OBSERVATIONAL AND EXPERIMENTAL-STUDY OF A CARNIVOROUS PLANT - ANT KLEPTOBIOTIC INTERACTION

I analyzed the characteristics of prey robbed by ants (Formica fusca group) from an endemic carnivorous plant (Pinguicula nevadense) of Sierra Nevada (southern Spain). The kleptobiotic interaction could be tested by detailed observations of ants when they searched for food near the plants. I observed a total of 60 ants stealing prey. Ants selectively steal the larger prey, which numerically represents a small fraction of the total prey. Ants also prefer to rob recently captured prey which do not show any signs of damage by the digestion of the plant. To quantify experimentally the rate of prey robbery, I put individuals of Drosophila melanogaster on labelled leaves. Forty seven % of the flies initially placed were robbed in the first 24 h in the site where ants occur. Extraction success depends on the position of the flies on the leaf. The curling movement of the leaves makes the detection and extraction of prey by the ants difficult. The quick extraction of the bigger prey could represent a strong limitation for the plant, as this kleptoparasitic interaction appears during the whole short growth and flowering period of this carnivorous plant.