iDiv Conference 2016 Abstracts Talks T-Adam Adam, Nora Biodiversity Functions Monday, 7 November 2016, 11:00 Past I - Thomas Eisner 10 min Nora Adam (MPI CE) Sex ratio of mirid populations shifts in response to hostplant co-infestation or altered cytokinin signaling Herbivore species sharing a host plant often compete. In this study, we show that host plant-mediated interaction between two insect herbivores – a generalist and a specialist – results in a sex ratio shift of the specialist’s offspring. We studied demographic parameters of the specialist Tupiocoris notatus (Hemiptera: Miridae) when co-infesting the host plant Nicotiana attenuata (Solanaceae) with the generalist leafhopper Empoasca sp. (Hemiptera: Cicadellidae). We show that the usually female-biased sex ratio of T. notatus shifts toward a higher male proportion in the offspring on plants co-infested by Empoasca sp. This sex ratio change did not occur after oviposition, nor is it due differential mortality of female and male nymphs. Based on pyrosequencing and PCR of bacterial 16S rRNA amplicons, we concluded that sex ratio shifts were unlikely to be due to infection with Wolbachia or other known sex ratio- distorting endosymbionts. Finally, we used transgenic lines of N. attenuata to evaluate if the sex ratio shift could be mediated by changes in general or specialized host plant metabolites. We found that the sex ratio shift occurred on plants deficient in two cytokinin receptors (irCHK2/3). Thus, cytokinin- regulated traits can alter the offspring sex ratio of the specialist T. notatus. Co-Authors Theresa Erler, Mario Kallenbach, Martin Kaltenpoth, Grit Kunert, Ian T. Baldwin, and Meredith C. Schuman (MPI CE) Keywords interspecific competition, sex ratio, jasmonic acid, cytokinin T-Ascen Ascensão, Fernando Biodiversity Patterns Monday, 7 November 2016, 10:35 Past I - Thomas Eisner 10 min Fernando Ascensão (CIBIO-InBio) Predicting wildlife-vehicle collisions using occupancy models 1. Wildlife-vehicle collisions (WVC) are more expected where species are more likely to occur. However, in many studies, the information regarding species’ presence and abundance in road surroundings is absent. On the other hand, WVC may be undetected in roadkill surveys. When this information is absent, it may lead to biased conclusions that ultimately jeopardize conservation actions. 2. We suggest using occupancy models, assuming occupancy as the probability of individuals using the immediate vicinity of a road section or using it for crossing (road-kill risk); and detectability as the combination of the probability of an individual being hit by a vehicle and, if so, its carcass being detected during a roadkill survey. We used this approach to assess how habitat influences species occupancy probability along the road roads, while accounting for imperfect detection. 3. We conducted road surveys biweekly, between April 2010 and March 2015, over 114 km of nine different roads in Brasília FD, Brazil. We developed a Bayesian hierarchical occupancy model to assess spatial patterns of WVC occurrence for a collection of the six most road-killed taxa (n=1711). 4. We estimated a generally higher roadkill risk in road segments near urban areas and with higher cover of open habitat. Detectability tended to be higher for four- lane roads and rainy season. From a conservation perspective, our results highlight the need to upgrade road stretches near urban areas and with higher cover of open habitat. 5. Our results provide an insight into the influence of habitat on roadkill risk for a collection of species, while accounting for different detectability. Yet, further model development should integrate colonization-extinction episodes, as well be able to disentangling both detectability processes. Co-Authors Rodrigo A. L. Santos (University of Brasília-UnB, Brasília), Mário Ferreira (Universidade do Porto) Keywords road ecology, conservation biology T-Backm Backmann, Pia Biodiversity Processes Monday, 7 November 2016, 12:35 Present I - E.O. Wilson 10 min Pia Backmann (iDiv) Attack my neighbour: Delayed induction of plant chemical defense can be an evolutionary stable strategy In plants, time delays in the activation of defense against herbivory are thought to be the principal disadvantage of induced instead of constitutive defense. This suggests strong selection for fast induction. However, observed time delays between the onset of herbivory and defense induction vary considerably. We postulate that strong competition with conspecifics is an important co-determinant of the cost-benefit balance for induced responses. As damage caused by early instars of the herbivore might be tolerable, plants might rather wait until later instars are large enough to be both mobile and cause severe