Filoplume morphology covaries with their companion primary suggesting that they are feather-specific sensors

The Auk ◽  
2021 ◽  
Author(s):  
Vanya G Rohwer ◽  
Sievert Rohwer ◽  
Larissa Kane
Keyword(s):  
Body Size ◽  
Life Span ◽  
Comparative Studies ◽  
Species Differences ◽  
Agelaius Phoeniceus ◽  
Primary Position ◽  
Cathartes Aura ◽  
Buteo Jamaicensis ◽  
Anas Crecca ◽  
Larus Delawarensis

Abstract Do birds detect and respond to forces acting on feathers through filoplumes, which appear to be unique mechanosensory feathers? If filoplumes function as sensors, their morphology should covary with the morphology of their companion feather to better detect feather movements and position. We explore covariation in filoplumes and primaries across 5 species of birds that vary in body size, molt strategy, and the functional life span of their primaries (Green-winged Teal [Anas crecca], Ring-billed Gull [Larus delawarensis], Turkey Vulture [Cathartes aura], Red-tailed Hawk [Buteo jamaicensis], and Red-winged Blackbird [Agelaius phoeniceus]). Filoplumes never extended beyond the coverts and inserted immediately adjacent to the base of their companion primaries, positioning them to detect subtle changes in feather vibration or movement. Far more variation in filoplume number and morphology was due to species differences than to individuals or position in the wing. Across species, filoplume length and number increased with calamus length of primaries. In the 2 species with growing primaries, the number and length of filoplumes were only weakly associated with molting primaries, suggesting that filoplumes were not replaced when their companion primary was replaced. Further, filoplumes associated with a growing primary were not replaced synchronously, leaving others to sense primary position and movement. Finally, filoplume number and length were greatest in Red-tailed Hawks, a species that carries individual feathers for multiple years, but links between filoplume morphology and molt strategy await broader comparative studies. Taken together, the morphology of filoplumes and their replacement schedule relative to their associated primary suggests that they are sensors, capable of detecting subtle differences in the position and movement of their companion feathers.

scholarly journals An Analysis of the Relationship Between Metabolism, Developmental Schedules, and Longevity Using Phylogenetic Independent Contrasts

2007 ◽  
Vol 62 (2) ◽  
pp. 149-160 ◽  
Author(s):  
João Pedro de Magalhães ◽  
Joana Costa ◽  
George M. Church
Keyword(s):  
Body Size ◽  
Life Span ◽  
Comparative Studies ◽  
Adult Life ◽  
Postnatal Growth ◽  
Developmental Time ◽  
Age At Maturity ◽  
Adult Life Span ◽  
The Relationship ◽  
Species Longevity

AbstractComparative studies of aging are often difficult to interpret because of the different factors that tend to correlate with longevity. We used the AnAge database to study these factors, particularly metabolism and developmental schedules, previously associated with longevity in vertebrate species. Our results show that, after correcting for body mass and phylogeny, basal metabolic rate does not correlate with longevity in eutherians or birds, although it negatively correlates with marsupial longevity and time to maturity. We confirm the idea that age at maturity is typically proportional to adult life span, and show that mammals that live longer for their body size, such as bats and primates, also tend to have a longer developmental time for their body size. Lastly, postnatal growth rates were negatively correlated with adult life span in mammals but not in birds. Our work provides a detailed view of factors related to species longevity with implications for how comparative studies of aging are interpreted.

scholarly journals Allometry unleashed: an adaptationist approach of brain scaling in mammalian evolution

2019 ◽  
Author(s):  
Romain Willemet
Keyword(s):  
Body Size ◽  
Allometric Scaling ◽  
Species Differences ◽  
Brain Size ◽  
Brain Evolution ◽  
Neural Systems ◽  
Selection Pressures ◽  
Number Of Factors ◽  
Functional Consequences ◽  
Main Factor

The idea that allometry in the context of brain evolution mainly result from constraints channelling the scaling of brain components is deeply embedded in the field of comparative neurobiology. Constraints, however, only prevent or limit changes, and cannot explain why these changes happen in the first place. In fact, considering allometry as a lack of change may be one of the reasons why, after more than a century of research, there is still no satisfactory explanatory framework for the understanding of species differences in brain size and composition in mammals. The present paper attempts to tackle this issue by adopting an adaptationist approach to examine the factors behind the evolution of brain components. In particular, the model presented here aims to explain the presence of patterns of covariation among brain components found within major taxa, and the differences between taxa. The key determinant of these patterns of covariation within a taxon-cerebrotype (groups of species whose brains present a number of similarities at the physiological and anatomical levels) seems to be the presence of taxon-specific patterns of selection pressures targeting the functional and structural properties of neural components or systems. Species within a taxon share most of the selection pressures, but their levels scale with a number of factors that are often related to body size. The size and composition of neural systems respond to these selection pressures via a number of evolutionary scenarios, which are discussed here. Adaptation, rather than, as generally assumed, developmental or functional constraints, thus appears to be the main factor behind the allometric scaling of brain components. The fact that the selection pressures acting on the size of brain components form a pattern that is specific to each taxon accounts for the peculiar relationship between body size, brain size and composition, and behavioural capabilities characterizing each taxon. While it is important to avoid repeating the errors of the “Panglossian paradigm”, the elements presented here suggests that an adaptationist approach may shed a new light on the factors underlying, and the functional consequences of, species differences in brain size and composition.

