Covariation of fluctuating asymmetry, herbivory and chemistry during birch leaf expansion

Abstract

Fluctuating asymmetry (FA) is used to describe developmental instability in bilateral structures. In trees, high FA of leaves has been assumed to indicate the level of environmental or genetic stress, and for herbivores leaves from such trees have been shown to be in some cases (though not invariably) of higher quality compared to trees with symmetrical leaves. We demonstrated that FA of birch leaves correlated positively with growth rate of leaves, and with the amount of leaf biomass consumed by larvae of the geometrid Epirrita autumnata. Since asymmetry per se cannot define leaf quality for a herbivore, we determined the biochemical compounds which covary with the degree of foliage FA, in order to elucidate relationships between leaf FA, chemistry and herbivory. High foliar FA was characteristic of birches with high initial concentrations, and rapid seasonal decline in the concentrations of gallic acid and hydrolysable tannins, and with rapid seasonal changes in the concentrations of flavonoid-glycosides and sugars. In contrast, leaf FA was not related to concentrations of proanthocyanidins, protein-bound amino acids or soluble phenylalanine, the precursor of proanthocyanidins and proteins with aromatic amino acids. The positive correlation between leaf FA and consumption by E. autumnata was presumably related to the previously demonstrated compensatory consumption of E. autumnata to high concentrations of foliar gallotannins. Furthermore, sugars are well-known feeding stimulants. We propose that the variable results in studies correlating leaf FA and herbivory may stem from variable chemical associations of FA in different plants and of species-specific effects of compounds on insects.

Fluctuating asymmetry and herbivory in two ontogenetical stages ofChamaecrista semaphorain restored and natural environments

“…While some studies show positive relationships (Møller 1995(Møller , 1996 2003; Stiling 2011, 2005), others show no relationship (Ban˜uelos et al 2004;Dı´az et al 2004;Telhado et al 2010). Differences in plant chemistry, plant age, environmental conditions, and enemy free-space have been suggested as possible causes for these differences (Lempa et al 2000;Cornelissen et al 2003;Ban˜uelos et al 2004;Cornelissen and Stiling 2005;Cuevas-Reyes et al 2011a, 2011b. Our results suggest that in both habitat conditions, symmetry of leaves did not change with the level of herbivory.…”

“…In some studies, leaf FA is positively related with the levels of herbivory suggesting that leaf FA serves as an indicator of plant stress as result of herbivore attack (e.g. Lempa et al 2000;Cuevas-Reyes et al 2011a), while in other studies no relationship has been found (Ban˜uelos et al 2004;Dı´az et al 2004;Telhado et al 2010). Differences in environmental conditions, enemy-free space, plant chemistry, and plant age have been suggested as possible causes for these differences (Ban˜uelos et al 2004;Cornelissen and Stiling 2005;Cornelissen et al 2003;Lempa et al 2000).…”

“…8, No. 2, 179Á186, http://dx.doi.org/10.1080/17429145.2012 # 2013 Taylor & Francis plant susceptibility to damage caused by herbivores (Lempa et al 2000;Cornelissen and Stiling 2005), in which plants with more asymmetric leaves should experience increased herbivory levels. The mechanism mediating such higher susceptibility of more asymmetrical plants is the higher nutritional quality of their leaves in comparison with symmetric leaves, suggesting that FA can also be used as an indicator of plant quality (Lempa et al 2000;Stiling 2005, 2011).…”

Efeito do herbicida chlorimuron-ethyl em biótipos resistente e suscetível de Euphorbia heterophylla

“…Em condições de estresse, como parasitismo e deficiências hídricas do ambiente, o crescimento dos limbos direito e esquerdo pode ser assimétrico (Lempa et al, 2000;Hódar, 2002). Os dados obtidos sugerem que a aplicação comercial (0,127 kg ha -1 ) de chlorimuron- Efeito do herbicida chlorimuron-ethyl em biótipos resistente e... ethyl pode provocar crescimento diferencial entre largura e comprimento da folhas de E. heterophylla.…”

Human–landscape interactions in the Conquezuela–Ambrona Valley (Soria, continental Iberia): From the early Neolithic land use to the origin of the current oak woodland

“…Nowadays, it is accepted that increased FA is related to genetic and environmental stress (Zakharov 1987;Parsons 1992;Clarke 1993;Graham et al 1993a;Markow 1994;Møller and Swaddle 1997) and poor individual quality (Møller and Pomiankowski 1993;Watson and Thornhill 1994;Markow 1995;Møller and Thornhill 1998). Several studies reported positive correlations between FA and insect herbivory (Møller 1995;Zvereva et al 1997;Martel et al 1999;Lempa et al 2000). Møller (1999b) presented evidence that FA of elm leaves (Ulmus glabra) reflects the susceptibility to disease as well as the negative effect of the disease on phenotypic development.…”