Aspects of the biology of Pantinonemertes californiensis,a high intertidal nemertean

I studied the distribution, feeding biology, and reproductive biology of Pantinonemertes californiensis, described as a semi-terrestrial nemertean, along the central California coast. At the sites used in this study, maximal tidal height is about 2 m, and P. californiensis typically occurred under boulders between 1.3 and 1.7 m tidal height. Worms fed primarily on the semi-terrestrial amphipod Traskorchestia traskiana. Distribution of nemerteans was similar to that of the prey, although prey extended higher on the beach than did the worms. Nemerteans were largest and most abundant at the site with highest abundance of T. traskiana and smallest and least abundant at the lowest prey abundance site. In laboratory feeding trials, nemerteans from the site with lowest prey abundance fed most readily. Non-reproductive nemerteans lived for at least a week when submerged in sea water; some prey died within a week of being submerged. Nemerteans only lived minutes when submerged in fresh water; 50% of prey lived 4.5 h. Eggs are approximately 90–100 μm in diameter and hundreds to thousands are shed per female. Larvae are planktonic and apparently planktotrophic, and are morphologically similar to other marine hoplonemertean larvae. At the sites studied life history characteristics of P. californiensis provided little evidence of adaptations to terrestrial life in these worms and were not helpful in elucidating the role of semi-terrestrial nemerteans in the evolution of terrestrial nemerteans.     

Vigilance behavior of Pyrenean chamois Rupicapra pyrenaica pyrenaica:Effect of sex and position in the herd

<正> The Pyrenean chamois Rupicapra pyrenaica pyrenaica is a mountain-dwelling ungulate with an extensive presencein open areas. Optimal group size results from the trade off between advantages (a reduction in the risk of predation) and disadvantages(competition between members of the herd) of group living. In addition, advantages and disadvantages of group livingmay vary depending on the position of each individual within the herd. Our objective was to study the effect of central vs. peripheralposition in the herd on feeding and vigilance behavior in male and female Pyrenean chamois and to ascertain if a group sizeeffect existed. We used focal animal sampling and recorded social interactions when a focal animal was involved. With males,vigilance rate was higher in the central part of the group than at the periphery, probably due to a higher density of animals in thecentral part of the herd and a higher probability of being disturbed by conspecifics. With females, vigilance rate did not differ accordingto position in the herd. Females spent more time feeding than males, and males showed a higher frequency of the vigilancebehavior than females. We did not observe a clear relationship between group size and vigilance behavior. The differencesin vigilance behavior might be due to social interactions     

Taxonomy-based differences in feeding guilds of fish

It has been taken for granted that feeding guilds and behavior in animals are linked to the taxonomic relatedness of species,but empirical evidence supporting such relationship is virtually missing.To examine the importance of taxonomy on trophic ecology,I here present the first well-resolved dietary taxonomy analysis based on feeding guilds(predation,herbivory,and filtering)among families and genera within the fish order Perciformes.Taxonomic relatedness in feeding did not vary with ecosystem dimension(marine vs.freshwater).Although predation dominates among Perciformes fishes,this study shows that in most cases taxonomic units(family or genus)are composed by species with several feeding guilds.Related species are more similar in feeding compared with species that are taxonomically more distant demonstrating that there is a greater variation of feeding guilds within families than genera.Thus,there is no consistency in feeding guilds between family-and genus-level taxonomy.This study provides empirical support for the notion that genera are more informative than families,underlining that family-level taxonomy should be avoided to infer feeding habits of fish species at finer taxonomic resolution.Thus,the choice of taxonomic resolution(family or genus level)in ecological studies is key to avoid information loss and misleading results.I conclude that high-rank taxonomic units(i.e.,above the generic level)are not appropriate to test research hypotheses about the feeding of fish.     

