Integrative Organismal Biology

Animal weapons are ecologically important traits that mediate contests over limiting resources and can strongly influence survival and reproduction. Weapon traits often exhibit substantial intraspecific morphological diversity, raising questions about the ecological drivers of this variation. Acrorhagi are weapons produced by sea anemones that are used in intraspecific territorial encounters. Although acrorhagial morphology varies widely within species, patterns of intraspecific variation remain poorly characterized, and the extent to which such variation reflects differences in local intraspecific competition is unclear. Here, we conduct morphometric analyses to characterize within-population variation and allometry in acrorhagial traits of the solitary anemone Anthopleura sola. We show that these traits covary with habitats differing in conspecific density. The number of acrorhagi scaled positively with body size, and individuals occupying a high-density habitat tended to possess more acrorhagi than did similar sized individuals from a low-density habitat. In addition, anemones from high-density habitats exhibited longer acrorhagial cnidae, a pattern that was not explained by differences in body size or acrorhagial density. Together, these results suggest that competitive context influences weapon-related traits at multiple levels of biological organization, potentially via phenotypic plasticity or selective processes. More broadly, our findings highlight how fine-scale ecological variation may contribute to the maintenance of trait diversity within and across species.

Cnidocytes (stinging cells), unique to cnidarians (corals, anemones, jellyfish), have diversified into distinct types with variable forms and functions. Nematocytes, cnidocytes found in all cnidarians, are used for prey capture and defense. When triggered, a pressurized capsule inside the nematocyte releases a harpoon-like structure attached to a hollow tubule that pierces prey and delivers venom. Ptychocytes, a cnidocyte unique to tube anemones (sister to corals and sea anemones) discharge a long spineless tubule used exclusively to build the tube in which the animal lives. Given that nematocytes and ptychocytes are specialized for different functions, we hypothesized that they might respond to firing cues in different ways. To test this, we examined the morphology, function, and distribution of nematocytes and ptychocytes in the North American Tube Anemone, Ceriantheopsis americana. We determined that ptychocytes have apical sensory structures like the cones previously described on nematocytes. Surprisingly, the body wall has a dense population of multiciliated cells that appear to function in tube formation. To determine how divergent selection pressures may have affected firing dynamics, we compared the discharge kinematics of cnidocytes from C. americana and the model sea anemone, Nematostella vectensis. Both nematocytes and ptychocytes from C. americana fired slower than nematocytes from N. vectensis, suggesting the rapid discharge speed of sea anemone nematocytes resulted from modification to these cells after sea anemones and tube anemones diverged from their common ancestor. By comparing the morphology and function of different cnidocytes, we can reconstruct the steps that gave rise to cnidocyte diversity.

The diversity of body shapes is one of the most prominent features of phenotypic variation in mammals. Yet, mammalian body shapes are poorly quantified and the underlying components contributing to its diversity as well as its relationship to other components of the skeleton are rarely tested. Here, we use lagomorphs (hares, rabbits and pikas) as a model system to (1) investigate which components of the skeleton contributed the most to body shape diversity, (2) examine the relationships between body shape and relative limb lengths, and (3) test how body size, ecotype, burrowing behavior, and locomotor mode influenced variation in lagomorph body shape and appendicular morphology. We quantified the body shape and functional proxies of the appendicular skeleton in 40 lagomorph species from osteological specimens held at museum collections. Using phylogenetic comparative methods, we found the relative length of the ribs and elongation or shortening of the thoracic and lumbar regions contributed the most to body shape evolution across lagomorphs. Second, we found that only leporids (hares and rabbits) exhibited a significant relationship between limb length and body shape, where more elongate species exhibit relatively shorter forelimbs and hindlimbs. Lastly, we found that models incorporating body size were the best predictors of lagomorph body shape and the majority of the appendicular traits, whereas models incorporating burrowing behavior and locomotor mode were largely poor fits. Broadly, these results indicate that larger lagomorphs tend to exhibit more robust body shapes with longer, more gracile forelimbs, whereas smaller lagomorphs tend to exhibit more elongate body shapes with shorter, more robust forelimbs. Overall, this work contributes to the growing understanding of mammalian body shape evolution and demonstrates the importance of not omitting body size in ecomorphological analyses.

