Ecology of the Mariposa Catalina lily


The coastal chaparral of southern California is the home of C. catalinae. Steep hills meet the sea in a zone which normally receives 10 to 20 inches of rain per year. In other words, this would be near-desert, except that the sea provides both cool air, thus lowering the temperature, and coastal fogs that give extra moisture. Almost all the rain falls between November and May, so the hottest months are also the dry months. Without the coastal fogs to mitigate the heat and dryness, many plants in the coastal chaparral could not survive.

The home of Catalina mariposas is also prime real estate in an area where that means tens, even hundreds, of millions of dollars. The pressures of real estate "development" have made this a rare species.



The steepness of the terrain and the sandiness of the soil mean that air flow is active and drainage is excellent.

The plants grow in exposed, sunny locations, which are nonetheless cool because of the good ventilation, and which are sheltered from the strongest winds.

Light frosts in winter, when the plants are dormant, do occur once every few years, so dormant bulbs can handle a couple of degrees of frost under dry conditions.


The chaparral has considerable variation in conditions on microscales. In this picture, the big white inflorescences of Yucca whipplei can be seen on the primarily south-facing side of this valley between two ridges, together with an opuntia cactus plant in the left foreground. The right, northern-facing side, is slightly cooler and wetter, and is also the type of area likelier to have catalina mariposas in it.

  A small area with numerous flowers besides catalina mariposas. The most obvious blue ones are blue-eyed grass (Sisyrhynchium bellum), which is actually in the iris family and is not a grass at all. The yellow flowers in the distance are members of the daisy family.  
  We've seen a number of different bees and beetles visiting the flowers of catalina mariposa lilies. However, especially early in the season, one species of bee (which I'm not enough of an entomologist to identify) positively camps at the base of the anthers with its head in the nectary. Many flowers have multiple bees, each sitting motionless on its own spot, as in the picture. They are unwilling to be disturbed even when the flower is tapped. This type of behavior is observed in some bees and orchids, when the flower is mimicking insect pheromones or is otherwise providing what amounts to a drug for the insect. The pheromone is easier for the plant to produce than "real" nectar containing sugar, so it gets pollinated while the bee wastes its time, although pleasantly so. Whether this is what is happening in C. catalinae, I don't know, but the behavior of the bees is most interesting.  


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