how to parasitoids life time increase and fecundity rate decrease

1. Trade off between longevity and fecundity
of parasitoids

2. What is trade off ?
• A trade-off is a situation that involves losing one
quality, aspect or amount of something in return for
gaining another quality, aspect or amount.
• If one thing increases, some other thing must
decrease.
Examples
Female parasitoids can adjust their fecundity
schedule according to host availability.

3. Trade off longevity and fecundity of parasitoids
• The trade off between early and late reproduction revealed
that this wasp was able to exploit practically all available hosts
during the first day or first few days of adult life.
• During spells of host unavailability, it was able to adjust its
fecundity schedule accordingly.

4. process involved
Ovisorbtion
When the synovigenic female unable to
find hosts for a period of time, then ripe eggs
in the ovarioles are absorbed.
Eggs can be produced at a later time when food
or hosts are found.
The conservation of reproductive material is
correlated with a high searching capacity.

5. ovisorbtion
Host
searching

6. Example
 The age-specific survival of T. platneri provided
different Trichoplusia ni egg densities.
 Wasps supplied five or 15 hosts per day lived 17.8
and 15.3 days, respectively, whereas those supplied
unlimited hosts lived 11.3 days.
 (L. Hohmann, Robert F. Luck-2004)

8. examples
Host availability regulate the fecundity and longevity
 Three experiment was conducted in three sp. of
Trichogramma
 (Manikavasagam et al.,2003)
1.An unlimited number of host hosts changed every
day
1st day
higher
fecundity
2nd
onwards
delined
the
fecundity

9. 2.Limited host number of host changed every
day
Gradually decline
in the fecundity
Further days of
two sp.

10. • 3. Limited host number of host changed every
three days
• This experiment proves could adjust their
fecundity to host availability