Changes in leaf chlorophyll content associated with flowering and its role in the diversity of phytophagous insects in a tree species from a semiarid Caatinga

Abstract

Phytophagous insects choose their feeding resources according to their own requirements, but their feeding preferences in the semiarid Caatinga have rarely been studied. Flowering trees leads to a greater diversity of flower visitors and their predators in the host plant, but little is known about why the diversity of phytophagous insects not associated with flowers is also increased. The purpose of this study was to evaluate the diversity of sap-sucking, wood-boring and leaf-chewing insects associated with leaf chlorophyll content in flowering and non-flowering plants of Poincianella pyramidalis, an endemic tree of Caatinga. We used a leaf chlorophyll index (LCI) as a surrogate for resource quality, and an entomological umbrella to collect phytophagous insects. We show that trees which bloomed demonstrated higher chlorophyll content, greater abundance and a significant difference in the composition of phytophagous insect species when compared to non-flowering trees (p < 0.05). The results suggest that not only the presence of flowers themselves, but also the higher nutritional quality of leaf tissue, can explain the differences in species diversity and abundance of phytophagous insects. Exceptional flowering trees in the Caatinga area studied may thus act as spots of high quality resources, favouring changes in the diversity of insects in this environment.

Intraspecific interaction of host plant influences local distribution of specialist herbivores through metabolic alterations in leaves

“…After days, we measured chlorophyll content and five organic acids as plant nutrients (see details in Supplementary methods). The chlorophyll content reflects the plant's nitrogen concentration and has been found to indirectly affect herbivore survival and distribution (Scheirs & De Bruyn, 2004, Sousa-Souto et al, 2018. Also, organic acids in the plant are necessary for the optimal development of phytophagous insects (Offor, 2010).…”

Nest refuse of Acromyrmex balzani (Hymenoptera: Formicidae) increases the plant vigor in Turnera subulata (Turneraceae)

“…The relative chlorophyll content (RCC) in plant leaves is a powerful indicator of foliar nitrogen that may indicate plants with higher nutritional quality (Djumaeva et al, 2012; Sousa-Souto et al, 2018). The RCC was determined with the aid of a chlorophyll meter (ChlorofiLOG ® model CFL 1030) that provides measurements of the contents of chlorophyll a, b and total (a + b), expressed in RCC units (Barbieri-Junior et al, 2012;Sousa-Souto et al, 2018). Since there were no variations in the proportions of chlorophyll a and b, we considered for analysis only the total chlorophyll content.…”

“…For the RCC samples, the first three leaves of each plant were evaluated. Measurements were made on the median adaxial part of each of the three leaves of the plant, according to the methodology described in Barbieri-Junior et al (2012) and Sousa-Souto et al (2018). Only mature leaves were evaluated, without signs of senescence, signs of predation or presence of pathogens.…”

The universal “bottom‐up” limitation of animal populations by their food is illustrated by outbreaking species

“…What looks like a sea of edible and nutritious foliage is nonetheless of such poor quality that it cannot support the survival and growth of a large population. They benefit, however, when the concentration of soluble nitrogenous nutrients increase either when trees are stressed (White, ) or once these nutrients accumulate to a level where the host plants can flower and set a mast seeding (Haynes et al, ; Sousa‐Souto, Bocchiglieri, Dias, Ferreira, & José Filho, ).…”