Diel Cycles in Chemosensory Behaviors of Free‐Ranging Rattlesnakes Lying in Wait for Prey

The sensory ecology of foragers is fundamentally influenced by changes in environmental conditions such as ambient light. Changes in ambient light may hinder the effectiveness of particular senses (e.g., impaired vision at night), but many predators rely on multiple sensory systems and may continue to forage despite changes in light availability. Exactly how predator behaviors and sensory systems compensate under changes in light availability in the field is not well understood. We used radio telemetry and portable video surveillance cameras to quantify the sit‐and‐wait chemosensory foraging behavior of free‐ranging red diamond (Crotalus ruber) and northern Pacific (Crotalus oreganus oreganus) rattlesnakes during day and night periods. The two most common behaviors we observed were chemosensory probes, a behavior we describe in detail for the first time, and mouth gapes. During chemosensory probes, rattlesnakes extend their head beyond their coil, explore the surrounding area while tongue‐flicking, and subsequently return to a stationary position inside their coil. Foraging rattlesnakes probed at significantly higher rates during nocturnal vs. diurnal hours. Similarly, mouth gaping occurred during a higher percentage of nocturnal vs. diurnal hours for foraging snakes. Nearly half of all mouth gapes were followed immediately with a chemosensory probe, suggesting that mouth gaping also serves a chemosensory function in this context. Our results suggest that chemical cues play an increasingly important role in mediating rattlesnake foraging behavior at night. Examining how abiotic factors, such as light availability, influence the sensory ecology of free‐ranging predators is essential for accurately characterizing their interactions with prey.     

One-male groups and intergroup interactions of mountain baboons

The behavioral ecology of mountain baboons, Papio ursinus,cuts across the traditional dichotomy between savannah and desert baboons, providing fresh opportunities to examine socioecological relationships. Mountain baboons were studied at a site where covariation in altitude and group size helps to clarify the influence of ecology on social behavior. One-male groups and lone males were regularly found in the highest-altitude zones. In encounters with multimale groups, a one-male group retreated; the group’s single male attacked his females, herding them far away from the multimale group. The male himself then approached and watched (and often loud-called at) this group. In a two-male group, the younger male herded the females, while the older sometimes defended the group. One-male groups did not show regular, stable aggregations, but two such groups seasonally coordinated their ranging “in tandem.” Ecological explanations for these behaviors and their relationship to the behavior of hamadryas baboons are evaluated, and a new theory of the origin of one-male groups in baboons is developed.     

Rank Differences in Ecological Behavior: A Comparative Study of Patas Monkeys (Erythrocebus patas) and Vervets (Cercopithecus aethiops)

One of the central dichotomies in primate behavior is between species in which there are relationships among females that include stable dominance relationships, and those in which the relationships include weak or unstable dominance relationships. This dichotomy has been attributed to differences in food resources, with stable dominance hierarchies occurring in species that feed on usurpable foods. We compared rank-related differences in nonagonistic behaviors considered to be tightly linked to ecology in broadly sympatric vervets (Cercopithecus aethiops) and patas monkeys (Erythrocebus patas), two closely related cercopithecines that are exemplars of this dichotomy, with the expectation that vervets would exhibit stronger rank differences than patas monkeys in these behaviors. Overall, rank explained more than twice as much variation among vervets as among patas monkeys in ranging behavior, activity budgets, and diet. Vervets did not, however, exhibit stronger rank differences when they used Acacia xanthophloea habitat, in which foods are more usurpable, compared to Acacia drepanolobium habitat, in which foods are less usurpable. In Acacia drepanolobium habitat, to which patas are restricted, higher-ranking vervets converged in behavior with patas monkeys to a greater extent than lower-ranking vervets, suggesting that social constraints interfere with the foraging efficiency of lower-ranking vervets even in habitats in which there are fewer opportunities to usurp foods.     

