Figure 1.
Diagrammatic representation of the two hypotheses describing the mutualism mechanism and details of the study system.
(A) Indirect mutualism situation where the mutualism patches do not generate spatial reservoirs of the predator, and (B) direct mutualism situation, where the mutualism patches generate spatial reservoirs. Solid black lines indicate strong effects, and black dotted lines indicate weak effects. An arrow indicates a positive effect on the target organism, a circle indicates a negative effect on the target organism, and text size indicates relative population density. (C) The details of the study system, where bold lines refer to the generalized interactions and non-bold lines to the details of the particular study system. The direct effect (i.e., not trait-mediated) is that the ant either consumes sufficient honeydew to prevent sooty mold or removes the sooty mold directly. The indirect effect (i.e., trait-mediated) is the behavioral effect the ants have on the ability of the predator adults to lay eggs in the general area where the hemipteran pest is located and the ability of the predator adults to consume the hemipterans. The positive effect the ants have by protecting the larval predators against their parasitoids does not negate the negative effects the ant has on the adult predator through direct interference with its ability to eat and oviposit. The question as to whether the system is a direct mutualism (B) or an indirect mutualism (A) depends on the relative values of all the interactions in the system details (C).
Figure 2.
Example of digital photograph-based estimate of C. viridis population parameters.
(A) The area of census includes the leaf area and all veins, starting from the pedicel till the 5th secondary vein for the top and bottom of the abaxial surface of the leaf. (B) Close up of dashed rectangular area of leaf on day 7, where a crawler (c), nymph (n), adult (a), and ant are marked.
Table 1.
Estimated parameter values for Lefkovitch transitions and predation rates.
Figure 3.
Negative log-likelihood profiles.
Profiles for (A) the transition probabilities of crawler to nymph and (B) the mean adult fecundity for C. viridus. In both graphs, ‘ant-tended’ (solid curves) and ‘non-tended’ (dashed curves) populations are indicated. The vertical lines show the 95% confidence limits for the prediction of these probabilities calculated by the likelihood ratio test.