Insect Outbreaks in Tropical Forests: Patterns, Mechanisms, and Consequences

Dyer, Lee A.; Carson, Walter P.; Leigh, Egbert Giles

doi:10.1002/9781118295205.ch11

Cited by 26 publications

(48 citation statements)

References 104 publications

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“…For example, studies of lowland forest in Papua New Guinea (PNG) have shown that community phylogenetic diversity increases as succession progresses, where early succession communities are typically dominated by a few large genera such as Macaranga and Trichospermum (Whitfeld et al ). The same trend has also been shown in Neotropical forests (Letcher et al ). On the other hand, temperate forests in China followed the opposite trajectory, becoming more phylogenetically uniform with time (Chai et al 2016).…”

Section: Introductionsupporting

confidence: 81%

“…High herbivore specialisation is often reported using both traditional and phylogenetically based measures of specialisation. For instance, lepidopteran communities in Mexican dry forest (Villa‐Galaviz et al ) were highly specialized measured using traditional measures, while herbivore communities from four distinct functional groups in PNG were highly phylogenetically specialised (Jorge et al ).…”

Section: Discussionmentioning

confidence: 99%

“…Exploring the changes that occur over time in these groups of strongly interacting species warrants further examination but extends beyond the scope of this study. While antagonistic networks often organise into such modules (Thébault and Fontaine , Cagnolo et al ), this is not always the case (Villa‐Galaviz et al ). Understanding modularity, and how module membership changes, is important as a modular structure increases the resilience of networks to the propagation of deleterious domino effects associated with perturbations such as species extinction or local extirpation, and species outbreaks (Stouffer and Bascompte ).…”

Section: Discussionmentioning

confidence: 99%

“…Such studies provide insights into factors underpinning community assembly and stability (see recent reviews by Tylianakis and Morris , Pellissier et al ). For antagonistic networks, studies commonly focus on spatial change, typically along latitudinal (Novotný et al , Morris et al ), altitudinal (Morris et al ) or land use gradients (Tylianakis et al ), while temporal change through succession has been comparatively overlooked (but see Villa‐Galaviz et al ). This is surprising as ecological succession is not only one of the few community‐level processes that we understand and can predict, but secondary regeneration is also increasingly prominent in tropical landscapes, arising through major land use changes and forest disturbance (Chazdon ).…”

Section: Introductionmentioning

confidence: 99%

“…where all woody species in a given area are completely sampled, produces networks which are truly quantitative. Similar proportional biomass sampling approaches are relatively uncommon in host‐herbivore interaction network studies, and have focused on quite distinct systems, including temperate forest (Volf et al ), or tropical dry forest communities (Villa‐Galaviz et al ).…”

Section: Introductionmentioning

confidence: 99%

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High specialization and limited structural change in plant‐herbivore networks along a successional chronosequence in tropical montane forest

et al. 2018

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Secondary succession is well‐understood, to the point of being predictable for plant communities, but the successional changes in plant‐herbivore interactions remains poorly explored. This is particularly true for tropical forests despite the increasing importance of early successional stages in tropical landscapes. Deriving expectations from successional theory, we examine properties of plant‐herbivore interaction networks while accounting for host phylogenetic structure along a succession chronosequence in montane rainforest in Papua New Guinea. We present one of the most comprehensive successional investigations of interaction networks, equating to > 40 person years of field sampling, and one of the few focused on montane tropical forests. We use a series of nine 0.2 ha forest plots across young secondary, mature secondary and primary montane forest, sampled almost completely for woody plants and larval leaf chewers (Lepidoptera) using forest felling. These networks comprised of 12 357 plant‐herbivore interactions and were analysed using quantitative network metrics, a phylogenetically controlled host‐use index and a qualitative network beta diversity measure. Network structural changes were low and specialisation metrics surprisingly similar throughout succession, despite high network beta diversity. Herbivore abundance was greatest in the earliest stages, and hosts here had more species‐rich herbivore assemblages, presumably reflecting higher palatability due to lower defensive investment. All herbivore communities were highly specialised, using a phylogenetically narrow set of hosts, while host phylogenetic diversity itself decreased throughout the chronosequence. Relatively high phylogenetic diversity, and thus high diversity of plant defenses, in early succession forest may result in herbivores feeding on fewer hosts than expected. Successional theory, derived primarily from temperate systems, is limited in predicting tropical host‐herbivore interactions. All succession stages harbour diverse and unique interaction networks, which together with largely similar network structures and consistent host use patterns, suggests general rules of assembly may apply to these systems.