Sensory ecology of salps (Tunicata,thaliacea): More questions than answers

There is still relatively little known about the natural history of gelatinous animals in the plankton, and their sensory ecology remains largely a matter of surmise, based on limited morphological, physiological and behavioral data. Pelagic tunicates are among the most widely distributed and abundant of the gelatinous zooplank‐ton, and display a range of behavior that is apparently cued by aspects of their environment. Different kinds of information may be important for different scales of behavior. Feeding and predator avoidance are likely to be affected by near‐field stimuli from visual, chemical or mechanical sources, while far‐field information such as gravity, light, temperature, or pressure are likely to cue behavior spanning larger time and space scales, such as vertical or ontogenetic migration, aggregation and reproductive cycles. A variety of sensory structures have been described in pelagic tunicates, including photoreceptors of varying complexity, and several structures that have been suggested to be mechano‐ or chemoreceptors. Focussing on salps, this paper describes behavior that depends on sensory information, reviews the known structure and function of sensory receptors, and suggests some hypotheses on mechanisms defining the sensory ecology of these planktonic organisms.     

Coordination of opposing sex-specific and core muscle groups regulates male tail posture during Caenorhabditis elegans male mating behavior

Background  

To survive and reproduce, animals must be able to modify their motor behavior in response to changes in the environment. We studied a complex behavior of Caenorhabditis elegans, male mating behavior, which provided a model for understanding motor behaviors at the genetic, molecular as well as circuit level. C. elegans male mating behavior consists of a series of six sub-steps: response to contact, backing, turning, vulva location, spicule insertion, and sperm transfer. The male tail contains most of the sensory structures required for mating, in addition to the copulatory structures, and thus to carry out the steps of mating behavior, the male must keep his tail in contact with the hermaphrodite. However, because the hermaphrodite does not play an active role in mating and continues moving, the male must modify his tail posture to maintain contact. We provide a better understanding of the molecular and neuro-muscular pathways that regulate male tail posture during mating.     

Spasm behavior and the diffuse nerve-net in Cassiopea xamachana (Scyphozoa: Coelenterata)

A quick train of diffuse nerve-net (DNN) impulses is required to initiate a patterned flurry of strong contractions, the ‘spasm,’ of the striated muscles of the rhizostome scyphomedusan Cassiopea xamachana. A number of spasms are illustrated. Using this response as a tool, the connectivity of the DNN has been established. The occurrence and variability of the spasm is illustrated with an analysis of their occurrence in a typical, extended experiment. It is proposed that the spasm is an integral and essential component of the behavior of scyphomedusae, and that its control by the DNN exemplifies how complex behavior is generated.     

流域生态学的发展困境——来自河流景观的启示

随着中国生态环境问题越来越多地呈现出流域特性,流域生态研究的重要性和紧迫性也日渐凸显。整合流域生态研究,形成一个有效的研究体系,流域生态学迄今未能予以实现。通过对"流域生态学"和"河流景观"这两个相近概念提出过程的比较研究,探讨流域生态学发展困境产生的原因,为流域生态研究体系的构建提供思路。分析结果显示流域生态学目前主要存在两个不足:1)因为提出流域生态学概念的关键现实需求不明确,导致难以确定其核心科学问题;2)因为没有相应的流域生态系统概念模型,进而也就难以带动相关研究落实跟进。要推进流域生态学的发展,第一步要做的就是明确流域生态研究体系构建的核心现实需求,并对流域生态系统进行一个概念模型上的相应设计。     

