Experimental demography and the vital rates of generalist and specialist insect herbivores on native and novel host plants

Carlos García-Robledo, Carol C Horvitz

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Colonization success of species when confronted with novel environments is of interest in ecological, evolutionary and conservation contexts. Such events may represent the first step for ecological diversification. They also play an important role in adaptive divergence and speciation. A species that is able to do well across a range of environments has a higher plasticity than one whose success is restricted to a single or few environments. The breadth of environments in which a species can succeed is ultimately determined by the full pattern of its vital rates in each environment. Examples of organisms colonizing novel environments are insect herbivores expanding their diets to novel host plants. One expectation for insect herbivores is that species with specialized diets may display less plasticity when faced with novel hosts than generalist species. We examine this hypothesis for two generalist and two specialist neotropical beetles (genus Cephaloleia: Chrysomelidae) currently expanding their diets from native to novel plants of the order Zingiberales. Using an experimental approach, we estimated changes in vital rates, life-history traits and lifetime fitness for each beetle species when feeding on native or novel host plants. We did not find evidence supporting more plasticity for generalists than for specialists. Instead, we found similar patterns of survival and fecundity for all herbivores. Larvae survived worse on novel hosts; adults survived at least as well or better, but reproduced less on the novel host than on natives. Some of the novel host plants represent challenging environments where population growth was negative. However, in four novel plant-herbivore interactions, instantaneous population growth rates were positive. Positive instantaneous population growth rates during initial colonization of novel host plants suggest that both generalist and specialist Cephaloleia beetles may be pre-adapted to feed on some novel hosts. This plasticity in host use is a key factor for successful colonization of novel hosts. Future success or failure in the colonization of these novel hosts will depend on the demographic rates described in this research, natural selection and the evolutionary responses of life-history traits in novel environments.

Original languageEnglish
Pages (from-to)976-989
Number of pages14
JournalJournal of Animal Ecology
Volume80
Issue number5
DOIs
StatePublished - Sep 1 2011

Fingerprint

demography
generalist
host plant
herbivore
herbivores
host plants
insect
insects
plasticity
colonization
population growth
beetle
diet
Coleoptera
life history trait
Zingiberales
life history
plant-herbivore interaction
host use
rate

Keywords

  • Cephaloleia
  • Demography
  • Exotic host plants
  • La Selva Biological Station
  • Native herbivores
  • Preadaptation
  • Zingiberales

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology, Evolution, Behavior and Systematics

Cite this

Experimental demography and the vital rates of generalist and specialist insect herbivores on native and novel host plants. / García-Robledo, Carlos; Horvitz, Carol C.

In: Journal of Animal Ecology, Vol. 80, No. 5, 01.09.2011, p. 976-989.

Research output: Contribution to journalArticle

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