Sondersammlungen

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Coffee berry borer control, but not coffee yield, is mediated by non-additive interaction between birds and ants across different cultivation systems
(2026) Cardona Tejada, Damaris A.; Parra, Juan L.; Grass, Ingo; Schurr, Frank M.
Coffee is one of the most traded tropical crops, cultivated in some of the most biodiverse regions on the planet. Coffee production can be seriously reduced by the coffee berry borer (CBB), a specialized beetle that feeds on the endosperm of coffee berries. Given the CBB's economic relevance, coffee-producing countries have developed extensive Integrated Pest Management programs. Nonetheless, most of these programs fail to incorporate CBB control by natural enemies such as birds and ants. While the effects of birds and ants on CBB suppression have been demonstrated to be positive when studied in isolation, their interactive effects have been little studied. To better understand the effects of the trophic interaction between birds and ants on CBB control, we conducted a full-factorial block experiment excluding birds and ants from coffee shrubs. We distributed 49 experimental blocks across three different coffee systems in a Colombian landscape: sun-exposed coffee, coffee-plantain intercropping, and shade coffee. We found birds to be key control agents of CBB: in the presence of ants, bird exclusion increased CBB infestation by 36 %. However, in the absence of ants, birds had little effect on CBB infestation, demonstrating that the effects of birds and ants were non-additive. This suggests that birds control CBB through a trophic cascade mediated by ants. We also found that the effects of exclusions were modified by the cultivation system, with the shade coffee system consistently reducing CBB infestation. Our experiment demonstrates that crop diversification is an effective measure for integrating local enemies into IPM strategies. Nonetheless, we acknowledge that trophic interactions are highly complex and exhibit a context-dependency that can result in the suppression of biological pest control. Therefore, we recommend conducting future analysis on evaluating the effects of predator´s community composition to encourage the development of IPM programs that leverage biodiversity in agroecosystems.
Comparative ungulate diversity and biomass change with human use and drought: implications for community stability and protected area prioritization in African savannas
(2025) Bartzke, Gundula S.; Ogutu, Joseph O.; Piepho, Hans‐Peter; Bedelian, Claire; Rainy, Michael E.; Kruska, Russel L.; Worden, Jeffrey S.; Kimani, Kamau; McCartney, Michael J.; Ng'ang'a, Leah; Kinoti, Jeniffer; Njuguna, Evanson C.; Wilson, Cathleen J.; Lamprey, Richard; Hobbs, Nicholas Thompson; Reid, Robin S.
Drought and human use may alter ungulate diversity and biomass in contrasting ways. In African savannas, resource‐dependent grazers such as wildebeest (Connochaetes taurinus) and zebra (Equus quagga) may decline or disperse as resources decline, opening space for more drought‐tolerant species such as gazelles (Eudorcas and Nanger) and impala (Aepyceros melampus). This shift can increase species richness, evenness, and overall ungulate diversity. Although higher diversity may stabilize ungulate communities, it may be associated with lower biomass (the total body mass of all individuals in a community), which in turn affects vegetation structure and composition, nutrient cycling, energy flows, and other organisms in savannas. While ungulate biomass often declines during drought or in areas of intense human use, the effects on diversity changes under low‐to‐moderate human use remain less clear. Our fine‐scale censuses in the Maasai Mara National Reserve and adjacent pastoral lands in Kenya showed that ungulate biomass declined more than diversity in the 1999 drought year. In the normal rainfall year of 2002, diversity peaked along the reserve boundary, but species richness leveled off in the drought year. Biomass peaked in the reserve in both census years, and migratory ungulates moved further into the reserve in the drought year, where diversity declined. These findings suggest that core protected areas are crucial for maintaining ungulate biomass, while transition zones from protected and pastoral lands support higher diversity unless drought reduces species richness.