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Section: Introductionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

High specialization and limited structural change in plant‐herbivore networks along a successional chronosequence in tropical montane forest

et al. 2018

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Impacts of insect frass and cadavers on soil surface litter decomposition along a tropical forest temperature gradient

Hwang

Giardina

Litton

et al. 2022

Ecology and Evolution

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Insect herbivores play important roles in shaping many ecosystem processes, but how climate change will alter the effects of insect herbivory are poorly understood. To address this knowledge gap, we quantified for the first time how insect frass and cadavers affected leaf litter decomposition rates and nutrient release along a highly constrained 4.3°C mean annual temperature (MAT) gradient in a Hawaiian montane tropical wet forest. We constructed litterbags of standardized locally sourced leaf litter, with some amended with insect frass + cadavers to produce treatments designed to simulate ambient (Control = no amendment), moderate (Amended‐Low = 2 × Control level), or severe (Amended‐High = 11 × Control level) insect outbreak events. Multiple sets of these litterbags were deployed across the MAT gradient, with individual litterbags collected periodically over one year to assess how rising MAT altered the effects of insect deposits on litter decomposition rates and nitrogen (N) release. Increased MAT and insect inputs additively increased litter decomposition rates and N immobilization rates, with effects being stronger for Amended‐High litterbags. However, the apparent temperature sensitivity (Q10) of litter decomposition was not clearly affected by amendments. The effects of adding insect deposits in this study operated differently than the slower litter decomposition and greater N mobilization rates often observed in experiments which use chemical fertilizers (e.g., urea, ammonium nitrate). Further research is required to understand mechanistic differences between amendment types. Potential increases in outbreak‐related herbivore deposits coupled with climate warming will accelerate litter decomposition and nutrient cycling rates with short‐term consequences for nutrient cycling and carbon storage in tropical montane wet forests.

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Hypotheses and lessons from a native moth outbreak in a low‐diversity, tropical rainforest

et al. 2022

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Outbreaks of defoliating insects in low-diversity tropical forests occur infrequently but provide valuable insights about outbreak ecology in temperate environments and in general. We investigated an extensive outbreak of the endemic koa moth (Scotorythra paludicola), which defoliated endemic koa trees (Acacia koa) over a third of their range on Hawai'i Island during 2013 and 2014. At Hakalau Forest National Wildlife Refuge, we observed the dynamics of the outbreak and its effects on host trees, nutrient cycling, and insectivorous consumers in reforestation stands of densely planted koa and in natural forest stands of mixed koa and ' ohi'a (Metrosideros polymorpha). Contrary to predictions of the resource concentration hypothesis, caterpillar biomass and defoliation severity were greater in the natural forest sites, where koa density was relatively low. Caterpillars preferentially consumed the most palatable koa foliage type (phyllodes), and koa initially refoliated with the least palatable foliage type (true leaves). Lightly defoliated small trees refoliated

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Insect Outbreaks in Tropical Forests: Patterns, Mechanisms, and Consequences

Cited by 26 publications

References 104 publications

High specialization and limited structural change in plant‐herbivore networks along a successional chronosequence in tropical montane forest

High specialization and limited structural change in plant‐herbivore networks along a successional chronosequence in tropical montane forest

Impacts of insect frass and cadavers on soil surface litter decomposition along a tropical forest temperature gradient

Hypotheses and lessons from a native moth outbreak in a low‐diversity, tropical rainforest

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