TY  - JOUR
A1  - Vogel, Sebastian
A1  - Prinzing, Andreas
A1  - Bußler, Heinz
A1  - Müller, Jörg
A1  - Schmidt, Stefan
A1  - Thorn, Simon
T1  - Abundance, not diversity, of host beetle communities determines abundance and diversity of parasitoids in deadwood
JF  - Ecology and Evolution
N2  - Most parasites and parasitoids are adapted to overcome defense mechanisms of their specific hosts and hence colonize a narrow range of host species. Accordingly, an increase in host functional or phylogenetic dissimilarity is expected to increase the species diversity of parasitoids. However, the local diversity of parasitoids may be driven by the accessibility and detectability of hosts, both increasing with increasing host abundance. Yet, the relative importance of these two mechanisms remains unclear. We parallelly reared communities of saproxylic beetle as potential hosts and associated parasitoid Hymenoptera from experimentally felled trees. The dissimilarity of beetle communities was inferred from distances in seven functional traits and from their evolutionary ancestry. We tested the effect of host abundance, species richness, functional, and phylogenetic dissimilarities on the abundance, species richness, and Shannon diversity of parasitoids. Our results showed an increase of abundance, species richness, and Shannon diversity of parasitoids with increasing beetle abundance. Additionally, abundance of parasitoids increased with increasing species richness of beetles. However, functional and phylogenetic dissimilarity showed no effect on the diversity of parasitoids. Our results suggest that the local diversity of parasitoids, of ephemeral and hidden resources like saproxylic beetles, is highest when resources are abundant and thereby detectable and accessible. Hence, in some cases, resources do not need to be diverse to promote parasitoid diversity.
KW  - barcoding
KW  - deadwood
KW  - experiment
KW  - host–parasitoid interaction
KW  - natural enemy
KW  - specialization
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238892
VL  - 11
IS  - 11
SP  - 6881
EP  - 6888
ER  - 
TY  - JOUR
A1  - Graf, Marlene
A1  - Lettenmaier, Ludwig
A1  - Müller, Jörg
A1  - Hagge, Jonas
T1  - Saproxylic beetles trace deadwood and differentiate between deadwood niches before their arrival on potential hosts
JF  - Insect Conservation and Diversity
N2  - Deadwood provides a variety of habitats for saproxylic beetles. Whereas the understanding of the drivers promoting saproxylic beetle diversity has improved, the process of deadwood colonisation and beetle's potential to trace resources is poorly understood. However, the mechanisms facilitating deadwood detection by saproxylic beetles appears to be essential for survival, as deadwood is usually scattered in time and space.
To investigate whether saproxylic beetles distinguish before their arrival on potential hosts between alive trees and deadwood (lying, stumps, standing), deadwood arrangement (aggregated, distributed) and different heights on standing resources (bottom = 0.5 m, middle = 4–5 m, top = 7.30–11.60 m), we sampled saproxylic beetles with sticky traps in a deadwood experiment.
We found on average 67% higher abundance, 100% higher species numbers and 50–130% higher species diversity of colonising saproxylic beetles consistently for all deadwood types compared to alive trees with a distinct community composition on lying deadwood compared to the other resource types. Aggregated deadwood arrangement, which is associated with higher sun‐exposure, had a positive effect on species richness. The abundance, species number and diversity, was significantly higher for standing deadwood and alive trees at the bottom section of tree trunks. In contrast to living trees, however, the vertical position had an additional effect on the community composition on standing deadwood.
Our results indicate that saproxylic beetles are attracted to potential deadwood habitats and actively select specific trunk sections before arriving on potential hosts. Furthermore, this study highlights the importance of sun‐exposed resources for species richness in saproxylic beetles.
KW  - deadwood
KW  - experiment
KW  - host discrimination
KW  - host selection
KW  - microclimate
KW  - saproxylic beetles
KW  - vertical stratification
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262507
VL  - 15
IS  - 1
SP  - 48
EP  - 60
ER  -