Connecting resonance theory with social-ecological thinking: Conceptualizing self-world relationships in the context of sustainability transformations
(2025) Brossette, Florian; Bieling, Claudia
Relationships and interactions between humans and their environment play an important role in sustainability transformations. However, their conceptualization remains a big challenge in current social-ecological research. We propose resonance theory by the German sociologist Hartmut Rosa as a fruitful framework to advance social-ecological thinking. Resonance theory investigates the quality of the relationships between self and world and scrutinizes their relevance for transformations. To illustrate the potentials of resonance theory, we use a vignette approach to cases of landscape stewardship initiatives in the Black Forest Biosphere Reserve in Germany. In distinguishing between self and world and highlighting the role of relationships, resonance theory brings ontological and epistemological clarity, while overcoming a strict dichotomy between social and ecological. We find that resonance theory provides a much needed framework to describe how system-wide transformations emerge from interactions and out of relationships at the individual level. We argue that resonance theory contributes to social-ecological systems thinking by adding the notion of uncontrollability in transformations and shifting the debate on agency towards relationships. Synthesis and applications: This paper demonstrates the meaningfulness of relational paradigms for real-world transformations in theory and practice.
Effects of dietary phosphorus and myo-inositol supplementation on NaPi-IIb and TRPV6 protein expression in duodenal apical membranes of laying hens from two strains
(2026) Shomina, Nataliia; Sommerfeld, Vera; Hanauska, Anna; Oster, Michael; Rodehutscord, Markus; Huber, Korinna
Phosphorus (P) and calcium (Ca) absorption in the intestine is mediated by apical brush border membrane (BBM) transporters, including the sodium-dependent phosphate (Pi) transporter NaPi-IIb and the Ca²⁺-selective channel TRPV6. Both are highly expressed in the duodenum and exhibit dietary adaptability; yet little is known about how this adaptability varies with strain and age in laying hens. The present study examined the effects of dietary mineral P renunciation and myo-inositol (MI) supplementation on NaPi-IIb and TRPV6 protein expression in the duodenal BBM of Lohmann Brown-Classic (LB) and Lohmann LSL-Classic (LSL) hens. Two independent feeding trials were conducted: hens received diets either with or without mineral P supplementation (wk 15 - 19 and 20 – 24), or with graded MI levels (0 - 3 g/kg; wk 26 – 30). At the end of each period, hens were euthanized and protein expression of NaPi-IIb and TRPV6 in duodenal BBM was studied by western blotting. Statistical correlation with additional traits of mineral metabolism was analyzed. An immunoreactive NaPi-IIb band was detected at ∼ 45 kDa; therefore, all results reported here refer to this NaPi-IIb fragment. Mineral P renunciation did not affect NaPi-IIb fragment or TRPV6 expression in either hen strain. In LSL hens NaPi-IIb fragment expression increased from wk 19 to wk 24, whereas in LB hens it remained unchanged. NaPi-IIb fragment expression was positively associated with duodenal phosphatase activity and plasma estradiol. TRPV6 expression tended to reduce in LB hens from wk 19 to wk 24, but remained stable in LSL hens. TRPV6 expression was positively associated with duodeno-jejunal P content. MI supplementation upregulated NaPi-IIb fragment expression in LB, but downregulated it in LSL hens with high dietary MI levels, without affecting TRPV6. These findings demonstrate strain-dependent regulatory patterns of duodenal expression of NaPi-IIb fragment and TRPV6 in response to physiological stage and MI supply, indicating that mineral feeding strategies may benefit from genotype-specific consideration, whereas the mechanisms underlying MI-related effects require further clarification.