Escape responses are a critical behavioural mechanism influencing survival during predation events. In most species of teleosts and several other lower vertebrates, these responses are triggered by Mauthner cells (M-cells), which generate faster escapes (characterised by higher turning rates and shorter response latencies) than non-M-cell triggered responses. Most adult elasmobranchs lack M-cells and consequently exhibit slower escape response timing than teleosts. Spotted Ratfish (Hydrolagus colliei) are a notable exception in that adults possess M-cells, yet their escape response performance has not been explored. Here, we quantify the kinematics and timing of ratfish escape responses elicited by a mechano-acoustic stimulus. We show that ratfish exhibit higher turning rates and shorter response latencies than other adult chondrichthyans, though their response latencies are also significantly longer than those of teleosts. These findings suggest that retention of M-cells confers enhanced escape performance in ratfish, with important implications for their vulnerability to predator attacks. Summary statementThis study reveals that adult Spotted Ratfish (Hydrolagus colliei) show fast escape response with a performance that is intermediate between teleosts and previously studied elasmobranchs.

Animals must continually balance foraging with the risk of predation. In complex natural environments, this means quickly distinguishing between threats and harmless situations. We investigated how site-associated coral reef fishes decide to escape in response to visual cues mimicking predator attacks, using controlled underwater presentations of looming stimuli at varying speeds. We measured escape responses across species and social contexts, comparing them to predator attack speeds observed in the same habitat. Escape responses were highly sensitive to the speed of the looming stimulus, with no responses occurring at low speeds. The speeds triggering escape matched those of predator attacks, whereas cruising swim speeds never triggered a response. Species employed distinct antipredator strategies: Brown Chromis foraged away from shelter with high responsiveness, whereas Bicolor Damselfish remained shelter-dependent with lower escape propensities. Contrary to expectations, the social factors did not affect responses in this study. These findings demonstrate that reef fish are highly sensitive to the approach speed of objects, with species-specific strategies further shaping behaviors. By combining realistic visual threats with natural predator attack data, this study offers insight into how animals make escape decisions in complex, real-world environments.

Factors varying along elevational gradients impose strong aerodynamic and physiological constraints on powered flight, yet the internal anatomical correlates of flight performance in animals under such conditions remain poorly understood. In hummingbirds, sustained hovering requires extreme muscular power output, making the pectoralis muscle a key interface between environmental constraint and performance. We tested whether elevation is associated with variation in pectoralis microanatomy across three hummingbird assemblages spanning a [~]1500 m gradient in the Colombian Andes. Using tissue morphometry of trichrome-stained transverse sections of the pectoralis, we measured interstitial collagen fraction as a proxy for extracellular matrix investment and quantified fiber cross-sectional area, packing density, and size heterogeneity. Collagen investment varied across elevational bands, peaking at mid elevation ([~]1750 m) and declining toward high elevation ([~]2600 m). In contrast, muscle fibers were smaller and more densely packed at higher elevations. Variation among species was small relative to differences among elevational assemblages. Formal model comparisons provided limited support for non-linear responses to elevation, indicating that patterns across traits are better explained by interacting constraints than by a single monotonic response to factors varying along elevational gradients. These results show that hummingbird flight muscle microanatomy varies with elevation in a trait-specific manner, with the strongest evidence in fiber geometry. More broadly, our findings highlight that multiple components of muscle microarchitecture, including the extracellular matrix, vary in a context-dependent manner across elevational gradients in an extreme volant system.

Silk glands have been found in two groups of amphipods: the Corophiida and the Ampeliscidae. The silk glands in Ampeliscidae, however, have yet to be examined in detail. Here we report, for the first time, the morphology and distribution of pereopodal glands in the Ampeliscidae, in non-thread producing Synopiidae, and in the Paragammaropsidae. In the Ampeliscidae we found two gland types distributed throughout all pereopods which have the ability to create threads. Pereopods three and four have additional silk extrusion morphology at the tip of the dactylus in which silk is transformed into semi-cylindrical threads used for building domiciles. Synopiid outgroup species have one of the gland types but lack silk extrusion morphology. Using ancestral state reconstruction analysis, we find that glands in the Synopiidae are likely ancestral and hypothesize that silk glands in Ampeliscidae are derived from these ancestral glands. Silk-spinning pereopods in the Paragammaropsidae had similarities with both Corophiida and Ampeliscidae but had distinctions. Ampeliscidae silk-spinning systems bear surprising resemblance to the Corophiida which presents one to reconsider the taxonomic placement of Ampeliscidae and the origins of silk-spinning in amphipods. This is the first comprehensive study on the glandular systems of Ampeliscidae, Synopiidae, and Paragammaropsidae using advanced microscopy, providing pertinent morphological data to the study of arthropod silk gland evolution and complex traits.

