Influence of soil biodiversity on above-ground insects
The central role in the generation and maintenance of life on earth are related to the mutualism(cooperative interaction between species),different forms of mutualism involves insects and plants(Bronstein et al.,2006),mutualism interactions between insects and plants are among the most interactions which have been studied(Bronstein,1994).
In natural systems,plants are selected by insects to feeding on and for oviposit,there are some insects feeding on root, others feeding on foliar,so this relation between insect and plant leads to deferent infractions between insect-plant and insect-herbivore (Solar et al., 2009). The interactions of bi-and tri-tropic in above-ground systems are the principle of recent studies throughout the last 20 years, which includes organizations among plants, insect herbivores, and their natural enemies such as parasitoids or predators(Soler et al.,2007 in Price et al.1980),these interactions are being received increasing attention from biology as well as agronomists,it's recognized that the plant kingdom and the class of insects represent two very extensive taxa of living organism,both in abundance of species and in amount of biomass.(Schoonhoven et al.,2005). Contrary different stages are included with plant protection in opposition to insect behaviour,throughout the production of morphological structures on the leaf surface (i.e.trichomes) that defer herbivores colonization, and by producing or increasing levels of toxic compounds that deleteriously affect the development of phytophages (Soler et al., 2007 in Vet and Dicke 1992, Dicke 1999, Vet 1999).
Overall,the role of plants in the connecting the dynamics of foliar-feeding insects and root-feeding nematodes on plant have been investigated (Kaplan et al., 2009).
"All terrestrial ecosystems are divided in a belowground and aboveground subsystems .These subsystems are obligately dependent upon one another". Whereas the primary production of the main source of organic carbon for the system takes place in above the ground, the recycling of organic matter takes place in below the ground (Poveda et al., 2005, in Scheu and Setala, 2002, Wardle 2002).Therefore the important thing is the study of the interactions that occur within and between these subsystems. In fact most ecologist have left study of the interactions between subsystems,while they have investigated belowground and aboveground communities separately (Poveda et al.,2005,in Bonkowski et al.,2001, Van der Putten et al.,2001).
The acknowledgements of most ecologists have been suggested ,there are complex interactions between both below and ground animals which's plant subject to these complex interactions(Poveda et al.,2005),also the interaction of above and belowground insects by effecting the growth, development and survival of each other when they feed on the same host plant has been observed(Soler et al.2009),while other studies have shown that the herbivorous insects were stimulus factor to plants in order to emit volatile compounds when they are attached by herbivorous insects,which may be used by parasitoids and predators to locate their host or prey (Soler et al.,2007),also this strategy has been observed by aphid parasitoids for the assessment of habitat profitability and the adaptation of patch exploitation,by the use of plant cues(Tentelier &Fauvergue,2007).
Several studies have focused on the effects of root-associated organisms on foliar herbivorous insects ,while the study of Soler et al (2007),has been shown the impact of foliar herbivory by Pieris brassicae L.(Lepidoptera:Pieridae) on the performance of the root herbivore Delia radicum L.(Diptera:Anthomyiidae)and its parasitoid ,the effect of foliar herbivory has decreased significantly the survival of root herbivory and theirs parasitoid by more than 50%. In addition, in the presence of foliar herbivory on the plants, newly emerged adults of both root herbivores and parasitoids were significantly smaller in comparison with control plants (Soler et al., 2007).
Through the attacks of insects,plant can changing their chemical profile as a reaction .these responses occur both locally and systemically throughout the plant ,this study have been shown how plants respond to two different root feeders and the effect of root feeders endoparasitic nematode and the larvae of the cabbage root fly on the survival and development of the shoot feeding larvae of pieris rapae L.(Lepidoptera:pieridae) which have been grew slower and produced fewer pupae on plants.( Van Dam et al.,2005). In other side soil organisms play main role in the interaction between aboveground plant herbivores and their parasitoid (Bezemer et al., 2005), whereas the aboveground insect herbivore performance can either increase or decrease via the shared host plant (Bezemer, et al.2005 in Masters et al.1993), in other rare study, showed that the parasitism rate of seed feeding insects have been increased (Bezemer et al,2005 in master et al, 2001).
Conclusions: The relationship between plants and herbivores (including insects and other animals ),is more significant,this relationship leads to the interactions between each other, some interactions are affecting positively by attracting the natural enemies of insects, or negatively by feeding on roots and shoots,the considerable interactions are observed among insects, herbivores and natural enemies,some studies are shown the effect of root-feeding herbivores on evolution and development of shoot-feeding insects, contrary other studies are focused on root-feeding insects which are affected by foliar-feeding insects .In the other side plants either effect on insects and herbivores or affect by insects .However there are many factors may effects on plants and insects should be focus on,in the future like the structure of soil and their elements, or the susceptibility of varieties of plant to infect by insects.
- Bezemer,T.M.,De Deyn,G.B.,Bossinga,T.M.,Van Dam,N.M.,Harvey,J.A.,& Van der Putten,W.H. (2005) Soil community composition drives aboveground plant-herbivore-parasitoid interactions.Ecological Letters, 8: 652-661.
- Bronstein, J.L. (1994) Our current understandind of mutualism. Quarterly Review of Biology, 69:31-51.
- Bronstein, J.L.,Alarcon, R.,& Geber, N. (2006) The evolution of plant-insect mutualisms.New Phytologist, 172: 412-428.
- Kaplan, I., Sardanelli, S., & Denno, R.F.(2009) Field evidance for indirect interactions between foliar-feeding insect and root-feeding nematode communities on Nicotiana tabacum , Ecological Entomology, 34: 262-270.
- Poveda, K., Steffan-Dewenter, I., Scheu, S. & Tscharntke, T.(2005) Effect of decomposers and herbivores on plant performance and aboveground plant-insect interactions. Oikos, 108: 503-510.
- Schoonhoven, L.M., Van Loon, J.J.A & Dicke, M. (2005) Insect-Plant Biology, From Physiology to Evolution, 2nd edn, Chapman and Hall,London,U.K.
- Soler, R., Harvey, J.A., Kamp, A.F.D., Vet, L.E.M., Van der Putten, W.H.,Van Dam, N.M. et al. (2007) Root herbivores influence the behaviour of an aboveground parasitoid through changes in plant-volatile signals, Oikos 116: 367-376.
- Soler, R., Schaper, S.V., Bezemer, T.M., Cortesero, A.M., Hoffmeister, T.S., Van Der Putten, W.H., Vet, L.E.M., & Harvey, J.A. (2009) Influence of presence and spatial arrangement of belowground insects on host-plant selection of aboveground insects: a field study, Ecological Entomology 34:339-345.
- Tentelier, C., & Fauvergue, X. (2007) Herbivore- induced plant volatiles as cues for habitat assessment by foraging parasitoid, Journal of Animal Ecology 76: 1-8.
- Van Dam, N.M.,Raaijmakers, C.E., & Van der Putten, W.H.(2005) Root herbivory reduces growth and survival of the shoot feeding specialist Pieris rapae on Brassica nigra, Entomologia Experimentalis et Applicata, 115: 161-170.