scholarly journals Resolving the roles of body size and species identity in driving functional diversity

2014 ◽  
Vol 281 (1781) ◽  
pp. 20133203 ◽  
Author(s):  
Volker H. W. Rudolf ◽  
Nick L. Rasmussen ◽  
Christopher J. Dibble ◽  
Benjamin G. Van Allen
Keyword(s):  
Body Size ◽  
Functional Diversity ◽  
Size Effects ◽  
Traditional Approach ◽  
Synergistic Effects ◽  
Ecological Interactions ◽  
Species Identity ◽  
Functional Differences ◽  
Species Specific ◽  
Natural Communities

Efforts to characterize food webs have generated two influential approaches that reduce the complexity of natural communities. The traditional approach groups individuals based on their species identity, while recently developed approaches group individuals based on their body size. While each approach has provided important insights, they have largely been used in parallel in different systems. Consequently, it remains unclear how body size and species identity interact, hampering our ability to develop a more holistic framework that integrates both approaches. We address this conceptual gap by developing a framework which describes how both approaches are related to each other, revealing that both approaches share common but untested assumptions about how variation across size classes or species influences differences in ecological interactions among consumers. Using freshwater mesocosms with dragonfly larvae as predators, we then experimentally demonstrate that while body size strongly determined how predators affected communities, these size effects were species specific and frequently nonlinear, violating a key assumption underlying both size- and species-based approaches. Consequently, neither purely species- nor size-based approaches were adequate to predict functional differences among predators. Instead, functional differences emerged from the synergistic effects of body size and species identity. This clearly demonstrates the need to integrate size- and species-based approaches to predict functional diversity within communities.

Correlations between call characteristics and morphology in male cricket frogs (Acris crepitans).

1996 ◽  
Vol 199 (9) ◽  
pp. 1907-1919
Author(s):  
B E McClelland ◽  
W Wilczynski ◽  
M J Ryan
Keyword(s):  
Body Size ◽  
Size Effects ◽  
Spectral Characteristics ◽  
Morphological Characteristics ◽  
Dominant Frequency ◽  
Advertisement Call ◽  
Acris Crepitans ◽  
Species Specific ◽  
Male Cricket ◽  
Cricket Frogs

We investigated the relationships among spectral and temporal advertisement-call characteristics and the sizes of the laryngeal and ear components thought to underlie the generation and reception of species-specific vocalizations in male cricket frogs (Acris crepitans). We tested the predictions that the volumes of the structural elements necessary for acoustic communication would be correlated with various parameters of the vocalizations. The anatomy of laryngeal and ear structures was reconstructed from serial sections of the heads of male cricket frogs of two subspecies collected from several sites across the range of this species in Texas, USA. The relationships among the anatomy and call parameters were assessed using several univariate and multivariate analyses. Highly significant univariate correlations among the laryngeal components suggest that the temporal and spectral characteristics of the calls are not independently produced. Dominant frequency correlates strongly with most of the other call and morphological characteristics. Removing body size effects, however, removes the relationship between dominant frequency and the volume of the whole larynx and ear. This is also the case for call pulse rate, indicating that for this species both spectral and temporal call parameters are biomechanically related to laryngeal size which is, in turn, largely mediated by body size. General body size effects might also explain the existence of significant relationships between ear size and temporal characteristics of the call that probably do not have a functional basis.

scholarly journals Consumer and host body size effects on the removal of trematode cercariae by ambient communities

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 342-347
Author(s):  
Jennifer E. Welsh ◽  
Anke Hempel ◽  
Mirjana Markovic ◽  
Jaap van der Meer ◽  
David W. Thieltges
Keyword(s):  
Body Size ◽  
Size Effects ◽  
Laboratory Experiments ◽  
Feeding Activity ◽  
Removal Rates ◽  
Host Interactions ◽  
Host Body ◽  
Species Specific ◽  
Host Body Size ◽  
Significant Mortality

AbstractParasite transmission can be altered via the removal of parasites by the ambient communities in which parasite–host interactions take place. However, the mechanisms driving parasite removal remain poorly understood. Using marine trematode cercariae as a model system, we investigated the effects of consumer and host body size on parasite removal rates. Laboratory experiments revealed that consumer or host body size significantly affected cercarial removal rates in crabs, oysters and cockles but not in shrimps. In general, cercarial removal rates increased with consumer (crabs and oysters) and host (cockles) body size. For the filter feeding oysters and cockles, the effects probably relate to their feeding activity which is known to correlate with bivalve size. Low infection levels found in cockle hosts suggest that parasite removal by hosts also leads to significant mortality of infective stages. The size effects of crab and shrimp predators on cercarial removal rates were more complex and did not show an expected size match-mismatch between predators and their cercarial prey, suggesting that parasite removal rates in predators are species-specific. We conclude that to have a comprehensive understanding of parasite removal by ambient communities, more research into the various mechanisms of cercarial removal is required.

