Intraspecific difference among herbivore lineages and their host-plant specialization drive the strength of trophic cascades

AbstractTrophic cascades—the indirect effect of predators on non-adjacent lower trophic levels—are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underlying ecological networks. Here we experimentally investigated how intraspecific difference among herbivore lineages specialized on different host plants influences the strength of trophic cascade in a terrestrial tritrophic system. We found that the occurrence and strength of the trophic cascade are strongly influenced by herbivores’ lineage and host-plant specialization but are not associated with density-dependent effects mediated by the growth rate of herbivore populations. Our findings stress the importance of intraspecific heterogeneities and evolutionary specialization as drivers of the strength of trophic cascades and underline that intraspecific variation should not be overlooked to decipher the joint influence of evolutionary and ecological factors on the functioning of multi-trophic interactions.

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Intraspecific difference among herbivore lineages and their host‐plant specialization drive the strength of trophic cascades

Ecology Letters ◽

10.1111/ele.13528 ◽

2020 ◽

Vol 23 (8) ◽

pp. 1242-1251 ◽

Cited By ~ 3

Author(s):

Arnaud Sentis ◽

Raphaël Bertram ◽

Nathalie Dardenne ◽

Jean‐Christophe Simon ◽

Alexandra Magro ◽

...

Keyword(s):

Host Plant ◽

Trophic Cascades ◽

Host Plant Specialization ◽

Intraspecific Difference

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Large mammals generate both top-down effects and extended trophic cascades on floral-visitor assemblages

Journal of Tropical Ecology ◽

10.1017/s0266467419000142 ◽

2019 ◽

Vol 35 (4) ◽

pp. 185-198 ◽

Cited By ~ 1

Author(s):

Allison Louthan ◽

Emily Valencia ◽

Dino J. Martins ◽

Travis Guy ◽

Jacob Goheen ◽

...

Keyword(s):

Trophic Cascade ◽

Structural Equation ◽

Trophic Cascades ◽

Trophic Levels ◽

Large Mammals ◽

Top Down ◽

Cascading Effects ◽

Floral Visitor ◽

Show Evidence ◽

Floral Visitors

AbstractCascading effects of high trophic levels onto lower trophic levels have been documented in many ecosystems. Some studies also show evidence of extended trophic cascades, in which guilds dependent on lower trophic levels, but uninvolved in the trophic cascade themselves, are affected by the trophic cascade due to their dependence on lower trophic levels. Top-down effects of large mammals on plants could lead to a variety of extended trophic cascades on the many guilds dependent on plants, such as pollinators. In this study, floral-visitor and floral abundances and assemblages were quantified within a series of 1-ha manipulations of large-mammalian herbivore density in an African savanna. Top-down effects of large mammals on the composition of flowers available for floral visitors are first shown, using regressions of herbivore activity on metrics of floral and floral-visitor assemblages. An extended trophic cascade is also shown: the floral assemblage further altered the assemblage of floral visitors, according to a variety of approaches, including a structural equation modelling approach (model with an extended trophic cascade was supported over a model without, AICc weight = 0.984). Our study provides support for extended trophic cascades affecting floral visitors, suggesting that trophic cascades can have impacts throughout entire communities.

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A Perspective on Body Size and Abundance Relationships across Ecological Communities

Biology ◽

10.3390/biology9030042 ◽

2020 ◽

Vol 9 (3) ◽

pp. 42

Author(s):

Vojsava Gjoni ◽

Douglas Stewart Glazier

Keyword(s):