Ontogeny of feeding in two native and one alien fish species from the Murray-Darling Basin, Australia

Investigations into the feeding of the early stages of fishes can provide insights into processes influencing recruitment. In this study, we examined ontogenetic changes in morphology and feeding behaviour of two native Australian freshwater species, Murray cod, Maccullochella peelii peelii, and golden perch, Macquaria ambigua, and the alien species, common carp, Cyprinus carpio. Murray cod free embryos are large and well developed at the onset of feeding, whereas the other two species begin exogenous feeding much younger and are smaller and less-developed. Carp commence exogenous feeding 3 days earlier than golden perch, and show more advanced development of the eyes and ingestive apparatus. We conducted feeding experiments, presenting larvae of the three species with a standardised prey mix (comprising equal numbers of small calanoid copepods, large calanoid copepods, small Daphnia, and large Daphnia). Larvae of most tested ages and species showed a preference for mid-sized prey (300–500 μm wide). This was true even when their gapes substantially exceeded the largest prey offered. Daphnia were consumed more than similar-sized copepods. The results of this study suggest that survival through their larval period will be threatened in all three species if catchable prey <500 μm in width are not available throughout such time. They also suggest that interspecific competition for prey may occur, especially when larvae are very young. The precocious development of structures involved in feeding and the extended transition from endogenous to exogenous feeding of early carp larvae are likely to have contributed to the success of this species since its introduction to Australia.     

Personality traits covary with individual differences in inhibitory abilities in 2 species of fish

In a number of animal species,individuals differ in their ability to solve cognitive tasks.However,the mechanisms underlying this variability remain unclear.It has been proposed that individual differences in cognition may be related to individual differences in behavior(i.e.,personality);a hypothesis that has received mixed support.In this study,we investigated whether personality correlates with the cognitive ability that allows inhibiting behavior in 2 teleost fish species,the zebrafish Danio rerio and the guppy Poecilia reticulata.In both species,individuals that were bolder in a standard personality assay,the open-field test,showed greater inhibitory abilities in the tube task,which required them to inhibit foraging behavior toward live prey sealed into a transparent tube.This finding reveals a relationship between boldness and inhibitory abilities in fish and lends support to the hypothesis of a link between personality and cognition.Moreover,this study suggests that species separated by a relatively large phylogenetic distance may show the same link between personality and cognition,when tested on the same tasks.     

Can an Invasive Prey Species Induce Morphological and Behavioral Changes in an Endemic Predator？ Evidence from a South Korean Snake （Oocatochus rufodorsatus）

Introduction of an invasive prey species into an ecosystem may affect an endemic predator＇s fitness by altering the prey-predator system. Successful adaptation may allow the endemic predator to eat and control the invasive species, while unsuccessful adaptation may result in extinction of the predator. We examine the possible effects of the invasive North American bullfrog （Rana [Lithobates] catesbeiana） on the endemic Red-backed rat snake （Oocatochus rufodorsatus） in South Korea. We do so by comparing the morphology and behavior of adult and hatchling snakes from bullfrog-exposed （Taean） and bullfrog-unexposed （Hongcheon） populations. Among the seven morphological characteristics investigated, relative tail length （tail length/snout-vent length） of both adults and hatchlings from Taean was significantly greater than that of adults and hatchlings from Hongcheon. Also, adult snakes from Taean had a signiifcantly shorter latency of ifrst tongue lfick in response to prey compared to adults from Hongcheon. This difference was not observed in hatchlings. In other snake species, a longer relative tail length and shorter latency of ifrst tongue lfick are known to improve foraging efifciency, and these characters may be adaptations ofO. rufodorsatus to prey on bullfrogs. This study provides preliminary evidence that the presence of an invasive prey species may cause morphological and behavioral changes in an endemic predator.     

Design and Implementation of Paired Pectoral Fins Locomotion of Labriform Fish Applied to a Fish Robot

In present,there are increasing interests in the research on mechanical and control system of underwater vehicles.Theseongoing research efforts are motivated by more pervasive applications of such vehicles including seabed oil and gas explorations,scientific deep ocean surveys,military purposes,ecological and water environmental studies,and also entertainments.However,the performance of underwater vehicles with screw type propellers is not prospective in terms of its efficiency andmaneuverability.The main weaknesses of this kind of propellers are the production of vortices and sudden generation of thrustforces which make the control of the position and motion difficult.On the other hand,fishes and other aquatic animals are efficient swimmers,posses high maneuverability,are able to followtrajectories,can efficiently stabilize themselves in currents and surges,create less wakes than currently used underwater vehicle,and also have a noiseless propulsion.The fish’s locomotion mechanism is mainly controlled by its caudal fin and paired pectoralfins.They are classified into Body and/or Caudal Fin(BCF)and Median and/or paired Pectoral Fins(MPF).The study of highlyefficient swimming mechanisms of fish can inspire a better underwater vehicles thruster design and its mechanism.There are few studies on underwater vehicles or fish robots using paired pectoral fins as thruster.The work presented in thispaper represents a contribution in this area covering study,design and implementation of locomotion mechanisms of pairedpectoral fins in a fish robot.The performance and viability of the biomimetic method for underwater vehicles are highlightedthrough in-water experiment of a robotic fish.     

