Alexandre V. Palaoro

Alexandre V. Palaoro
Clemson University | CU · Department of Materials Science & Engineering

PhD

About

41
Publications
8,944
Reads
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341
Citations
Introduction
Horns, claws, spines, proboscises, and tusks are examples of morphological structures that range from relatively tiny to proportionally gigantic in the lineages in which they occur. Think of elephant tusks - they range from a regular canine tooth to a protruding tusk that can have more than 3 meters in length. Understanding how and why such structures grow and evolve are the types of questions I am interested in.
Additional affiliations
March 2015 - September 2015
University of Plymouth
Position
  • International PhD Student
November 2008 - February 2017
Universidade Federal de Santa Maria
Position
  • PhD Student
Education
March 2013 - February 2017
Universidade Federal de Santa Maria
Field of study
  • Animal Biodiversity
March 2011 - February 2013
Universidade Federal de Santa Maria
Field of study
  • Animal Biodiveristy
March 2007 - February 2011
Universidade Federal de Santa Maria
Field of study
  • Biological Sciences

Publications

Publications (41)
Article
Full-text available
Theoretical models have been developed to understand how animals decide to withdraw from a contest. They provide testable predictions regarding the relationship between resource holding potential (RHP) and contest duration that assume linear relationships among RHP traits. However, RHP traits might scale with body size according to power laws. Furt...
Article
Full-text available
How animals decide to withdraw from a contest has puzzled researchers for years. Currently, four models try to explain how this decision is made: war of attrition (WOA); cumulative assessment (CAM); opponent-only assessment (OOA); and sequential mutual assessment (SAM). Although their predictions differ, they must be simultaneously tested to infer...
Article
Full-text available
This study compared aggression in two morphologically similar neotropical burrowing crayfishes, Parastacus pilimanus, a primary burrower, and Parastacus brasiliensis, a secondary burrower. Intraspecific pairs were formed, with a maximum 15% difference in carapace and chelae length within each pair. Pairs were allowed to interact for 20 min, during...
Article
Full-text available
Animals living in extreme environments with predictable seasonality may have important life history events correlated to favourable periods. These animals pass critical life stages in protected habitats, especially during early life, often receiving parental care. It is thus hypothesized that juveniles rely on protective microhabitats provided by t...
Article
Full-text available
Invasive species are one of the most severe threats to biodiversity, and an ability to predict the extent of potential invasions can help conservation strategies. Species distribution models (SDMs) have been widely used to project the potential range of invasive species. These models assume that species retain their niche properties during invasion...
Article
In many species that fight over resources, individuals use specialized structures to gain a mechanical advantage over their rivals during contests (i.e. weapons). Although weapons are widespread across animals, how they affect the probability of winning contests is still debated. According to theory, understanding weapon function during contests is...
Article
Animal weapons are generally complex systems composed of more than one structure. A crab’s claw, for instance, is composed of a dactyl (a movable finger) and a propodus (where the muscle resides). Any weapon feature that increases winning probability also increases an individual’s fitness, meaning that all moving parts of a weapon will be under the...
Article
Full-text available
Birds are a remarkable example of how sexual selection can produce diverse ornaments and behaviours. Specialised fighting structures like deer's antlers, in contrast, are mostly absent among birds. Here, we investigated if the birds’ costly mode of locomotion—powered flight—helps explain the scarcity of weapons among members of this clade. Our simu...
Article
Full-text available
Animal contests involve threatening displays and physical coercion, which are respectively performed by threat devices used in mutual evaluation of size or strength, and weapons used for grasping, stabbing, striking, or dislodging a rival. According to the functional allometry hypothesis, directional selection consistently favors hyper-allometry in...
Article
In many species, males possess specialized weaponry that confers benefits during male-male combat. Because male weapons are often disproportionately larger versions of preexisting body parts, females often possess reduced versions of male weaponry. Most research focuses exclusively on sexual dimorphism in the size of male and female weapons, even t...
Article
Full-text available
Crustaceans are known for their ability to autotomize and regenerate their appendages. The appendages that are most often autotomized are their chela, often specialized as claws, which serve essential functions including foraging, fighting, mating, and predator defense. Crustaceans with autotomized or regenerated chelae may suffer decreases in thei...
