Dr. Franziska Lemmel-Schädelin

Konrad-Lorenz-Institut für Vergleichende Verhaltensforschung
Department für Integrative Biologie und Evolution
Veterinärmedizinische Universität Wien
Savoyenstr. 1a
A-1160 Wien

T +43 (1) 25077 7354
F +43 (1) 25077 94 7354

E-Mail an Franziska Schädelin senden [Link 1]

Research interests

  • Cooperation
  • Sexual selection
  • Mating systems evolution
  • Parental care and adoption
  • Colony formation
  • Extended phenotypes/ Animal architecture
  • Public information

Current Project

FWF-Project: Ecological constraints of fish breeding systems. 01.02.2015-31.01.2018 (grant #P27461 [Link 2])

Inducing cooperative breeding: ecological constraints and flexibility of fish breeding systems: The widespread occurrence of animals caring for unrelated young has challenged evolutionary biologists for decades. Cooperative breeding, in which subordinate, mature individuals delay their own reproduction to care for the offspring of others, is one of the most extreme examples of alloparental care. A major explanation of why helpers care for the offspring of others is the ecological constraints model which proposes that helping behavior is an adaption to shortages of resources such as breeding territories and mates.

The ecological constraints approach has also been used to explain polygyny, another breeding strategy enigma in species where both sexes provide parental care. The question is why some females choose to share a male’s parental effort with other females when they could receive the full effort of one male. The ability of males to monopolize the resources needed to attract multiple females should be determined by the distribution of those resources.

Although the ecological constraints approach has been useful in studying cooperative breeding and polygyny, we continue to lack a comprehensive framework for explaining these phenomena. In this project we propose to manipulate ecological factors and hormones to attempt to induce cooperative breeding and polygyny in a non-cooperative, monogamous fish. We will perform parallel experiments with a congeneric, sympatric species that is both cooperative and polygynous. Our experiments are designed to sequentially determine key factors that permit or constrain the two breeding systems. If we are able to induce cooperative breeding, our experiments may produce the strongest evidence yet of the influence of particular ecological constraints on breeding systems.

Past Projects

FWF-Project: Mechanisms of breeding aggregations in fish. 01.05.2008-30.04.2013 (grant #P20401 [Link 3])

The question of why many animals breed in crowded colonies has vexed ecologists for decades. Colonies are aggregations of breeding sites used only to raise offspring. The most venerable hypothesis, arising in the 1930’s, is that colonial animals benefit from high density breeding by finding safety from predators in dense groups.  Although this idea has been examined throughout the history of the field, surprisingly, there have been no studies that have experimentally manipulated the formation of colonies. One reason for this gap is that the predominant study animals – birds – are not conducive to such experiments. We side-stepped this constraint by setting up fish colonies in our institute’s giant 16,000 liter ring-shaped aquarium. We introduced 16 males and 16 females of our study species, Neolamprologus caudopunctatus, into the tank and allowed them to pair up, build nests and lay eggs.  Over a 2-year period, we observed the formation of 14 colonies, with alternative colonies having predators or no predators present in the tank. We found that breeders aggregated their nests at significantly higher densities when predators were present, making this the first study to experimentally demonstrate that predation can drive colony formation.

We combined such aquarium experiments with field research in which our team studied N. caudopunctatus in their native Lake Tanganyika in Africa. By mapping the nests and obtaining DNA samples from families in a colony of 126 nests, we obtained substantial new knowledge about the behavior of this colonial species. After performing DNA analyses in our institute’s genetics lab to determine the relatedness of individual fish to each other, we discovered that there were no extra-pair fertilizations. This means, that in contrast to most socially monogamous bird species, ‘adulterous’ matings apparently do not occur wherein the female of the pair produces offspring that were fathered by an outside male. Instead, our DNA analyses revealed the common occurrence of apparent adoption. We found that most broods were a mixture of natal fry that were produced by both parents and foreign fry that were unrelated to both ‘parents’. For the first time in a study of adoption, we were able to genetically match a number (12) of foreign fry to their actual parents, and in several cases, the distances between the birth and foster nests were so far (maximum >40 meters) as to make it virtually inconceivable that tiny juveniles could have traversed them without being predated by numerous predators surrounding the colony. In human terms, it would be like a toddler crossing a busy city on its own without mishap. Further analyses led to evidence that these fry were carried in the mouths of their parents (which occurs in this species) and deposited into other nests, where adoptive parents apparently allowed the unrelated fry to mix with their own. Such unselfish behavior appears to be a Darwinian paradox (i.e. organisms are expected to maximize their own reproductive success, and would obtain zero evolutionary fitness by raising unrelated young).  However, there is an adaptive explanation for adoption, namely that one’s own offspring are less likely to be predated in a larger group.  Thus our adoption study adds to the evidence of our colony formation experiment that predation may be a driving force of coloniality, to which animals evolve multiple behavioral adaptations.

 

FWF-Project: Habitat selection and male mating success in a colonial fish. 01.03.2005-01.03.2008 (grant #P17468 [Link 4] to Dr. Richard Wagner)

In collaboration with Dr. R. Wagner I address the role of sexual selection in the formation of colonies. The hidden lek hypothesis suggests that the same mechanism responsible for lek formation could lead to the formation of colonies (Wagner 1993, Danchin & Wagner 1997, Hoi-Leitner & Hoi 1997, Tarof 2005, Etterson 2003). To investigate this experimentally, we focus on breeding aggregations of fishes. We manipulate the environmental and social conditions in aquaria experiments to identify the process leading to the aggregation of fish breeding sites.

Colonial breeding is prevalent in the animal kingdom yet the phenomenon is not well understood. The goal of this project is to identify mechanisms that produce breeding aggregations of sheepshead minnows Cyprinodon variegatus, a small freshwater fish in which males often form breeding colonies that females visit for matings. We will apply models that have been developed to explain leks - in which males aggregate in display territories and do not provide parental care - to colonial fishes in which males defend breeding territories and do provide parental care. Our first set of experiments will determine whether any of three models of lek formation can contribute to colony formation and distinguish between the relative power of the models to generate aggregations of male breeding territories. We will then observe the creation of colonies under controlled conditions to determine whether the behavior performed by individuals in our first experiments are replicated when males are permitted to settle in aquariums large enough to resemble natural conditions. These experiments will culminate in the use of microsatellite markers to measure actual male fertilization success in relation to the parameters predicted by the lek models. These experiments will set the stage for future studies that integrate sexual selection with classical costs and benefits of high density breeding. If we can demonstrate that sexual selection affects habitat selection by parentally caring males our results may have broad ramifications for the habitat requirements of territorial animals.

Curriculum Vitae

Education

  • 2015-present: Principal Investigator, Austrian Science Fund (FWF) Konrad Lorenz Institute of Ethology
  • 2008-2014: Co- Principal Investigator, Austrian Science Fund (FWF) Konrad Lorenz Institute of Ethology
  • 2005-2008: Post-doc, KLIVV, Vienna, Austria
  • 2001-2004: PhD in Bern, Switzerland
  • Okt. 2000: M.Sc. Basel, Switzerland
  • 1999-2000: University Leiden, EEW, the Netherlands
  • 1997: TBA course in Kibale forest, Uganda held by the Tropical Biology Association
  • 1994-1999: Study biology I in Basel, Switzerland
  • 1994 Matura degree (mathematical focus) in Basel, Switzerland

Publications

Publikationen [Link 5]

  

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