Body Size ◽

Ecological Factors ◽

Trophic Levels ◽

Marine Phytoplankton ◽

Published Data ◽

Scaling Exponent ◽

Ecological Communities ◽

Macroinvertebrate Communities ◽

Power Functions ◽

Phytoplankton Communities

Recently, several studies have reported relationships between the abundance of organisms in an ecological community and their mean body size (called cross-community scaling relationships: CCSRs) that can be described by simple power functions. A primary focus of these studies has been on the scaling exponent (slope) and whether it approximates −3/4, as predicted by Damuth’s rule and the metabolic theory in ecology. However, some CCSR studies have reported scaling exponents significantly different from the theoretical value of −3/4. Why this variation occurs is still largely unknown. The purpose of our commentary is to show the value of examining both the slopes and elevations of CCSRs and how various ecological factors may affect them. As a heuristic exercise, we reanalyzed three published data sets based on phytoplankton, rodent, and macroinvertebrate assemblages that we subdivided according to three distinctly different ecological factors (i.e., climate zone, season, and trophic level). Our analyses reveal significant variation in either or both the CCSR slopes and elevations for marine phytoplankton communities across climate zones, a desert rodent community across seasons, and saltwater lagoon macroinvertebrate communities across trophic levels. We conclude that achieving a comprehensive understanding of abundance-size relationships at the community level will require consideration of both slopes and elevations of these relationships and their possible variation in different ecological contexts.

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Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds

Science Advances ◽

10.1126/sciadv.1500310 ◽

2015 ◽

Vol 1 (8) ◽

pp. e1500310 ◽

Cited By ~ 8

Author(s):

Harold F. Greeney ◽

M. Rocio Meneses ◽

Chris E. Hamilton ◽

Eli Lichter-Marck ◽

R. William Mannan ◽

...

Keyword(s):

Climate Change ◽

Habitat Fragmentation ◽

Breeding Success ◽

Indirect Effects ◽

Trophic Cascade ◽

Terrestrial Ecosystems ◽

Trophic Levels ◽

Ecological Communities ◽

Top Predators ◽

Enemy Free Space

The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.

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Beyond the fish-Daphnia paradigm: testing the potential for Neoplea striola (Hemiptera: Pleidae) to cause a trophic cascade in subtropical ponds

10.1101/2021.04.14.439893 ◽

2021 ◽

Author(s):

Chase J. Rakowski ◽

Mathew A. Leibold

Keyword(s):

Food Web ◽

Trophic Cascade ◽

Trophic Cascades ◽

Zooplankton Community ◽

Trophic Levels ◽

Food Web Interactions ◽

Top Predators ◽

Invertebrate Predators ◽

Consumption Rates ◽

Central Texas

AbstractTrophic cascades, or indirect effects of predators on non-adjacent lower trophic levels, are thought to pervade diverse ecosystems, though they tend to be stronger in aquatic ecosystems. Most research on freshwater trophic cascades focused on temperate lakes where Daphnia tend to dominate the zooplankton community, and these studies identified that Daphnia plays a key role in facilitating trophic cascades by linking fish to algae with strong food web interactions. However, Daphnia are rare or absent in most tropical and subtropical lowland freshwaters, and many invertebrate predators have received little attention in food web research despite being common and widespread. Therefore, we aimed to test whether trophic cascades are possible in small warmwater ponds where small invertebrates are the top predators and Daphnia are absent. We collected naturally occurring plankton communities from small fishless water bodies in central Texas and propagated them in replicate pond mesocosms. We removed zooplankton from some mesocosms, left the plankton community intact in others, and added one of two densities of the predaceous insect Neoplea striola to others. Following an incubation period we then compared biomasses of plankton groups to assess food web effects between the trophic levels including whether Neoplea caused a trophic cascade by reducing zooplankton. The zooplankton community became dominated by copepods which prefer large phytoplankton and exhibit a fast escape response. Perhaps due to these qualities of the copepods and perhaps due to slow consumption rates by Neoplea on key grazers, no food web effects were found other than zooplankton marginally reducing large phytoplankton. More research is needed to understand the behavior and ecology of Neoplea, but trophic cascades may generally be weak or absent in subtropical and tropical lowland freshwaters where Daphnia is rare.

