https://hdl.handle.net/20.500.11811/631 Fri, 10 Apr 2026 21:45:14 GMT 2026-04-10T21:45:14Z https://hdl.handle.net/20.500.11811/10615 Intrasexual selection: Kin competition increases male-male territorial aggression in a monogamous cichlid fish Vitt, Simon; Hiller, Jenny; Thünken, Timo During intrasexual competition, individuals of the same sex compete for access to breeding sites and mating partners, often accompanied by aggressive behavior. Kin selection theory predicts different kin-directed social interactions ranging from cooperation to aggression depending on the context and the resource in question. Kin competition reducing indirect fitness might be avoided by actively expelling relatives from territories and by showing higher aggression against kin. The West-African cichlid Pelvicachromis taeniatus is a monogamous cave breeder with males occupying and defending breeding sites against rivals. This species is capable of kin recognition and shows kin-preference during juvenile shoaling and mate choice. However, subadults of P. taeniatus seem to avoid the proximity of same-sex kin. In the present study, we examined territorial aggression of territory holders against intruding related and unrelated males as well as intruder's behavior. We observed higher aggression among related competitors suggesting that related males are less tolerated as neighbors. Avoidance of intrasexual competition with relatives might increase indirect fitness of males in monogamous species. Sat, 12 Sep 2020 00:00:00 GMT https://hdl.handle.net/20.500.11811/10615 2020-09-12T00:00:00Z https://hdl.handle.net/20.500.11811/10548 Population size estimates based on the frequency of genetically assigned parent–offspring pairs within a subsample Müller, Björn; Mercker, Moritz; Brün, Jörg Estimating population density as precise as possible is a key premise for managing wild animal species. This can be a challenging task if the species in question is elusive or, due to high quantities, hard to count. We present a new, mathematically derived estimator for population size, where the estimation is based solely on the frequency of genetically assigned parent–offspring pairs within a subsample of an ungulate population. By use of molecular markers like microsatellites, the number of these parent–offspring pairs can be determined. The study's aim was to clarify whether a classical capture–mark–recapture (CMR) method can be adapted or extended by this genetic element to a genetic-based capture–mark–recapture (g-CMR). We numerically validate the presented estimator (and corresponding variance estimates) and provide the R-code for the computation of estimates of population size including confidence intervals. The presented method provides a new framework to precisely estimate population size based on the genetic analysis of a one-time subsample. This is especially of value where traditional CMR methods or other DNA-based (fecal or hair) capture–recapture methods fail or are too difficult to apply. The DNA source used is basically irrelevant, but in the present case the sampling of an annual hunting bag is to serve as data basis. In addition to the high quality of muscle tissue samples, hunting bags provide additional and essential information for wildlife management practices, such as age, weight, or sex. In cases where a g-CMR method is ecologically and hunting-wise appropriate, it enables a wide applicability, also through its species-independent use. Fri, 24 Jul 2020 00:00:00 GMT https://hdl.handle.net/20.500.11811/10548 2020-07-24T00:00:00Z