scholarly journals How Precise are Size-Based Age Estimations in the Sand Lizard (Lacerta Agilis)?

2011 ◽  
Vol 56 (1-4) ◽  
pp. 11-17 ◽  
Author(s):  
Bartosz Borczyk ◽  
Łukasz Paśko
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Life Span ◽  
Age Estimation ◽  
The Body ◽  
Average Error ◽  
Ecological Studies ◽  
Age Classes ◽  
Sand Lizard ◽  
Lacerta Agilis

How Precise are Size-Based Age Estimations in the Sand Lizard (Lacerta Agilis)?Reptiles show a positive correlation between age and body size and it is common practice to infer the age of an animal from its size. However, the growth rate often differs between individuals, thus such practice may lead to false conclusions. Because age of an animal is a very important factor in many ecological studies, it should be determined with a minimum of error. Here, we compare the body size distribution among different age classes of the sand lizard (Lacerta agilis) to infer if it is possible to correctly determine their age on the basis of the body length. Our results show that the average error in age estimation on the basis of the lizard size is 1.36 year which is approximately 1/3 the average sand lizard life span.

Melanism and ontogeny: a case study in lizards of the Liolaemus fitzingerii group (Squamata: Liolaemini)

2016 ◽  
Vol 94 (3) ◽  
pp. 199-206 ◽  
Author(s):  
P.C. Escudero ◽  
I. Minoli ◽  
M.A. González Marín ◽  
M. Morando ◽  
L.J. Avila
Keyword(s):  
New Species ◽  
Body Size ◽  
Comparative Studies ◽  
Species Group ◽  
Evolutionary Adaptation ◽  
Body Measurements ◽  
Adaptation Studies ◽  
Present Evidence ◽  
Over Time

Color polymorphisms in general and melanism in particular have been the focus of many evolutionary adaptation studies. In lizards of the genus Liolaemus Wiegmann, 1834, patterns of melanism have been poorly studied, although they have been used as diagnostic characters for identifying and describing new species. We investigated the relationships between melanism, body size, sex, and time in a population of Rawson Lizard (Liolaemus xanthoviridis Cei and Scolaro, 1980) with extensive ventral melanism. The study took place in Bahía Isla Escondida, Chubut (Argentina), during three summer seasons (2012 to 2014). We tagged each individual, recorded body measurements and sex, and took ventral photographs to estimate the proportion of melanism. Our results showed that ventral melanism increased over time as each individual increased its snout–vent length (SVL). Body size explained 44% of the variation in melanism and males were more melanistic than females. Previous comparative studies of lizards in this species group showed no relationship between melanism and different taxonomic units or with thermal functionality. Here, we present evidence suggesting that melanism might be a character with an ontogenetic origin that is strongly associated with sex and body size. This pattern could be shared among species of this group of lizards, and even more importantly, it may be related to variable selection forces occurring throughout ontogeny.

scholarly journals Lamin regulates the dietary restriction response via the mTOR pathway in Caenorhabditis elegans

2021 ◽  
Author(s):  
Chayki Charar ◽  
Sally Metsuyanim-Cohen ◽  
Daniel Z. Bar
Keyword(s):  
Body Size ◽  
Caenorhabditis Elegans ◽  
Life Span ◽  
Dietary Restriction ◽  
Metabolic Regulation ◽  
Fat Content ◽  
Mtor Pathway ◽  
Reduced Body ◽  
Animal Size ◽  
Mtor Complex 1

Animals subjected to dietary restriction (DR) have reduced body size, low fecundity, slower development, lower fat content and longer life span. We identified lamin as a regulator of multiple dietary restriction phenotypes. Downregulation of lmn-1, the single Caenorhabditis elegans lamin gene, increased animal size and fat content, specifically in DR animals. The LMN-1 protein acts in the mTOR pathway, upstream to RAPTOR and S6K, key component and target of mTOR complex 1 (mTORC1), respectively. DR excludes the mTORC1 activator RAGC-1 from the nucleus. Downregulation of lmn-1 restores RAGC-1 to the nucleus, a necessary step for the activation of the mTOR pathway. These findings further link lamin to metabolic regulation.

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