Orientation of larval and juvenile horseshoe crabs Limulus polyphemus to visual cues: Effects of chemical odors

Adult horseshoe crabs Limulus polyphemus have long served as models for the study of vision in marine arthropods. Yet, little is known about the ability of early life history stages to detect and respond to visual cues. We examined the visually directed movements of larvae and first stage juveniles to horizons containing dark visual targets of different sizes. The study tested the hypotheses that （1） larval and juvenile crabs can detect and respond to visual targets and （2） the direction of orientation varies with the presence of chemical cues associated with settlement habitats. Orientation of larval and juvenile crabs to rectangles subtending angles from 30--330~ was tested in a circular arena containing water that either lacked estuarine chemical cues （offshore water） or contained odors from aquatic vegetation or known predators. In the absence of chemical odors, larvae oriented toward and juveniles moved away from dark horizons subtending angles 〉 60~. When placed in water containing chemical odors from potential nursery habitats, including the seagrasses Halodule wrightii and Syringodium filiforme, crabs reversed their direction of orientation relative to their responses in offshore water. Odors from two known predators, the mummichug Fundulus grandis and blue crab Callinectes sapidus, had no affect on the orientation of larvae. Yet, juveniles responded to both odors by moving toward the visual target. Results support the hypothesis that the visual orientation of larval and juvenile horseshoe crabs changes upon exposure to habitat and predator cues and that the direction of the response undergoes an ontogenetic shift following metamorphosis

Memory for location and visual cues in white-eared hummingbirds Hylocharis leucotis

In nature hummingbirds face floral resources whose availability, quality and quantity can vary spatially and temporally. Thus, they must constantly make foraging decisions about which patches, plants and flowers to visit, partly as a function of the nectar reward. The uncertainty of these decisions would possibly be reduced if an individual could remember locations or use visual cues to avoid revisiting recently depleted flowers. In the present study, we carried out field experiments with white-eared hummingbirds Hylocharis leucotis, to evaluate their use of locations or visual cues when foraging on natural flowers Penstemon roseus. We evaluated the use of spatial memory by observing birds while they were foraging between two plants and within a single plant. Our results showed that hummingbirds prefer to use location when foraging in two plants, but they also use visual cues to efficiently locate unvisited rewarded flowers when they feed on a single plant. However, in absence of visual cues, in both experiments birds mainly used the location of previously visited flowers to make subsequent visits. Our data suggest that hummingbirds are capable of learning and employing this flexibility depending on the faced environmental conditions and the information acquired in previous visits [Current Zoology 57 （4）： 468-476, 2011].

Research on the Intervention of Visual Cue Strategy on Self-Care Ability of Children with Autism

The formation of self-care ability is the first step for children with autism to enter the society,and it is also a prerequisite and guarantee for their independent survival.This study aimed to explore the impact of visual cue strategies on the self-care ability of children with autism.Based on the ABA design of a single case study,this research conducted a four-month intervention on a seven-year-old child with autism via visual cue strategy as independent variables and sock-wearing skills as dependent variables,in order to explore the effect of visual cue strategy on self-care ability of children with autism.It turned out that visual cue strategy exerts a positive immediate sustained effect and social validity on the self-care ability of children with autism.Lastly,suggestions were provided for future related research based on the research process,results,and limitations.

Predatory Cues Influence the Behavioral Responses and Metamorphic Traits of Polypedates maculatus(Anura: Rhacophoridae)