Sieve element occlusion provides resistance against Aphis gossypii in TGR-1551 melons

Feeding behavior and plant response to feeding were studied for the aphid Aphis gossypii Glover on susceptible and resistant melons(cv.Iroquois and TGR-1551,respectively).Average phloem phase bout duration on TGR-1551 was<7% of the duration on Iroquois.Sixty-seven percent of aphids on TGR-1551 never produced a phloem phase that attained ingestion(EPG waveform E2)in contrast to only 7% of aphids on Iroquois.Average bout duration of waveform E2(scored as zero if phloem phase did not attain E2)on TGR-1551 was<3% of the duration on Iroquois.Conversely,average bout duration of EPG waveform El(sieve element salivation)was 2.8 times greater on TGR-1551 than on Iroquois.In a second experiment,liquid nitrogen was used to rapidly cryofix leaves and aphids within a few minutes after the aphids penetrated a sieve element.Phloem near the penetration site was then examined by confocal laser scanning microscopy.Ninety-six percent of penetrated sieve elements were occluded by protein in TGR-1551 in contrast to only 28% in Iroquois.Usually in TGR-1551,occlusion was also observed in nearby nonpenetrated sieve elements.Next,a calcium channel blocker,trivalent lanthanum,was used to prevent phloem occlusion in TGR-1551,and A.gossypii feeding behavior and the plants phloem response were compared between lanthanum-treated and control TGR-1551.Lanthanum treatment eliminated the sieve element protein occlusion response and the aphids readily ingested phloem sap from treated plants.This study provides strong evidence that phloem occlusion is a mechanism for resistance against A.gossypii in TGR-1551.     

The influence of time and temperature on molecular gut content analysis： Adalia bipunctata fed with Rhopalosiphum padi

Gut content analysis is a useful tool when studying arthropod predator-prey interactions. We used polymerase chain reaction （PCR） technique to examine how detection of prey DNA in the gut content of predators was influenced by digestion time and temperature. Such knowledge is critical before applying PCR-based gut content analysis to field collected predators. Larvae of the two-spotted ladybeetle （Adalia bipunctata L.） were fed with the bird cherry-oat aphid （Rhopalosiphum padi L.） at either 21℃ or 14℃. After consuming one aphid, the predators were allowed to digest the prey for a range of time periods up to 24 hours. The influence of temperature on A. bipunctata feeding behavior was also recorded. From the fed larvae, total DNA was extracted and PCR reactions with R. padi specific primers were run. The number ofA. bipunctata that tested positive for R. padi DNA was negatively related to the length of digestion time. Temperature influenced larval feeding behavior but did not have a significant effect on R. padi DNA detection. After pooling the data from both temperature treatments we estimated the time point when R. padi DNA could be amplified from 50% of the fed A. bipunctata by PCR to be 4.87 hours. With such a rapid decrease in prey DNA detection success, positive PCR reactions will most likely be the result of predation events occurring shortly before capture. If a defined digestion temperature range has proven not to influence prey detection, PCR data obtained from predators collected within that particular range can be interpreted in the same way.     

