@article{GrafePreiningerSztatecsnyetal.2012,
  author    = {Grafe, T. Ulmar and Preininger, Doris and Sztatecsny, Marc and Kasah, Rosli and Dehling, J. Maximilian and Proksch, Sebastian and H{\"o}dl, Walter},
  title     = {Multimodal Communication in a Noisy Environment: A Case Study of the Bornean Rock Frog Staurois parvus},
  series = {PLoS One},
  volume    = {7},
  journal   = {PLoS One},
  number    = {5},
  doi       = {10.1371/journal.pone.0037965},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133718},
  year      = {2012},
  abstract  = {High background noise is an impediment to signal detection and perception. We report the use of multiple solutions to improve signal perception in the acoustic and visual modality by the Bornean rock frog, Staurois parvus. We discovered that vocal communication was not impaired by continuous abiotic background noise characterised by fast-flowing water. Males modified amplitude, pitch, repetition rate and duration of notes within their advertisement call. The difference in sound pressure between advertisement calls and background noise at the call dominant frequency of 5578 Hz was 8 dB, a difference sufficient for receiver detection. In addition, males used several visual signals to communicate with conspecifics with foot flagging and foot flashing being the most common and conspicuous visual displays, followed by arm waving, upright posture, crouching, and an open-mouth display. We used acoustic playback experiments to test the efficacy-based alerting signal hypothesis of multimodal communication. In support of the alerting hypothesis, we found that acoustic signals and foot flagging are functionally linked with advertisement calling preceding foot flagging. We conclude that S. parvus has solved the problem of continuous broadband low-frequency noise by both modifying its advertisement call in multiple ways and by using numerous visual signals. This is the first example of a frog using multiple acoustic and visual solutions to communicate in an environment characterised by continuous noise.},
  language  = {en}
}
@article{ScharmannThornhamGrafeetal.2013,
  author    = {Scharmann, Mathias and Thornham, Daniel G. and Grafe, T. Ulmar and Federle, Walter},
  title     = {A Novel Type of Nutritional Ant-Plant Interaction: Ant Partners of Carnivorous Pitcher Plants Prevent Nutrient Export by Dipteran Pitcher Infauna},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {5},
  doi       = {10.1371/journal.pone.0063556},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130952},
  pages     = {e63556},
  year      = {2013},
  abstract  = {Many plants combat herbivore and pathogen attack indirectly by attracting predators of their herbivores. Here we describe a novel type of insect-plant interaction where a carnivorous plant uses such an indirect defence to prevent nutrient loss to kleptoparasites. The ant Camponotus schmitzi is an obligate inhabitant of the carnivorous pitcher plant Nepenthes bicalcarata in Borneo. It has recently been suggested that this ant-plant interaction is a nutritional mutualism, but the detailed mechanisms and the origin of the ant-derived nutrient supply have remained unexplained. We confirm that N. bicalcarata host plant leaves naturally have an elevated \(^{15}N/^{14}N\) stable isotope abundance ratio (\(\delta ^{15}N\)) when colonised by C. schmitzi. This indicates that a higher proportion of the plants' nitrogen is insect-derived when C. schmitzi ants are present (ca. 100\%, vs. 77\% in uncolonised plants) and that more nitrogen is available to them. We demonstrated direct flux of nutrients from the ants to the host plant in a \(^{15}N\) pulse-chase experiment. As C. schmitzi ants only feed on nectar and pitcher contents of their host, the elevated foliar \(\delta ^{15}N\) cannot be explained by classic ant-feeding (myrmecotrophy) but must originate from a higher efficiency of the pitcher traps. We discovered that C. schmitzi ants not only increase the pitchers' capture efficiency by keeping the pitchers' trapping surfaces clean, but they also reduce nutrient loss from the pitchers by predating dipteran pitcher inhabitants (infauna). Consequently, nutrients the pitchers would have otherwise lost via emerging flies become available as ant colony waste. The plants' prey is therefore conserved by the ants. The interaction between C. schmitzi, N. bicalcarata and dipteran pitcher infauna represents a new type of mutualism where animals mitigate the damage by nutrient thieves to a plant.},
  language  = {en}
}
@article{GrafeSchmuckLinsenmair1992,
  author    = {Grafe, T. Ulmar and Schmuck, Richard and Linsenmair, Karl Eduard},
  title     = {Reproductive energetics of the African Reed Frogs, Hyperolius viridiflavus and Hyperolius marmoratus},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31187},
  year      = {1992},
  abstract  = {No abstract available},
  language  = {en}
}