The evolution of body shape reflects the interplay between functional constraints and habitat structure. In fishes, cave environments are well known for promoting regressive traits such as eye and pigment loss, yet their influence on overall body form remains poorly understood. Here, we examine patterns of body shape variation in cave- and surface-dwelling trichomycterid catfishes from northeastern Colombia to assess whether consistent associations exist between habitat type and morphology. Using geometric morphometric analyses, we quantified differences in body shape among species inhabiting subterranean and surface environments. Our results reveal significant habitat-associated differentiation in body shape along the main axes of morphological variation. Cave-dwelling species exhibit more elongated and fusiform body shapes, whereas surface-dwelling species tend to show deeper and more robust morphologies. In a functional context, these contrasting body patterns suggest associations with differing locomotor demands imposed by subterranean versus surface habitats. Although we do not explicitly test convergence or performance, the recurrence of similar body shapes among species from different clades occupying comparable habitats is consistent with repeated morphological responses to shared ecological constraints. Research HighligthsO_LIMultivariate shape analyses reveal significant habitat-associated variation in trichomycterid fishes. Recurrent morphological patterns suggest repeated responses potentially mediated by habitat constraints. C_LIO_LIBody shape differs consistently between cave- and surface-dwelling trichomycterids. Cave species exhibit more elongated and fusiform forms, whereas surface species display deeper body configurations. C_LI

Protogynous sex change, where individuals first function as females and later as males, is a key life-history strategy among polygynous reef fishes. In haremic systems, sex change is typically socially regulated, with dominants suppressing subordinates sex change through aggression. Females within a harem form a size-based hierarchy that can remain stable in most species through the threat of eviction. We studied a different situation in the cleaner wrasse Labroides dimidiatus, where larger females have incomplete control, as they spend most of their time alone at their own cleaning territory. We tracked over 400 individuals for 12 months, recording growth, behavior, social organization, and sex change. We confirmed earlier reports that both sexes direct aggression primarily at those ranked immediately below them. However, we observed 30 cases where smaller females outgrew larger ones, revealing hierarchy instability. Of 42 sex change events, 43% occurred in presence of the male, and half of these early sex changers were not the largest female, but individuals overlooked by the male. Fast growth relative to harem-mates and harem switching increased the likelihood of sex change. Local population densities also influenced growth and sex change, with individuals in high-density demes growing faster and changing sex at larger sizes. Our findings reveal flexible sex change dynamics in a system with incomplete social dominance. Such incomplete control and observations that becoming male confers both higher reproductive success and survival highlight the need to expand game-theoretical and life-history frameworks to encompass such strategic flexibility. Lay summaryDominant cleaner wrasse cannot fully control subordinates as individuals occupy distinct core areas. Tracking 400 fish for a year, we found that smaller females could outgrow initially larger ones, and early sex change despite a larger male. Fast growth and harem switching increased the chances of becoming male. Population density also shaped these strategies. Our findings reveal flexible sex change dynamics in a system where becoming male confers both higher reproductive success and survival.

Although predation is a major driver of group living across taxa and the antipredator benefits of grouping are well established, the energetic costs experienced by groups under predation remain largely unexplored. In the current study, we use wild, white mullet (Mugil curema, Valenciennes 1836), to provide the first real-time quantification of the energetic cost of escape in schooling fish using intermittent, closed-loop respirometry. We found that small groups exposed to predators showed a 53.8% increase in their organismal metabolic rate (MO2) as compared to groups without predator exposure. When we evaluated antipredator behaviors such as escape response, group cohesion, and displacement of the group centroid, we found a positive correlation to energetic costs. We then investigated whether escape responses are socially modulated by comparing the energetic costs of escape across solitary individuals, solitary individuals with visual access to a group, and groups. We found that escape frequency and energetic costs to predation were comparable across social contexts, indicating that escape may be an intrinsic survival response independent of cues from group members. Furthermore, we found that fish exposed to predators showed markedly reduced feeding, suggesting that predation constrains energy acquisition in addition to imposing direct energetic costs. Our results provide the first direct quantification of the energetic costs of escape in a schooling fish, offering new insights into the physiological trade-offs underlying collective antipredator defenses.