scholarly journals Size Matters, but Species Do Not: No Evidence for Species-Specific Swimming Performance in Co-Occurring Great Basin Stream Fishes

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2570
Author(s):  
John R. Aedo ◽  
Keith R. Otto ◽  
Russell B. Rader ◽  
Rollin H. Hotchkiss ◽  
Mark C. Belk
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
Great Basin ◽  
Swimming Performance ◽  
Fish Passage ◽  
Stream Fishes ◽  
Species Identity ◽  
Trade Off ◽  
Critical Measure ◽  
Species Specific

For fishes, swimming performance is an important predictor of habitat use and a critical measure for the design of effective fish passage systems. Few studies have examined burst and prolonged types of swimming performance among several co-occurring species, and swimming performance in many fish communities is undocumented. In this study, we characterize both burst (c-start velocity) and prolonged speed (critical swim speed) across a poorly documented, co-occurring group of stream fishes within the Great Basin of the western USA. We documented the variation in swim speed associated with species, habitat, and body size. Body size had an overwhelming effect on both burst speed and prolonged speed, whereas habitat use and species identity were not significant predictors. Among species, there is no evidence of a trade-off between burst swim speed and prolonged swim speed. Lack of a trade-off in performance between burst swim speed and prolonged swim speed among species may be due to unexpectedly high prolonged swim speeds exhibited by species that used substrate-bracing behaviors. Incorporating body size and variation in behavior, such as substrate-bracing behaviors, into fish passage models will likely be sufficient to ensure the passage of all species without the need to account for species-specific swimming abilities. However, these results characterize the swimming performance for threatened and common fish species such that other comparisons can be made and species-specific studies can access accurate data.

Species identity matters: Functional responses to warming in congeneric turfs differ from those of a canopy algae but are species-specific

2021 ◽  
pp. 107396
Author(s):  
Isabella Provera ◽  
Cristina Piñeiro-Corbeira ◽  
Rodolfo Barreiro ◽  
Laura Díaz-Acosta ◽  
Pilar Díaz-Tapia
Keyword(s):  
Functional Responses ◽  
Species Identity ◽  
Species Specific ◽  
Canopy Algae

Explaining variability in parasite aggregation levels among host samples

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN
Keyword(s):  
Body Size ◽  
Strong Relationship ◽  
Host Susceptibility ◽  
Helminth Parasites ◽  
Susceptibility To Infection ◽  
Host Body ◽  
Parasite Aggregation ◽  
Using Data ◽  
Species Specific ◽  
Host Body Size

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.

scholarly journals Pup ultrasonic isolation calls of six gerbil species and the relationship between acoustic traits and body size

2021 ◽  
Vol 8 (3) ◽  
pp. 201558
Author(s):  
Julia D. Kozhevnikova ◽  
Ilya A. Volodin ◽  
Alexandra S. Zaytseva ◽  
Olga G. Ilchenko ◽  
Elena V. Volodina
Keyword(s):  
Body Size ◽  
Discriminant Analysis ◽  
Peak Frequency ◽  
Meriones Unguiculatus ◽  
Similar Relationship ◽  
Species Identity ◽  
Call Duration ◽  
Acoustic Adaptation ◽  
Ultrasonic Calls ◽  
The Relationship

Among Gerbillinae rodents, ultrasonic calls of adults of small-sized species are typically higher frequency than those of adults of large-sized species. This study investigates whether a similar relationship can be found in pups of six gerbil species ( Dipodillus campestris , Gerbillus perpallidus , Meriones unguiculatus , Meriones vinogradovi , Sekeetamys calurus and Pachyuromys duprasi ). We compared the average values of acoustic variables (duration, fundamental and peak frequency) of ultrasonic calls (20 calls per pup, 1200 in total) recorded from 6- to 10-day-old pups (10 pups per species, 60 in total) isolated for 2 min at 22°C and then weighed and measured for body variables. The longest calls (56 ± 33 ms) were found in the largest species, and the highest frequency calls (74.8 ± 5.59 kHz) were found in the smallest species. However, across species, call duration (ranging from 56 to 159 ms among species) did not display a significant relationship with pup body size; and, among frequency variables, only the minimum fundamental frequency depended on pup body size. Discriminant analysis assigned 100% of calls to the correct species. The effect of species identity on the acoustics was stronger than the effect of body size. We discuss these results with the hypotheses of acoustic adaptation, social complexity, hearing ranges and phylogeny.

scholarly journals The return to water in ancestral Xenopus was accompanied by a novel mechanism for producing and shaping vocal signals

