Eye size and investment in frogs and toads correlate with adult habitat, activity pattern and breeding ecology

Frogs and toads (Amphibia: Anura) display diverse ecologies and behaviours, which are often correlated with visual capacity in other vertebrates. Additionally, anurans exhibit a broad range of relative eye sizes, which have not previously been linked to ecological factors in this group. We measured relative investment in eye size and corneal size for 220 species of anurans representing all 55 currently recognized families and tested whether they were correlated with six natural history traits hypothesized to be associated with the evolution of eye size. Anuran eye size was significantly correlated with habitat, with notable decreases in eye investment among fossorial, subfossorial and aquatic species. Relative eye size was also associated with mating habitat and activity pattern. Compared to other vertebrates, anurans have relatively large eyes for their body size, indicating that vision is probably of high importance. Our study reveals the role that ecology and behaviour may have played in the evolution of anuran visual systems and highlights the usefulness of museum specimens, and importance of broad taxonomic sampling, for interpreting macroecological patterns.

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Mammalian body size is determined by interactions between climate, urbanization, and ecological traits

Communications Biology ◽

10.1038/s42003-021-02505-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Maggie M. Hantak ◽

Bryan S. McLean ◽

Daijiang Li ◽

Robert P. Guralnick

Keyword(s):

Body Size ◽

Resource Availability ◽

Critical Role ◽

Size Variation ◽

Ecological Factors ◽

Species Traits ◽

Body Size Variation ◽

Resource Availability Hypothesis ◽

Urban Heat ◽

Thermal Buffering

AbstractAnthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.

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Eye shape and the nocturnal bottleneck of mammals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.2258 ◽

2012 ◽

Vol 279 (1749) ◽

pp. 4962-4968 ◽

Cited By ~ 64

Author(s):

Margaret I. Hall ◽

Jason M. Kamilar ◽

E. Christopher Kirk

Keyword(s):

Visual Acuity ◽

Detailed Analysis ◽

Statistical Methods ◽

Activity Pattern ◽

Activity Patterns ◽

Time Of Day ◽

Visual Sensitivity ◽

Early Evolution ◽

Eye Size ◽

Diurnal Species

Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal ‘bottleneck’ in the early evolution of crown mammals.

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Threatened birds of Guatemala: a random subset of the avifauna?

Bird Conservation International ◽

10.1017/s0959270911000517 ◽

2011 ◽

Vol 22 (3) ◽

pp. 348-353

Author(s):

ANDREA NÁJERA ◽

JAVIER A. SIMONETTI

Keyword(s):

Body Size ◽

Geographical Distribution ◽

Scientific Information ◽

Bird Species ◽

Critically Endangered ◽

Aquatic Species ◽

Random Subset ◽

The Pacific ◽

Taxonomic Affiliation

SummaryIdentifying attributes that affect the vulnerability of a species to extinction is important as it allows conservation efforts to be focused on more susceptible species. We assessed whether threatened birds of Guatemala are a random subset of the avifauna, considering their taxonomic affiliation, body size, diet and geographical distribution. We found that threatened bird species in Guatemala were neither taxonomically nor geographically randomly distributed. Large-bodied species and Psittaciformes, Galliformes, Falconiformes and Ciconiformes were among the most threatened groups, and the Pacific slopes of the country hosted more threatened birds than would be expected. Published scientific information regarding Critically Endangered bird species in Guatemala is scant and biased against nocturnal and aquatic species. Research and conservation efforts ought to be oriented toward these species and regions to safeguard the Guatemalan avifauna. This study allows an overall consideration on whether we are conserving the species and areas that are important for threatened birds.

