilium pits- 8

12. AS VECTOR OF PLAGUE
•Common indian rat flea Xenopsylla cheopis is
primary vector for bubonic plague pathogen
Bacillus pestis . Ratflea spreads bacillus in man
through bites.
Other species of vector of plague
•Xenopsylla asta (ratflea)
•Pulex irritans (human flea)
•Ctenocephalides canis (dog flea)
•Ctenocephalides felis (cat flea)
pulicidae
ctenophthalmidaeECONOMIC IMPORTANCE;

13. Symptoms of bubonic plague include swollen lymph
nodes, which can be as large as chicken eggs, in the
groin, arm pit or neck. Others include fever, chills,
headache, fatigue and muscle aches.
Flea bite Bubonic plague

14. Bubonic plague -- an infection of the lymph nodes
Pneumonic plague -- an infection of the lungs
Septicemic plague -- an infection of the blood

15. •Strepsi=twisted
•Ptera=winged
•Commonly called
‘stylopids’
• Order comprise of 370
species.
‘twisted wing insect’

16. Small endoparasitic endopterygotes,in homoptera,
hymenoptera,diptera.(stylopization)
oCHARACTERS
Body – Females are larviform,apodous ,apterous
,without eyes, antennae,ocelli ,mouth parts and have
large unsegmented abdomen.
Males are winged with cephalic appendages,and
other structures .

17. Female
Male
oHead –Hypognathous, well developed in males. In
females,cephalothorax formed.
oAntennae- 4-7 segmented,branched structures.
Shows sexual dimorphism…….

18. oMouth parts –Vestigial, mandible is sickle like,maxilla
2 segmented palps.
oEyes –Stemmata,Each of 20-50 simple eyes. Compound
eye absent.
oThorax – Metathorax large,other are small.
oWings- Forewings reduced to halters, Hindwings large
fan shaped and with reduced venation.
oAbdomen - 10 segmented.
oAbsence of cerci.

19. oLegs – Tarsi 4 segmented,without trochanter and claw
but with adhesive segmental pad.
oAedeagus on 9th sternum , copulation and
emergence of larva through large posterior genital
pore(viviparity).
oSpiracle -1 or 2 thoracic,8 abdominal in female.
oMale reproductive organs are a pair of
testes,vasadeferentia and ejaculatory duct.
Female with eggmasses in abdominal cavity.Female
genitalpore vary from 2-5. No genital ducts.
Parthenogenesis is common.
oAdult male is short lived for few hours.

20. FEMALE

21. BIOLOGY
Lifecycle

22. •Male mate with females which are inside host and doesn't move
from it.
•The eggs develop and hatch inside the female's body.
•The larvae hatch from the eggs through brood pouch and find a
new host.
•Once they latch onto a host, they enter it by secreting enzymes
that soften the cuticle, usually in the abdominal region of the host.
•On the host, they undergo hypermetamorphosis and become a less
mobile, legless larval form.
•They induce the host to produce a bag-like structure inside which
they feed and grow. This structure, protects them from the immune
defences of the host.
• Larvae go through four more instars, and in each moult separation
of the older cuticle occurs, but no discarding,leading to multiple
layers being formed around the larvae.

23. •Male larvae produce pupae after the last moult, but females
directly become neotenous adults. The parasites then
undergo pupation to become adults. Adult males emerge from the
host bodies, while females stay inside
Clausen (1940) noted that a parasitized host is said to be
stylopized and parasitization by a strepsipteran is referred to as
stylopization.It known to cause morphological,
behavioural,physiological changes in host.
They include changes in antennae,wing and other structures and
impair egg development, sexual characters,fertility of host. They
becomeless active.
ECONOMIC IMPORTANCE

24. Female cephalothorax with hood,claws absent
=Myrmecolacidae (male ants ,female orthoptera)
Female with elongate cephalothorax,Genital tubes- 4-5
=Callipharixinidae (heteroptera)
Female free living with single posterior genital
opening,Scutellum very long, Hindwing with MA1
dominant vein.
=Mangenillidae
5 segmented tarsi,scutellum widely spherical in front
=Mengeidae
Prescutem narrow at base, scutellum truncated
=Corioxenidae (bees,wasp, hemiptera)
3 segmented tarsi,narrow linear brood passage,stipes fuse
with head capsule
=halictophagidae
CLASSIFICATION
families

25. Antennae -5-6 fabellate segmented,mandibles short no
MA1 vein
=Bohartillidae
Lacking flabellate on antennae, very long
mandibles,cephalothorax of females with one pair of
spiracles,genital tubes- 2-5
=Stylopidae