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Predator complementarity dampens variability of phytoplankton biomass in a diversity-stability trophic cascade

10.1101/851642 ◽

2019 ◽

Author(s):

Chase J. Rakowski ◽

Caroline E. Farrior ◽

Schonna R. Manning ◽

Mathew A. Leibold

Keyword(s):

Trophic Cascade ◽

Phytoplankton Biomass ◽

Trophic Cascades ◽

Trophic Levels ◽

Cascading Effects ◽

Predator Diversity ◽

Laboratory Microcosm ◽

Average Biomass ◽

Basal Resources ◽

The Stability

AbstractTrophic cascades – indirect effects of predators that propagate down through food webs – have been extensively documented, especially in aquatic ecosystems. It has also been shown that predator diversity can mediate these trophic cascades, and, separately, that herbivore biomass can impact the stability of primary producers. However, whether predator diversity can cause cascading effects on the stability of lower trophic levels has not yet been studied. We conducted a laboratory microcosm experiment and a field mesocosm experiment manipulating the presence and coexistence of two heteropteran predators and measuring their effects on zooplankton herbivores and phytoplankton basal resources. We predicted that, if the predators partitioned their herbivore prey, for example by size, then co-presence of the predators would lead to 1) increased average values and 2) decreased temporal variability of phytoplankton basal resources. We present evidence that the predators partitioned their herbivore prey and found that their simultaneous suppression of herbivore groups reduced the variability of edible (smaller) phytoplankton biomass, without affecting mean phytoplankton biomass. We also found that phytoplankton that were more resistant to herbivory were not affected by our manipulations, indicating that the zooplankton herbivores played an important role in mediating this cascading diversity-stability effect. Our results demonstrate that predator diversity may indirectly stabilize basal resource biomass via a “diversity-stability trophic cascade,” seemingly dependent on predator complementarity and the vulnerability of taxa to consumption, but independent of a classic trophic cascade in which average biomass is altered. Predator diversity, especially if correlated with diversity of prey use, may be important for regulating ecosystem stability, and this relationship suggests biological control methods for improving the reliability of microalgal yields.

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Host Plant Specialization Driven by Sexual Selection

The American Naturalist ◽

10.2307/4137001 ◽

2007 ◽

Vol 169 (6) ◽

pp. 830

Author(s):

Tiago B. Quental ◽

Manus M. Patten ◽

Pierce

Keyword(s):

Sexual Selection ◽

Host Plant ◽

Host Plant Specialization

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The draft genome of the specialist flea beetle Altica viridicyanea (Coleoptera: Chrysomelidae)

BMC Genomics ◽

10.1186/s12864-021-07558-6 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Huai-Jun Xue ◽

Yi-Wei Niu ◽

Kari A. Segraves ◽

Rui-E Nie ◽

Ya-Jing Hao ◽

...

Keyword(s):

Host Plant ◽

Plant Cell Wall ◽

Flea Beetle ◽

Repetitive Sequences ◽

Draft Genome ◽

Gene Families ◽

Ecological Speciation ◽

Secondary Chemistry ◽

Host Plant Specialization ◽

Insight Into

Abstract Background Altica (Coleoptera: Chrysomelidae) is a highly diverse and taxonomically challenging flea beetle genus that has been used to address questions related to host plant specialization, reproductive isolation, and ecological speciation. To further evolutionary studies in this interesting group, here we present a draft genome of a representative specialist, Altica viridicyanea, the first Alticinae genome reported thus far. Results The genome is 864.8 Mb and consists of 4490 scaffolds with a N50 size of 557 kb, which covered 98.6% complete and 0.4% partial insect Benchmarking Universal Single-Copy Orthologs. Repetitive sequences accounted for 62.9% of the assembly, and a total of 17,730 protein-coding gene models and 2462 non-coding RNA models were predicted. To provide insight into host plant specialization of this monophagous species, we examined the key gene families involved in chemosensation, detoxification of plant secondary chemistry, and plant cell wall-degradation. Conclusions The genome assembled in this work provides an important resource for further studies on host plant adaptation and functionally affiliated genes. Moreover, this work also opens the way for comparative genomics studies among closely related Altica species, which may provide insight into the molecular evolutionary processes that occur during ecological speciation.

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