Habitat and the evolution of social and reproductive behavior in callitrichidae

The numerous remarkable traits characterizing the ecology and behavior of callitrichids have inspired considerable research and discussion of the flexible mating system (cases of monogamy, polygyny, and polyandry), cooperative breeding, reproductive inhibition by dominant females, rapid reproductive rate, significance of dietary differences (gum feeding, frugivory, and insectivory), and demographics and social characteristics of the four genera, Cebuella, Callithrix, Saguinus, and Leontopithecus. The majority of functional explanations evaluate costs, benefits, and alternative strategies but do not address the critical selective forces that led to the behaviors in the first place. In this paper, it is argued that Callithrix and Saguinus evolved to occupy a small insectivore/frugivore niche in secondary growth forest patches (gaps arising from tree falls), and other successional forests and edge habitats; that Cebuella evolved to occupy a gum-feeding/insectivore niche in inundated forest; and that Leontopithecus is above all a small animal predator/frugivore and a mature forest genus. The keys to explanations concerning the evolution of the social and reproductive systems of these animals lie in an understanding of the resource base in these different habitats. Finally, it should be remembered that studies of callitrichids have in the main part been carried out in habitats highly altered by human activities (especially the Brazilian Atlantic forest, home to marmosets and lion tamarins) and are not the environments in which their social and breeding behavior evolved. © 1996 Wiley-Liss, Inc.     

Age‐dependent changes in response property and morphology of a thermosensory neuron and thermotaxis behavior in Caenorhabditis elegans

Age‐dependent cognitive and behavioral deterioration may arise from defects in different components of the nervous system, including those of neurons, synapses, glial cells, or a combination of them. We find that AFD, the primary thermosensory neuron of Caenorhabditis elegans, in aged animals is characterized by loss of sensory ending integrity, including reduced actin‐based microvilli abundance and aggregation of thermosensory guanylyl cyclases. At the functional level, AFD neurons in aged animals are hypersensitive to high temperatures and show sustained sensory‐evoked calcium dynamics, resulting in a prolonged operating range. At the behavioral level, senescent animals display cryophilic behaviors that remain plastic to acute temperature changes. Excessive cyclase activity of the AFD‐specific guanylyl cyclase, GCY‐8, is associated with developmental defects in AFD sensory ending and cryophilic behavior. Surprisingly, loss of the GCY‐8 cyclase domain reduces these age‐dependent morphological and behavioral changes, while a prolonged AFD operating range still exists in gcy‐8 animals. The lack of apparent correlation between age‐dependent changes in the morphology or stimuli‐evoked response properties of primary sensory neurons and those in related behaviors highlights the importance of quantitative analyses of aging features when interpreting age‐related changes at structural and functional levels. Our work identifies aging hallmarks in AFD receptive ending, temperature‐evoked AFD responses, and experience‐based thermotaxis behavior, which serve as a foundation to further elucidate the neural basis of cognitive aging.     

Escape behavior of Acartia hudsonica copepods during interactions with scyphomedusae

Calanoid copepods possess remarkable abilities to detect andescape from hydrodynamic disturbances, such as those createdby approaching predators. At the same time, a number of studiesin coastal ecosystems have suggested that gelatinous predators,including medusae in the Class Scyphozoa, exert top-down controlon copepod populations. Although prey escape behavior playsa critical role in predation models, we have relatively littleempirical data on how copepods respond to encounters with scyphomedusae.In this study, I used video to quantify encounter rates andescape behaviors of the copepod Acartia hudsonica during interactionswith two scyphomedusae, Aurelia aurita and Cyanea sp., in twoflow regimes. Escapes were complex, variable and effective.Fewer than 1% of encounters resulted in ingestion. Typically,A.hudsonica avoided contact by responding when predators remainedseveral body lengths (4 to 10 mm) distant and stringing togethermany escape jumps at submaximum velocities (33 to 59 mm s^–1).In addition, copepodite stages behaved passively—or failedto respond—following encounters with medusae more oftenthan did adults. Because escape behavior exhibited by A.hudsonicawas so variable, it is unlikely that medusae capture copepodsusing a single, quantifiable mechanism. A range of responseswithin populations and individuals may be the best strategyfor zooplankton faced with strong predation pressure from avariety of predators.     