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Infection patterns of helminths in Norops brasiliensis (Squamata, Dactyloidae) from a humid forest, Northeastern Brazil and their relation with body mass, sex, host size, and season

Helminthologia ◽

10.2478/helm-2019-0011 ◽

2019 ◽

Vol 56 (2) ◽

pp. 168-174 ◽

Cited By ~ 1

Author(s):

D. M. Amorim ◽

R. W. Ávila

Keyword(s):

Body Size ◽

Ecological Factors ◽

Parasite Load ◽

Helminth Fauna ◽

Northeastern Brazil ◽

Rainfall Regime ◽

New Host ◽

Humid Forest ◽

Host Sex ◽

New Host Records

SummaryClimatic and ecological factors can influence the parasite load of a host. Variation in rainfall, body size, and sex of the hosts may be related to the abundance of parasites. This study investigated the helminth fauna associated with a population of Norops brasiliensis, together with the effect of host biology (sex, body size, and mass) and variation in rainfall regime on the abundance of helminths. Species of three groups of endoparasites were found (Nematoda, Cestoda, and Trematoda), with nematodes as the most representative taxa with eight species, prevalence of 63.2 %, mean intensity of 4.0 ± 0.58 (1 – 25), and mean abundance of 2.66 ± 0.44 (0 – 25). Nine helminth species are new host records for N. brasiliensis. The nematode Rhabdias sp. had the highest prevalence (53.3 %). There was no significant relationship between abundance of the trematode Mesocoelium monas and host sex or season, although the abundance of this parasite increased significantly with host body size and mass, while abundance of nematodes was related to season and host mass. This study increases the knowledge about the diversity of helminth fauna associated with N. brasiliensis, revealing infection levels of hosts from northeastern Brazil.

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Ecological factors affecting body size of Japanese adolescents

American Journal of Physical Anthropology ◽

10.1002/ajpa.1330910305 ◽

1993 ◽

Vol 91 (3) ◽

pp. 299-303 ◽

Cited By ~ 6

Author(s):

Akira Endo ◽

Katsuhiko Omoe ◽

Hitoshi Ishikawa

Keyword(s):

Body Size ◽

Ecological Factors ◽

Factors Affecting ◽

Japanese Adolescents

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Investigating the role of body size, ecology, and behavior in anuran eye size evolution

Evolutionary Ecology ◽

10.1007/s10682-019-09993-0 ◽

2019 ◽

Vol 33 (4) ◽

pp. 585-598 ◽

Cited By ~ 4

Author(s):

Chun Hua Huang ◽

Mao Jun Zhong ◽

Wen Bo Liao ◽

Alexander Kotrschal

Keyword(s):

Body Size ◽

Eye Size ◽

Size Evolution ◽

And Behavior

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Environmental and ecological factors mediate taxonomic composition and body size of polyplacophoran assemblages along the Peruvian Province

Scientific Reports ◽

10.1038/s41598-019-52395-z ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Christian M. Ibáñez ◽

Melany Waldisperg ◽

Felipe I. Torres ◽

Sergio A. Carrasco ◽

Javier Sellanes ◽

...

Keyword(s):

Body Size ◽

Species Composition ◽

Size Structure ◽

Environmental Gradients ◽

Ecological Factors ◽

Taxonomic Composition ◽

Latitudinal Gradients ◽

Size Segregation ◽

Biogeographic Patterns ◽

Diversity Gradient

Abstract Intertidal communities’ composition and diversity usually exhibit strong changes in relation to environmental gradients at different biogeographical scales. This study represents the first comprehensive diversity and composition description of polyplacophoran assemblages along the Peruvian Province (SE Pacific, 12°S–39°S), as a model system for ecological latitudinal gradients. A total of 4,775 chitons from 21 species were collected on twelve localities along the Peruvian Province. This sampling allowed us to quantitatively estimate the relative abundance of the species in this assemblage, and to test whether chitons conform to elementary predictions of major biogeographic patterns such as a latitudinal diversity gradient. We found that the species composition supported the division of the province into three ecoregional faunal groups (i.e. Humboldtian, Central Chile, and Araucanian). Though chiton diversity did not follow a clear latitudinal gradient, changes in species composition were dominated by smaller scale variability in salinity and temperature. Body size significantly differed by ecoregions and species, indicating latitudinal size-structure assamblages. In some localities body size ratios differed from a random assemblage, evidencing competition at local scale. Changes in composition between ecoregions influence body size structure, and their overlapping produce vertical size segregation, suggesting that competition coupled with environmental conditions structure these assemblages.

