Sabine Frohschammer

Institute of Evolution, Behaviour & Genetics
Biology I
University of Regensburg
D-93040 Regensburg
Phone +49 941 943 1677


Comparative analysis of reproductive tactics in Cardiocondyla males

The ant genus Cardiocondyla is exceptional in that it exhibits a large diversity of male reproductive tactics. Whereas in many other ants, mating takes place during a short and highly localized nuptial flight, Cardiocondyla sexuals usually mate inside the nest. The resulting seraglio situation, which allows individual males to monopolize mating with all female sexuals, has resulted in the evolution of unique, wingless fighter males. In some species of Cardiocondyla, such “ergatoid males” have fully replaced the ancestral winged males, while in other species both male types co-occur. Ergatoid males of most species kill all freshly eclosing ergatoid rivals and, in a few species, also adult competitors, using their strong mandibles. However, in particular in species from xeric environments several ergatoid males may peacefully coexist in a nest.
We investigate various aspects of life history evolution and reproductive tactics in this genus Cardiocondyla. In my project I performed experiments on Cardiocondyla venustula, a species in which males show a surprising novel strategy: many of them defend “home ranges” within the nest against other males. In addition, I investigate the morphology of male genitals, as they likely reflect the astonishing diversity of fighting and mating tactics. Finally, I study benefits and costs of inbreeding, which very frequent occurs in Cardiocondyla by conducting crossing experiments.

Cardiocondyla venustula- a new male mating strategy

C.venustula male

experimental nest

C.venustula is an originally african species introduced to Florida, the Caribbean Islands and Hawaii. In the polygyn species only ergatois males are known. Cardiocondyla venustula ergatoid males display a mixture of strategies familiar from other species. They also engage in fights that -against freshly eclosing rivals- may end deathly for the jounger male. Adult males however show a novel strategy: they tend to establish “home ranges” which they defend against other opponents. I did first observations and experiments on this novel strategy.

Morphology of male genitals




Different male mating strategies may aquire different male genitals. I will compare male genitals from Caridiocondyla species with varying mating strategies. Data will be also valuable for the full description of Cardiocondyla male morphology.

Inbreeding- costs and benefits

C.kagutsuchi  male

Inbreeding in Cardiocondyla is quite frequent as in several species sexuals mate inside the nest and colony disperses through budding.
I conducted crossing experiments with sexuals of Cardiocondyla kagutsuchi  from different populations (Hawaii, Kauai, Okinawa) and compared founding success and longevity of queens and offspring sex ratio between inbred and outbred colonies.


10.1997 - 10.2000
Study of Biology at the University of Regensburg

10.2000 - 06. 2001
Study of Biology at the University of Würzburg

08.2001 - 08. 2002
Exchange study at the Universidad de Costa Rica (UCR), Costa Rica

08.2002 -  07.2004
Study of Biology at the University of Würzburg

07.2004 - 07. 2005
Diploma thesis
Comparative investigation of resource supply of two ant plants  and their effect
on specific ant partners

12.2005 - 08.2006
work as scientific assistent at the University of Regensburg

PhD thesis at the department of Prof. Jürgen Heinze; University of Regensburg

Topic: Comparative analysis of different mating tactics in Cardiocondyla males