Preprint
Full-text available
In many species that fight over resources, individuals use specialized structures to gain mechanical advantage over their rivals during contests (i.e., weapons). Although weapons are widespread across animals, how they affect the probability of winning contests is still debated. According to theory, understanding the weapons’ function in contests d...
Article
Full-text available
Horizontal transmission between distantly related species has been used to explain how Wolbachia infect multiple species at astonishing rates despite the selection for resistance. Recently, a terrestrial isopod species was found to be infected by an unusual strain of supergroup F Wolbachia. However, only Wolbachia of supergroup B is typically found...
Preprint
In many species, males possess specialized weaponry that have evolved to confer a benefit during aggressive interactions. Because male weaponry is typically an exaggerated or extreme version of pre-existing body parts, females often possess reduced or weaponry. Although much research has investigated sexual dimorphism in the sizes of such weapons,...
Article
Sexual selection influences the evolution of morphological traits that increase the likelihood of monopolizing scarce resources. When such traits are used during contests, they are termed weapons. Given that resources are typically linked to monopolizing mating partners, theory expects only males to bear weapons. In some species, however, females a...
Article
Full-text available
In many species, individuals contest resources using specialized morphologies to overpower rivals, hereafter referred to as weapons. Despite their importance in fights, little is known about the selective forces affecting weapon evolution. This may be particularly important to understand why weapons are highly variable among species. Due to their r...
Article
Full-text available
Once thought to be the magical horn of a unicorn, narwhal tusks are one of the most charismatic structures in biology. Despite years of speculation, little is known about the tusk's function, because narwhals spend most of their lives hidden underneath the Arctic ice. Some hypotheses propose that the tusk has sexual functions as a weapon or as a si...
Chapter
Due to an exceptional variety of habitats, body plans, and lifestyles, crustaceans exhibit a wide array of mating systems. Some groups engage in simple, pure- search polygamous systems in which males usually search for receptive females. In other groups, males defend valuable resources to attract and/ or guard females to ensure paternity. Some spec...
Chapter
Many crustacean species are known to provide parental care, with behaviors ranging from ventilating the eggs to providing food for young. This chapter provides an overview of parental care patterns across crustaceans, and then compares crustacean parental care to that of select other taxa (insects, fishes, frogs) that share important traits with cr...
Article
Full-text available
Animal contests are energetically costly, but injuries are said to be rare. In gladiator frogs, the males possess a spine beneath their pollex (i.e., prepollex) that can be used as weapons and frequently leave scars during contests over spawning areas. Knowing how scars are made, and how scars are distributed among individuals, might prove valuable...
Article
Full-text available
Contesting scarce resources can trigger the evolution of specialized morphological structures (i.e., animal weapons). While most research focus on male weapons, females might also bear weapons, although generally smaller and less conspicuous than male weapons. Social selection is evoked to explain female weaponry in which females fight for nonsexua...
Article
Exaggerated morphologies may increase fitness, but they might be costly to bear; heavy weight, for instance, might hinder locomotion. Evidence supporting these costs are sparse because animals that move on land or swim have traits reducing those costs, called compensatory traits. Animals that walk underwater, however, are under different environmen...
Article
Since the 1970's, models based on evolutionary game theory, such as war of attrition (WOA), energetic war of attrition (E-WOA), cumulative assessment model (CAM) and sequential assessment model (SAM), have been widely applied to understand how animals settle contests. Despite the important theoretical advances provided by these models, empirical ev...
Article
Full-text available
Patterns of allocation between reproduction, survival and maintenance are what we call life history. By investigating the life history strategy of sympatric species, we may understand how they are able to coexist, as different strategies are expected to evolve in species that occupy similar niche space. Terrestrial isopods are a group in which mult...
Article
Full-text available
Invasive species are one of the major threats to biodiversity, which is aggravated in poorly known groups, such as cladocerans. Daphnia lumholtzi Sars (Cladocera: Anomopoda: Daphniidae) is currently invading the Neotropical region, and there are few records of this process. Our goal was to predict the invasive scenario for D. lumholtzi in the Neotr...
