Kramer, Jos

Jos Kramer
Wissenschaftlicher Mitarbeiter

Curriculum Vitae


2013 – present

PhD-student; Johannes Gutenberg University Mainz

2006 - 2012

Diploma studies in Biology at the University of Freiburg, Germany with focus on Evolutionary Biology & Animal Ecology, Animal Behavior, Developmental Biology and Anthropology
Diploma Thesis: Das Aggressionsverhalten in Gruppen des kooperativ brütenden Orcessittichs (Pyrrhura orcesi) [Aggressive behavior in groups of the cooperatively breeding El-Oro-Parakeet (Pyrrhura orcesi)]


2011 – 2012

Ecuador; Thesis-related fieldwork in the reserve “Buenaventura”. Behavioral observation and trapping of group-living parakeets.

2010 – 2011

Australia; Internship at the University of Tasmania, travel funded by the DAAD (German Academic Exchange Service). Capture and radio-tracking of bats, collection of skinks, remote camera trapping.


Austria; Practical course in the national park „Neusiedler See“. Collection and identification of Ground beetles.


Germany; Ornithological excursion to the “Westhavelland”, Brandenburg.


France; Practical course in marine biology in Banyuls-sur-Mer. Characterization of swarming behavior in costal fish.


Germany; Internship in the “Biodiversity Exploratories” of the DFG (German Science Foundation). Assessment of the diversity of flowering plants.


2015 Talk: “Negative association between sibling cooperation and parental care in earwigs: a new perspective on the evolution of family life?” 15th Congress of the European Society for Evolutionary Biology (ESEB) in Lausanne, Switzerland


Talks: “Do not only rely on your mother - Food sharing among offspring of the European earwig (Forficula auricularia) as an unexplored evolutionary driver of family life“DZG evolutionary biology graduate meeting in Bremen, Germany & Ecology and Behavior meeting in Montpellier, France

Poster: “Maternal Presence under harsh environmental conditions: blessing or curse?” Annual Meeting of the German Zoological Society (DZG) in Göttingen, Germany

Soft Skills

2014 Workshop “Social evolution: merits and limitations of inclusive fitness theory” (Arolla, Switzerland; 3 days)
2014 Winter school “Linear mixed effect models and GLMM in R” (Tübingen, Germany; 5 days)
2013 Workshop "Presentation Skills" (2 days) Teaching


2015 Co-Supervision of a Master student

Co-Supervision of a Master student


Teaching assistant for undergraduates: Histology, Embryology and Anatomy of Vertebrates.

2008 & 2009

Teaching assistant for undergraduates: Zoological Species Identification.

Research Interests

Research Interests

Evolution of Social Life, Cooperation & Conflict

I am generally interested in the evolution of social life and the associated emergence of mechanisms promoting conflict resolution and cooperation within groups. The evolutionary transition from solitary life to group living generally requires that the inherent costs of group living (e.g. the increased competition and the higher rate of pathogen transmission) are counterbalanced by its benefits. Especially in advanced social systems, benefits of group living are often mediated by cooperative interactions between group members. Cooperation between group members is however always vulnerable to cheating and will only prevail as long as conflicts between interacting individuals do not lead to an overall negative cost-to-benefit ratio of cooperation. I am especially interested in how different factors (e.g. life-history traits, environmental conditions) influence the shift between open conflict and cooperation.


1. Sibling Cooperation and the early Evolution of Family Life

Cooperation between group members is a key feature of many advanced social systems and is especially likely to evolve if the members of a group are closely related. Families are groups of closely related kin and their members should thus frequently engage in cooperative interactions. However, research on family interactions has until recently been focused on intra-familial conflicts (parental antagonism, parent-offspring conflict, sibling rivalry) mediated by competitive behaviors. In contrast, the potential role of cooperation between siblings in a variety of (non eusocial) family groups has only recently received attention. Using the European Earwig Forficula auricularia as a model system, I will perform a combination of experimental manipulations and behavioral observations to investigate how cooperative interactions among siblings shape the cost-to-benefit ratio of group living. In this way, I hope to shed light on the potential role of sibling cooperation in the early evolution of family life.

2. Environmental Conditions, Life-History Traits and the early Evolution of Family Life

Environmental conditions are considered to be key parameters in the evolution of family life and associated life-history traits of family members. For example, limitations in the availability of essential resources (notably food) are common consequences of harsh environmental conditions and can influence the optimal amount of care parents should provide to their offspring. Life-history traits can furthermore also be influenced by conflicts between family members. To date, it remains unexplored whether and how much the effects of environmental conditions and conflicts between family members on family interactions are interrelated. In European Earwigs, the presence of the mother can become detrimental to her offspring under limited food conditions, possibly indicating an open mother-offspring conflict over food access under harsh environmental conditions. Using a series of cross-breeding and cross-fostering experiments, I will investigate to what extent this conflict over food access is shaping family life independent of or entangled with the influence of conflicts between family members.


Ratz T, Kramer J, Veuille M and Meunier J. The population determines whether and how life-history traits vary between reproductive events in an insect with maternal care. Oecologia, in press.

Kramer J and Meunier J. (2016) Kin and multilevel selection in social evolution: a never-ending controversy? F1000Research, 5 (F1000 Faculty Rev): 776.

Kramer J, Klauke N, Bauer M and Schaefer HM (2016) No evidence for enforced alloparental care in a cooperatively breeding parrot. Ethology, 122, 389-398.

Kramer J and Meunier J (2016) Maternal condition determines offspring behavior towards family members in the European earwig. Behavioral Ecology, 27, 494-500.

Thesing J*, Kramer J*, Koch LK and Meunier J (2015) Short-term benefits, but transgenerational costs of maternal loss in an insect with facultative maternal care. Proceedings of the Royal Society B: Biological Sciences. 282: 20151617. (* Authors contributed equally to the work)

Kramer J, Thesing J and Meunier J (2015) Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life? Journal of Evolutionary Biology. 28, 1299–1308.

Weiss C, Kramer J, Holländer K and Meunier J (2014) Influences of relatedness, food deprivation and sex on adult behaviors in the group-living insect Forficula auricularia. Ethology, 120, 923-932

Klauke N, Jansen J, Kramer J and Schaefer HM (2014) Food allocation rules vary with age and experience in a cooperatively breeding parrot. Behavioral Ecology and Sociobiology 68: 1037-1047.