Influence of social upbringing on the activity pattern of captive lion Panthera leo cubs:Benefits of behavior enrichment

<正> The influence of social upbringing on the activity pattern of lion Panthera leo cubs was investigated at three sites. Inthis study, stimulus objects such as sticks, grass, fresh dung (elephant Loxondota africana, zebra Equus quagga, impala Aepycerosmelampus, duiker Sylvicapra grimmia, kudu Tragelaphus strepsiceros, giraffe Girajfa camelopardalis and wildebeestConnochaetes taurinus) and cardboard boxes, were utilized in an enrichment program aimed at encouraging active behaviors ofcaptive lion cubs at Antelope Park and Masuwe. Lion cubs at Chipangali were not behaviorally enriched. Activity patterns wererecorded for 10 days at each site. We recorded moving, resting, playing, grooming, visual exploration and display of hunting instincts.We found that behavioral enrichment enhanced the active behaviors of captive lion cubs. Orphan-raised cubs spent moretime moving, playing and displaying hunting instincts than mother-raised cubs, but the time spent grooming was similar acrossareas and suggests that grooming is not influenced by enrichment. Mother-raised cubs spent more time engaged in visual explorationthan orphan-raised cubs and this could be a behavior acquired from mothers or a result of confidence to explore because oftheir presence. Activity patterns were different among time treatments across our three study sites. Based on these findings, wesuggest that lion cubs raised in captivity could benefit from behavioral enrichment to encourage active behaviors essential foreventual reintroduction into the wild .     

Daily shoaling patterns in the zebrafish Danio rerio

Shoaling intensity in zebrafish Danio rerio is believed to vary throughout subjective day and night hours. This experiment examines long term variations in shoaling behavior. Adult zebrafish Dan io rerio were maintained under a 12：12 LD cycle （with dim red light serving as reduced visibility during subjective dark hours）, and their shoaling behavior was monitored every hour for a three-day period of time. Our results show that zebrafish perform shoaling behavior throughout subjective day and under reduced visibility conditions, although mean shoaling times during the light phase were significantly higher than mean shoaling times during the dark phase. However, on the 3^rd day of the experiment, mean shoaling times during the subjective night had increased and mean shoaling times during the subjective day had decreased. This shift in intensity was not seen on the first two days of the study, and may represent the influence of experience on the behavior of the test fish. We believe this study shows that shoaling behavior changes with light/dark cycles and that fish shoal even during reduced visibility conditions.     

Methoprene application and diet protein supplementation to male melon fly,Bactrocera cucurbitae,modifies female remating behavior

Methoprene （an analogue of juvenile hormone） application and feeding on a protein diet is known to enhance male melon fly, Bactrocera cucurbitae Coquillett （Diptera： Tephritidae）, mating success. In this study, we investigated the effect of these treatments on male B. cucurbitae＇s ability to inhibit female remating. While 14-d-old females were fed on protein diet, 6-d-old males were exposed to one of the following treatments： （i） topical application of methoprene and fed on a protein diet; （ii） no methoprene but fed on a protein diet; （iii） methoprene and sugar-fed only; and （iv） sugar-fed, 14-d-old males acted as controls. Treatments had no effect on a male＇s ability to depress the female remating receptivity in comparison to the control. Females mated with protein-deprived males showed higher remating receptivity than females first mated with protein-fed males. Methoprene and protein diet interaction had a positive effect on male mating success during the first and second mating of females. Significantly more females first mated with sugar-fed males remated with protein-fed males and females first mated with methoprene treated and protein-fed males were more likely to remate with similarly treated males. Females mating latency （time to start mating） was significantly shorter with protein-fed males, and mating duration was significantly longer with protein-fed males compared with protein-deprived males. These results are discussed in the context of methoprene and/or dietary protein as prerelease treatment of sterile males in area-wide control of melon fly integrating the sterile insect technique （SIT）.     

Using the movement patterns of reintroduced animals to improve reintroduction success

Despite their importance to conservation, reintroductions are still a risky endeavor and tend to fail, highlighting the need for more efficient post-release monitoring techniques. Reintroduced animals are released into unfamiliar novel environ ments and must explore their surroundings to gain knowledge in order to survive. According to theory, knowledge gain should be followed by subsequent changes to the animal＇s movement behavior, making movement behavior an excellent indicator of reintroduction progress. We aim to conceptually describe a logical process that will enable the inclusion of behavior （in particular, movement behavior） in management decision-making post-reintroductions, and to do so, we provide four basic components that a manager should look for in the behaviors of released animals. The suggested components are release-site fidelity, recurring locations, proximity to other individuals, and individual variation in movement behavior. These components are by no means the only possible ones available to a manager, but they provide an efficient tool to understanding animals＇ decision-making based on ecological theory; namely, the exploration-exploitation trade-off that released animals go through, and which underlies their behavior. We demonstrate our conceptual approach using data from two ungulate species reintroduced in Israel： the Persian fallow deer Dama mesopotamica and the Arabian oryx Oryx leucoryx [Current Zoology 60 （4）： 515-526, 2014] .     

