Evidence for competition and cooperation among climbing plants

Abstract

A plant's best strategy for acquiring resources may often depend on the identity of neighbours. Here, I ask whether plants adjust their strategy to local relatedness: individuals may cooperate (reduce competitiveness) with kin but compete relatively intensely with non-kin. In a greenhouse experiment with Ipomoea hederacea, neighbouring siblings from the same inbred line were relatively uniform in height; groups of mixed lines, however, were increasingly variable as their mean height increased. The reproductive yield of mixed and sibling groups was similar overall, but when adjusted to a common mean height and height inequality, the yield of mixed groups was significantly less. Where this difference in yield was most pronounced (among groups that varied most in height), mixed groups tended to allocate more mass to roots than comparable sibling groups, and overall, mixed groups produced significantly fewer seeds per unit mass of roots. These results suggest that, from the group perspective, non-kin may have wasted resources in below-ground competition at the expense of reproduction; kin groups, on the other hand, displayed the relative efficiency that is expected of reduced competitiveness.

Intraspecific genetic variation and species coexistence in plant communities

“…Genetically similar plants are expected to also be similar in resource requirements, and competition with kin should therefore be stronger than with non-kin. However, some species exhibit a kind of kin-facilitation where plants reduce their competitive effects towards kin relative to unrelated conspecifics [38,39]. With kin-facilitation, individuals perform better when interacting with kin compared with a non-related conspecific.…”

Kin selection or resource partitioning for growing with siblings: implications from measurements of nitrogen uptake

“…3 and 4). However, two theories (i.e., kin selection and resource partitioning) cannot fully explain the cooperation and competition (Chu et al 2008;Biernaskie 2011) between the siblings of these two crop species.…”

Fitness consequences of plants growing with siblings: reconciling kin selection, niche partitioning and competitive ability

“…Fitness measures are confounded if multiple processes of niche partitioning, kin selection and competitive ability [30] can co-occur. Credible evidence for their co-occurrence has been found in morning glory [37]. In this study, three inbred lines were grown in sibling and stranger groups, and measures of morphology, allocation and fitness were made at harvest.…”

“…The finding of plant kin recognition has renewed interest in the fitness consequences of sibling competition [24,30,37,46], including three new group studies [24,30,37], discussion of whether group studies should accompany kin recognition studies [24,46] and a critique of the group study methodology [30]. But rather than carrying out more group studies, we advocate that researchers must measure how the traits of individuals and their neighbours affect fitness.…”