Figure 2. Growth improvement conferred by Camponotus schmitzi to its host-plant Nepenthes bicalcarata.

While the total leaf area increased linearly with plant size for plants occupied by C. schmitzi (in blue), this was not the case for unoccupied plants. A common non-significant regression line was estimated for pitcher-bearing (green) and pitcher-lacking (red) unoccupied plants. Filled points are plants which have produced only lower pitchers; empty points are plants which have developed upper pitchers. 175cm is the size threshold at which occupied plants begin to enter the climbing phase. At this threshold, the total leaf area of occupied plants was estimated to be 2.9 times greater than that estimated for unoccupied plants; total leaf nitrogen content was estimated to be 3.3 times greater.