Arboreal insects have developed various strategies to navigate their discontinuous habitats. Many insects, including leafhoppers, katydids, and praying mantises, exhibit the ability to actively leap across their leafy platforms and land on a distant substrate. This behavior is especially important for non-winged insects, including nymphal forms of winged insects, which cannot fly between these substrates. To make a targeted jump, an animal must first orient towards the target, estimate the target distance and angular location, and jump with the appropriate take-off speeds and angles to land on their intended substrate. In three-dimensional space, jumping from one point to another requires estimating distance, as well as azimuthal and elevational angles. Jumping insects such as mantises typically reorient their bodies on the substrate to align with the azimuthal direction of the target. This behavior effectively reduces the task to a two-dimensional problem, in which they must estimate only the distance to the target and its elevational angle. Many insects, including praying mantises, perform rhythmic lateral head movements called peering before performing a targeted jump. Although previous studies suggest that mechanisms such as motion parallax while peering are used for distance estimation, the full repertoire of behaviors that enable mantises to jump to arbitrarily located substrates remains unclear. We hypothesized that mantises have distinct behaviors for distance and elevation angle estimation, which enable them to independently modulate their take-off speeds and angles before jumping. To test this hypothesis, we developed behavioral assays in which mantises were placed on a launch platform and jumped to a target platform positioned at variable distances and angles. Using this apparatus, we filmed the jumps of Giant Asian mantis nymphs (Hierodula spp.) with high-speed videography and tracked body parts to quantify take-off speed and angle. Because mantis jumps are ballistic, their trajectories can be modeled as projectile motion. Our results indicate that mantises estimate target distance and elevation angle using two separate behavioral strategies: distance is assessed through peering maneuvers that generate motion parallax, whereas elevation angle is determined through visual fixation of the target accompanied by specific postural adjustments. By combining these behaviors, mantises modulate the magnitude and direction of propulsive force to achieve successful jumps.

Historically, venom potencies have been assessed using measures of lethality, such as the median lethal dose (LD50). However, venoms may be selected primarily for their ability to rapidly incapacitate rather than cause mortality, meaning LD50 may not capture the efficacy of venoms in an ecological and evolutionary context. To capture this context, recent studies have adapted measures that assess venoms ability to rapidly incapacitate, such as the median effective dose (ED50). However, while ED50 values are expected to provide a more proximate assessment of ecological variation in venom potency, it is unknown whether historically available LD50 values are still useful proxies of ecologically relevant potency or whether they capture independent axes of venom variation. Here, we test the relationship between LD50 and ED50 in spider venoms by experimentally estimating LD50 and ED50 for 12 species and collating additional potency data for 40 species retrieved from the literature. We observed an isometric relationship between LD50 and ED50 in both analyses, showing these potency measures are both strongly coupled, with an increase in paralysis efficiency associated with a similar increase in lethality. Our results suggest that the functional aspects of venom potency, paralysis and lethality, are intrinsically linked, and due to this strong mechanistic coupling, historically available LD50 values may be used to compare general venom potencies in spiders, provided that they are based on the same prey model.

Capturing and handling wild animals is essential for ecological and evolutionary research, yet their effects on physiology, behaviour, and reproductive success remain poorly understood. We investigated short- and longer-term consequences of a capture-handling-restraint protocol in wild great tits (Parus major) over three breeding seasons. To assess short-term responses, we measured circulating corticosterone, a metabolic hormone that responds to unpredictable challenges, and automatically recorded provisioning behaviour. We also explored whether environmental and individual traits were related to provisioning latency (i.e., time to resume provisioning after capture). To evaluate longer-term effects, we monitored provisioning in the days following capture and related it to reproductive success (fledgling number and body condition). We predicted that longer handling would increase stress-induced corticosterone and provisioning latency, that these variables would be positively correlated, and that higher corticosterone and longer latencies would be associated with lower reproductive success. After capture, great tits showed elevated corticosterone and delayed provisioning. Contrary to our predictions, handling duration was negatively associated with stress-induced corticosterone in males (but not females) and did not affect provisioning latency. Provisioning latency was unrelated to corticosterone, environmental, or individual variables. Following capture, parents resumed provisioning, and short-term responses had little influence on reproductive success. We show that parental behaviour and physiology are affected by capture restraint protocols on the short term, but offspring condition and survival are not. However, these results should be interpreted cautiously, as our study lacks an uncaptured control group. Our findings highlight that evaluating welfare impacts requires rigorous study design incorporating both immediate and longer-term behavioural and fitness effects.