Age and ovarian development are related to worker personality and task allocation in the ant Leptothorax acervorum

In social insects, workers of different morphological castes and age are known to act differently. Yet, it is unclear how body size and ovarian development influence worker personalities （i.e. consistent behavioral variation） and task allocation in similar aged ant workers of monomorphic species. Behavioral variation is thought to be a key element of division of labor, but few studies have linked worker personality to task allocation. We investigated individual behavior in Leptothorax acervorum ant workers at two time points during the first three months of their life and in two different settings. We observed worker behavior in the nest （i.e. task allocation） and in standardized aggression, exploration and brood care experiments （i.e. personality） and found behavioral repeatability in foraging and exploration. Further, workers acted consistently across settings： workers with a more ag gressive and exploratory personality type were more active in the nest. Moreover, ovarian development was associated with worker personality and task allocation： older workers with welldeveloped ovaries foraged less, but were more aggressive and exploratory. In accordance with the typical agepolyethism of social insects, workers became more active and foraged more as they grew older. Consequently, our study suggests that task allocation in Leptothorax acervorum is not only influenced by ovari an development and age, but moreover by the personalities of its workers .     

Antipredator deception in terrestrial vertebrates

Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds     

Development of foraging behavior in juvenile northern elephant seals

Rapid development of foraging ability is critical for phocids. In northern elephant seals Mirounga angustirostris , juvenile survivorship is low compared with adults and foraging difficulties are potentially associated with increased mortality. At Año Nuevo, California, foraging behavior of nine juvenile females during their third foraging migration and five juvenile females on their fourth foraging migration were documented using a variety of commercially available and custom time depth recorders. Foraging success, diving ability, time at depth, bouts of behavior and body composition changes were compared between trips to sea. There were no significant differences in foraging success measured as mass gain between the third and fourth trips to sea. There were differences in how energy was deposited between lean and adipose tissue compartments. Diving ability developed between trips to sea, reflected in significant increases in depth, dive duration and bottom time. Development also occurred within trips to sea. Depth, dive duration and bottom time increased with time at sea. Aerobic capacity appears to increase between the third and fourth trip, with a significantly increased percentage of total time submerged and a significantly lower diving rate. All juveniles on the fourth trip and four out of nine juveniles on the third trip followed marked diel patterns, foraging deep during the day and shallow at night. Like adults, juveniles appeared to stay primarily aerobic with surface intervals independent of dive durations. These results confirm that female juvenile northern elephant seals undergo important developmental changes in foraging behavior between the third and fourth trip, but these changes do not significantly impact foraging success.     

The influence of cooperative foraging with fishermen on the dynamics of a bottlenose dolphin population

Recent years have seen an increasing interest in individual behavioral variation. However, the implications of such variation for population dynamics are often unknown. We studied the dynamics of a bottlenose dolphin (Tursiops truncatus gephyreus) population from southern Brazil, where some individuals forage cooperatively with artisanal fishermen. We fitted mark‐recapture models to 10 yr of photo‐identification data to investigate the influence of this foraging specialization on dolphins’ population parameters, controlling for sex and ranging behavior. We estimated adult survival to be high (0.949 ± 0.015 SE), weakly influenced by home range size, sex or the frequency of interaction with fishermen. The slightly higher survival probability for individuals with smaller home ranges could stem from the benefits of reduced spatial requirements implied by the specialized foraging. Foraging also influenced the probability of resighting individuals, and there was no temporary or permanent emigration. Abundance fluctuated slightly over the years from 54 (95% CI = 49–59) to 60 (95% CI = 52–69) individuals, with no evident population trend. Despite such apparent population stability, we confirm this population remains small and geographically isolated which may threaten its viability and the viability of its unusual, localized foraging specialization. Our study also illustrates how accounting for individual variation can portray animal population dynamics more realistically.     

