Low host specificity and abundance of frugivorous lepidoptera in the lowland rain forests of Papua New Guinea.

We studied a community of frugivorous Lepidoptera in the lowland rainforest of Papua New Guinea. Rearing revealed 122 species represented by 1,720 individuals from 326 woody plant species. Only fruits from 52% (171) of the plant species sampled were attacked. On average, Lepidoptera were reared from 1 in 89 fruits and a kilogram of fruit was attacked by 1.01 individuals. Host specificity of Lepidoptera was notably low: 69% (33) of species attacked plants from >1 family, 8% (4) fed on single family, 6% (3) on single genus and 17% (8) were monophagous. The average kilogram of fruits was infested by 0.81 individual from generalist species (defined here as feeding on >1 plant genus) and 0.07 individual from specialist species (feeding on a single host or congeneric hosts). Lepidoptera preferred smaller fruits with both smaller mesocarp and seeds. Large-seeded fruits with thin mesocarp tended to host specialist species whereas those with thick, fleshy mesocarp were often infested with both specialist and generalist species. The very low incidence of seed damage suggests that pre-dispersal seed predation by Lepidoptera does not play a major role in regulating plant populations via density-dependent mortality processes outlined by the Janzen-Connell hypothesis

Overlap of Lepidoptera species in frugivorous (this study) and leaf-chewer (different study, [68]) guilds.

<p>Overlap of Lepidoptera species in frugivorous (this study) and leaf-chewer (different study, [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171843#pone.0171843.ref068" target="_blank">68</a>]) guilds.</p

The number of plant species attacked (black bar) and not attacked (white bar) by frugivorous Lepidoptera in samples categorized by (a) fruit weight and (b) the number of fruits.

<p>The number of plant species attacked (black bar) and not attacked (white bar) by frugivorous Lepidoptera in samples categorized by (a) fruit weight and (b) the number of fruits.</p

Relationship between seed and mesocarp volume for 268 plant species attacked and not attacked by Lepidoptera.

<p>Relationship between seed and mesocarp volume for 268 plant species attacked and not attacked by Lepidoptera.</p

Density of all frugivorous Lepidoptera, and both specialist and generalists, per fruit.

<p>Host species are ranked from highest to lowest density for 326 plant species with samples of >1 kg and >50 fruits. Note that all plants to the right of each curve exhibited zero density for the herbivore category in question that cannot be shown on the log scale d y axis.</p

Mean volume for whole fruit, mesocarp and seeds (a) and fleshiness (b) in plant species attacked and not attacked by Lepidoptera.

<p>The differences between attacked and non-attacked species are significant (whole fruit: U _106,151 = 5624, Z = 3.064, P = 0.002; mesocarp: U _106,151 = 5828, Z = 2.69, P = 0.007; seeds: U _106,151 = 5346, Z = 3.574, P < 0.0010), (b) Fleshiness (i.e. proportion of mesocarp in whole fruit) did not have significant effect on infestation (U _106,151 = 6839, Z = 0.83, P = 0.401).</p

Plant phylogeny from Varyingly hungry caterpillars: predictive models and foliar chemistry suggest how to eat a rainforest

The phylogeny of plant hosts sampled in this study for geometrids or pyraloids

Le Courrier

01 septembre 18291829/09/01 (N244)