damage. Then, if expelled by chemical defense, larvae might attack neighbouring plants and thereby reducing the competitive pressure on the focal plant. To explore this idea quantitatively, we developed an individual-based model which is based on data from wild tobacco, Nicotiana attenuata, and its specialized herbivore, larvae of the moth Manduca sexta. Plant competition was represented with the zone-of-influence (ZOI) approach. Chemical defense was assumed to be costly in terms of reduced plant growth, while herbivory reduced above-ground biomass. We used a genetic algorithm with the plant’s delay time as a heritable trait. We found that a stationary distribution of delay times emerged, which under high herbivore densities peaked at higher values. We conclude that if plants grow in stands of dense cohorts, there is no strong selection pressure to minimize delay times for herbivore-induced responses. Co-Authors Nicole Van Dam (iDiv), Volker Grimm (UFZ), Ian T. Baldwin (MPI CE), Eckhard Finke, Gottfried Jetschke (FSU), Yue Lin (Northwest University, Xi'an city), Matthijs Vos (University of Oldenburg) Keywords computer simulations, individual-based model, plant-herbivore interactions, induced defense, trait diversity, Monodominance, percolation, dispersal T-Banna Bannar-Martin, Katherine Biodiversity Functions Tuesday, 8 November 2016, 9:10 Past III - Rosalind Franklin 15 min Katharine Bannar-Martin (sDiv/iDiv) Integrating community assembly into biodiversity-ecosystem function relationships- results from the sCAFE working group. Over the past two decades, the biodiversity-ecosystem-function (BEF) research program has proliferated, linking changes in biodiversity to changes in ecosystem functions and services. However, the extent to which the results of BEF studies, focused on local experimental systems, can be extended to natural systems is the subject of much debate. Specifically, the applicability of the BEF framework is complicated by the fact that real-world biodiversity is an emergent property of (meta)community processes, which determine how communities assemble across environments through the dispersal, colonization, and extinction of species. Although these processes strongly affect the diversity, composition, stability, and function of ecosystems, their role is rarely considered in BEF research. Consequently, advancing the study of ecosystem function requires integrating the valuable discoveries of BEF research with (meta)community theory. In the sCAFE working group, we adapted and extended a novel approach to incorporating community assembly into diversity-ecosystem-function research (the CAFE approach) using the Price Equation. We use the Price Equation as an integrative tool allowing for a broader empirical examination of how community assembly (species gains and losses), together with changes in species number impact ecosystem function. We show how the CAFE approach can reveal important contributions of community composition and assembly to ecosystem function using empirical examples of grassland seed addition experiments, species invasions, and recovery of small mammal communities over time after a disturbance event. Considering the CAFE approach in studies of ecosystem function illustrates the importance of metacommunity processes for explaining the linkages between diversity, ecosystem function, and ultimately the ecosystem services on which we depend. Co-Authors Colin Kremer (Yale), S.K. Morgan Ernest (University of Florida), Mathew A. Leibold (University of Texas), sCAFE Working Group (iDiv) Keywords biodiversity, ecosystem function, community assembly, metacommunity, dispersal, Price equation T-Benne Bennett, Joanne Biodiversity Patterns Tuesday, 8 November 2016, 12:05 Present VI - Georgina Mace 5 min Joanne Bennett (iDiv) Global change drivers are increasing pollen limitation in wild plants The majority of the world’s plants (~87%) rely on animal pollination at least to some degree for reproduction. Reports of global pollinator declines have raised concerns that wild and crop plants are facing a pollination crises. Pollinator declines are expected to lead to a reduction in the reproductive success of flowering plants, but a lack of suitable data has hampered attempts to assess whether this is occurring in nature. In plants the degree of pollen limitation (a reduction in fruit or seed set as a result of limited pollen supply) can be used as a direct assessment of plant reproductive success in relation to pollination services. We created a global pollen limitation dataset, containing over 3,000 experimental measures of pollen limitation for a ~1,200 wild plant species, over a 40 year period to document spatiotemporal changes in pollen limitation. We found an increase in pollen limitation through time