Trophodynamics of Southern Ocean pteropods on the southern Kerguelen Plateau

Pteropods are a group of small marine gastropods that are highly sensitive to multiple stressors associated with climate change. Their trophic ecology is not well studied, with most research having focused primarily on the effects of ocean acidification on their fragile, aragonite shells. Stable isotopes analysis coupled with isotope‐based Bayesian niche metrics is useful for characterizing the trophic structure of biological assemblages. These approaches have not been implemented for pteropod assemblages. We used isotope‐based Bayesian niche metrics to investigate the trophic relationships of three co‐occurring pteropod species, with distinct feeding behaviors, sampled from the Southern Kerguelen Plateau area in the Indian Sector of the Southern Ocean—a biologically and economically important but poorly studied region. Two of these species were gymnosomes (shell‐less pteropods), which are traditionally regarded as specialist predators on other pteropods, and the third species was a thecosome (shelled pteropod), which are typically generalist omnivores. For each species, we aimed to understand (a) variability and overlap among isotopic niches; and (b) whether there was a relationship between body size and trophic position. Observed isotopic niche areas were broadest for gymnosomes, especially Clione limacina antarctica, whose observed isotopic niche area was wider than expected on both δ¹³C and δ¹⁵N value axes. We also found that trophic position significantly increased with increasing body length for Spongiobranchaea australis. We found no indication of a dietary shift toward increased trophic position with increasing body size for Clio pyramidata f. sulcata. Trophic positions ranged from 2.8 to 3.5, revealing an assemblage composed of both primary and secondary consumer behaviors. This study provides a comprehensive comparative analysis on trophodynamics in Southern Ocean pteropod species, and supports previous studies using gut content, fatty acid and stable isotope analyses. Combined, our results illustrate differences in intraspecific trophic behavior that may be attributed to differential feeding strategies at species level.     

Mice lacking Asic3 show reduced anxiety‐like behavior on the elevated plus maze and reduced aggression

Sensing external stimulation is crucial for central processing in the brain and subsequent behavioral expression. Although sensory alteration or deprivation may result in behavioral changes, most studies related to the control of behavior have focused on central mechanisms. Here we created a sensory deficit model of mice lacking acid‐sensing ion channel 3 (Asic3^?/?) to probe behavioral alterations. ASIC3 is predominately distributed in the peripheral nervous system. RT‐PCR and immunohistochemistry used to examine the expression of Asic3 in the mouse brain showed near‐background mRNA and protein levels of ASIC3 throughout the whole brain, except for the sensory mesencephalic trigeminal nucleus. Consistent with the expression results, Asic3 knockout had no effect on synaptic plasticity of the hippocampus and the behavioral tasks of motor function, learning and memory. In anxiety behavior tasks, Asic3^?/? mice spent more time in the open arms of an elevated plus maze than did their wild‐type littermates. Asic3^?/? mice also displayed less aggressiveness toward intruders but more stereotypic repetitive behaviors during resident–intruder testing than did wild‐type littermates. Therefore, loss of ASIC3 produced behavioral changes in anxiety and aggression in mice, which suggests that ASIC3‐dependent sensory activities might relate to the central process of emotion modulation.     

Water detection in the desert sand scorpion,Paruroctonus mesaensis (Scorpionida,Vaejovidae)

Summary For the sand scorpion, Paruroctonus mesaensis, substrate moisture is a powerful and fast-acting stimulus of discrete behaviors related to localization and imbibitory uptake of water. These behaviors are readily observed in the field and quantified in the laboratory when free-roaming animals encounter sand substrates dampened by small amounts of water. Of 10 behaviors we monitored in laboratory tests, 5 (pedipalp-pull, rototiller-digging, prolonged stops, headstand, and backingup) occurred only after contact with a moistened substrate. These water-stimulated behaviors were selectively blocked when all 8 tarsal leg segments were coated with wax; coverings of the chemosensory pectine appendages had little to no effect. Electrophysiological recordings from chemoreceptor organs on the tarsi showed that neurons innervating the dorsal tarsal organ, were highly sensitive to humid air stimuli while the numerous, poretipped hairs on the ventral surface were responsive to aqueous solutions applied directly to their tips. Selective blocking of the 8 tarsal organs had no effect on water sensitive behavior indicating that the chemosensory hairs mediate detection of substrate moisture. Such localized, sensory triggering of a robust and directed behavior presents a useful model for further neuroethological studies.Abbreviations H headstand - PP pedipalp-pull - RD rototillerdigging - B backing-up - C wall-climbing - P pause - W walk-through - S stop - T turn - R rest - PST pacific standard time - SEM scanning electron microscopy     