Article
Full-text available
An animal's decision to enter into a fight depends on the interaction between perceived resource value (V) and fighting costs (C). Both could be altered by predictable environmental fluctuations. For intertidal marine animals, such as the sea anemone Actinia equina, exposure to high flow during the tidal cycle may increase V by bringing more food....
Article
Fighting is a costly behavior, consuming both time and energy. As a result, the benefits of acquiring resources must outweigh these costs. Resource value will thus influence willingness to invest in a contest through its objective (the intrinsic properties of the resource) and subjective value (context/state dependent). In burrowing crayfish, subje...
Article
Full-text available
Species with similar niches may exhibit adaptations to diminish competitive pressure and allow sympatry; freshwater decapods are interesting models for the investigations of these strategies. We studied the behavior of two co-occurring decapod species: the anomuran Aegla longirostri and the crayfish Parastacus pilimanus, and investigated the follow...
Article
Full-text available
Biological invasions are a major cause of biodiversity loss, and early action in these cases is more cost-effective than dealing with widespread invasions. Thus, understanding possible consequences of invasions is essential for control and management actions. Given the early stage of invasion of South America by Procambarus clarkii, a potentially h...
Article
Agonistic behavior can be either extremely variable or extremely conserved among species of the same genus. In general, species with similar morphologies and ecology tend to show similar agonistic behaviors. Understanding the variability of agonistic behavior is essential for elucidating the main drivers of the evolution of aggressive behavior. Aeg...
Article
Full-text available
Aeglids are freshwater anomurans that are endemic from southern South America. While their population biology at the species-level is relatively well understood, intraspecific variation within populations has been poorly investigated. Our goal was to investigate the population biology of Aegla platensis Schmitt, 1942 from the Uruguay River Basin, a...
Article
Full-text available
Crayfish from the Neotropical region comprise a unique group among crustaceans. Their burrowing habits have severe consequences for many ecological, morphological, and behavioral traits. Although they are all considered true burrowers, the degree of these adaptations and their relationships to the behavioral repertoires of these crustaceans have be...
Article
Full-text available
This study analyzed sexual selection in Aegla longirostri through one of the mechanisms that can alter species’ evolution: mate choice. Y maze experiments were performed by placing a male or a receptive female (chooser) in the center of the maze; and two other individuals were placed each in a differ-ent corridor, according to the chooser: a recept...
Article
Full-text available
Communication plays a large role in resource competition, especially for potential mates, and is used by members of the competing sex to assess each other, and simultaneously to evaluate the other sex, which may be advertising its status. To assess the effects of female advertisement on male aggression, males of the decapod Aegla were paired accord...
Article
Full-text available
This study describes the mother-offspring behaviour in the South American burrowing crayfish Parastacus pilimanus (Von Martens, 1869), by testing the mother’s offspring-recognition abilities (and vice-versa) and the tolerance of a non-parental adult to juveniles. A female carrying first-instar juveniles was collected and acclimated in the laborator...

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Project
Sexually selected traits can vary widely in their function, with the most common being ornaments, which are used to attract mates, and weapons, which are used to fights with same-sexed individuals. To achieve their goal of increasing the bearer’s fitness, these traits need to be flashy and/or mechanically efficient, and when combined with high levels of intrassexual competition, environmental and sexual selection pressures, these traits can reach exaggerated sizes and forms. Although exaggeration may increase fitness, it may also impose survival costs to the individual, either via decreased locomotor performance or increased exposure to predators. To mitigate such costs, individuals can present a wide range of morphological/physiological adaptations to counter that cost - the compensatory traits. Aegla longirostri crabs have the left claw adapted for fighting, which means they invest heavily in musculature and size to be able to overcome their opponents in fights. This increased size and weight could impair the male locomotor’s performance even within an aquatic environment. Therefore, given that exaggerated traits may decrease males’ locomotor performance and hence survival, our goal is to test if A. longirostri is morphologically compensating for its’ large and heavy claw.