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Facultative bacterial endosymbionts shape parasitoid food webs in natural host populations: A correlative analysis
Facultative bacterial endosymbionts shape parasitoid food webs in natural host populations: A correlative analysis
- Source :
- The Journal of Animal Ecology
- Publication Year :
- 2018
- Publisher :
- John Wiley and Sons Inc., 2018.
-
Abstract
- Facultative bacterial endosymbionts can protect their aphid hosts from natural enemies such as hymenopteran parasitoids. As such, they have the capability to modulate interactions between aphids, parasitoids and hyperparasitoids. However, the magnitude of these effects in natural aphid populations and their associated parasitoid communities is currently unknown. Moreover, environmental factors such as plant fertilization and landscape complexity are known to affect aphid–parasitoid interactions but it remains unclear how such environmental factors affect the interplay between aphids, parasitoids and endosymbionts.Here, we tested whether facultative endosymbionts confer protection to parasitoids in natural populations of the English grain aphid, Sitobion avenae, and if this is affected by plant fertilization and landscape complexity. Furthermore, we examined whether the effects of facultative endosymbionts can cascade up to the hyperparasitoid level and increase primary‐hyperparasitoid food web specialization.Living aphids and mummies were collected in fertilized and unfertilized plots within 13 wheat fields in Central Germany. We assessed the occurrence of primary parasitoid, hyperparasitoid and endosymbiont species in aphids and mummies using a newly established molecular approach.Facultative endosymbiont infection rates were high across fields (~80%), independent of whether aphids were parasitized or unparasitized. Aphid mummies exhibited a significantly lower share of facultative endosymbiont infection (~38%). These findings suggest that facultative endosymbionts do not affect parasitoid oviposition behaviour, but decrease parasitoid survival in the host. Facultative endosymbiont infection rates were lower in mummies collected from fertilized compared to unfertilized plants, indicating that plant fertilization boosts the facultative endosymbiont protective effect. Furthermore, we found strong evidence for species‐specific and negative cascading effects of facultative endosymbionts on primary and hyperparasitoids, respectively. Facultative endosymbionts impacted parasitoid assemblages and increased the specialization of primary‐hyperparasitoid food webs: these effects were independent from and much stronger than other environmental factors.The current findings strongly suggest that facultative endosymbionts act as a driving force in aphid–parasitoid–hyperparasitoid networks: they shape insect community composition at different trophic levels and modulate, directly and indirectly, the interactions between aphids, parasitoids and their environment.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Food Chain
media_common.quotation_subject
Oviposition
Wasps
Zoology
Insect
010603 evolutionary biology
01 natural sciences
Plant reproduction
Parasitoid
Host-Parasite Interactions
03 medical and health sciences
defensive symbiosis
Germany
Animals
parasitoid community
ecological networks
Symbiosis
Ecology, Evolution, Behavior and Systematics
Trophic level
media_common
2. Zero hunger
host–parasitoid interactions
Facultative
Aphid
biology
Host (biology)
fungi
food and beverages
biochemical phenomena, metabolism, and nutrition
biology.organism_classification
Food web
Trophic Interactions
030104 developmental biology
aphid
Aphids
bacteria
Animal Science and Zoology
Female
hyperparasitoid
Research Article
Subjects
Details
- Language :
- English
- ISSN :
- 13652656 and 00218790
- Volume :
- 87
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- The Journal of Animal Ecology
- Accession number :
- edsair.doi.dedup.....6efe5805b2c9b88986cc0aeb6ada9b60