Comparative Roosting Ecology of Cynopterus (Chiroptera: Pteropodidae) Fruit Bats in Peninsular Malaysia1

Although the use of modified roosts has been reported in more than 20 species of bats in the tropics, comparative studies of the roosting ecology of congeneric tent‐roosting species are notably lacking. In the Paleotropics, this unique behavior has been described in two species belonging to the genus, Cynopterus: C. sphinx and C. brachyotis. However, it is not known whether tent roosting is an essential component of their roosting ecology, or whether the behavior is found in other members of the genus. In this study we characterize the roosting ecology of four sympatric species of Cynopterus in peninsular Malaysia and use these data to address two main questions. (1) Do all four species use modified roosts and, in those that do, is tent‐roosting obligate or opportunistic? (2) Do species pairs overlap in roost preferences and roosting habitat and, if so, is there evidence for interspecific interactions in relation to these resources? We radio‐tracked bats at two floristically distinct sites and located a total of 249 roosts. Interspecific roost niche overlap was minimal at both sites and we found no evidence for interspecific competition for roost resources at the local level. Species differences in roosting ecology were defined primarily by spatial separation of roosting habitats and secondarily by within‐habitat differences in roost selection. Importantly, we found that although periodic use of modified roosts was a characteristic shared by all four species, most roosts were unmodified, indicating that tent roosting is a facultative behavior in Malaysian Cynopterus.     

Some remarks on the mathematical bio-sociology of the relativity of injustice

The author's theory of the adoption of certain types of behavior patterns (Rashevsky, N., 1957, “Contributions to the Theory Initiative Behavior”.Bull. Maths. Biophysics,19, 91–119; 1968,Looking at History through Mathematics, Cambridge, Massachusetts: M.I.T. Press) consisting of elementary behaviors for each of which there is an opposite one and the two are mutually exclusive, is applied to describe the changes in the general type of behavior of a society. The elementary acts of which the whole problem consists may be either overt activities or beliefs or opinions. The general behavior patternsadopted by the society are considered as the “proper” or “just” ones. Any deviation from it in either one or more of the component elementary behaviors is considered as “unjust” and is subject to some punitive action. The total number of possible mutually exclusive behavior patterns is very large but finite. Within this very large range of possible patterns, we find that this notion of justice is relative, because changes from any behavior pattern to any other may occur. It is further shown that the amount of punishment for the deviation from the accepted pattern in order to be effective as well as efficient must be applied in different ways to different individuals even for the same transgression.     

Do Movement Patterns Differ Between Laboratory and Field Suction Feeding Behaviors in a Mexican Cichlid?

Synopsis We analyzed feeding behavior of individuals of Herichthys minckleyi, the Cuatro Ciénegas cichlid, under laboratory conditions and freely behaving in their natural environment using high-speed video imaging. In a multivariate analysis of suction feeding behaviors there was no clear grouping of feeding events based on the environment, which suggests that most of the variability in the data was unrelated to differences between lab and field behaviors. In fact, the variability within an environment was far greater than the variability between the two environments. These results suggest that laboratory studies can accurately describe the kinematics of behaviors seen in the field. However, although lab based studies can quantify behaviors seen in the field, natural habitats are complex and provide individuals with the opportunity to exploit a wide range of food types and microhabitats, which may elicit behaviors not observed in the laboratory. However, feeding behaviors observed in the lab are representative of frequently used feeding behaviors in the field, at least for this species. Thus, we suggest that laboratory studies of feeding behavior, particularly those that test biomechanical or performance-based hypotheses can be extrapolated to natural environments.     