Non-avian reptiles have been assumed to be non-social for many years, yet recent studies show diverse social behaviours in squamates, crocodilians, and turtles. Here, we investigate social structure within feeding aggregations of three freshwater turtle species caught in baited traps in a coastal marsh over 12 years. In 488 instances in which traps contained turtles, 45% contained multiple individuals, and these aggregations were strongly positively assorted by species. midland painted turtles (Chrysemys picta) and Blandings turtles (Emydoidea blandingii) were captured with conspecifics more often than expected in a non-social null model. Snapping turtles (Chelydra serpentina), the largest species in this study, were caught with conspecifics at rates consistent with the non-social null model, and were avoided by heterospecifics. This suggests that species differences play a role in how feeding aggregations are structured, with painted and Blandings turtles driving positive species assortment while avoiding snapping turtles around food sources. We did not detect significant intraspecific sex assortment in any of the three species, nor did turtle body size strongly affect the probability of aggregating with conspecifics at the perceived food source in the traps. Our study illustrates how long-term monitoring data can be used to investigate social structure in wild populations, an approach that may be valuable for species of conservation concern. Significance StatementReptile sociality has been historically overlooked, but recent work has revealed intriguing social behaviours in non-avian reptiles. We investigated associations among three species of freshwater turtle, captured in baited traps over 12 years of trapping. Turtles in these feeding aggregations grouped with their own species more often than expected by chance. This result was driven by the two smaller-bodied species (midland painted turtle and Blandings turtle), which were more likely to be caught with conspecifics than with other species. In contrast, the largest species (snapping turtle) showed no evidence of attraction to other snapping turtles, and midland painted turtles and Blandings turtles showed avoidance of the larger snapping turtles. Our analyses illustrate how long-term monitoring data can be used to uncover previously unrecognized social behaviour in turtles and other species in which behaviour is difficult to observe directly.

Interactions between cleaner fish Labroides dimidiatus and client fish, from which cleaners remove ectoparasites and mucus, represent a textbook example of mutualism involving sophisticated strategic decision-making. However, cleaners must also face intraspecific social challenges within a size-based hierarchy, where the largest females may eventually change sex and become males with higher reproductive rates. Following 540 individuals over 11 months, we found that, contrary to expectations, slow-growing females spent more time cleaning and cheated more frequently, without causing more negative client responses than fast-growing females did. Instead, variation in growth was best explained by social factors: fast-growing individuals experienced reduced social control, while slow growers spent more time in proximity to dominant individuals. As there was no evidence that spawning activity affected growth patterns, it appears that fast growth as a viable strategy for becoming a male largely depends on the lack of control by dominants.

Sarita Lake, British Columbia houses a distinctive population of threespine stickleback (Gastrosteus aculeatus L.) with a phenotype characterized by unusually large individuals relative to nearby conspecifics. We tested the hypothesis that members of this population are not isometrically larger but rather exhibit variation in allometric trajectories that reflect changes in developmental timing impacting the developmental-genetic architecture of the phenotype. We used 3D geometric morphometrics to characterize the size and shape of skulls, pectoral girdles and pelvic girdles from a sample of individuals from nearby freshwater and marine populations and compare them to a sample from Sarita Lake. We showed that individuals from the Sarita Lake population are larger in each body region compared to most other populations examined. Further, these individuals have dorsally expanded skulls and relatively robust pelvic armour. We also showed that the relationship between size and shape is differently structured among body regions and is heavily influenced by non-uniform sexually-mediated variation across populations sampled. Our results reflect complex underlying developmental trajectories, and we suggest that the large phenotype observed may be driven by fecundity selection on female size in combination with a limnetic trophic niche and relatively increased predation pressure in Sarita Lake.

