Insect folivory in Didymopanax vinosum (Apiaceae) in a vegetation mosaic of Brazilian cerrado

Abstract

Susceptibility of Didymopanax vinosum (Apiaceae) to insect herbivores was investigated in three sites of a cerrado mosaic -composed of campo cerrado (a grassland with scattered trees and shrubs), cerradão (a tall woodland) and cerrado sensu stricto (intermediate between the two) -situated in Cerrado Pé-deGigante, Santa Rita do Passa Quatro, SP, Brazil. We also examined the relationship of folivory with the composition and abundance of the insect herbivore fauna, and with several nutritional and defensive plant characteristics (water, nitrogen, cellulose, lignin, tannin leaf contents, and leaf toughness). We collected insects associated with D. vinosum every month, and we measured leaf damage every three months. In general, the annual folivory differed among sites. It reached the highest rates in site 1 and site 3: 7.33 and 8.5 percent, respectively. Only 1.32 percent of annual folivory was observed in site 2. These levels resulted from the higher abundance, in sites 1 and 3, of the thrips Liothrips didymopanacis (Phlaeothripidae), the most abundant herbivore sampled, responsible for more than 90 percent of the observed damage. However, no significant relationship was found between insect activity and the chemical and physical composition of the leaves. Our findings suggest that, at least in this species, other chemical compounds or variables related to plant apparency and resource availability to herbivores (e.g. plant architecture) might play a more decisive role in the spatial variation of folivory than the nutritional and defensive traits that were analyzed.Keywords: cerrado, Didymopanax vinosum, folivory, herbivory, plant defenses. RESUMO Folivoria por insetos em Didymopanax vinosum (Apiaceae) em um mosaico de vegetação no cerrado brasileiroA susceptibilidade de Didymopanax vinosum (Apiaceae) a insetos herbívoros foi investigada em três localidades de um mosaico de cerrado -composto de campo cerrado, cerrado sensu stricto e cerradão -localizado no Cerrado Pé-de-Gigante, Santa Rita do Passa Quatro, SP, Brasil. Nosso objetivo foi também relacionar a folivoria com a composição e abundância da fauna de insetos herbívoros, e com várias características nutritivas e defensivas da planta (conteúdo foliar de água, nitrogênio, celulose, lignina, taninos e dureza foliar). Para tanto, coletamos mensalmente os insetos associados a D. vinosum e a cada três meses medimos as injúrias foliares. De modo geral, a herbivoria anual variou entre as localidades. Os maiores valores foram encontrados em plantas da localidade 1 e localidade 3: 7,33 e 8,5 por cento, aproximadamente, contra apenas 1,32 por cento na localidade 2. Esses níveis são resultado da maior abundância, nas localidades 1 e 3, do trips Liothrips didymopanacis (Phlaeothripidae), o principal herbívoro amostrado, responsável por mais de 90% das injúrias observadas. Entretanto, não se encontrou relação entre a atividade desses insetos e a composição química e física das folhas. Nossos resultados indicam que, ao menos para esta espécie, outros compostos químico...

Herbivory on Handroanthus ochraceus (Bignoniaceae) along a successional gradient in a tropical dry forest

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Canopy Herbivory and Insect Herbivore Diversity in a Dry Forest–Savanna Transition in Brazil

“…For the Cerrado, Marquis et al (2001) found annual cumulative herbivory rates of 6.59 percent for 25 different plants species (10 trees, 10 shrubs and 5 herbs). Also, Ribeiro (2003) reported annual rates of leaf area loss of 18 percent for Tabebuia (Bignoniaceae), and Varanda and Pais (2006) found rates of 1.3-8.5 percent in Didymopanax vinosum (Apiaceae) in the Brazilian Cerrado. However, it is important to stress that studies performing discrete herbivory measurements can underestimate the levels of leaf damage up to five times (average discrepancy quotient of 2.5), when compared with studies conducting long-term observations (Lowman 1984).…”

Herbivoria e biomassa foliar em Peltogyne confertiflora (Mart. ex Hayne) Benth. Fabales Bromhead Fabaceae Lindl. em ambientes de Floresta e Cerrado

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