Time-restricted foraging under natural light/dark condition shifts the molecular clock in the honey bee,Apis mellifera

ABSTRACT

Honey bees have a remarkable sense of time and individual honey bee foragers are capable of adjusting their foraging activity with respect to the time of food availability. Although, there is compelling experimental evidence that foraging behavior is guided by the circadian clock, nothing is known about the underlying molecular mechanisms. Here we present for the first time a study that explores whether time-restricted foraging under natural light-dark (LD) condition affects the molecular clock in honey bees. Food was presented in an enclosed flight chamber (12 m × 4 m × 4 m) either for 2 hours in the morning or 2 hours in the afternoon for several consecutive days and daily cycling of the two major clock genes, cryptochrome2 (cry2) and period (per), were analyzed for three different parts of the nervous system involved in feeding-related behaviors: brain, subesophageal ganglion (SEG), and the antennae with olfactory sensory neurons. We found that morning and afternoon trained foragers showed significant phase differences in the cycling of both clock genes in all three tissues. In addition, the phase differences were more pronounced when the feeder was scented with the common plant odor, linalool. Together our findings suggest that foraging time may function as a Zeitgeber that might have the capability to modulate the light entrained molecular clock.     

Classifying and inferring behaviors using real‐time acceleration biotelemetry in reproductive steelhead trout (Oncorhynchus mykiss)

Movement behaviors are central to ecology and conservation. Movement sensing technologies can monitor behaviors that are otherwise difficult to observe under field conditions and may enhance the ability to quantify behaviors at the population scale. We monitored steelhead trout (Oncorhynchus mykiss) spawning behaviors in a seminatural enclosure using accelerometer telemetry tags while simultaneously observing behaviors with underwater cameras. Behavioral assignments from visual observations were compared to acceleration histories to develop assignment criteria for acceleration data, including for a key behavior (oviposition). Behavioral events independently classified using acceleration data prior to reviewing video were compared to video scoring and 97% of holding behaviors, 93% of digging behaviors, and 86% of oviposition/covering behaviors were correctly assigned using acceleration data alone. We applied the method to at‐liberty steelhead in spawning tributaries. Acceleration records revealed putative spawning and oviposition in at‐liberty female steelhead, and time budgets for at‐liberty steelhead were similar to those monitored within enclosures. The use of similar movement sensing tags and classification approaches offers a method for monitoring movement behavior, activity budgets, and habitat use in a broad array of aquatic and terrestrial taxa, and may be especially useful when behaviors are cryptic.     

A comparison of techniques for classifying behavior from accelerometers for two species of seabird

The behavior of many wild animals remains a mystery, as it is difficult to quantify behavior of species that cannot be easily followed throughout their daily or seasonal movements. Accelerometers can solve some of these mysteries, as they collect activity data at a high temporal resolution (<1 s), can be relatively small (<1 g) so they minimally disrupt behavior, and are increasingly capable of recording data for long periods. Nonetheless, there is a need for increased validation of methods to classify animal behavior from accelerometers to promote widespread adoption of this technology in ecology. We assessed the accuracy of six different behavioral assignment methods for two species of seabird, thick‐billed murres (Uria lomvia) and black‐legged kittiwakes (Rissa tridactyla). We identified three behaviors using tri‐axial accelerometers: standing, swimming, and flying, after classifying diving using a pressure sensor for murres. We evaluated six classification methods relative to independent classifications from concurrent GPS tracking data. We used four variables for classification: depth, wing beat frequency, pitch, and dynamic acceleration. Average accuracy for all methods was >98% for murres, and 89% and 93% for kittiwakes during incubation and chick rearing, respectively. Variable selection showed that classification accuracy did not improve with more than two (kittiwakes) or three (murres) variables. We conclude that simple methods of behavioral classification can be as accurate for classifying basic behaviors as more complex approaches, and that identifying suitable accelerometer metrics is more important than using a particular classification method when the objective is to develop a daily activity or energy budget. Highly accurate daily activity budgets can be generated from accelerometer data using multiple methods and a small number of accelerometer metrics; therefore, identifying a suitable behavioral classification method should not be a barrier to using accelerometers in studies of seabird behavior and ecology.