Within species, individuals of the same age can differ in size. Previously, parental genetics, nutrition, space, and social interactions have been suggested to explain different growth rates. However, direct effects of larger individuals on the physiology and growth of smaller individuals are poorly understood. In this study, we investigated how larger individuals of the marine worm Platynereis dumerilii can impact the growth of smaller conspecifics. Comparing growth distributions in communally and individually reared worms, we show that larger worms suppress the growth of smaller ones. Furthermore, we were able to demonstrate that this suppression is chemically mediated. The chemical cue does not originate from faeces but is water soluble, stable for several days and smaller than 3 kDa. Our findings highlight the importance of non-reproduction related chemical signalling, showing evidence that dominant individuals can chemically suppress the growth of their conspecifics. This study provides new insights into how hierarchy can be established and maintained in a population and is particularly relevant for the growing community studying this model species.

Multimodal communication plays a central role in animal behavior, particularly when individuals must integrate information from different sensory channels to make rapid decisions. In aquatic environments, chemical and visual cues differ markedly in their spatial and temporal properties, such that chemical signals may be constrained by limited spatial resolution and temporal instability, potentially requiring visual information to reliably guide social decisions. In decapod crustaceans, both cue types are known to mediate reproduction, yet their relative contribution to mate-location behavior remains unclear. Here, we tested how visual and chemical cues from males influence mate-location behavior in females of the prawn Macrobrachium rosenbergii. Females were placed in a central arena and exposed to four stimulus configurations combining visual cues (a life-size photograph of a male or a control background) and chemical cues (water from an aquarium with or without a male). Attraction was quantified as the time spent in each half of the arena. Females showed no directional preference when exposed to chemical cues alone or when visual and chemical cues were spatially incongruent. In contrast, females spent significantly more time near male-associated stimuli only when visual and chemical cues were spatially congruent. These results indicate that mate-location behavior in this species depends on multimodal integration with a strong contextual dependence on visual information, which appears to gate the effectiveness of chemical cues. Spatially congruent multimodal signals are therefore necessary to guide orientation during mate search, suggesting that disruption of visual or chemical information in aquaculture systems may impair mating efficiency.

Group-living animals often coordinate their behavior using "contact calls". Identifying the function of these calls requires testing whether they are intended for any group member or targeted to specific preferred associates. If contact calling is used to coordinate with preferred associates, then higher rates of contact calling are expected between group members with a history of more frequent affiliation and cooperation. To test this hypothesis, we constructed a contact-calling network using synchronized recordings of vocal interactions between all 28 possible pairs of 8 female common vampire bats with well-sampled histories of social grooming and regurgitated food sharing. Bayesian multilevel models show that pairwise rates of contact calling were clearly predicted by social grooming and cooperative allofeeding rates in ways not explained by kinship. These findings show that common vampire bats use contact calls to coordinate with specific same-sex associates, unlike other studied bat species where individuals produce contact calls at similar rates towards different group members. We also found that, compared to white-winged vampire bats, common vampire bats are ten times less likely to rapidly respond to a contact call; this suggests yet-to-be-discovered differences in social behavior between vampire bat species. Finally, we discuss implications for the vocal grooming hypothesis.

Linking animal movements to environmental drivers is essential for understanding ecological processes and anticipating species responses to climate change. We investigated habitat-specific movements in a globally significant aggregation of loggerhead turtles (Caretta caretta) nesting in Cabo Verde. Satellite tags on 15 adults (12 females, 3 males) provided multi-year tracks spanning breeding, migration, and foraging habitats. Movements and phenology differed by habitat. During the breeding season, females used either coastal areas, remaining within [~]20 m depth, or undertook long looping forays up to 360 km. Males showed two strategies: two remained resident in Cabo Verde waters, including Fra, the largest male tracked (Curved carapace length of 105 cm compared with a male mean of 90.7 {+/-} 10.3 cm), while the third migrated annually to distant foraging grounds and returned ahead of the subsequent breeding season. In foraging habitats, turtles adopted neritic or oceanic strategies: neritic turtles remained localised in warm, productive waters, whereas oceanic turtles ranged widely in deeper, less productive areas. Time- and space-shift analyses showed that oceanic foragers used intermediate sea surface temperature and chlorophyll-a conditions relative to nearby or temporally shifted alternatives, consistent with movement within a thermal-trophic trade-off. Together, these results show how sex, body size, and energy balance drive habitat-specific movement dynamics in a changing ocean.