Genetics of Pitcher Plants:
Pitcher plants trap insects as a dietary supplement. Most of North America has a single pitcher plant species, Sarracenia purpurea, while the southeastern U.S. is home to 7 additional species, each with different pitcher morphologies. An additional complication is that hybrids frequently form between these species. We have generated F2 offspring from crosses between different Sarracenia species, and are studying the inheritance of pitcher morphology. It is possible to determine the insects that have entered the pitchers since their chitin is not digested. Hence, we can study the genetics of insect predation preference in the same F2 plants. The picture on the left is of a hybrid plant showing features of both parents, Sarracenia purpurea and Sarracenia psitticina.
We are currently preparing a large F2 population so that we can determine the genetic architecture underlying both the pitcher plant morphology and insectivorous traits. We have generated a number of molecular markers useful for both mapping and for population characterization.
Genetics of Community Ecology:
Sarracenia purpurea and S. rosea digest insects with the aide of a microbial food web which exists in fluids in the pitcher. This food web consists of 4-5 trophic layers, and has been considered as a model for a simple community ecology that can be experimentally manipulated to determine the ecological principles that underlie food webs. Other Sarracenia species have been reported to use a more active, enzymatic, digestion of trapped insects.
The F2 plants we have generated between Sarracenia purpurea and S. psitticina provide an opportunity to determine how genetic variation in the foundation species of a community affects the structure of that community. In this case we will study the types of food webs that are setup in the F2 recombinant pitchers. This approach should let us determine both the nature of the Sarracenia genetic traits that support the food web, and we can also determine what perturbations of the food web occur in the recombinant plants. This approach, sometimes referred to as "community genetics" should give unique insights into the factors and principles that govern the organisms that make up the food web community.
Sarracenia Wall Mural:
Photograph of a wall mural painted in the Malmberg lab by botanical illustrator Christie Newman.