2018 ◽  
Author(s):  
Ursula Kwong-Brown ◽  
Martha L. Tobias ◽  
Damian O. Elias ◽  
Ian C. Hall ◽  
Coen P.H. Elemans ◽  
...  
Keyword(s):  
Sound Production ◽  
Neuromuscular Control ◽  
Current Theory ◽  
Species Divergence ◽  
Species Identity ◽  
Rapid Separation ◽  
Resonance Modes ◽  
Acoustic Signature ◽  
Vocal Signals ◽  
Species Specific

AbstractSpecies-specific vocal signals allow listeners to locate potential mates. During the tetrapod transition from water to land, lungs replaced gills, allowing expiration to drive sound production. Several groups, e.g. cetaceans and some frogs, then returned to water. Here we explore how air-driven sound production changed upon re-entry and how essential acoustic information on species identity was preserved in the secondarily aquatic frog Xenopus. We filmed movements of cartilage and muscles during evoked sound production in isolated larynges. Our results refute the current theory for Xenopus vocalization, cavitation, and instead favor sound production by mechanical excitation of laryngeal resonance modes following rapid separation of laryngeal arytenoid discs. The resulting frequency resonance modes (dyads) are intrinsic to the larynx rather than due to neuromuscular control. We show that dyads are a distinctive acoustic signature across species. While dyad component frequencies overlap across species, their ratio is shared within each Xenopus clade and thus provide information on species identity, potentially facilitating both conspecific localization and ancient species divergence.

scholarly journals Low functional diversity promotes niche changes in natural island pollinator communities

2017 ◽  
Vol 284 (1846) ◽  
pp. 20162218 ◽  
Author(s):  
Masayoshi K. Hiraiwa ◽  
Atushi Ushimaru
Keyword(s):  
Functional Diversity ◽  
Fruit Set ◽  
Oceanic Islands ◽  
Flower Visit ◽  
Continental Islands ◽  
Niche Shifts ◽  
Island Communities ◽  
Negative Impacts ◽  
Plant Pollinator ◽  
Natural Communities

Functional diversity loss among pollinators has rapidly progressed across the globe and is expected to influence plant–pollinator interactions in natural communities. Although recent findings suggest that the disappearance of a certain pollinator functional group may cause niche expansions and/or shifts in other groups, no study has examined this prediction in natural communities with high plant and pollinator diversities. By comparing coastal pollination networks on continental and oceanic islands, we examined how community-level flower visit patterns are influenced by the relative biomass of long-tongued pollinators (RBLP). We found that RBLP significantly correlated with pollinator functional diversity and was lower in oceanic than in continental islands. Pollinator niches shifted with decreasing RBLP, such that diverse species with various proboscis lengths, especially short-tongued species, increasingly visited long-tubed flowers. However, we found no conspicuous negative impacts of low RBLP and the consequent niche shifts on pollinator visit frequencies to flowers in oceanic island communities. Notably, fruit set significantly decreased as RBLP decreased in a study plant species. These results suggest that niche shifts by other functional groups can generally compensate for a decline in long-tongued pollinators in natural communities, but there may be negative impacts on plant reproduction.

scholarly journals Can snakes use yolk reserves to maximize body size at hatching?

2018 ◽  
Vol 65 (6) ◽  
pp. 627-631 ◽  
Author(s):  
Yan-Fu Qu ◽  
Shu-Zhan Zhao ◽  
Xu-Fei Jiang ◽  
Long-Hui Lin ◽  
Xiang Ji
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Tail Length ◽  
Linear Size ◽  
Egg Mass ◽  
Fat Bodies ◽  
Free Body ◽  
Species Specific ◽  
Naja Atra

Abstract We experimentally miniaturized freshly laid eggs of the Chinese cobra Naja atra (Elapidae) by removing ∼10% and ∼20% of original yolk. We tested if yolk-reduced eggs would produce 1) normal-sized hatchlings with invariant yolk-free body mass (and thus invariant linear size) but dramatically reduced or even completely depleted residual yolk, 2) smaller hatchlings with normal-sized residual yolk but reduced yolk-free body mass, or 3) smaller hatchlings of which both yolk-free body mass and residual yolk are proportionally reduced. Yolk quantity affected hatchling linear size (both snout-vent length and tail length) and body mass. However, changes in yolk quantity did not affect incubation length or any hatchling trait examined after accounting for egg mass at laying (for control and sham-manipulated eggs) or after yolk removal (for manipulated eggs). Specifically, yolk-reduced eggs produced hatchlings of which all major components (carcass, residual yolk, and fat bodies) were scaled down proportionally. We show that snakes cannot use yolk reserves to maximize their body size at hatching. Furthermore, our data also suggest that the partitioning of yolk in embryonic snakes is species-specific.

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