OBITUARIES

ABSTRACT

Prey often exhibit avoidance behaviors when predators are present. We observed diminished loudness of mating choruses of male silver perch Bairdiella chrysoura in spawning areas when vocalizing bottlenose dolphins Tursiops truncatus, which hunt fish acoustically, were present. Experimental playback of bottlenose dolphin sounds revealed that male silver perch mating calls were reduced by an average of 9 dB. This “acoustical avoidance” behavior, demonstrated previously for interactions involving bats hunting insects and frogs, may also be a common phenomenon in acoustically mediated predator-prey interactions in the sea.     

Mechanisms of carbohydrate‐fuelled ecological dominance in a tropical rainforest canopy‐foraging ant

1. Canopy‐foraging ants have carbohydrate‐rich diets and the stoichiometric excess of carbon may result in energetic allocation decisions that facilitate ecological dominance. 2. If dietary carbohydrates facilitate ecological dominance in canopy ants, then the mechanism for this relationship is unknown. 3. Four hypotheses were posit that may explain how a carbohydrate‐rich diet might facilitate ecological dominance in canopy ants: Aggressive Defense, Metabolic Fuel, Foraging Success, and Prey Acquisition. 4. To assess these hypotheses, experiments were conducted on the canopy‐foraging bullet ant, Paraponera clavata (Fabricius), an omnivorous species that demonstrates high variability in the relative contribution of carbohydrates to the diets of colonies. 5. No support was found for the Aggressive Defense, Metabolic Fuel and Prey Acquisition hypotheses. 6. The Foraging Success hypothesis was supported, as the proportion of nectar in the diet predicted the overall foraging success. 7. It was argued that there is no explicit advantage in the exploitation of nectar over other food resources, other than the fact that it is the most accessible food resource in the rainforest canopy.     

Phytochemical complementarities among endophyte-infected tall fescue, reed canarygrass, birdsfoot trefoil and alfalfa affect cattle foraging

We determined whether plant diversity and sequence of plant ingestion affected foraging when cattle chose from plants that varied in concentrations of alkaloids, tannins and saponins. We hypothesized cattle that ate high-alkaloid grasses (endophyte-infected tall fescue (TF) or reed canarygrass (RCG)) would prefer forages high in tannins (birdsfoot trefoil, BFT+) or saponins (alfalfa, ALF+), because tannins and saponins can bind to alkaloids, presumably reducing their absorption. We further hypothesized that forages with tannins or saponins consumed before, rather than after, foraging on high-alkaloid grasses would promote greater use of those grasses presumably by binding to alkaloids, thereby reducing their absorption. In Phase 1, cattle (n = 32) grazed on either high (+) or low (-) alkaloid grass (TF or RCG) pastures for 30 min each morning at 0600 h and were then offered a choice of BFT+, BFT-, ALF+ and ALF- for 60 min each day for 12 days. In Phase 2, cattle (n = 32) were first offered a choice of BFT+ or ALF+ for 30 min at 0600 h and then placed on grass (TF+ or -, or RCG+ or -) pastures for 60 min for 12 days. In both phases, we had four spatial replications of four treatments with 2 per calves assigned to each of the 16 replications per treatment combinations. Scan samples of individuals at 2-min intervals were used to determine incidence of foraging on each plant species (%). Cattle grazed more on RCG than on TF in Phases 1 (62% v. 27%; P = 0.0015) and 2 (71% v. 32%; P = 0.0005). In Phase 1, cattle that first foraged on RCG+ or TF- subsequently preferred ALF over BFT, whereas cattle offered RCG- or TF+ foraged on ALF and BFT equally. Foraging by cattle on RCG was cyclic during Phase 1, whereas cattle foraging on TF markedly decreased incidence of use of TF from 41% to only 16% by the end of the 12-day trial (P = 0.0029). Contrary to the cyclic (RCG) or steadily declining (TF) use of grasses in Phase 1, cattle steadily and dramatically increased foraging on both RCG and TF throughout Phase 2, when they first grazed BFT+ or ALF+ followed by high-alkaloid grasses (P = 0.0159). Our findings suggest that in plant species the sequence of ingestion influenced foraging behavior of cattle and that secondary compounds influenced those responses.