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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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Diel activity pattern of meso-carnivores in the suburban tropical dry evergreen forest of the Coromandel Coast, India

Journal of Threatened Taxa ◽

10.11609/jott.4850.11.8.13960-13966 ◽

2019 ◽

Vol 11 (8) ◽

pp. 13960-13966

Author(s):

Kangaraj Muthamizh Selvan ◽

Bawa Mothilal Krishnakumar ◽

Pasiyappazham Ramasamy ◽

Thangadurai Thinesh

Keyword(s):

Activity Pattern ◽

Activity Patterns ◽

Camera Trap ◽

Diel Activity ◽

Evergreen Forest ◽

Breeding Ecology ◽

Canis Aureus ◽

Diel Activity Pattern ◽

Diel Activity Patterns ◽

Felis Chaus

Sympatric and similar body-sized species exhibit interspecific competition for resources. The present study investigated diel activity of five meso-carnivore species (Canis aureus, Felis chaus, Paradoxurus hermaphroditus, Viverricula indica, and Herpestes edwardsii) in a human-dominated region of Auroville and around Pondicherry University using camera-trap survey data. Diel activity pattern and overlap were estimated using the kernel density method. The Jungle Cat Felis chaus and the Golden Jackal Canis aureus exhibited cathemeral diel activity with a high overlap between them (Δ̂1 = 0.78). The Indian Grey Mongoose Herpestes edwardsii displayed a diurnal activity pattern and had low overlap with the Small Indian Civet Viverricula indica (Δ̂1 = 0.34). Moderate overlap was found between the Small Indian Civet and the Palm Civet Paradoxurus hermaphroditus (Δ̂1 = 0.32). Therefore, diel activity patterns of mesocarnivores indicate inter- and intra-specific trade-off competition avoidance resulting in successful foraging. The present camera-trap survey has provided insights into diel activity patterns and more attention is required to be paid to the study of feeding and breeding ecology of these species in human-dominated landscapes.

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Morphological Divergence of Hermann’s Tortoise (Testudo hermanni boettgeri) in Albania

10.20944/preprints202012.0462.v1 ◽

2020 ◽

Author(s):

Sokol Duro ◽

Bektas Sönmez ◽

Ozan Gündemir ◽

Tefik Jashari ◽

Tomasz Szara

Keyword(s):

Body Size ◽

Carapace Length ◽

Morphological Characteristics ◽

Ecological Factors ◽

The Body ◽

Local Conditions ◽

Geographical Regions ◽

Testudo Hermanni ◽

Different Populations ◽

Morphological Differences

Testudines show phenotypic plasticity, and variation among specific populations within a species is widespread. Morphological differences between populations reflect ecological factors that drive adaptation to local conditions. In this context, gathered basic data on morphology of the Hermann’s tortoise (Testudo hermanni boettgeri) to document their variation across different geographical regions. We surveyed Hermann’s tortoises, in five different locales within Albania during April and May 2020 and measured 20 morphological characteristics, including carapace and plastron dimensions. We measured 188 tortoises (81 males, 107 females) in this study, and females were larger (P=.0001) and heavier (P=.0001) than males. Mean straight carapace length [SCL] and body mass were = 172.4 mm and 1128.8 g, respectively, for females and 151.3 mm and 735 g, respectively, for males. The overall Albanian T. h. boettgeri population were regionally diverged into 3 different populations that were situated in northern (Shkodra), central (Tirana, Berati and Ballshi) and southern (Saranda) Albania. The body size (curved carapace length; CCL) of females was positively correlated (r=0.216; P=0.025) with the latitude degree, in accordance with Bergmann's rule. However, there was no correlation between body size and degrees north latitude in males. These striking regional differences among Albanian T. h. boettgeri strongly suggest that further study of molecular variations in and reproductive output of Hermann’s tortoises is warranted.

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