Mechanisms of predator detection and the influence of the presence of nonlethal predators on antipredator defense behavior and metamorphic traits were studied in the Indian tree frog, Polypedates maculatus. Exposure of P. maculatus tadpoles to chemical cues of caged predator（crabs, Barytelphusa spp.） fed with either conspecific or heterogeneric tadpoles, or were starved elicited defense behavior（by avoiding predator zone） in them. Such a behavior was not evident when exposed to predators housed in a glass beaker（visual cues）. Both early（Gosner stage 27–28） and later（Gosner stage 35–36） stage tadpoles when exposed to caged predators（fed with conspecific tadpoles）, prey tadpoles spent less time swimming and remained motionless for longer periods. Yet, the time spent by prey in feeding was unaffected. Further, the predator avoidance behavior exhibited by them was of the same intensity regardless of whether the caged predators were fed or starved implying the influence of predator＇s kairomones. Tadpoles reared with caged predator reached the metamorphic climax stage（MC stage; Gosner stage 42） earlier than those reared without a predator. Size at emergence（Gosner stage 46） was comparable in both the groups. The findings suggest that P. maculatus tadpoles assess predation risk chiefly by sensing kairomones of the predator in eliciting antipredator defense behaviors. Accelerated development and early metamorphosis without any compromise of the size at emergence may be due to their unaltered feeding activity.

Evaluation of trap effi ciency for the Asian longhorned beetle,Anoplophora glabripennis

The Asian longhorned beetle(ALB),Anoplophora glabripennis,is a well-known stem borer with high polyphagous properties causing frequent outbreaks in northeast China.An attractant-based trap is needed to improve the sensitivity,reliability,and effi ciency for detection of the beetle.In this study,the eff ects of attractants,trap types and color synergy of a trapping system were evaluated.Attractant blends comprised of the male-produced,two-component pheromone plus plant volatiles were used in the fi eld in Hengshui city.Plant volatiles(e.g.,1-pentanol,and 2-pentanol)in combination with male pheromones increased the mean number of trapped ALB compared to the pheromone alone.Males responded better than females to traps baited with plant volatiles alone,whereas traps emitting plant volatiles plus pheromone,regardless of trap type,captured more females than males.The ALB-trapping effi ciency of a modifi ed fl ight intercept panel trap was more than ten times as high as a woodborer panel trap and 1.2 times a fl ight intercept panel trap.The 1-pentanol and 2-pentanol attractants alone or in combination with male-produced pheromone were more eff ective for monitoring ALB than common lures.In laboratory Y-tube olfactometer experiments,the color brown was better at increasing attraction of both males and females to 1-pentanol,2-pentanol,1-pentanol+pheromone,and 2-pentanol+pheromone compared to the clear-glass control arm.The fi ndings provide a reliable and eff ective trap system to monitor ALB infestations.

Pollinator attraction in Cornus capitata (Cornaceae): the relative role of visual and olfactory cues

Aims it is generally accepted that visual displays and floral scent play important roles in communication between flowering plants and their pollinators.However,the relative role of visual and olfactory cues in pollinator attraction is largely unknown.in this study,we determined the roles of both types of cue in attracting pollinators to Cornus capitata,a medium sized tree with each capitulum sur-rounded by four large,white,petaloid bracts.Methods Pollinator observations and pollination experiments were con-ducted in a natural population;the inflorescences’visual and olfactory signals were characterized by spectral and chemical analyses;the responses of pollinators to visual and olfactory cues were tested using dual-choice behavioural bioassays;the relative roles of visual and olfactory cues in pollinator attrac-tion were tested by comparing the responses of pollinators to inflorescences subjected to three experimental treatments(intact,all bracts removed,and capitulum removed)within the natural population.Important Findings For fruit set,C.capitata is entirely dependent on pollinators,with a bee,Anthophora sp.,being the main pollinator.bracts present high colour distance and green contrast against the leaves.Twelve volatile compounds in the floral scent were detected,most of which have previously been reported to be attractive to a broad spectrum of bee species.behavioural bioassays showed that both,visual cues alone and olfactory cues alone,are attractive to pollinating bees.However,vis-ual cues alone attracted significantly more approaches than olfactory cues alone,while olfactory cues alone elicited a significantly higher landing percentage than visual cues alone.The finding suggests that,in the C.capitata-Anthophora sp.interaction,visual cues are mainly used for location from long distances,while olfactory cues mainly aid landing from short distances.our results indicate that different modalities of floral cues should be considered together to understand fully the communication between flowering plant and pollinators.