Genomic landscape of high‐altitude adaptation in East African mountain honey bees (Apis mellifera)
(2025) Mazzoni, Marco; Loidolt, Florian; Kersten, Sonja; Amulen, Deborah Ruth; Vudriko, Patrick; Meyer, Philipp; Scharnhorst, Victor Sebastian; Scheiner, Ricarda; Hasselmann, Martin
Understanding the evolutionary processes leading to differentiation within species is a central goal in population biology. A key process is local adaptation, for which organisms evolve traits enhancing the survival and reproduction in specific environments. Honey bees ( Apis mellifera ) in East Africa are well adapted to highland environments, showing different phenotypes, including behavior, compared to lowland bees. Despite these differences, highland and lowland honey bees show very low genetic differentiation, with the exception of two segments on chromosome 7 (r7) and chromosome 9 (r9), which were previously identified as chromosomal inversions. These inversions are rare in lowland populations, suggesting a key role in adaptation to high‐elevation habitats. In this study, we obtained 24 whole genomes from honey bees of Western Uganda and compared these with existing data from Kenya. We show that the chromosomal inversions play a pivotal role in local adaptation in both regions but with substantial differentiation. Genome‐wide analysis of polymorphism revealed additional genomic regions potentially involved in high‐altitude adaptation. The acquisition of transcriptome data from highland and lowland honey bees in Uganda has enabled the first insights into the differential expression of genes between these bees. Our findings elucidate the involvement of genes in behavioral and oxygen consumption processes. This paves the way to clarify the interplay of r7 and r9 with gene expression and to unravel the regulatory network underlying A. mellifera adaptation to high‐elevation habitats. Our study will contribute to a better understanding of the evolutionary processes in honey bee populations driven by environmental conditions.
Monomorium dine sp. nov. (Hymenoptera, Formicidae): a new inquiline social parasite ant species from North America
(2025) Cover, Stefan P.; Rabeling, Christian
Among the very rarest of Nearctic ants are three species of inquiline social parasites belonging to the genus Monomorium, namely Monomorium inquilinum DuBois, Monomorium pergandei (Emery), and Monomorium talbotae DuBois. All three species are known only from the type collections. Here, we describe Monomorium dine Cover & Rabeling, sp. nov., from the Navajo Nation in New Mexico, USA, a new species closely similar to the three known social parasites. Like them, M. dine appears to be a workerless inquiline that exploits a free-living Monomorium host. We also provide keys to the queens of the Nearctic Monomorium inquilines, provide the first images of these species, report new collections for Monomorium talbotae DuBois, discuss host-parasite associations, and summarize what is presently known about these mysterious social parasites.
Pathways for biodiversity enhancement in German agricultural landscapes
(2025) Sponagel, Christian; Thompson, Amibeth; Paetow, Hubertus; Mupepele, Anne‐Christine; Bieling, Claudia; Sommer, Martin; Klein, Alexandra‐Maria; Settele, Josef; Finger, Robert; Huber, Robert; Albert, Christian; Filser, Juliane; Jansen, Florian; Kleemann, Janina; Schreiner, Vera; Lakner, Sebastian
Conserving biodiversity, especially in agricultural landscapes, is a major societal challenge. Broad scientific evidence exists on the impacts of single drivers on biodiversity, such as the intensification of agriculture. However, halting biodiversity decline requires a systemic understanding of the interactions between multiple drivers, which has hardly been achieved so far. Selecting Germany as a case study, the goal of our analysis is (i) to understand how various socio‐economic drivers of biodiversity in agricultural landscapes interact at the national scale, (ii) to identify plausible pathways that most likely will lead to an improvement of biodiversity in agricultural landscapes and (iii) to discuss guiding principles for policy‐making based on the pathways. We applied the expert‐based Cross‐Impact‐Balance (CIB) methodology to the German agri‐food system (target year 2030). Seven descriptors that represent the most relevant socio‐economic drivers of biodiversity (here, we focus on species richness) in agricultural landscapes in Germany were defined. In three workshops with different groups of experts, we assessed all the interactions and impacts between these descriptors. From the workshops, seven overlapping scenarios were identified and aggregated into four main future pathways for enhancing biodiversity in agricultural landscapes. These pathways are: (1) ‘Innovation and stricter legislation’, (2) ‘Major change in protein production and CAP shift’, (3) ‘Major change in protein production and national legislation’ and (4) ‘Major social changes compensate for a lack of innovation in food production’. Socio‐economic drivers interact to varying degrees. Societal values have a strong active influence on the system, e. g. agricultural policy, whereas the orientation and objectives of agriculture, e. g. focus on public goods, are rather passively determined. Conserving biodiversity thus depends upon the evolution of societal values, European and national nature conservation and agricultural policies, innovations in plant and protein production as well as on global commodity markets. A key message for policymakers is that there are generally different, complementary options for achieving the objective of improving biodiversity. This is important when specific drivers such as the CAP cannot be steered in a particular desired direction.

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