Winkler, Lennart

Tribolium Lab – Janicke & Winkler

WinklerI am PhD student, supervised by Tim Janicke and Klaus Reinhardt.
My project examines how sexual selection is aligned with natural selection. We aim to investigate the influence of sexual selection on the capacities for adaption of species to novel environments and its influence on population fitness. Theory predicts that by reducing the frequency of deleterious mutations / mutation load, sexual selection might increase overall population fitness, while for example sexual conflict might reduce it. In this project we will (amongst other techniques) apply meta-analyses and experimental evolution (using the model system Tribolium castaneum) to test these hypotheses.

Some current interests are: Sexual selection, sperm competition, selfish genetic elements, genic capture, plasticity


  • Winkler L & Lindholm AK. A meiotic driver alters sperm form and function in house mice : a possible example of spite. Chromosome Res. 2022;(0123456789).
  • Winkler L, Moiron M, Morrow EH, Janicke T. Stronger net selection on males across animals. eLife. Nov 17, 2021
  • Winkler L, Lindholm AK, Ramm SA, Sutter A. The baculum affects paternity success of first but not second males in house mouse sperm competition. BMC Ecol Evol. 2021;21(159).
  • Carlitz, E. H. D. et al. Steroid hormones in hair reveal sexual maturity and competition in wild house mice (Mus musculus domesticus). Sci. Rep. 9, 1–10 (2019).
  • Winkler, L., Kirch, L. M., Reinhold, K. & Ramm, S. A. Impact of low sperm competition on male reproductive trait allometries in a bush-cricket. BMC Evol. Biol. 19, 185 (2019).
  • Winkler, L. & Ramm, S. A. Experimental evidence for reduced male allocation under selfing in a simultaneously hermaphroditic animal. Biol. Lett. 14, (2018).

Building BIO Room 257
Twitter: @lennarthamburg

Current students:
Johanna Kaidel (MSc Student) – Thesis on ‘Genitalia morphology in the red flour beetle’


Ronja Eilhardt (BSc Student) – Thesis: ‘Impact of population density on sexual selection in the red flour beetle’
Emma Markwardt (BSc Student) – Thesis: Sex-specific genetic variance under heat stress in the red flour beetle’
Birte Martens (BSc Student) – Thesis: ‘No Evidence for Benefits of Same-Sex Copulations in Red Flour Beetles

BSc and MSc projects in the Tribolium lab

We are happy to host projects and/or theses. If you are interested in joining our team, please get in contact.Tribolium_Research_lable_Mina_2020

Evolutionary and behavioural biology

Supervisor: Dr. Tim Janicke, Lennart Winkler (BIO Room 257)
Study organism: red flour beetle Tribolium castaneum
Project start: From summer 2022

Strategic sperm allocation in the red flour beetle

Not only females but also males are expected to allocate their gametes prudently. Sexual selection theory predicts that males should adjust the number of transferred sperm in response to the risk of sperm competition. In T. castaneum males transfer a spermatophore to the female, containing sperm and seminal fluid (Qazi et al. 2015). It has been shown that the spermatophore is apparently only filled with sperm by the male, after the spermatophore is already transferred to the female (Fedina 2007). This might enable males to plastically adjust the amount of transferred sperm during mating. We might test the hypothesis of plastic sperm allocation in response to sperm competition by comparing the number of transferred sperm between virgin and mated females or between females of different size. This project requires preliminary experiments to establish a protocol to quantify the amount of sperm transferred to a female. The project would involve observation of mating behaviour and sperm microscopy techniques.


Fedina TY. 2007. Cryptic female choice during spermatophore transfer in Tribolium castaneum (Coleoptera: Tenebrionidae). J Insect Physiol. 53(1):93–98.

Qazi MCB, Herbeck JT, Lewis SM. 2015. Mechanisms of Sperm Transfer and Storage in the Red Flour Beetle ( Coleoptera : Tenebrionidae ). Ann Entomol Soc Am. 89(6):892–897.