The “sequential cues hypothesis”: a conceptual model to explain host location and ranking by polyphagous herbivores

Successfully locating a host plant is crucial for an insect herbivore to feed and/or oviposit.However,locating a host within a complex environment that may contain an array of different plant species is a difficult task.This is particularly the case for polyphagous herbivores,which must locate a host within environments that may simultaneously contain multiple suitable and unsuitable hosts.Here we review the mechanisms of host selection used by polyphagous herbivores,as well as exploring how prior experience may modify a generalist's response to host cues.We show that recent research demonstrates that polyphagous herbivores have the capacity to detect both common cues from multiple host species,as well as specific cues from individual host species.This creates a paradox in that generalists invariably rank hosts when given a choice,a finding at odds with the“neural limitations”hypothesis that says generalist insect herbivores should not have the neural capacity to identify cues specific to every possible host.To explain this paradox we propose a model,akin to parasitoid host location,that postulates that generalist herbivores use different cues sequentially in host location.We propose that initially common host cues,associated with all potential hosts,are used to place the herbivore within the host habitat and that,in the absence of any other host cues,these cues are sufficient in themselves to lead to host location.As such they are true “generalist”cues.However,once within the host habitat,we propose that the presence of a smaller group of cues may lead to further host searching and the location of preferred hosts:these are“specialist”cues.This model explains the current conflict in the literature where generalists can respond to both common and specific host-plant cues,while also exhibiting specialist and generalist host use behavior under different conditions.

Sex recognition does not modulate aggression toward nest intruders in a paper wasp

During social interactions,the behavior of an individual often depends on the sex of its social partner.Many animal societies have males and females that play very different behavioral roles,although they coexist and interact non-sexually.At specific phases of the colony cycle,social wasp females and males are contemporaries within a nest,they often interact,although mating occurs mostly off the nest,therefore providing an opportunity to test sex discrimination in contexts other than classical sexual ones.We performed a lure presentation experiment to test if Mischocyttarus metathoracicus discriminate between conspecifics of the 2 sexes during on-nest social interactions.Female wasps discriminated conspecific sex during experimentally simulated nest intrusions.Visual and chemical cues may account for this sex discrimination.Despite sex discrimination(evidenced by differential inspective behavior from the nest females toward the female and the male lures),female wasps were as aggressive toward lures of both sexes.In the female-dominated hymenopteran societies,males are often subordinate and not aggressive on nest,resulting in females directing less aggression to them compared to other females.Instead,M.metathoracicus males and females are both aggressive toward nestmates,so they might be perceived as similar threat during on-nest social interactions.

Can native species crucian carp Carassius auratus recognizes the introduced red swamp crayfish Procambarus clarkii？

Procambarus clarkii is native to the south-central United States （Louisiana） and northeastern Mexico, and is a highly efficient predator that poses a damager to native species after its introduction or invasion. In its natural habitat, P. clarkii consumes Carassius auratus, however, whether C. auratus recognizes P. clarkii as a predator is not yet clear. In laboratory experiments, we investigated whether experienced and inexperienced C. auratus recognize P. clarkii as a predatory threat and the specific sensory modality used by C. auratus to respond to chemical and visual stimuli from P. clarkii. In the chemical stimuli experiment, two kinds of chemical stimuli were used, water from a tub containing P. clarkii previously fed with C. auratus （C. auratus diet cues） and water from a tub containing unfed P. clarkii （P. clarkii cues）. In the visual experiment, experienced C. auratus decreased activity, but inexperienced C.auratus avoided the predator compartment. When C. auratus diet cues were presented, both experienced and inexperienced C. auratus increased the use of shelter, decreased activity in the initial response phase. Compared with the blank treatment, experienced C. auratus responded to P. clarkii cues by decreasing activity; however, inexperienced C. auratus showed no reduction in activity. C. auratus appears to recognize P. clarkii as a predator both through visual and chemical cues. Further analysis revealed that C. auratus may recognize R clarkii visually through the disturbances caused by P. clarkii movement and chemically by detecting conspecific alarm cues in the diet of P. clarkii. The results also indicate that ex- perienced C. auratus can recognize R clarkii by innate chemical cues from P. clarkii, whereas inexperienced C. auratus cannot [Current Zoology 57 （3）： 330-339, 2011].