<< Chapter < Page Chapter >> Page >

*Data extracted from Whitfield 1998, Whitefield 2003 and Dowton 2001

Ecological constraints and parasitoid development

Parasite lineages tend to parallel those of their hosts (Brooks and McLennan, 1993). A number of studies have shown patterns of coevolution between parasitoid wasps and their hosts. Fig-pollinating wasps, which originated from a parasitoid ancestor, appear to have evolved in response to their host plants (Machado et al., 2001).

a diagram of Co-speciation of figs and their pollinators
Co-speciation of figs and their pollinators (Courtesy of Cook and Rasplus, 2003). Phylogenies of Ceratosolen pollinators show significant congruence with their host figs.

The relationship between parasitoid and host is attributed to mortality risk (Strand, 2000). A trade-off exists between size and development time – an organism must choose between growing larger at the cost of greater mortality risk due to increased development time and developing rapidly to reduce mortality risk at the cost of reduced size (Abrams, 1996). Thus, conditions that increase development time increase risk of mortality for both the host and parasitoid. Because of this trade-off, parasitoids that face high mortality risk favor shorter development times and are smaller. Conversely, species that face low mortality risks favor size at the cost of increased development time. Parasitoids that attack exposed species appear to experience higher levels of intraguild competition than parasitoids that attack concealed hosts (Blackburn, 1991). In response to this increase in mortality risk, parasitoids that attack exposed hosts have shorter development times.

Nonpollinating fig wasps

Although this paper focuses on parasitism of insect hosts, wasps also parasitize plants. Like many other mutualisms, the fig-pollinator association has been exploited by wasp parasites (Yu, 2001). One fig species can host up to 30 different species of nonpollinating fig wasps. Niche space within the syconium is separated by different subsets of flowers, timing of oviposition, and by larval diets. Nonpollinating fig wasps can be split into different functional groups (Cook and Rasplus, 2003):

  • Large gall-inducers and their parasitoids: these wasps are much larger than pollinator wasps and oviposit from outside the syconium at or before pollination.
  • Small gall-inducers: these wasps oviposit from outside at or mostly after pollination, but the wasps are similar in size to the pollinations.
  • Internal parasites: these wasps only occur in the old World and enter figs along with similar sized pollinators.

It has been hypothesized that figs do not exclude nonpollinating fig wasps because defenses against these parasitoid wasps might also exclude necessary pollinators (Cook and Rasplus, 2003). Some parasitoid wasps use the same cues as pollinators to oviposit at the same time, and defenses against these wasps might come at the cost of attracting pollinators to disperse seeds.

Another factor related to development time is fecundity. Parasitoids must compensate for the increase in mortality risk that accompanies host exposure. Therefore, parasitoid fecundity is expected to rise as opportunities of finding hosts increases and the probability of offspring surviving to adulthood declines (Price, 1980). Early host stages such as eggs and young larvae are more abundant and exposed than later host stages, so parasitoids that attack young hosts are expected to have larger fecundities than those who attack older hosts. Conversely, parasitoids that attack concealed hosts are predicted to have lower fecundities (Price, 1980). As predicted, wasps that parasitize young larvae are associated with higher fecundities and are typically endoparasitic koinobionts, while wasps that parasitize pupae are associated with lower fecundities and are typically idiobionts (Mayhew and Blackburn, 1999).

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Mockingbird tales: readings in animal behavior. OpenStax CNX. Jan 12, 2011 Download for free at http://cnx.org/content/col11211/1.5
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Mockingbird tales: readings in animal behavior' conversation and receive update notifications?