Effects of drought stress on oviposition preference and offspring performance of the lace bugCorythucha marmorataon its goldenrod host,Solidago altissima

Abstract

Stress and vigor are endpoints on a continuum of the suitability of plants for insect herbivores. Senescence-feeding insects, such as the chrysanthemum lace bug, Corythucha marmorata (Uhler) (Hemiptera: Tingidae, Tingitini), are hypothesized to benefit from any stressor hastening the senescence of plant tissues, such as drought. They are also hypothesized to prefer feeding and ovipositing on stressed plants, due to increased performance of themselves and their offspring. We conducted choice and no-choice field-cage experiments to test the effects of drought stress on the oviposition preference and nymph survival of C. marmorata on its goldenrod host, Solidago altissima L. (Asteraceae). We placed lace bugs on high-and low-water treatment plants, surveyed egg and nymph densities twice weekly, and at the end of the experiment, collected newly developed adults, weighed them, and determined their nitrogen concentration. Low-water treatment plants experienced decreased growth and increased leaf senescence. Lace bug nymphs had significantly greater survival, faster maturation, and higher adult mass on low-water treatment plants than on high-water treatment plants. We observed a non-significant, though consistent trend toward increased oviposition preference for lowwater treatment plants. Nitrogen concentrations of lace bugs did not differ by treatment, but lace bugs from low-water treatment plants contained more nitrogen in total due to their higher mass. These results suggest that lace bugs perform better on drought-stressed plants due to mobilization of structural nitrogen increasing the nutritional quality of stressed tissues.

Relative importance of drought, soil quality, and plant species in determining the strength of plant–herbivore interactions

“…Except for leaf toughness, this result may also be explained by a higher content of secondary metabolites in the drought-stressed plants (Prill et al, 2014). Drought-stress plants were also preferred by a range of other herbivore species (Meyer et al, 2006;Neto et al, 2012;Helmberger et al, 2016). The results on herbivore preference for watered plants, however, contrast with the results of Gutbrodt et al (2011), demonstrating that generalist S. littoralis preferred drought-stressed plants due to fewer secondary metabolites in these plants.…”

“…more secondary metabolites in drought-stressed plants, this may also mean that the effect of drought stress on the content of secondary metabolites depends on the plant species and/or metabolite studied. Drought-stress plants were also preferred by a range of other herbivore species (Meyer et al, 2006;Neto et al, 2012;Helmberger et al, 2016). Meyer et al (2006) suggested that this preference may be caused by higher concentrations of proline and non-structural carbohydrates in the leaves.…”

Disentangling herbivore impacts in primary succession by refocusing the plant stress and vigor hypotheses on phenology

“…Instead, analyses involving factors such as insect developmental stage and host tissue age, would provide a clearer picture of the overall usefulness of this unified plant stress/vigor hypothesis. Unfortunately, experimental tests typically do not include these factors in their design (for example, see Krugner et al 2009, Mody et al 2009, Paine and Hanlon 2010, Gutbrodt et al 2011, Simpson et al 2012, Tariq et al 2012, Banfield-Zanin and Leather 2015a, b, Couture et al 2015, Dardeau et al 2015, Brewer et al 2016, Helmberger et al 2016, Pineda et al 2016, Valim et al 2016, even though such elements are central to this unified hypothesis.…”

Environmentally triggered variability in the genetic variance–covariance of herbivory resistance of an exotic plantSolidago altissima

“…An alternative explanation for the difference in covariance of resistance on US plants in US and Japanese gardens is that difference in the lace bug phenology between locations may cause difference in plant quality caused by other insect herbivory. Helmberger, Craig, and Itami () reported that lace bugs perform better on drought‐stressed S. altissima due to mobilization of structural nitrogen increasing the nutritional quality of stressed tissues. In addition to drought stress, stress from early herbivory may positively affect lace bug performance, as early herbivory has been reported to increase nitrogen and increase herbivory by later herbivores (Danell & Huss‐Danell, ).…”

“…The reason why a positive genetic covariance was detected in US plants in US garden is unclear; however, since there were no differences in the G-matrices between plant origins within the US gardens it is unlikely that this positive value has ecological TA B L E 2 Observed scale G-matrices for resistance indices of S. altissima obtained from the 1,000 samples of posterior distribution of the MCMC analyses of (a) US plants in US gardens, (b) US plants in Japanese gardens, (c) Japanese plants in US gardens, and (d) An alternative explanation for the difference in covariance of resistance on US plants in US and Japanese gardens is that difference in the lace bug phenology between locations may cause difference in plant quality caused by other insect herbivory. Helmberger, Craig, and Itami (2016) reported that lace bugs perform better on droughtstressed S. altissima due to mobilization of structural nitrogen increasing the nutritional quality of stressed tissues. In addition to drought stress, stress from early herbivory may positively affect lace bug performance, as early herbivory has been reported to increase nitrogen and increase herbivory by later herbivores (Danell & Huss-Danell, 1985).…”